ATSAMG55J19B-AU - MICROCHIP TECHNOLOGY

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Description

The Atmel® | SMART SAM G55 is a series of Flash microco ntrollers based on the

high-perfor mance 32-bit ARM® Cortex®-M4 RISC processor with FPU (Floating

Point Unit). It operates at a maximum speed of 120 MHz and features 512 Kbytes

of Flash and up to 176 Kbytes of SRAM. The peripheral set inc lud e s eig h t fle xib le

communication units comprising USARTs, SPIs and I2C-bus interfaces (TWIs),

two three-channel general-purpose 16-bit timers, two I2S controllers, one-channel

pulse density modulation, one 8-ch annel 12-bit ADC, one re al-time timer (RTT)

and one real-time clock (RTC), both located in the ultra low-power backup area.

The Atmel | SMART SAM G55 devic es have thre e softwar e-selec table lo w-power

modes: Sleep, Wait and Backup. In Sleep mode, the processor is stopped while

all other functions can be kept running. In Wait mode, all clocks and functions are

stopped but some peripherals can be configured to wake up the system based on

events, including partial asynchronous wakeup (SleepWalking™). In Backup

mode, RTT, RTC and wakeup logic are running.

For power consumption optimization, the flexible clock system offers the capability

of having different clock frequencies for some peripherals. Moreover, the

processor and bus clock frequency can be modified without affecting the

peripheral processing.

The real-time event management allows peripherals to receive, react to and send

events in Active and Sleep modes without processor intervention.

The SAM G55 devices are general-purpose low-power microcontrollers that offer

high perfo rmance, pr ocessing power and small packa ge options c ombined with a

rich and flexible peripheral set. With this unique combination of features, the SAM

G55 series is suitable for a wide range of applications including consumer,

industrial control and PC peripherals.

The device operates from 1.62V to 3.6V and is available in three packages:

49-pin WLCSP, 64-pin QFN and 64-pin LQFP.

SAM G55G / SAM G55J

Atmel | SMART ARM-based Flash MCU

DATASHEET

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Features

Core

ARM Cortex-M4 with up to 16 Kbytes SRAM on I/D bus providing 0 wait state execution at up to

120 MHz (1)

Memory Protection Unit (MPU)

DSP Instructions

Floating Point Unit (FPU)

Thumb®-2 instruction set

Note: 1. 120 MHz with VDDCOREXT120 or with VDDCORE trimmed by regulator.

Memories

Up to 512 Kbytes embedded Flash

Up to 176 Kbytes embedded SRAM

8 Kbytes ROM with embedded boot loader, single-cycle access at full speed

System

Embedded voltage regulator for single-supply operation

Power-on reset (POR) and Watchdog for safe operation

Quartz or ceramic resonator oscillators: 3 to 20 MHz with clock failure detection and 32.768 kHz for

RTT or system clock

High-precision 8/16/24 MHz factory-trimmed internal RC oscillator. In-application trimming access for

frequency adjustment

Slow clock internal RC oscillator as permanent low-power mode device clock

PLL range from 48 MHz to 120 MHz for device clock

PLL range from 24 MHz to 48 MHz for USB device and USB OHCI

Up to 30 peripheral DMA (PDC) channels

256-bit General-Purpose Backup Registers (GPBR)

16 external interrupt lines

Peripherals

8 flexible communication units supporting:

USART

SPI

Two-wire Interface (TWI) featuring TWI masters and high-speed TWI slaves

Crystal-less USB 2.0 Device and USB Host OHCI with On-chip Transceiver

2 Inter-IC Sound Controllers (I2S)

1 Pulse Density Modulation Interface (PDMIC) (supports up to two microphones)

2 three-channel 16-bit Timer/Counters (TC) with capture, waveform, compare and PWM modes

1 48-bit Real-Time Timer (RTT) with 16-bit prescale r and 32-bit counter

1 RTC with calendar and alarm features

1 32-bit Cyclic Redundancy Check Calculation Unit (CRCCU)

I/O

Up to 48 I/O lines with external interrupt capability (edge or level), debouncing, glitch filtering and on-

die series resistor termination. Individually programmable open-dra in, pull-up and pull-down resistor

and synchronous output

Two PIO Controllers provide control of up to 48 I/O lines

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Analog

One 8-channel ADC, resolution up to 12 bits, sampling rate up to 500 ksps

Package

49-lead WLCSP

64-lead LQFP

64-lead QFN

Operating Temperature Range

Industrial (-40°C to +85°C)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1. Configuration Summary

Table 1-1 summarizes the SAM G55 device configurations.

Table 1-1. Configuration Summary

Feature SAM G55G19 SAM G55J19

Flash 512 Kbytes 512 Kbytes

Cache (CMCC) up to 8 Kbytes up to 8 Kbytes

SRAM 160 Kbytes

+ up to 16 Kbytes (Cache + I/D RAM) 160 Kbytes

+ up to 16 Kbytes (Cache + I/D RAM)

Package WLCSP49 QFN64, LQFP64

Number of PIOs 38 48

Event System Yes Yes

External Interrupt 16 16

12-bit ADC 8 channels

Performance: 500 kSps 8 channels

Performance: 500 kS ps

16-bit Timer 6 channels

(3 external channels) 6 channels

(3 external channels)

I2SC/PDM 2 / 1-channel 2-way 2 / 1-channel 2-way

PDC Channels 28 30

USART

78SPI

TWI

USB Full Speed / OHCI Full Speed / OHCI

CRCCU 1 1

RTT 1 (backup area) 1 (backup area)

RTC 1 (backup area) 1 (backup area)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

2. Block Diagram

Figure 2-1. SAM G55 Block Diagram

AHB/APB

Bridge

PCK[2:0]

XIN32

XOUT32

ERASE

VDDCORE

ADTRG

System Controller

TCK/SWCLK

TDI

TDO

JTAGSEL

VDDIO

VDDOUT

JTAG and Serial Wire

Flash

Unique

Identifier

Voltage

Regulator

TST

12-bit ADC

TCLK[2:0]

TIOA[2:0]

TIOB[2:0]

USB 2.0

Full-speed

In-Circuit Emulator

MPU

Cortex-M4 Processor

MAX

120 MHz

NVIC 24-bit SysTick

Counter

DSP

Flash

512 Kbytes

PDC

User

Signature

WKUP[15:0]

FPU

MUX

Transceiver

VDDIO

XIN

XOUT

VDDUSB

(64-pin package only)

NRST

AD[7:0]

PIOA/PIOB

TMS/SWDIO

PDC

Timer Counter A

TC[0..2]

Timer Counter B

TC[3..5]

SRAM

160 Kbytes

ROM

8 Kbytes

Event System

SRAM

Up to 16 Kbytes

Watchdog

Timer

PLLA

Power

Management

Controller

RC OSC

8/16/24 MHz

PLLUSB

CMCC

2/4/8 KB Cache

CRCCU

8 x

USART, SPI, TWI

PDC

2668

bytes

FIFO

Supply

Monitor

USB OHCI

I2SDI0...1

I2SWS0...1

I2SCK0...1

I2SDO0...1

I2SMCK0...1

2 x I2SC

PDC

PDMIC_CLK

PDMIC_DAT

PDMIC0

PDC

PDMIC1

PDC

DMA

Backup area

Power-on

Reset

32K OSC

32K RC

Supply

Controller

Real-time

Timer

Real-time

Clock

Tamper Detection

RXD_MISO_TWCK0...7

TXD_MOSI_TWD0...7

SCK_SPCK0...7

RTS_NPCS1_0...7

CTS_NPCS0NSS_0...7

FLEXCOM

Reset

Controller

256-bit

General-purpose

Backup Registers

4-layer AHB Bus Matrix

fMAX 120 MHz

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

3. Signal Description

Table 3-1 gives details on the signal names classified by peripheral.

Table 3-1. Signal Description List

Signal Name Function Type Active

Level Voltage

Reference Comments

Power Supplies

VDDIO Peripheral I/O Lines, Voltage Regulator,

ADC Power Supply Power – – 1.62V to 3.6V

VDDOUT Voltage Regulator Output Power – – 1.08V to 1.32V

VDDCORE Core Chip Power Supply Power – – Connected externally to

VDDOUT or VDDCOREXT100 or

VDDCOREXT120

VDDUSB USB Power Supply Power – – Only available on 64-pin

package

GND Ground Ground – – –

Clocks, Oscillators and PLLs

XIN Main Oscillator Input Input – VDDIO Reset state:

- PIO input

- Internal pul l- up disa bl e d

- Schmitt Trigger enabled

XOUT Main Oscillator Output Output – –

XIN32 Slow Clock Oscillator Input Input – VDDIO

XOUT32 Slow Clock Oscillator Output Output – –

PCK0–PCK2 Programmable Clock Output Output – –

Reset state:

- PIO input

- Internal pull-up enabled

- Schmitt Trigger enabled

ICE and JTAG

TCK Test Clock Input – VDDIO No pull-up resistor

TDI Test Data In Input – VDDIO No pull-up resistor

TDO Test Data Out Output – VDDIO –

TRACESWO Trace Asynchronous Data Out Output – VDDIO –

SWDIO Serial Wire Input/Output I/O – VDDIO –

SWCLK Serial Wire Clock Input – VDDIO –

TMS Test Mode Select Input – VDDIO No pull-up resistor

JTAGSEL JTAG Selection Input High VDDIO Pull-down resistor

Flash Memory

ERASE Flash and NVM Configuration Bits Erase

Command Input High VDDIO Pull-down (15 kΩ) resistor

Reset/Test

NRST Microcontroller Reset I/O Low VDDIO Pull-up resistor

TST Test Mode Select Input – VDDIO Pull-down resistor

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

PIO Controller - PIOA - PIOB

PA0–PA3 1 Parallel I/O Controller A I/O – VDDIO Pulled-up input at reset. No

pull-down for PA3/PA4/PA14

PB0–PB15(1) Parallel I/O Controller B I/O – VDDIO Pulled-up input at reset

Wakeup Pins

WKUP0–15 Wakeup Pin / External Interrupt I/O – VDDIO Wakeup pins are used also

as External Interrupt

Serial Peripheral Interface - SPIx

MISOx Master In Slave Out I/O – – –

MOSIx Master Out Slave In I/O – – –

SPCKx SPI Serial Clock I/O – – High Speed Pad

NPCS0x SPI Peripheral Chip Select 0 I/O Low – –

NPCS1x SPI Peripheral Chip Select Output Low – –

Two-Wire Interface - TWIx

TWDx TWIx Two-wire Serial Data I/O – – High Sp eed Pad for TWD0

TWCKx TWIx Two-wire Serial Clock I/O – – High Speed Pad for

TWDCK0

Universal Synchronous Asynchronous Receiver Transmitter USARTx

SCKx USART Serial Clock I/O – – –

TXDx USART Transmit Data I/O – – –

RXDx USART Receive Data Input – – –

RTSx USART Request To Send Output – – –

CTSx USART Clear To Send Input – – –

Timer/Counter - TCx

TCLKx TC Channel x External Clock Input Input – – –

TIOAx TC Channel x I/O Line A I/O – – –

TIOBx TC Channel x I/O Line B I/O – – –

12-bit Analog-to-Digital Converter - ADC

AD0–AD7 Analog Inputs Ana lo g – – –

ADTRG ADC Trigger Input – – –

ADVREF ADC Voltage Reference Input – – Only available on 64-pin

package

Inter-IC Sound Controller - I2SCx

I2SMCKx Master Clock Output – – –

I2SCKx Serial Clock I/O – – –

I2SWSx I2S Word Select I/O – – –

I2SDIx Serial Data Input Input – – –

I2SDOx Serial Data Output Output – – –

Table 3-1. Signal Description List (Continued)

Signal Name Function Type Active

Level Voltage

Reference Comments

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Note: 1. Pull-up disabled on PB8/PB9.

Pulse Density Modulation Interface Co ntro ller - PDMICx

PDMIC_CLK Pulse Density Modulation Clock Output – – –

PDMIC_DAT Pulse Densi ty Modulation Data Input – – –

USB OHCI/FS - USB

DM USB Data -

Analog, Digital –

WLCSP49:

VDDIO

64-pin

package:

VDDUSB

DM and DP in PIO

configuration

DP USB Data +

Table 3-1. Signal Description List (Continued)

Signal Name Function Type Active

Level Voltage

Reference Comments

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

4. Package and Pinout

4.1 49-ball WLCSP Pinout

Table 4-1. SAM G55 Packages

Device Package

SAM G55G19 WLCSP49

SAM G55J19 QFN64

LQFP64

Table 4-2. SAM G55G19 49-ball WLCSP Pinout

A1 PA9 B6 NRST D4 PB10 F2 PA19/AD2

A2 GND B7 PB12 D5 PA1 F3 PA17/AD0

A3 PA24 C1 VDDCORE D6 PA5 F4 PA21

A4 PB8/XOUT C2 PA11 D7 VDDCORE F5 PA23

A5 PB9/XIN C3 PA12 E1 PB2/AD6 F6 PA16

A6 PB4 C4 PB6 E2 PB0/AD4 F7 PA8/XOUT32

A7 VDDIO C5 PA4 E3 PA18/AD1 G1 VDDIO

B1 PB11 C6 PA3 E4 PA14 G2 VDDOUT

B2 PB5 C7 PA0 E5 PA10 G3 GND

B3 PB7 D1 PA13 E6 TST G4 VDDIO

B4 PA2 D2 PB3/AD7 E7 PA7/XIN32 G5 PA22

B5 JTAGSEL D3 PB1/AD5 F1 PA20/AD3 G6 PA15

G7 PA6

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

4.2 64-lead QFN/LQFP Pinout

4.2.1 64-lead QFN / LQFP Pinout

Note: 1. The bottom pad of the QFN package must be tied to ground.

Table 4-3. SAM G55J19 64-pin LQFP and QFN Pinout

1 VDDIO 17 PA6 33 PA17 49 PA9

2 NRST 18 PA16 34 PA18 50 PB5

3 PB12 19 PA30 35 PA19 51 PA27

4 PA4 20 PA29 36 PA20 52 PA26

5 PA3 21 PA28 37 PB0 53 GND

6 PA0 22 PA15 38 PB1 54 PB6

7 PA1 23 PA23 39 PB2 55 PB7

8 PA5 24 PA22 40 PB3 56 PA25

9 VDDCORE 25 PA21 41 PA14 57 PB13

10 TEST 26 VDDUSB 42 PA13 58 PA24

11 PA7 27 VDDIO 43 PA12 59 PB8/XOUT

12 PA8 28 ADVREF 44 PA11 60 PB9/XIN

13 GND 29 GND 45 VDDCORE 61 PA2

14 PB15 30 VDDOUT 46 PB10 62 PB4

15 PB14 31 VDDIO 47 PB11 63 JTAGSEL

16 PA31 32 VDDIO 48 PA10 64 VDDIO

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

5. Power Considerations

5.1 Power Supplies

The SAM G55 has the following power supply pins:

VDDCORE pins: Power the core, including the processor, the embedded memories and the peripherals,

except the RTC, R T T, and Supply controller (SUPC). It is recommended to connect VDDCORE to VDDOUT.

VDDIO pins: Power the peripheral I/O lines, RTC, RTT, and SUPC peripherals, voltage regulator and ADC;

voltage ranges from 1.62V to 3.6V.

VDDUSB pins: Power the USB (only for devices with 64-pin package), volt age ranges from 3.0V to 3.6V.

The ground pins GND are common to VDDCORE and VDDIO.

5.2 Powerup Considerations

In order to prevent any overcurrent at powerup, it is recommended to connect pin ADVREF to VDDIO, or to get

ADVREF to rise as much as possible at the same time as VDDIO.

Note: Pin ADVREF is only available on 64-pin packages QFN and LQFP.

5.2.1 VDDIO Versus VDDCORE

VDDIO must always be higher than or equal to VDDCORE.

VDDIO must reach its minimum operating voltage (1.62 V) before VDDCORE has reached VDDCOREXT(min). The

minimum slope for VDDCORE is defined by (VDDCOREXT(min) - VTH+) / tRES.

If VDDCOREXT rises at the same time as VDDIO, the VDDIO rising slope must be higher than or equal to 7V/ms.

If VDDCORE is powered by the internal regulator, all powerup considerations are met.

Figure 5-1. VDDCORE and VDDIO Constraints at Startup

At powerdown, there is no constraint on VDDCORE and VDDIO as the regulator must be enabled.

Supply (V)

Time (t)

RES

VDDIO

VTH+

VDDCORE

VDDIO(min)

VDDCORE(min)

Core supply POR output

SLCK

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

5.3 Voltage Regulator

The SAM G55 embeds a core voltage regulator that is managed by the Supply Controll er and that supplies the

Cortex-M4 core, internal memories (SRAM, ROM and Flash logic) and the peripherals. An internal adaptive

biasing adjusts the regulator quiescent current depending on the required load current.

For adequate input and output power supply decoupling/bypassing, refer to Table 39-4 “VDDCORE Voltage

Regulator Characteristics” in section “Electrical Characteristics”.

In case of dual supply, the voltage regulator must be enabled and VDDOUT must be used as input control of the

external DC/DC. This will allow a correct slope at first startup and for low power mode.

5.4 Typical Powering Schematics

The SAM G55 supports single and dual voltage supply, with VDDIO from 1.62V to 3.6V and VDDCORE from

external DC/DC controlled by the internal regulator. Figure 5-2 and Figure 5-3 illustrate the power schematics.

To achieve system performances, the internal voltage regulator must be used.

5.4.1 Single Supply

The SAM G55 supports a 1 .62V to 3.6V single supply mode. The internal voltage regulator input is connected to

the source and its output feeds VDDCORE. Figure 5-2 illustrates the power schematics.

Figure 5-2. Single Supply

VDDIO

Voltage

Regulator

VDDOUT

Main Supply (1.62V–3.6V)

VDDCORE

(3.0V–3.6V)

VDDUSB

(only on 64-pin

packages)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

5.4.2 Dual Supply

In dual voltage supply, the voltage regulator must always be enabled and must be used as input control of the

external DC/DC, to control the slope of VDDCORE after low power mode.

Figure 5-3. Dual Supply

In Wait mode, by default, the voltage regulator is down to VDDOUT Wait mode minimum value. Consequently, it

must be configured to keep VDDOUT in Running mode. To avoid any issue, the regulator must be configured by

software to deliver the correct supply voltage. To do this, use the following procedure:

Read the unique identifier bytes [65..64]

Write the four LSB bits of unique identifier bytes [65..64] in SUPC_PWMR.LPO W ER 0– LP OWER3

Enable SUPC_PWMR.LPOWERS

VDDIO

Voltage

Regulator

VDDOUT

VDDCORE

(3.0V–3.6V)

DC/DC

VIN

VOUT

ENA

VDDUSB

(only on 64-pin

packages)

1.2V

Main Supply

(1.62V–3.6V)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

5.5 Functional Modes

5.5.1 Active Mode

Active Mode is the normal running mode with the core clock running from the fast RC oscillator, the main crystal

oscillator or the PLL. The power management controll er can be used to adapt the frequency and to disable the

peripheral clocks.

5.5.2 Backup Mode

The purpose of Backup mode is to achieve the lowest power consumption possible in a system which is

performing periodic wakeups to perform tasks but not requiring fast startup time.

The zero-power power-on reset, SUPC, RTT, RTC, general-purpose backup registers (GPBR) and 32 kHz

oscillator (RC or crystal oscillator selected by software in the Supply Controller) are running. The regulator and the

core supply are off.

The SAMG55 can be awakened from this mode using the pins WKUP0–15, the supply monitor (SM), the RTT, or

the RTC.

Backup mode is entered by writing a 1 to the VROFF bit of the Supply Controller Control Register (SUPC_CR) (a

key is needed to write the VROFF bit, refer to section Supply Controller SUPC) and with the SLEEPDEEP bit in the

Cortex-M4 System Control Register set to 1 (see power m anagement description in section ARM Cortex-M4

Processor). To reduce consumption, the supply monitor on VDDIO can be disabled.

To enter Backup mode using the VROFF bit:

Write a 1 to the VROFF bit of SUPC_CR.

To enter Backup mode using the WFE instruction:

Write a 1 to the SLEEPDEEP bit of the Cortex-M4 processor.

Execute the WFE instruction of the processor.

In both cases, exit from Backup mode happens if one of the following enable wake up even ts occurs:

Pins WKUPEN0–15 (level tr ansition, configurable debouncing)

Supply Monitor alarm

RTC alarm

RTT alarm

5.5.3 Wait Mode

Wait mode allows the device to achieve very low power consumption levels while remaining in a powered state

with a wakeup time of less than a few µs. In Wait mode, the clocks of the core, the peripherals and memories are

stopped. However, power supplies are maintained to ensure memory and CPU context retention.

The wakeup time is achieved when entry into and exit from Wait mode are performed in internal SRAM. The

wakeup time increases to 6.9 µs if entry into Wakeup mode is performed in internal Flash.

Wait mode is entered using either the WAITMODE bit in the PMC Clock Generator Main Oscillator register

(CKGR_MOR) or the Wait for Event (WFE) instruction. Before entering Wait mode, the POR core must be

disabled. Detailed sequences are provided below.

Note that the WFE instruction can add complexity in application state machines due to the fact that the WFE

instruction go es alo n g w i th an e v ent fla g of th e Cortex core (cannot be managed by the software application). The

event flag can be set by interrupts, a debug event or an event signal from another processor. Since an interrupt

can take place just before the execution of WFE, WFE takes into account events that happened in the past. As a

result, WFE prevents the device from entering Wait mode if an interrupt event has occurred. To work around this

complexity, follow the sequence using the WAITMODE bit described below.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

The Cortex-M4 proce ssor is able to han dle external or in tern al events in order to wake up the core. This is done by

configuring the ext ernal lines WKUP0–15 as fast startup wakeup p ins (refer to Section 5.6 “Fast Sta rtup”) or the

RTT and RTC alarms, USB in terrup t line or Slee pWalking for FLEXCOM0–7 (USART/SPI/TWI) for internal events.

To enter Wait mode using the WAITMODE bit:

1. Select the 8/16/24 MHz fast RC oscillator as the Main Clock. If frequency of 24 MHz is selected and the code

is running from the SRAM.

2. Program the FLPM field in the PMC Fast Startup Mode Register (PMC_FSMR)(1).

3. Set the number of Flash wait states to 1 by writing a one to the FWS field in the EEFC Flash Mode Register

(EEFC_MR).

4. Write a one to the WAITMODE bit in the CKGR_MOR.

5. Wait for MCKRDY = 1 in the PMC Status Register (PMC_SR).

To enter Wait mode using the WFE instruction:

1. Select the 8/16/24 MHz fast RC oscillator as the Main Clock. If 24 MHz is selected and the code is running

on the SRAM.

2. Program the FLPM field in the PMC Fast Startup Mode Register (PMC_FSMR)(1).

3. Set the number of Flash wait states to 1 by writing a one to the FWS field in the EEFC Flash Mode Register

(EEFC_MR).

4. Write a one to the LPM bit in PMC_FSMR.

5. Execute the Wait For Event (WFE) instruction of the processor.

Note: 1. Depending on the value of the field FLPM, the Flash enters on of three different modes:

FLPM = 0: Flash in Standby mode (low power consumption levels)

FLPM = 1: Flash in Deep-powerdown mode (extra low powe r con s umption levels)

FLPM = 2: Flash in Idle mode. Memory ready for Read access.

5.5.4 Sleep Mode

In Sleep mode, power consumption of the device versus response time is optimized. Only the core clock is

stopped. The peripheral clocks can be enabled. The current consumption in Sleep mode is application-dependent.

Sleep mode is entered via Wait for Interrupt (WFI) instructions.

The processor can be awakened from an interrupt if the WFI instruction of the Cortex-M4 is used.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

5.5.5 Low-power Mode Configuration Summary

Table 5-1 summarizes the power consumption, wakeup time and system state in Wait mode and in Sleep mode.

Notes: 1. If the supply monitor is enabled, the Wakeup can be done through the SM.

2. The ext e rna l lo ad s on PIOs are not take n into account in the cal cu lation.

3. BOD current consumption is not included.

4. Refer to Section 39.4 “Power Consumption” in the electrical characteristics.

5. When considering wakeup time, the time required to start the PLL is not taken into account. Once started, the device works

with the 8/16/24 MHz Fast RC oscillator . The user has to add the PLL startup time if it is needed in the system. The wakeup

time is defined as the time taken for wake up until the first instruction is fetched.

Table 5-1. Low-power Mode Configuration Summary

Component or Parameter

Low-power Mode

Backup Mode W a it Mo de with Fl ash in

Deep-powerdown mode Sleep Mode

SUPC, 32 kHz Oscillator,

RTT, POR, Vo ltage

Regulator ON ON ON

POR, Supply Monitor on

VDDIO OFF(1) OFF ON

RAM Power Switch Not powered From all RAM powered

8 Kbytes RAM powered Powered

Core, Memory, Peripherals Not powered Powered (Not clocked) Powered (Not clocked)

Mode Entry SUPC_CR.VROFF = 1

+ SCB_SCR.SLEEPDEEP = 1

PMC_FSMR.FLPM = 1

+ CKGR_MOR.WAITMODE = 1

SCB_SCR.SLEEPDEEP = 0

+ PMC_FSMR.FLPM = 1

+ PMC_FSMR.LPM = 1

+ WFE

WFI

+ SCB_SCR.SLEEPDEEP = 0

+ PMC_FSMR.LPM = 0

Potential Wakeup Sources Pins WKUP0–15

RTC alarm

RTT alarm

Any event from:

- Fast startup through pins

WKUP0–15

- RTT alarm

- RTC alarm

- USB device interrupt line

- FLEXCOM0–7 and ADC

SleepWalking

Entry mode = WFI interrupt

only; any enabled interrupt

Core at Wakeup Reset Clocked back Clocked back

PIO State while in Low-

power Mode Previous state saved Previous state saved Previous state saved

PIO State at Wakeup PIOA & PIOB Inputs with pull-

ups Unchanged Unchanged

Consumption(2) (3) Refer to Table 39-9 Refer to Table 39-10 (4)

Wakeup Time(5) – Refer to Table 39-11 –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

5.6 Fast Startup

The SAM G55 allows the processor to restart in a few microseconds while the processor is in Wait mode. A fast

startup can occur upon detection of a low level on one of the 18 wakeup inputs.

The fast restart circuitry is fully asynchronous and provides a fast startup signal to the Power Management

Controller. As soon as the fast startup signal is asserted, the PMC restarts from the last Fast RC selected (the

embedded 24 MHz Fast RC oscillator), switches the master clock on the last clock of RC os cillator and reenables

the processor clock. At the wakeup of Wait mode, the code is executed in the SRAM.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

6. Product Mapping

Figure 6-1. SAM G55 Product Mapping

Address memory space

Code

0x00000000

Internal SRAM

0x20000000

Peripherals

0x40000000

Reserved

0x60000000

System

0xE0000000

0xFFFFFFFF

Code

Boot Memory

0x00000000

GPNVM[1] = 0 Boot Memory = ROM

GPNVM[1] = 1 Boot Memory = Flash

Internal Flash

0x00400000

Internal ROM

0x00800000

Reserved

0x00C00000

0x1FFFFFFF

Internal SRAM

SRAM

0x20000000

Undefined (Abort)

0x20480000

0x3FFFFFFF

Peripherals

I2SC0 16

0x40000000

I2SC1 17

0x40004000

USART/TWI/SPI5 8

0x40008000

0x4000C000

TC0 TC0

0x40010000

TC0 TC1

+0x40

TC0 TC2

+0x80

TC1 TC3

0x40014000

TC1 TC4

+0x40

TC1 TC5

+0x80

USART/TWI/SPI3 14

0x40018000

USART/TWI/SPI4 19

0x4001C000

0x40020000

USART/TWI/SPI2 21

0x40024000

MEM2MEM 15

0x40028000

PDMIC0 13

0x4002C000

PDMIC1 18

0x40030000

USART/TWI/SPI7

0x40034000

ADC 29

0x40038000

CMCC

0x4003C000

USART/TWI/SPI6

0x40040000

UDP

0x40044000

CRCCU

0x40048000

System Controller

0x400E0000

Reserved

0x400E4000

0x60000000

System Controller

Reserved

0x400E0000

MATRIX

0x400E0200

PMC 5

0x400E0400

0x400E0600

CHIPID

0x400E0740

0x400E0800

EFC 6

0x400E0A00

Reserved

0x400E0C00

PIOA 11

0x400E0E00

PIOB 12

0x400E1000

Reserved

0x400E1200

SYSC RSTC

0x400E1400

SYSC SUPC

+0x10

SYSC RTT

+0x30

SYSC WDT

+0x50

SYSC RTC

+0x60

SYSC GPBR

+0x140

reserved

0x400E1600

0x400E3FFF

offset

(+ : wired-or)

peripheral

block

USART/TWI/SPI1

Reserved

USART/TWI/SPI0

RAM CMCC

0x1FFFC000

UHP DPRAM

0x20400000

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

7. Bootloader

The SAM G55 devices ship with a bootloader in ROM , used to downlo ad code, in interna l Flash, either th rough th e

SPI or through the TWI3.

The Bootloader mode is en tered automatically on powerup if no valid firmware is detected in the Flash. A valid

firmware is detected by performing a CRC on the content of the Flash. If the CRC is correct, the application is

started. Otherwise, the Bootloader mode is entered.

Alternatively, the Bootloader mode can be forced by applying low pulses on the NRST line. The NRST should be

asserted 10 times for a minimum of 1 µs at an interval less than 50 ms. When the bootloader detects this

sequence, it asserts the pin PA01 (NCHG) low as an acknowledge.

The Bootloader mode initializes the TWI3 in Slave Mode with the I2C address 0x26 and the SPI in Slave Mode, 8-

bit data length, SPI Mode 1.

Table 7-1 provides informatio n on the pins used by the bootloader.

For further details on bootloader operations, refer to the application note AT09002: Atmel SAM I2C - SPI

Bootloader on www.atmel.com.

Table 7-1. Boot Loader Pin Description

Pin Name Function Bootloader Use Description

PA01 NCHG Driven at 0 or pulled up Boot loader handshake

PA03 TWD Open drain input/output TWI/I2C data line

PA04 TWCK Open drain input/output TWI/I2C clock

PA11 NPCS0/NSS Input NSS, SPI slave select

PA12 MISO Push-pull output SPI master in slave out

PA13 MOSI Input SPI master out slave in

PA14 SPCK Input SPI clock

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

8. Memories

8.1 Internal SRAM

The SRAM G55 embeds a total of 176 Kbytes of high-speed SRAM, accessible at address 0x1FFF_C000.

The 160 Kbytes of SRAM are accessible over the Cortex-M4 system bus at address 0x2000 0000. The SRAM is in

the bit band region. The bit band alias region is from 0x2200 0000 and 0x23FF FFFF. The SRAM is composed of

five blocks of 32 Kbytes. The five blocks have a power switch. Each power switch controls the supply of the SRAM

block to save power. The power switch control (SRAMxON) is in the SUPC_PWMR register (refer table 8-1).

The SRAM G55 also embeds up to 16 Kbytes of SRAM accessible at address 0x1FC0_0000. The 16 Kbytes of

SRAM can be assigned by the customer to Data Cache RAM and/or Tightly Coupled Memory (TCM) RAM

(CMCC) and on I/D bus following this configuration (PRGCSIZE) in the CMCC_CFG register:

2 Kbytes of Data RAM Cache and 14 Kbytes TCM RAM on I/D Bus (CMCC)

4 Kbytes of Data RAM Cache and 12 Kbytes TCM RAM on I/D Bus (CMCC)

8 Kbytes of Data RAM Cache and 8 Kbytes TCM RAM on I/D Bus (CMCC)

The 16 Kbytes of SRAM (Data Cache/TCM SRAM) also has a power switch (CDPSWITCH) on SUPC_MR which

controls the supply of the block.

8.2 Internal ROM

The SAMG55 product embeds an Internal ROM.

At any time, the ROM is mapped at address 0x0080 0000.

8.3 Embedded Flash

8.3.1 Flash Overview

The memory is organized in s ectors. Each sector comprises 128 Kbytes. The first sector of 128 Kbytes is divided

into three smaller sectors.

The three smalle r sectors are comprised of two sectors of 8 Kbytes and one sector of 112 Kbytes.

Refer to Figure 8-1.

Table 8-1. SRAM Power Switch vs SRAM Block

Power Switch SRAM Block SRAM Size Address SUPC_PWMR

0Block 0 8 Kbytes 0x2000_0000 SRAM0ON

1Block 0 8 Kbytes 0x2000_2000 SRAM1ON

2Block 0 16 Kbytes 0X2000_4000 SRAM2ON

3Block 1 32 Kbytes 0x2000_8000 SRAM3ON

4Block 2 32 Kbytes 0x2001_0000 SRAM4ON

5Block 3 32 Kbytes 0x2001_8000 SRAM5ON

6Block 4 32 Kbytes 0x2002_0000 SRAM6ON

7USB DPRAM – – DPRAMON

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 8-1. Global Flash Orga nization

Each sector is organized in pages of 512 bytes.

For sector 0:

The smaller sector 0 has 16 pages of 512 bytes.

The smaller sector 1 has 16 pages of 512 bytes.

The larger secto r ha s 22 4 pages of 512 by te s.

From sector 1 to n:

The rest of the array is comp osed of 128 -Kbyte sectors of 256 pages of 512 bytes each. Refer to Figure 8-2.

Figure 8-2. Flash Sector Organization

The SAM G55 Flash size is 512 Kbytes. Refer to Figure 8-3 for the organization of the Flash.

Flash Organization

Small Sector 0

8 Kbytes

Small Sector 1

8 Kbytes

Larger Sector

112 Kbytes

Sector 1

128 Kbytes

128 Kbytes Sector n

Sector 0

Sector size Sector name

Sector 0

Sector n

Smaller sector 0

Smaller sector 1

Larger sector

A sector size is 128 Kbytes

16 pages of 512 bytes

224 pages of 512 bytes

256 pages of 512 bytes

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 8-3. Flash Size

The following era se co mm a nd s ca n be use d de pe ndin g on the sect or size:

8 Kbyte small sector

Erase and write page (EWP)

Erase and write page and lock (EWPL)

Erase sector (ES) with FARG set to a page number in the sector to erase

Erase pages (EPA) with FARG [1:0] = 0 to erase 4 pages, FARG [1:0] = 1 to erase 8 pages or FARG

[1:0] = 2 to erase 16 pages. FARG [1:0] = 3 must not be used.

112 Kbyte and 128 Kbyte sectors

One block of 16 pages inside any sector, with the command Erase pages (EPA) and FARG[1:0] = 2

One block of 32 pages inside any sector, with the command Erase pages (EPA) and FARG[1:0] = 3

One sector with the command Erase sector (ES) and FARG set to a page number in the secto r to

erase

Entire memory plane

The entire Flash, with the command Erase all (EA)

The memory has one additional reprogrammable page that can be used as page signature by the user. It is

accessible through specific modes, for erase, write and read operations. Erase pin assertion will not erase the user

signatur e page.

Flash 512 Kbytes

2 * 8 Kbytes

1 * 112 Kbytes

3 * 128 Kbytes

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

8.3.1.1 Enhanced Embedded Flash Controller

The Enhanced Em bedded Flash Co ntroller m anage s accesses performed by the masters of th e system. It enables

reading the Flash and writing the write buffer. It also contains a User Interface, mapped on the APB.

The Enhanced Embedded Flash Controller ensures the interface of the Flash block.

It manages the programming, erasing, locking and unlocking sequences of the Flash using a full set of commands.

One of the commands returns the embedded Flash descriptor definition that informs the system about the Flash

organization, thus making the software generic.

8.3.1.2 Flash Speed

The user needs to set the number of wait states depending on the frequency used:

For more details, refer to Section 39.9 “AC Characteristics”.

8.3.1.3 Lock Regions

Several lock bits are used to protect write and erase operations on lock regions. A lock region is composed of

several consecutive pages, and each lock region has its associated lock bit.

If the erase or program command of a locked region occurs, the command is aborted and the EEFC triggers an

interrupt.

The lock bits ar e software pro grammable through the EEFC User Interface. The command “Set Lock Bit” enables

the protection. The command “Clear Lock Bit” unlocks the lock region.

Asserting the ERASE pin clears the lock bits, thus unlocking the entire Flash.

8.3.1.4 User Signature

Each device contains a user signature of 512 bytes. The user signature can be used to store customer information

such as trimming, keys, etc., that the customer does not want erased when asserting the ERASE pin or by

software ERASE command.

Read, write and erase of this area is allowed.

Table 8-2. Lock Bit Number

Product Number of Lock Bits Lock Region Size

SAM G55 64 8 Kbytes

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

8.3.1.5 Unique Identifier

The G55 Flash contains two pages of 512 bytes called unique identifier. These two pages are read-only and

cannot be erased even by the Erase pin. Ea ch device integrates its own 128-bit unique identifier. These bits are

factory-configured and cannot be changed by the user.

The sequence to read the unique identifier area is described in Section 23.4.3.8 “Unique Identifier Area”.

Some bytes within the unique identifier pages are reserved for the trimming information of the 32 kHz RC oscillator

and the internal voltage regulator.

The mapping is as follows:

Bytes [15..0]: 128 bits for unique identifier

Bytes [47..16]: Atmel reserved

Bytes [49..48]: Measured frequency (on tester) of the internal 32 kHz RC when VDDIO= 3.3V (measurement

performed at 25°C). These two bytes contain the frequency in hertz.

Bytes [51..50]: Measured frequency (on tester) of the internal 32 kHz RC when VDDIO= 1.8V (measurement

performed at 25°C). These two bytes contain the frequency in hertz.

Bytes [63..52]: Atmel reserved

Bytes [65..64]: Trimmed code of the internal regulator which allows the device to run at up to 120 MHz. The

four LSB bits must be written in the SUPC_PWMR.ECPWRx.

Bytes [67..66]: Trimmed code of the internal regulator which allows the device to run at up to 100 MHz. Only

the four LSB bits are used. They must be written in the SUPC_PWMR.ECPWRx. It is the default value after

reset.

Bytes [67..511]: Atmel reserved

8.3.1.6 General-Purpose Non-Vo latile Memory Bits

The SAM G55 features three GPNVM bits that can be cleared or set, respectively, through the commands “Clear

GPNVM Bit” and “Set GPNVM Bit” of the EEFC User Interface.

8.3.1.7 Boot Strategies

The system always boots at address 0x0. To ensure maximum boot possibilities, the memory layout can be

changed using GPNVM bits.

A general-purpose NVM (GPNVM) bit is used to boot either on the ROM (default) or from the Flash.

The GPNVM bit can be cleared or set respectively through the comm ands “Clear GPNVM Bit” and “Set GPNVM

Bit” of the EEFC User Interface.

Setting GPNVM1 selects the boot from th e Flash. Clearing it selects the boot from the ROM. Asserting ERASE

clears the GPNVM1 and thus selects the boot from the ROM by default.

Table 8-3. General-purpose Non-volatile Memory Bits

GPNVM Bit Function

0 Security bit

1 Boot Mode Selection

2 Reserved (do not use)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

8.3.1.8 Calibration Bits

The GPNVM bits are used to calibrate the POR, the voltage regulator and RC 8/16/24. These bits are factory-

configured and cannot be changed by the user. The ERASE pin has no effect on the calibration bits.

See Section 23.4.3.6 “Calibration Bit” for more information.

8.3.1.9 Security Bit

The SAM G55 features a se curity bit, based on a specific general-purpose NVM bit (GPNVM bit 0). When the

security is enabled, any access to the Flash, SRAM, core registers and internal periphera ls through the ICE

interface is forbidden. This ensures the confidentiality of the code programmed in the Flash.

The security bit can only be enabled with the command “Set GPNVM Bit 0” of the EEFC User Interface. Disabling

the security bit can only be done by asserting the ERASE pin to 1, and after a full Flash erase is performed. When

the security bit is deactivated, all accesses to the Flash, SRAM, core registers and internal peripherals are

permitted.

The ERASE pin integrates a permanent pull-down. As a result, it can be left unconnected during normal operation.

However, it is recommended, in harsh environments, to connect it directly to GND if the erase operation is not

used in the application.

To avoid unexpected erase at powerup, a minimum ERASE pin assertion time is required. This time is defined in

Table 39-50 “AC Flash Characteristics”.

The erase operation is not performed when the system is in Wait mode with the Flash in Deep-powerdown mode.

To ensure that the erase operation is performed after power up, the system must not reconfigu re the ERASE pin as

GPIO or enter Wait mode with Flash in Deep-powerdown mode before the ERASE pin assertion time has elapsed.

The following sequ e nc e de ta ils the step s of th e er ase operation:

1. Assert the ERASE pin (High).

2. Assert the NRST pin (Low).

3. Power cycle the device.

4. Maintain the ERASE pin high for at least the minimum assertion time.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

9. Peripherals

9.1 Peripheral Identifiers

Table 9-1 defines the peripheral identifiers of the SAM G55. A peripheral identifier is required:

for the control of the peripheral interrupts by the Nested Vectored Interrupt Controller

to enable/disable the peripheral clocks by means of the Peripheral Clock Enable and Disable registers

(PMC_PCERx, PMC_PCDRx) in the Power Management Controller.

The external interrupts are connected to WKUP pins (level detection managed by the SUPC) and the default

detection is in low level.

Table 9-1. Peripheral Identifiers

Instance ID Instance Name NVIC Interrupt PMC Clock Control Instance Description

0 SUPC X – Supply Controller

1 RSTC X – Reset Controller

2 RTC X – Real-time C lo c k

3 RTT X – Real-time Timer

4 WDT X – Watchdog Timer

5 PMC X – Power Management Controller

6 EFC X – Enhanced Flash Controller

7 USART7, SPI7, TWI7 X X USART/SPI/TWI 7

8 USART0, SPI0, TWI0 X X USART/SPI/TWI 0

9 USART1, SPI1, TWI1 X X USART/SPI/TWI 1

10 Reserved – – –

11 PIOA X X Parallel I/O Contro ller A

12 PIOB X X Parallel I/O Controller B

13 PDMIC0 X X Pulse Density Modulation Interface Controller 0

14 USART2, SPI2, TWI2 X X USART/SPI/TWI 2

15 MEM2MEM X X Memory to Memory

16 I2SC0 X X Inter-IC Sound Controller 0

17 I2SC1 X X Inter-IC Sound Controller 1

18 PDMIC1 X X Pulse Density Modulation Interface Controller 1

19 USART3, SPI3, TWI3 X X USART/SPI/TWI 3

20 USART4, SPI4, TWI4 X X USART/SPI/TWI 4

21 USART5, SPI5, TWI5 X X USART/SPI/TWI 5

22 USART6, SPI6, TWI6 X X USART/SPI/TWI 6

23 TC0 X X Timer/Counter 0

24 TC1 X X Timer/Counter 1

25 TC2 X X Timer/Counter 2

26 TC3 X X Timer/Counter 3

27 TC4 X X Timer/Counter 4

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

9.2 Peripheral Signal Multiplexing on I/O Lines

The SAM G55 features two PIO controllers, PIOA and PIOB, which multiplex the I/O lines of the peripheral set.

Each line can be assigned to one of two peripheral functions: A or B. The multiplexing tables in this section define

how the I/O lines of the peripherals A and B are multiplexed on the PIO controllers.

Note that some peripheral functions which are output only may be duplicated within both tables.

28 TC5 X X Timer/Counter 5

29 ADC X X Analog-to-Digital Converter

30 ARM X – FPU

31 WKUP0 X – External interrupt 0

32 WKUP1 X – External interrupt 1

33 WKUP2 X – External interrupt 2

34 WKUP3 X – External interrupt 3

35 WKUP4 X – External interrupt 4

36 WKUP5 X – External interrupt 5

37 WKUP6 X – External interrupt 6

38 WKUP7 X – External interrupt 7

39 WKUP8 X – External interrupt 8

40 WKUP9 X – External interrupt 9

41 WKUP10 X – External interrupt 10

42 WKUP11 X – External interrupt 11

43 WKUP12 X – External interrupt 12

44 WKUP13 X – External interrupt 13

45 WKUP14 X – External interrupt 14

46 WKUP15 X – External interrupt 15

47 UHP X X USB OHCI

48 UDP X X USB Device FS

49 CRCCU X X Cyclic Redundancy Check Calculation Unit

Table 9-1. Peripheral Identifiers (Continued)

Instance ID Instance Name NVIC Interrupt PMC Clock Control Instance Description

Table 9-2. Available PIO Lines per Package

PIO Controller

PIO Lines per Package

49-Lead Package 64-Lead Package

PIOA 25 32

PIOB 13 16

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

9.2.1 PIO Controller A Multiplexing

Notes: 1. WKUPx can be used if PIO cont roller defines the I/O line as "input".

2. Refer to Section 9.3 “System I/O Lines”.

3. To select this extra function, refer to Section 39.5.3 “I/O Lines” .

Table 9-3. Multiplexing on PIO Controller A (PIOA)

I/O Line Peripheral A Peripheral B Extra Function System Function

PA0 I2SCK0 TIOA0 WKUP0(1) –

PA1 I2SWS0 TIOB0 WKUP1(1) –

PA2 TCLK0 I2SDI0 WKUP2(1) –

PA3 TXD3/SPI3_MOSI/TWD3 I2SDO0 WKUP9(1) –

PA4 RXD3/SPI3_MISO/TWCK3 I2SMCK0 WKUP10(1) –

PA5 RXD2/SPI2_MISO/TWCK2 SPI5_NPCS1/RTS5 WKUP4(1) –

PA6 TXD2/SPI2_MOSI/TWD2 PCK0 – –

PA7 – – – XIN32(2)

PA8 – ADTRG WKUP5(1) XOUT32(2)

PA9 RXD0/SPI0_MISO/TWCK0 PDMIC_DAT WKUP6(1) –

PA10 TXD0/SPI0_MOSI/TWD0 PDMIC_CLK – –

PA11 SPI5_NPCS0/CTS5 – – –

PA12 RXD5/SPI5_MISO/TWCK5 – – –

PA13 TXD5/SPI5_MOSI/TWD5 – – –

PA14 SCK5/SPI5_SPCK – WKUP8(1) –

PA15 SPI2_NPCS1/RTS2 SCK2/SPI2_SPCK – –

PA16 SPI2_NPCS0/CTS2 TIOB1 WKUP7(1) –

PA17 I2SDO0 PCK1 AD0(3) –

PA18 I2SMCK0 PCK2 AD1(3) –

PA19 TCLK1 I2SCK1 AD2(3) –

PA20 TCLK2 I2SWS1 AD3(3) –

PA21 TIOA2 PCK1 – DM

PA22 TIOB2 I2SDI1 – DP

PA23 I2SDO1 TIOA1 WKUP3(1) –

PA24 I2SMCK1 SCK2/SPI2_SPCK WKUP11(1) –

PA25 SPI0_NPCS0/CTS0 I2SDO1 – –

PA26 SPI0_NPCS1/RTS0 I2SMCK1 – –

PA27 SCK1/SPI1_SPCK RXD7/SPI7_MISO/TWCK7 – –

PA28 SPI1_NPCS0/CTS1 TXD7/SPI7_MOSI/TWD7 – –

PA29 SPI1_NPCS1/RTS1 SCK7/SPI7_SPCK – –

PA30 PCK1 SPI7_NPCS0/CTS7 – –

PA31 PCK2 SPI7_NPCS1/RTS7 – –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

9.2.2 PIO Controller B Multiplexing

Note: 1. Each TWI (TWI4,TWI6) can be routed on two different pairs of IOs. TWI1 and TWI2 share one pair of IOs (PB10 and PB1 1).

The configuration of the shared IOs determines which TWI is selected.

2. To select this extra function, refer to Section 39.5.3 “I/O Lines”.

3. Analog input has priority ove r WKU Px pi n.

4. WKUPx can be used if PIO controller defines the I/O line as “input”.

5. Refer to Section 9.3 “System I/O Lines”.

Table 9-4. Multiplexing on PIO Controller B (PIOB)

I/O Line Peripheral A Peripheral B Extra Function System Function

PB0 SCK0/SPI0_SPCK TXD6/SPI6_MOSI/TWD6 AD4(2) –

PB1 SCK4/SPI4_SPCK RXD6/SPI6_MISO/TWCK6 AD5(2) –

PB2 RXD1/SPI1_MISO/TWCK1 SPI5_NPCS1/RTS5 AD6/WKUP12(3) –

PB3 TXD1/SPI1_MOSI/TWD1 PCK2 AD7//WKUP13(3) –

PB4 – – – TDI(5)

PB5 – – – TDO/ TRACESWO(5)

PB6 – – – TMS/SWDIO(5)

PB7 – – – TCK/SWCLK(5)

PB8 TXD4/SPI4_MOSI/TWD4 SPI4_NPCS0/CTS4 WKUP14(4) XOUT(5)

PB9 RXD4/SPI4_MISO/TWCK4 SPI4_NPCS1/RTS4 WKUP15(4) XIN(5)

PB10 TXD4/SPI4_MOSI/TWD4(1) TXD6/SPI6_MOSI/TWD6(1) ––

PB11 RXD4/SPI4_MISO/TWCK4(1) RXD6/SPI6_MISO/TWCK6(1) ––

PB12 – – – ERASE(5)

PB13 SCK3/SPI3_SPCK SCK6/SPI6_SPCK – –

PB14 SPI3_NPCS0/CTS3 SPI6_NPCS0/CTS6 – –

PB15 SPI3_NPCS1/RTS3 SPI6_NPCS1/RTS6 – –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

9.2.2.1 TWI Multiplexing

The TWI function must first be selected through the FLEXCOM interface (OPMODE field in FLEXCOM_MR).

The selection of the TWI used in PB10 and PB11 is determine d by the configuration of PB10 and PB11. Th ree

modes are possible: Normal Mode, Alternative Mode TWI4 and Alternative Mode TWI6.

Normal Mode

Only TWI4 used: PB09 and PB08 must be configured as PIO Peripheral A

Only TWI6 used: PB00 and PB01 must be configured as PIO Peripheral B

Both TWI4 and TWI6 used: PB09 and PB08 must be configured as PIO Peripheral A and PB00 and PB01

must be configured as PIO Peripheral B.

Alternative Mode TWI4

TWI4 is multiplexed on PB10 and PB11: PB10 and PB11 must be configured as PIO Peripheral A. PB8 and PB9

can be configured as GPIO, WKUP pin or XIN, XOUT. PB8 and PB9 cannot be used as peripherals.

Alternative Mode TWI6

TWI6 is multiplexed on PB10 and PB11: PB10 and PB11 must be configured as PIO Peripheral B. PB0 and PB1

can be configured as GPIO, Analog Input. PB0 and PB1 cannot be used as peripherals.

Example of Alternative Mode TWI4:

PB10 is driven by TWD4 signal if the PB10 is configured as peripheral (PIO_PSR[10] = 1 and

PIO_ABCDSR1[10] = PIO_ABCDSR2[10] = 0).

PB11 is driven by TWCK4 signal if the PB11 is configured as peripheral (PIO_PSR[11] = 1 and

PIO_ABCDSR1[11] = PIO_ABCDSR2[11] = 0).

Note: 1. Configuration of PBx can be done after the configuration of PB10 and PB11.

Table 9-5. TWI Multiplexing

Required

Configuration

PIO Configuration

PB0 PB1 PB8 PB9 PB10 PB11PB10 PB11

Normal Mode

TWI1 and/or

TWI2 Used

Enable

PIO_PER[10] Enable

PIO_PER[11] TWD6 TWCK6 TWD4 TWCK4 GPIO GPIO

Alternative

Mode TWI1

Config PB10

Peripheral A

Config PB11

Peripheral A TWD6 TWCK6

GPIO

PIO_periphB

WKUP pin(1)

GPIO

PIO_periphB

WKUP pin(1)

TWD4 TWCK4

Alternative

Mode TWI2

Config PB10

Peripheral B

Config PB10

Peripheral B

GPIO

PIO_periphB

AD Input(1)

GPIO

PIO_periphB

AD Input(1)

TWD4 TWCK4 TWD6 TWCK6

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 9-1. TWI Master PIO Muxing Selection

Mux Selection

(PIO_ABCDSR1/2)

TWI1

TWI2

PB8

PB9

PB10

PB11

PB0

PB1

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

9.3 System I/O Lines

Table 9-6 lists the SAMG55 system I/O lines shared with PIO lines. These pins are software configurable as

general purpose I/O or system pins. At startup, the default function of thes e pins is always use d .

Notes: 1. If PB12 is used as PIO input in user applications, a low level must be ensured at startup to prevent Flash erase before the

user application sets PB12 into PIO mode.

2. Refer to Section 26.4.2 “Slow Clock Generator”.

3. Refer to Section 17.5.3 “3 to 20 MHz Crystal or Ceramic Resonator-ba sed Oscillator”.

Table 9-6. System I/O Configuration Pin List

CCFG_SYSIO

Bit No. Default Function

after Reset Other Function Constraints

for Normal Start Configuration

12 ERASE PB12 Low Level at startup(1)

In Matrix User Interface Registers

(Refer to the System I/O Configuration Register

in Section 15. “Bus Matrix (MATRIX)”.)

11 DP PA22 –

10 DM PA21 –

7 TCK/SWCLK PB7 –

6 TMS/SWDIO PB6 –

5 TDO/TRACESWO PB5 –

4 TDI PB4 –

–PA7 XIN32 –

(2)

–PA8 XOUT32–

– PB9 XIN – (3)

– PB8 XOUT –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

10. Real-time Event Management

The events generated by peripherals are designed to be directly routed to peripherals managing/using these

events without processor interventio n. Peripherals receiving events contain logic used to select the required

peripheral.

10.1 Embedded Characteristics

T imers, IO, peripher als generate event triggers which ar e directly route d to event managers such as ADC, to

start measureme nt /co nv er sio n with out pr ocessor interven tio n.

USART, SPI, TWI, ADC also generate event trig gers directly connected to Peripheral DMA Controller (PDC)

for data transfer without processor intervention.

PMC security event (clock failure detection) can be programmed to switch the MCK on a reliable main RC

internal clock withou t pr oc essor interventio n.

10.2 Real-time Event Mapping

Notes: 1. Refer to “Main Clock Failure Detection” in section “Power Management Controller (PMC)”

2. Refer to “Low-power Tamper Detection and Anti-Tampering” in section “Supply Controller (SUPC)” and “General Purpose

Backup Register x” in section “General Purpose Backup Register (GPBR)”

3. Refer to “ADC Mode Register (ADC_MR)” in section “Analog-to-Digital Converter (ADC)”.

4. Refer to “Waveform Generation” in section “Real-time clock (RTC)”

5. Refer to “Block Diagram” in section “Real-time Timer (RTT)”

6. Refer to “Last Channel Specific Measurement Trigger” in section “Analog-to-Digital Converter (ADC)”

7. Refer to “Block Diagram” and “Real-time Timer Modulo Selection Register (RTT_MODR)” in section “Real-time Timer

(RTT)”

8. Refer to “Peripheral DMA Controller (PDC)”.

Table 10-1. Real-time Event Mapping List

Function Application Description Event Source Even t Destinatio n

Safety General-purpose Automatic switch to reliable main RC

oscillator in case of main crystal clock

failure(1)

Power Management

Controller (PMC) PMC

Security General-purpose Immediate GPBR clear (asynchronous)

on tamper detection through WKUP0/1

IO pins(2) PIO: WKUP0/1 GPBR

Measurement

trigger General-purpose Trigger source selection in ADC(3)

PIO: ADTRG ADC

TC: TIOA0 ADC

TC: TIOA1 ADC

TC: TIOA2 ADC

RTC: RTCOUT0(4) ADC

RTT: 16-bit prescaler output(5) ADC

Last Channel Specific Measurement

Trigger(6) RTC: RTCOUT1(4) ADC

SleepW alking Trigger source selection in ADC(3) RTT: RTTEVENT(7) ADC

Direct Memory

Access General-purpose Peripheral trigger event generation to

transfer data to/from system memory(8)

FLEXCOM (USART/TWI/SPI)

0/1/2/3/4/5/6/7, ADC, TC,

I2SC0/1, PDMIC0/1 PDC

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

11. Debug and Test Features

11.1 Description

The SAM G55 features a number of complementary debug and test capabilities. The Serial Wire/JTAG Debug Port

(SWJ-DP) combin ing a Serial Wire Debug Port (SW-DP) and JTAG Deb ug Port (JTAG-DP) is used for stand ard

debugging functions, such as downloading code and single-stepping through programs. It also embeds a serial

wire trace.

11.2 Embedded Characteristics

Debug access to all memories an d registers in the system, including Cort ex-M4 register bank when the core

is running, halted, or held in reset.

Serial Wire Debug Port (SW-DP) and Serial Wire JTAG Debug Port (SWJ-DP) debug access.

Flash Patch and Breakpoint (FPB) unit for implementing breakp oin ts and code patches.

Data Watchpoint and Trace (DWT) unit for implementing watchpoints, data tracing, and system profiling.

Instrumentation Trace Macrocell (ITM) for support of printf style debugging.

IEEE1149.1 JTAG Boundary-scan on all digital pins.

11.3 Debug and Test Block Diagram

Figure 11-1. Debug and Te s t Block Diagram

TST

TMS

TCK/SWCLK

TDI

JTAGSEL

TDO/TRACESWO

Boundary

TAP SWJ-DP

Reset

and

Test

POR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

11.4 Application Examples

11.4.1 Debug Environment

Figure 11-2 shows a complete debug environment example. The SWJ-DP interface is used for standard

debugging functions, such as downloading code and single-stepping through the program, and viewing core and

peripheral registers.

Figure 11-2. Application Debug Environment Example

11.4.2 Test Environment

Figure 11-3 shows a te st environment example (JTAG boundary scan). Test vectors are sent and interpreted by

the tester. In this example, the “board in test” is designed using a number of JTAG-compliant devices. These

devices can be connected to form a single scan chain.

SAM G55

Host Debugger

SAM G55-based Application Board

SWJ-DP

Connector

SWJ-DP

Emulator/Probe

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 11-3. Application Test Environment Example

11.5 Debug and Test Pin Description

Note: 1. TDO pin is set in input mode when the Cortex-M4 Core is no t in debug mode. Thus the internal pull-up

corresponding to this PIO line must be enabled to avoid current consumption due to floating input.

Chip 2

Chip n

Chip 1

SAM G55

SAM G55-based Application Board In Test

JTAG

Connector

Tester

Test Adaptor

JTAG

Probe

Table 11-1. Debug and Test Signal List

Signal Name Function Type Active Level

Reset/Test

NRST Microcontroller Reset Input/Output Low

TST Test Select Input

SWD/JTAG

TCK/SWCLK Test Clock/Serial Wire Clock Input

TDI Test Data In Input

TDO/TRACESWO Test Data Out/Trace Asynchronous Data Out Output (1)

TMS/SWDIO Test Mode Select/Serial Wire Input/Output Input

JTAGSEL JTAG Selection Input High

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

11.6 Functional Description

11.6.1 Test Pin

One dedicated pin, TST, is used to define the device oper ating mode . When this pin is at low level during powerup,

the device is in normal operating mode. When at high level, the device is in test mode. The TST pin integrates a

permanent pull-down resistor of about 15 k Ω, so that it can be left unconnected for normal operation. Note that

when setting the TST pin to low or high level at power up, it must remain in the same state during the duration of

the whole operation.

11.6.2 NRST Pin

The NRST pin is bidirectional. It is handled by the on-chip reset controller and can be driven low to provide a reset

signal to the external components or asserted low externally to reset the microcontroller. It will reset the Core and

the peripherals except the Backup region (RTC, RTT and Supply Controller). There is no constraint on the length

of the reset pulse and the reset controller can guarante e a minimum pulse length. The NRST pin integrates a

permanent pull-up resistor to VDDIO of about 100 kΩ. By default, the NRST pin is configured as an input.

11.6.3 ERASE Pin

The ERASE pin is used to reinitialize the Flash content (and some of its NVM bits) to an erased state (all bits read

as logic level 1). The ERASE pin and the ROM code ensure an in-situ reprogrammability of the Flash content

without the use of a debug tool. When the security bit is activated, the ERASE pin provides the capability to

reprogram the Flash content. It integrates a pull-down resistor of about 100 kΩ to GND, so that it can be left

unconnected for normal operations.

This pin is debounced by SCLK to improve the glitch tolerance. To avoid unexpected erase at powerup, a

minimum ERASE pin assertion time is required. This time is defined in Table 39-50 “AC Flash Characteristics”.

The ERASE pin is a system I/O pin and can be used as a standard I/O. At startup, the ERASE pin is not configured

as a PIO pin. If the ERASE pin is used as a standard I/O, startup level of this pin must be low to prevent unwanted

erasing. Also, if the ERASE pin is used as a standard I/O output, asserting the pin to low does not erase the Flash.

For details, please refer to Section 9.2 “Peripheral Signal Multiplexing on I/O Lines”.

11.6.4 Debug Architecture

Figure 11-4 shows the Debug Architecture used in the SAM G55. The Cortex-M4 embeds five functional units for

debug:

SWJ-DP (Serial Wire/JTAG Debug Port)

FPB (Flash Patch Breakpoint

DWT (Data Watchpoint and Trace)

ITM (Instrumentation Trace Macrocell)

TPIU (Trace Port Interface Unit)

The debug architecture information that follows is mainly dedicated to developers of SWJ-DP emulators/probes

and debugging tool vendors for Cortex M4-based microcontrollers. For further details on SWJ-DP see the Cortex

M4 technical refe re nce manual.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 11-4. Debug Architecture

11.6.5 Serial Wire/JTAG Debug Port (SWJ-DP)

The Cortex-M4 embeds a SWJ-DP debug port which is the standard CoreSight™ debug port. It combines Serial

Wire Debug Port (SW-DP), from 2 to 3 pins and JTAG Debug Port (JTAG-DP), 5 pins.

By default, the JTAG Debug Port is a ctive. If the host debugger wa nts to switch to the Serial Wire Debug Port, it

must provide a ded icated JTAG sequence on TMS/SWDIO and TCK/SWCLK which disables JTAG-DP and

enables SW-DP.

When the Serial Wire Debug Port is active, TDO/TRACESWO can be used for trace. The asynchronous TRACE

output (TRACESWO) is multiple xed with TDO. So the asynchronous trace can only be used with SW-DP, not

JTAG-DP.

SW-DP or JTAG-DP mode is selected when JTAGSEL is low. It is not possible to switch directly between SWJ-DP

and JTAG boundary scan operations. A chip reset must be performed after JTAGSEL is changed.

11.6.5.1 SW-DP and JTAG-DP Selection Mechanism

Debug port selection mechanism is done by sending specific SWDIOTMS sequence. The JTAG-DP is selected by

default after reset.

Switch from JTAG-DP to SW-DP. The sequence is:

Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1

Send the 16-bit sequence on SWDIOTMS = 0111100111100111 (0x79E7 MSB first)

Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1

Switch from SWD to JTAG. The sequence is:

Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1

4 watchpoints

PC sampler

data address sampler

data sampler

interrupt trace

CPU statistics

DWT

6 breakpoints

FPB

software trace

32 channels

time stamping

ITM

SWD/JTAG

SWJ-DP

SWO trace

TPIU

Table 11-2. SWJ-DP Pin List

Pin Name JTAG Port Serial Wire Debug Port

TMS/SWDIO TMS SWDIO

TCK/SWCLK TCK SWCLK

TDI TDI –

TDO/TRACESWO TDO TRACESWO (optional: trace)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Send the 16-bit sequence on SWDIOTMS = 0011110011100111 (0x3CE7 MSB first)

Send more than 50 SWCLKTCK cycles with SWDIOTMS = 1

11.6.6 FPB (Flash Patch Breakpoint)

The FPB:

 Implements hardware brea kpoint s.

 Patches code and data from code space to system space.

The FPB unit cont ain s:

Two literal comparators for matching against lite ral loads from code space, and remapping to a

corresponding area in system space.

Six instruction comparators for matching against instruction fetches from code space and remapping to a

corresponding area in system space.

Alternatively, comp ar ators ca n also be co nfigured to generate a brea kp oint in str uction to th e p rocessor core

on a match.

11.6.7 DWT (Data Watchpoint and Trace)

The DWT contains four comparators which can be configured to generate the following:

PC sampling packets at set intervals.

PC or data watchpoint packets.

Watchpoint even t to ha lt cor e.

The DWT contains counters for the items that follow:

Clock cycle (CYCCNT).

Folded instructions.

Load Store Unit (LSU) operations.

Sleep cycles.

CPI (all instruction cycles except for the first cycle).

Interrupt overhead.

11.6.8 ITM (Instrumentation Trace Macrocell)

The ITM is an application driven trace source that supports printf style debugging to trace Operating System (OS)

and application events, and emits diagnostic system information. The ITM emits trace information as packets

which can be generated by three diffe rent sources with several priority levels:

Software trace: Software can write directly to ITM stimulus registers. This can be done thanks to the “printf”

function. For more information, refer to Section 11.6.8.1 “How to Configure the ITM”.

Hardware trace: The ITM emits packets generated by th e DWT.

Time stamping: Timestamps are emitted relative to packets. The ITM contains a 21-bit counter to generate

the timestamp.

11.6.8.1 How to Configure the ITM

The following example describes how to output trace data in asynchronous trace mode.

Configure the TPIU for asynchronous trace mode (refer to Section 11.6.8.3 “How to Configure the TPIU”).

Enable the write accesses into the ITM registers by writing “0xC5ACCE55” into the Lock Access Register

(address: 0xE0000FB0).

Write 0x00010015 into the Trace Control Register:

Enable ITM.

Enable synchronization packets.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Enable SWO behavior.

Fix the ATB ID to 1.

Write 0x1 into the Trace Enable Register:

Enable the stimulus port 0.

Write 0x1 into the Trace Privilege Register:

Stimulus port 0 only accessed in privileged mode (clearing a bit in this register will result in the

corresponding stimulus port being accessible in user mode).

Write into the Stimulus Port 0 Register: TPIU (Trace Port Interface Unit).

The TPIU acts as a bridge between the on-chip trace data and the Instruction Trace Macrocell (ITM).

The TPIU formats and transmits trace data off-chip at frequencies asynchronous to the core.

11.6.8.2 Asynchronous Mode

The TPIU is configured in asynchronous mode, trace data are output using the single TRACESWO pin. The

TRACESWO signal is multiplexed with the TDO signal of the JTAG Debug Po rt. As a con sequence, asynchr onous

trace mode is only available when the serial wire debug mode is selected since TDO sig nal is u sed in JTAG debu g

mode.

Two encoding formats are available for the single pin output:

 Manchester encoded stream. This is the reset value.

 NRZ-based UART byte structure.

11.6.8.3 How to Configure the TPIU

This example only concerns the asynchronous trace mode.

Set the TRCENA bit to 1 into the Debug Exception and Monitor Register (0xE000EDFC) to enable the use of

trace and debug blocks.

Write 0x2 into the Selected Pin Protocol Register.

Select the Serial Wire Output – NRZ.

Write 0x100 into the Formatter and Flush Control Register.

Set the suitable clock prescaler value into the Async Clock Prescaler Register to scale the baud rate of the

asynchronous output (this can be done automatically by the debugging tool ).

11.6.9 IEEE 1149.1 JTAG Boundary Scan

IEEE 1149.1 JTAG Boundary Scan allows pin-level access independent of the device packaging technology.

IEEE1149.1 JTAG Boundary Scan is enabled when TST is tied to high, PD0 tied to low, and JTAGSEL tied to high

during powerup. These pins must be maintained in their respective states for the duration of the boundary scan

operation. The SAMPLE, EXTEST and BYPASS functions are implemented. In SWD/JTAG debug mode, the ARM

processor responds with a non-JTAG chip ID that identifies the processor. This is not IEEE 1149.1 JTAG-

compliant.

It is not possible to switch directly between JTAG Boundary Scan and SWJ Debug Port operations. A chip reset

must be performed after JTAGSEL is changed. A Boundary-scan Descriptor Language (BSDL) file is provided on

www.atmel.com to set up the test.

11.6.9.1 JTAG Boundary-scan Register

The Boundary-scan Register (BSR) contains a number of bits which corresponds to active pins and associated

control signals.

Each SAM G55 input/output pin corresponds to a 3-bit field in the BSR. The OUTPUT bit contains data that can be

forced on the pad. The INPUT bit facilitates the observability of data applied to the pad. The CONTROL bit selects

the direction of the pad.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

For more information, please refer to BSDL files available for the SAM G55.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

11.6.10 ID Code Register

Access: Read-only

• VERSION[31:28]: Product Version Number

Set to 0x0.

• PART NUMBER[27:12]: Product Part Number

• MANUFACTURER IDENTITY[11:1]

Set to 0x01F.

• Bit[0] Required by IEEE Std. 1149.1.

Set to 0x1.

31 30 29 28 27 26 25 24

VERSION PART NUMBER

23 22 21 20 19 18 17 16

PART NUMBER

15 14 13 12 11 10 9 8

PART NUMBER MANUFACTURER IDENTITY

76543210

MANUFACTURER IDENTITY 1

PART NUMBER

0x05B3E

JTAG ID Code

0x05B3_E03F

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

12. Chip Identifier (CHIPID)

12.1 Description

Chip Identifier (CHIPID) registers are used to recognize the device and its revision. These registers provide the

sizes and types of the on-chip memories, as well as the set of embedded peripherals.

Two CHIPID registers are embedded: Chip ID Register (CHIPID_CIDR) and Chip ID Extension Register

(CHIPID_EXID). Both registers contain a hard-wired value that is read-only.

The CHIPID_CIDR register contains the following fie lds:

VERSION: Identifies the revision of the silicon

EPROC: Indicates the embedded ARM processor

NVPTYP and NVPSIZ: Identify the type of embedded non-volatile me mor y an d th e si ze

SRAMSIZ: Indicates the size of the embedded SRAM

ARCH: Identifies the set of embedded peripherals

EXT: Shows the use of the extension identifier register

The CHIPID_EXID reg iste r is dev ice -d ep en d ent an d re ad s 0 if CHIPID_CIDR.EXT = 0.

12.2 Embedded Characteristics

Chip ID Registers

Identification of the Device Revision, Sizes of the Embedded Memories, Set of Peripherals,

Embedded Processor

Table 12-1. SAM G55 Chip ID Registers

Chip Name CHIPID_CIDR CHIPID_EXID

SAM G55G19 Rev. A 0x2447_0AE0 0x0

SAM G55J19 Rev. A 0x2457_0AE0 0x0

SAM G55G19 Rev. B 0x2447_0AE1 0x0

SAM G55J19 Rev. B 0x2457_0AE1 0x0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

12.3 Chip Identifier (CHIPID) User Interface

Table 12-2. Register Mapping

Offset Register Name Access Reset

0x0 Chip ID Register CHIPID_CIDR Read-only –

0x4 Chip ID Extension Register CHIPID_EXID Read-o nly –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

12.3.1 Chip ID Register

Name: CHIPID_CIDR

Address: 0x400E0740

Access: Read-only

• VERSION: Vers io n of th e Devi ce

Current version of the device.

• EPROC: Embedded Processor

• NVPSIZ: Nonvolatile Program Memory Size

31 30 29 28 27 26 25 24

EXT NVPTYP ARCH

23 22 21 20 19 18 17 16

ARCH SRAMSIZ

15 14 13 12 11 10 9 8

NVPSIZ2 NVPSIZ

76543210

EPROC VERSION

Value Name Description

0 SAM x7 Cortex-M7

1 ARM946ES ARM946ES

2 ARM7TDMI ARM7TDMI

3 CM3 Cortex-M3

4 ARM920T ARM920T

5 ARM926EJS ARM926EJS

6 CA5 Cortex-A5

7 CM4 Cortex-M4

Value Name Description

0NONE None

18K 8 Kbytes

2 16K 16 Kbytes

3 32K 32 Kbytes

4– Reserved

5 64K 64 Kbytes

6– Reserved

7 128K 128 Kbytes

8 160K 160 Kbytes

9 256K 256 Kbytes

10 512K 512 Kbytes

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• NVPSIZ2: Second Nonvolatile Program Memory Size

• SRAMSIZ: Internal SRAM Size

11 – Reserved

12 1024K 1024 Kbytes

13 – Reserved

14 2048K 2048 Kbytes

15 – Reserved

Value Name Description

0NONE None

18K 8 Kbytes

2 16K 16 Kbytes

3 32K 32 Kbytes

4– Reserved

5 64K 64 Kbytes

6– Reserved

7 128K 128 Kbytes

8– Reserved

9 256K 256 Kbytes

10 512K 512 Kbytes

11 – Reserved

12 1024K 1024 Kbytes

13 – Reserved

14 2048K 2048 Kbytes

15 – Reserved

Value Name Description

0 48K 48 Kbytes

1 192K 192 Kbytes

2 384K 384 Kbytes

36K 6 Kbytes

4 24K 24 Kbytes

54K 4 Kbytes

6 80K 80 Kbytes

7 160K 160 Kbytes

88K 8 Kbytes

9 16K 16 Kbytes

10 32K 32 Kbytes

11 64K 64 Kbytes

Value Name Description

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• ARCH: Architecture Identifier

• NVPTYP: Nonvolatile Program Memory Type

• EXT: Extension Flag

0: Chip ID has a single register definition without extension.

1: An extended Chip ID exists.

12 128K 128 Kbytes

13 256K 256 Kbytes

14 96K 96 Kbytes

15 512K 512 Kbytes

Value Name Description

0x44 SAM G55 SAM G55 (49-lead version)

0x45 SAM G55 SAM G55 (64-lead version)

Value Name Description

0ROM ROM

1 ROMLESS ROMless or on-chip Flash

2 FLASH Embedded Flash Memory

3 ROM_FLASH ROM and Embedded Flash Memory

 NVPSIZ is ROM size

 NVPSIZ2 is Flash size

4 SRAM SRAM emulating ROM

Value Name Description

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

12.3.2 Chip ID Extension Register

Name: CHIPID_EXID

Address: 0x400E0744

Access: Read-only

• EXID: Chip ID Extension

This field is cleared if CHIPID_CIDR.EXT = 0.

31 30 29 28 27 26 25 24

EXID

23 22 21 20 19 18 17 16

EXID

15 14 13 12 11 10 9 8

EXID

76543210

EXID

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

13. ARM Cortex-M4 Processor

13.1 Description

The Cortex-M4 processor is a high performance 32-bit processor designed for the microc ontr oller m arke t. It offers

significant benefits to developers, including outstanding processing performance combined with fast interrupt

handling, enhanced system debug with extensive breakpoint and trace capabilities, efficient processor core,

system and memories, ultra-low power consumption with integrated sleep modes, and platform security

robustness, with integrated memory protection unit (MPU).

The Cortex-M4 processor is built on a high-performance processor core, with a 3-stage pipeline Harvard

architecture, making it ideal for demanding embedded a pplications. The processor delivers exceptional power

efficiency through an e fficient instruction set and extensively optimized d esign, providing high-end processing

hardware including IEEE754-compliant single-precision floating-point computation, a rang e of single-cycle and

SIMD multiplication and multiply-with-accumulate c apabilities, saturating arithmetic and dedicated hardware

division.

To facilitate the design of cost-sensitive devices, the Cortex-M4 processor implements tightly-coupled system

components that reduce processor area while significantly improving interrupt handling and system debug

capabilities. The Cortex-M4 processor implements a version of the Thumb instruction set based on Thumb-2

technology, ensuring high code density and reduced program memory requirements. The Cortex-M4 instruction

set provides the exceptional performance expected of a modern 32-bit architecture, with the high code density of

8-bit and 16-bit microcontrollers.

The Cortex-M4 processor closely integrates a configurable NVIC, to deliver industry-leading interrupt

performance. The NVIC includes a non-maskable interrupt (NMI), and provides up to 256 interrupt priority levels.

The tight integration of the processor core and NVIC provides fast execution of interrupt service routines (ISRs),

dramatically reducing the interrupt latency. This is achieved through the hardware stacking of registers, and the

ability to suspend load-multiple and store-multiple operations. Interrupt handlers do not require wrapping in

assembler code, removing any code over head from the ISRs. A tail-chain optimization also significantly re duces

the overhead when switching from one ISR to another.

To optimize low-power designs, the NVIC integrates with the sleep modes, that include a deep sleep function that

enables the entire device to be rapidly powered down while still retaining program state.

13.1.1 System Level Interface

The Cortex-M4 processor provides multiple interfaces using AMBA® technology to provide high speed, low latency

memory acces ses. It supports unaligned data accesses and implements atomic bit manipulation that enables

faster peripheral controls, system spinlocks and thread-safe Boolean data handling.

The Cortex-M4 processor has a Memory Protection Unit (MPU) that provides fine grain memory control, enabling

applications to utilize multiple privilege levels, separating and protecting code, data and stack on a task-by-task

basis. Such requirements are becoming critical in many embedded applications such as autom ot ive .

13.1.2 Integrated Configurable Debug

The Cortex-M4 processor implements a complete hardware debug solution. This provides high system visibility of

the processor and memory through either a traditional JTAG port or a 2-pin Serial Wire Debug (SWD) port that is

ideal for microcontrollers and other small package devices.

For system trace the processor integrates an In strumentation Trace Macrocell (ITM) a longside data wa tchpoints

and a profiling unit. T o enable simple and cost-ef fective profiling of the system eve nts these generate, a Serial

Wire Viewer (SWV) can export a stream of software-ge nerated messages, data trace, and profiling inform ation

through a single pin.

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The Flash Patch and Breakpoint Unit (FPB) provides up to eight hardware breakpoint comparators that debuggers

can use. The comparators in the FPB also pr ovide rema p functions of up to eight wo rds in the pr ogram code in the

CODE memory region. This enables applications stored o n a non-erasable, ROM-base d microcontroller to be

patched if a small programmable memory, for example flash, is available in the device. During initialization, the

application in ROM dete cts, from the programm able memory, whethe r a patch is required. If a patch is required,

the application programs the FPB to remap a number of addresses. When those addresses are accessed, the

accesses are redirected to a remap table sp ecified in the FPB configuration, which means the program in the non-

modifiable ROM can be patched.

13.2 Embedded Characteristics

Tight integration of syste m per iph er a ls red uc es are a an d deve lo pm e nt co sts

Thumb instruction set combines high code density with 32-bit performance

IEEE754-compliant single-precision FPU

Code-patch ability for ROM system upda tes

Power control optimization of system components

Integrated sleep modes for low power consumption

Fast code execution permits slower processor clock or increases sleep mode time

Hardware division and fast digital-signal-processing oriented multiply accumulate

Saturating arithmetic for signal processing

Deterministic, high-performance interrupt handling for time-critical applications

Memory Protection Unit (MPU) for safety-critical applications

Extensive debug and trace capabilities:

Serial Wire Debug and Serial Wire Trace reduce the number of pins required for debugging, tracing,

and code profiling.

13.3 Block Diagram

Figure 13-1. Typical Cortex-M4F Implementation

NVIC

Debug

Access

Port

Memory

Protection Unit

Serial

Wire

Viewer

Bus Matrix

Code

Interface

SRAM and

Peripheral Interface

Data

Watchpoints

Flash

Patch

Cortex-M4F

Processor

Core

FPU

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13.4 Cortex-M4 Models

13.4.1 Programmers Model

This section describes the Cortex-M4 programmers model. In addition to the individual core register descriptions, it

contains information about the processor modes and privilege levels for software execution and stacks.

13.4.1.1 Processor Modes and Privilege Levels for Software Execution

The processor modes are:

Thread mode

Used to execute application software. The processor enters the Threa d mode when it comes out of reset.

Handler mode

Used to handle exceptions. The processor returns to the Thread mode when it has finished exception

processing.

The privilege levels for software execution are:

Unprivileged

The software:

Has limited access to the MSR and MRS instructions, and cannot use the CPS instruction

Cannot access the System Timer, NVIC, or System Control Block

Might have a restricted access to memory or peripherals.

Unprivileged software executes at the unprivileged level.

Privileged

The software can use all the instructions and has access to all resources. Privileged software executes at

the privileged level.

In Thread mode, the Control Register controls whether the software execution is privileged or unprivileged, see

“Control Register”. In Handler mode, software execution is always privileged.

Only privileged software can write to the Control Register to change the privilege level for software execution in

Thread mode. Unprivile ged software can use the SVC inst ruction to make a supervisor call to transfer c ontrol to

privileged software.

13.4.1.2 Stacks

The processor uses a full descending stack. This means the stack pointer holds the address of the last stacked

item in memory When the processor pushes a new item onto the stack, it decrements the stack pointer and then

writes the item to the new memory lo cation. The pr ocessor implements two stacks, the main stack and the process

stack, with a pointer for each held in independent register s, see “Stack Pointer”.

In Thread mode, the Control Register controls whether the processor uses the main stack or the process stack,

see “Control Register”.

In Handler mode, the processor always uses the main stack.

The options for processor operations are:

Note: 1. See “Control Registe r”.

Table 13-1. Summary of Processor Mode, Execution Privilege Level, and Stack Use Options

Processor

Mode Used to Execute Privilege Level for

Software Execution Stack Used

Thread Applications Privileged or unprivileged(1) Main stack or process stack(1)

Handler Exception handlers Always privileged Main stack

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13.4.1.3 Core Registers

Figure 13-2. Processor Core Registers

Notes: 1. Describes access type during program execution in thread mode and Handler mode. Debug access can differ.

2. An entry of Either means privileged and unprivileged software can access the register.

SP (R13)

LR (R14)

PC (R15)

R10

R11

R12

Low registers

High registers

MSP‡

PSP‡

PSR

PRIMASK

FAULTMASK

BASEPRI

CONTROL

General-purpose registers

Stack Pointer

Link Register

Program Counter

Program status register

Exception mask registers

CONTROL register

Special registers

‡Banked version of SP

Table 13-2. Core Processor Registers

General-purpose registers R0–R12 Read/Write Either Unknown

Stack Pointer MSP Read/W r it e Privileged See description

Stack Pointer PSP Read/Write Either Unknown

Link Register LR Read/Write Either 0xFF FF FF FF

Program Counter PC Read/Write Either See description

Program Status Register PSR Read/Write Privileged 0x01000000

Application Program Status Register APSR Read/Write Either 0x00000000

Interrupt Program Status Register IPSR Read-only Privileged 0x00000000

Execution Program Status Register EPSR Read-only Privileged 0x01000000

Priority Mask Register PRIMASK Read/Write Privileged 0x00000000

Fault Mask Register FAULTMASK Read/Write Privileged 0x00000000

Base Priority Mask Register BASEPRI Read/Write Privileged 0x00000000

Control Register CONTROL Read/Write Privileged 0x00000000

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13.4.1.4 General-purpose Registers

R0–R12 are 32 -b it ge ne ra l- pu rp os e re gisters for data opera t io ns .

13.4.1.5 Stack Pointer

The Stack Pointer (SP) is register R13. In Thread mode, bit[1] of the Control Register indicates the stack pointer to

use:

0 = Main Stack Pointer (MSP). This is the reset value.

1 = Process Stack Pointer (PSP).

On reset, the processor loads the MSP with the value from address 0x00000000.

13.4.1.6 Link Register

The Link Register (LR) is register R14. It stores the return information for subroutines, function calls, and

exceptions. On reset, the processor loads the LR value 0xFFFFFFFF

13.4.1.7 Program Counter

The Progra m Coun te r ( PC) is r eg ister R15. It con tains th e cur rent pro gr am addr ess. On r eset, the pr ocesso r lo ads

the PC with the value of the reset vector, which is at address 0x00000004. Bit[0] of the value is loa ded into the

EPSR T-bit at reset and must be 1.

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13.4.1.8 Program Status Register

Name: PSR

Access: Read/Write

Reset: 0x000000000

The Program Status Register (PSR) combines:

•Application Program Status Register (APSR)

•Interrupt Program Status Register (IPSR)

•Execution Program Status Register (EPSR).

These registers are mutually exclusive bitfields in the 32-bit PSR.

The PSR accesses these registers individually or as a combination of any two or all three registers, using the register

name as an argument to the MSR or MRS instructions. For example:

• Read of all the registers using PSR with the MRS instruction

• Write to the APSR N, Z, C, V and Q bits using APSR_nzcvq with the MSR instruction.

The PSR combinations and attributes are:

Notes: 1. The processor ignores writes to the IPSR bits.

2. Reads of the EPSR bits return zero, and the processor ignores writes to these bits.

See the instruction descriptions “MRS” and “MSR” for more information about how to access the program status registers.

31 30 29 28 27 26 25 24

NZCVQ ICI/IT T

23 22 21 20 19 18 17 16

–

15 14 13 12 11 10 9 8

ICI/IT – ISR_NUMBER

76543210

ISR_NUMBER

Name Access Combination

PSR Read/Write(1)(2) APSR, EPSR, and IPSR

IEPSR Read-only EPSR and IPSR

IAPSR Read/Write(1) APSR and IPSR

EAPSR Read/Write(2) APSR and EPSR

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13.4.1.9 Application Program Status Register

Name: APSR

Access: Read/Write

Reset: 0x000000000

The APSR contains the current state of the condition flags from previous instruction executions.

• N: Negative Flag

0: Operation result was positive, zero, greater than, or equal

1: Operation result was negative or less than.

• Z: Zero Flag

0: Operation result was not zero

1: Operation result was zero.

• C: Carry or Borrow Flag

Carry or borrow flag:

0: Add operation did not result in a carry bit or subtract operation resulte d in a borrow bit

1: Add operation resulted in a carry bit or subtract operatio n did not result in a borrow bit.

• V: Overflow Flag

0: Operation did not result in an overflow

1: Operation resulted in an overflow.

• Q: DSP Overflow and Saturation Flag

Sticky saturation flag:

0: Indicates that saturation has not occurred since reset or since the bit was last cleared to zero

1: Indicates when an

SSAT

USAT

instruction results in saturation.

This bit is cleared to zero by software using an

MRS

instruction.

• GE[19:16] : Gre ater Th an or Eq ua l Fl ag s

See “SEL” for more information.

31 30 29 28 27 26 25 24

NZCVQ –

23 22 21 20 19 18 17 16

– GE[3:0]

15 14 13 12 11 10 9 8

–

76543210

–

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13.4.1.10 Interrupt Program Status Register

Name: IPSR

Access: Read/Write

Reset: 0x000000000

The IPSR contains the exception type number of the current Interrupt Service Routine (ISR).

• ISR_NUMBER: Number of the Current Exception

0 = Thread mode

1 = Reserved

2 = NMI

3 = Hard fault

4 = Memory management fault

5 = Bus fault

6 = Usage fault

7–10 = Reserved

11 = SVCall

12 = Reserved for Debug

13 = Reserved

14 = PendSV

15 = SysTick

16 = IRQ0

61 = IRQ49

See “Exception Types” for more information.

31 30 29 28 27 26 25 24

–

23 22 21 20 19 18 17 16

–

15 14 13 12 11 10 9 8

– ISR_NUMBER

76543210

ISR_NUMBER

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13.4.1.11 Execution Program Status Register

Name: EPSR

Access: Read/Write

Reset: 0x000000000

The EPSR contains the Thumb state bit, and the execution state bits for either the If-Then (IT) instruction, or the Interrupt-

ible-Continuable Instruction (ICI) field for an interrupted load multiple or store multiple instruction.

Attempts to read the EPSR directly through application software using the MSR instruction always return ze ro. Attempts to

write the EPSR using the MSR instruction in the application software are ignored. Fault handlers can examine the EPSR

value in the stacked PSR to indicate the operation that is at fault. See “Exception Entry and Return”.

• ICI: Interruptible-continuable Instruction

When an interrupt occurs during the execution of an LDM, STM, PUSH, POP, VLDM, VSTM, VPUSH, or VPOP instruction,

the processor:

– Stops the load multiple or store multiple instruction operation temporarily

– Stores the next register operand in the multiple operation to EPSR bits[15:12].

After servicing the interrupt, the processor:

– Returns to the register pointed to by bits[15:12]

– Resumes the execution of the multiple load or store instructi on.

When the EPSR holds the ICI execution state, bits[26:25,11:10] are zero.

• IT: If-Then Instruction

Indicates the execution state bits of the IT instruction.

The If-Then block contains up to four instructions following an IT instruction. Each instruction in the block is conditional.

The conditions for the instructions are either all the same, or some can be the inverse of others. See “IT” for more

information.

• T: Thumb State

The Cortex-M4 processor only supp or ts the execution of instructions in Thumb sta te. Th e following ca n clea r the T b it to 0:

– Instructions BLX, BX and POP{PC}

– Restoration from the stacked xPSR value on an exce p tion re tu rn

– Bit[0] of the vector value on an exception entry or reset.

Attempting to execute instructions when the T bit is 0 results in a fault or lockup. See “Lockup” for more information.

31 30 29 28 27 26 25 24

–ICI/ITT

23 22 21 20 19 18 17 16

–

15 14 13 12 11 10 9 8

ICI/IT –

76543210

–

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13.4.1.12 Exception Mask Registers

The exception mask registers disable the handling of exceptions by the processor. Disable exceptions where they

might impact on timing critical tasks.

To access the exception mask registers use the MSR and MRS instructions, or the CPS instruction to change the

value of PRIMASK or FAULTMASK. See “MRS”, “MSR”, and “CPS” for more information.

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13.4.1.13 Priority Mask Register

Name: PRIMASK

Access: Read/Write

Reset: 0x000000000

The PRIMASK register prevents the activation of all exceptions with a configurable priority.

•PRIMASK

0: No effect

1: Prevents the activation of all exceptions with a configurable priority.

31 30 29 28 27 26 25 24

–

23 22 21 20 19 18 17 16

–

15 14 13 12 11 10 9 8

–

76543210

– PRIMASK

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13.4.1.14 Fault Mask Register

Name: FAULTMASK

Access: Read/Write

Reset: 0x000000000

The FAULTMASK register prevents the activation of all exceptions except for Non-Maskable Interrupt (NMI).

• FAULTMASK

0: No effect.

1: Prevents the activation of all exceptions except for NMI.

The processor clears the FAULTMASK bit to 0 on exit from any exception handler except the NMI handler.

31 30 29 28 27 26 25 24

–

23 22 21 20 19 18 17 16

–

15 14 13 12 11 10 9 8

–

76543210

– FAULTMASK

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13.4.1.15 Base Priority Mask Register

Name: BASEPRI

Access: Read/Write

Reset: 0x000000000

The BASEPRI register defines the minimum priority for exception processing. When BASEPRI is set to a nonzero value, it

prevents the activation of all exceptions with same or lower priority level as the BASEPRI value.

• BASEPRI

Priority mask bits:

0x0000: No effect

Nonzero: Defines the base priority for exception pr oc es sin g

The processor does not process any exception with a priority value greater than or equal to BASEPRI.

This field is similar to the priority fields in the interrupt priority registers. The processor implements only bits[7:4] of this

field, bits[3:0] read as zero and ign ore writes. See “Interrupt Priority Registers” for more information. Remember that higher

priority field values correspond to lower exception priorities.

31 30 29 28 27 26 25 24

–

23 22 21 20 19 18 17 16

–

15 14 13 12 11 10 9 8

–

76543210

BASEPRI

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13.4.1.16 Control Register

Name: CONTROL

Access: Read/Write

Reset: 0x000000000

The Control Register contro ls the stack used and the p rivilege level for software execution when the processor is in Thread

mode and indicates whether the FPU state is active.

• FPCA: Floating-point Context Active

Indicates whether the floating-point context is currently active:

0: No floating-point context active.

1: Floating-point context active.

The Cortex-M4 uses this bit to determine whether to preserve the floating-point state when processing an exception.

• SPSEL: Active Stack Pointer

Defines the current stack:

0: MSP is the current stack pointer.

1: PSP is the current stack pointer.

In Handler mode, this bit reads as zero and ignores writes. The Cortex-M4 updates this bit automatically on exception

return.

• nPRIV: Thread Mode Privilege Lev el

Defines the Thread mode privilege level:

0: Privileged.

1: Unprivileged.

Handler mode always uses the MSP, so the processor ignores explicit writes to the active stack pointer bit of the Control

EXC_RETURN value.

In an OS environment, ARM recommen ds that threa ds running in Thr ead mode use the proce ss stack, and the kernel and

exception handlers use the main stack.

By default, the Thread mode uses the MSP. To switch the stack pointer used in Thread mode to the PSP, either:

•Use the MSR instruction to set the Active stack pointer bit to 1, see “MSR”, or

•Perform an exception return to Thread mode with the appropriate EXC_RETURN value, see Table 13-10.

31 30 29 28 27 26 25 24

–

23 22 21 20 19 18 17 16

–

15 14 13 12 11 10 9 8

–

76543210

– FPCA SPSEL nPRIV

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Note: When changing the stack pointer, the software must use an ISB instruction immediately after the MSR instruction. This ensures

that instructions after the ISB execute using the new stack pointer. See “ISB”.

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13.4.1.17 Exceptions and Interrupts

The Cortex-M4 processor supports interrupts and system exceptions. The processor and the Nested Vectored

Interrupt Controller (NVIC) prioritize and handle all exceptions. An exception changes the normal flow of software

control. The processor uses the Handler mode to handle all exceptions except for reset. Se e “Exception Entry” and

“Exception Return” for more information.

The NVIC registers control interrupt handling. See “Nested Vectored Interrupt Controller (NVIC)” for more

information.

13.4.1.18 Data Types

The processor supports the following data types:

32-bit words

16-bit halfwords

8-bit bytes

The process or ma nage s all da ta memor y acc es se s as little-e nd ian . In str uc tio n me m or y an d Private

Peripheral Bus (PPB) accesses are always little-endian. See “Memory Regions, Types and Attributes” for

more information.

13.4.1.19 Cortex Microcontroller Software Interface Standard (CMSIS)

For a Cortex-M4 microcontroller system, the Cortex Microcontroller Software Interface Standard (CMSIS) defines:

A common way to:

Access peripheral registers

Define exception vectors

The names of :

The registe rs of the co re per iph e ra ls

The core exception vectors

A device-independent interface for RTOS kernels, including a debug channel.

The CMSIS includes address definitions and data structures for the core peripherals in the Cortex-M4 processor.

The CMSIS simplifies the software development by enabling the reuse of template code and the combination of

CMSIS-compliant software components from various middleware vendors. Software vendors can expand the

CMSIS to include their peripheral definitions and access functions for those periph erals.

This document includes the register names defined by the CMSIS, an d gives short descriptions of the CMSIS

functions that address the processor core and the core peripherals.

Note: This document uses the register short names defined by the CMSIS. In a few cases, these differ from the architectural

short names that might be used in other documents.

The following sections give more information about the CMSIS:

Section 13.5.3 ”Power Management Programm ing Hints”

Section 13.6.2 ”CMSIS Functions”

Section 13.8.2.1 ”NVIC Programming Hints”.

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13.4.2 Memory Model

This section describes the processor memory map, the behavior of memory accesses, and the bit-banding

features. The processor has a fixed memory map that provides up to 4 GB of addressable memory.

Figure 13-3. Memory Map

The regions for SRAM and peripherals include bit-band r egions. Bit-banding provides atomic operatio ns to bit

data, see “Bit-banding”.

The processor reserves regions of the Private peripheral bus (PPB) address range for core peripheral registers.

This memory mapping is gen eric to ARM Cortex-M 4 products. To get the sp ecific memory map ping of this product,

refer to section Memories.

Vendor-specific

memory

External device

External RAM

Peripheral

SRAM

Code

0xFFFFFFFF

Private peripheral

bus

0xE0100000

0xE00FFFFF

0x9FFFFFFF

0xA0000000

0x5FFFFFFF

0x60000000

0x3FFFFFFF

0x40000000

0x1FFFFFFF

0x20000000

0x00000000

0x40000000

32 MB Bit-band alias

0x400FFFFF

0x42000000

0x43FFFFFF

1 MB Bit-band region

32 MB Bit-band alias

0x20000000

0x200FFFFF

0x22000000

0x23FFFFFF

1.0 GB

0.5 GB

0x DFFFFFFF

0xE000 0000

1.0 MB

511 MB

1 MB Bit-band region

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13.4.2.1 Memory Regions, Types and Attributes

The memory map and the programming of the MPU split the memory map into regions. Each region has a defined

memory type, and some regions have additional memo ry attributes. The memory type and attributes determin e the

behavior of accesses to the region.

Memory Types

Normal

The processor can re-order transactions for e fficiency, or perform speculative reads.

Device

The processor preserves transaction order relative to other transactions to Device or Strongly-ordered

memory.

Strongly-ordered

The processor preserves transaction order relative to all other tr ansactions.

The different ordering requirements for Device and Strongly-ordered memory mean that the memory system can

buffer a write to Device memory, but must not buffer a write to Strongly-ordered memory.

Additional Memory Attributes

Shareable

For a shareable memor y region, the memory system pr ovides data synchronizatio n between bus masters in

a system with multiple bus masters, for example, a processor with a DMA controller.

Strongly-ordered memory is always shareable.

If multiple bus masters can access a non-shareable memory region, the software must ensure data

coherency between the bus masters.

Execute Never (XN)

Means the processor prevents instruction accesses. A fault exception is generated only on execution of an

instruction executed from an XN region.

13.4.2.2 Memory System Ordering of Memory Accesses

For most memory accesses caused by explicit memory access instructions, the memory system does not

guarantee that the order in which the accesses complete matches the program order of the instructions, providing

this does not affect the behavior of the instruction sequence. Normally, if correct progr am execution depends on

two memory accesses completing in program order, the software must in sert a me mory barrier instructi on betwee n

the memory access instructions, see “Software Ordering of Memory Accesses”.

However, the memory system does guarantee some ordering of accesses to Device and Strongly-ordered

memory. F or t wo m e mo ry a ccess instructio n s A1 a nd A2, if A1 occurs before A2 in program order, the ordering of

the memory accesses is described below.

Where:

– Means that the memory system does not guarantee the ordering of the accesses.

< Means that accesses are observed in program order, that is, A1 is always observed before A2.

Table 13-3. Orde ring of the Memory Accesses Caused by Two Instructions

Normal Access

Device Access Strongly-ordered

AccessA1 Non-shareable Shareable

Normal Access ––––

Device access, non-shareable – < – <

Device access, shareable – – < <

Strongly-ordered access – < < <

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13.4.2.3 Behavior of Memory Accesses

The following table describes the behavior of accesses to each region in the memory map.

Note: 1. See “Memory Regions, Types and Attributes” for more information.

The Code, SRAM, and externa l RAM regions can hold progr ams. However, ARM recommends that programs

always use the Code region. This is beca use the processor has separ ate buses that enable instruction fetches and

data accesses to occur simultaneously.

The MPU can overr ide the default memory acce ss behavior described in this section. For more in formation, see

“Memory Protection Unit (MPU)”.

Additional Memory Access Constraints For Caches and Shared Memory

When a system includes caches or shared memory, some memory regions have additional access constraints,

and some regions are subdivided, as Table 13-5 shows.

Notes: 1. See “Memory Regions, Types and Attributes” for more information.

2. WT = Write through, no write allocate. WBWA = W rite back, write allocate. See the “Glossary” for more information.

Instruction Prefetch and Branch Prediction

The Cortex-M4 processor:

Prefetches instructions ahead of execution

Speculatively prefetches from branch t arget addresses.

Table 13-4. Memory Access Behavior

Address Range Memory Region Memory Type XN Description

0x00000000–0x1FFFFFFF Code Normal(1) –Executable region for program code. Data can also

be put here.

0x20000000–0x3FFFFFFF SRAM Normal(1) –Executable region for data. Code can also be put

here. This region includes bit band and bit band alias

areas, see Table 13-6.

0x40000000–0x5FFFFFFF Peripheral Device(1) XN This region in cludes bit band and bit band ali as

areas, see Table 13-6.

0x60000000–0x9 FFFFFFF External RAM Normal(1) – Executable region for data

0xA0000000–0xDFFFFFFF External device Device(1) XN External Device memory

0xE0000000–0xE00FFFFF Private Peripheral Bus Strongly-

ordered(1) XN This region includes the NVIC, system timer, and

system control block.

0xE0100000–0xFFFFFFFF Reserved Device(1) XN Reserved

Table 13-5. Memory Region Shareability and Cache Policies

Address Range Memory Region Memory Type Shareability Cache Policy

0x00000000–0x1FFFFFFF Code Normal(1) –WT

(2)

0x20000000–0x3FFFFFFF SRAM Normal(1) –WBWA

(2)

0x40000000–0x5FFFFFFF Peripheral Device(1) ––

0x60000000–0x7FFFFFFF External RAM Normal(1) –WBWA(2)

0x80000000–0x9FFFFFFF WT(2)

0xA0000000–0xBFFFFFFF External device Device(1) Shareable(1) –

0xC0000000–0xDFFFFFFF Non-shareable(1)

0xE0000000–0xE00FFFFF Private Peripheral Bus Strongly-ordered(1) Shareable(1) –

0xE0100000–0xFFFFFFFF Vendor-specific device Device(1) ––

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13.4.2.4 Software Ordering of Memory Accesses

The order of instructions in the program flow does not always guarantee the order of the corresponding memory

transactions. This is because:

The processor can reorder some memory accesses to improve efficiency, providing this does not affect the

behavior of the instruction sequence.

The processor has multiple bus interfaces

Memory or devices in the memory map have diff erent wait states

Some memory accesses are buffered or speculative.

“Memory System Ordering of Memory Accesses” describes the cases where the memory system guarantees the

order of memory accesses. Otherwise, if the order o f memory accesses is critical, the software must include

memory barrier instructions to force that ordering. The processor provides the following memory barrier

instructions:

DMB

The Data Memory Barrier (DMB) instruction ensures that outstanding memory transactions complete before

subsequent memory transactions. See “DMB”.

DSB

The Data Synchronization Barrier (DSB) instruction ensures tha t outstanding memory transactions complete

before subsequent instructions execute. See “DSB”.

ISB

The Instruction Synchronization Barrier (ISB) ensures that the effect of all completed memory transactions is

recognizable by subsequent instructions. See “ISB”.

MPU Programming

Use a DSB followed by an ISB instruction or exception return to ensure that the new MPU configuration is used by

subsequent instructions.

13.4.2.5 Bit-banding

A bit-band re gion maps each word in a bit-band alia s region to a sing le bit in the bit-band region. The bit-ba nd

regions occupy the lowest 1 MB of the SRAM and peripher al memory regions.

The memory map has two 32 MB alias regions that map to two 1 MB bit-band regions:

Accesses to the 32 MB SRAM alias region map to the 1 MB SRAM bit-band region, as shown in Tabl e 13- 6.

Accesses to the 32 MB peripheral alias region map to the 1 MB peripheral bit-band region, as shown in

Table 13-7.

Table 13-6. SRAM Memory Bit-banding Regions

Address Range Memory Region Instruction and Data Accesses

0x20000000–0x200FFFFF SRAM bit-band region Direct accesses to this memory range behave as SRAM memory accesses,

but this region is also bit-addressable through bit-band alias.

0x22000000–0x23FFFFFF SRAM bit-band alias Data accesses to this region are remapped to bit-band regio n. A write

operation i s per fo rme d as read-modify-write. Instruction accesses are not

remapped.

Table 13-7. Peripheral Memory Bit-banding Regions

Address Range Memory Region Instruc tion and Data Accesses

0x40000000–0x400FFFFF Peripheral bit-band alias Direct accesses to this memory range behave as peripheral memory

accesses, but this region is also bit-addressable through bit-band alias.

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Notes: 1. A word access to the SRAM or peripheral bit-band alias regions map to a single bit in the SRAM or peripheral bit-band

region.

2. Bit-band accesses can use byte, halfword, or word transfers. The bit-band transfer size matches the transfer size of the

instruction making the bit-band access.

The following formula shows how the alias region maps onto the bit-band region:

bit_word_offset = (byte_offset x 32) + (bit_number x 4)

bit_word_addr = bit_band_base + bit_word_offset

where:



Bit_word_offset

is the position of the target bit in the bit-band memory region.



Bit_word_addr

is the address of the word in the alias memory region that maps to the targeted bit.



Bit_band_base

is the starting address of the alias region.



Byte_offset

is the number of the byte in the bit-band region that contains the targeted bit.



Bit_number

is the bit position, 0–7, of the targeted bit.

Figure 13-4 shows examples of bit-band mapping between the SRAM bit-band alias region and the SRAM bit-

band region:

The alias word at 0x23FFFFE0 maps to bit[0] of the bit-band byte at 0x200FFFFF: 0x23FFFFE0 =

0x22000000 + (0xFFFFF*32) + (0*4).

The alias word at 0x23FFFFFC maps to bit[7] of the bit-band byte at 0x200FFFFF: 0x23FFFFFC =

0x22000000 + (0xFFFFF*32) + (7*4).

The alias word at 0x22000000 maps to bit[0] of the bit-band byte at 0x200 00000: 0x22000000 =

0x22000000 + (0*32) + (0*4).

The alias word at 0x2200001C maps to bit[7] of the bit-band byte at 0x20000000: 0x2200001C =

0x22000000+ (0*32) + (7*4).

Figure 13-4. Bit-band Mapp ing

0x42000000–0x43FFFFFF Peripheral bit-band regi on Da ta accesses to this region are remapped to bit-band region. A write

operation is performed as read-modify-write. Instruction accesses are not

permitted.

Table 13-7. Peripheral Memory Bit-banding Regions (Continued)

Address Range Memory Region Instruc tion and Data Accesses

0x23FFFFE4

0x22000004

0x23FFFFE00x23FFFFE80x23FFFFEC0x23FFFFF00x23FFFFF40x23FFFFF80x23FFFFFC

0x220000000x220000140x220000180x2200001C 0x220000080x22000010 0x2200000C

32 MB alias region

7 0

0x200000000x200000010x200000020x20000003

6 5 4 3 2 1 07 6 5 4 3 2 1 7 6 5 4 3 2 1 07 6 5 4 3 2 1

07 6 5 4 3 2 1 6 5 4 3 2 107 6 5 4 3 2 1 07 6 5 4 3 2 1

0x200FFFFC0x200FFFFD0x200FFFFE0x200FFFFF

1 MB SRAM bit-band region

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Directly Accessing an Alias Region

Writing to a word in the alias region updates a single bit in the bit-band region.

Bit[0] of the value written to a word in the alias region determines the value written to the targeted bit in the bit-

band region . Writin g a va lue wit h bit[ 0] se t to 1 writes a 1 to the bit-band bit, and writing a value with bit[0] set to 0

writes a 0 to the bit-band bit.

Bits[31:1] of the alias word have no effect on the bit-band bit. Writing

0x01

has the same effect as writing

0xFF

Writing

0x00

has the same effect as writing

0x0E

Reading a word in the alias region:

0x00000000 indicates that the targeted bit in the bit-band region is set to 0

0x00000001 indicates that the targeted bit in the bit-band region is set to 1

Directly Accessing a Bit-band Region

“Behavior of Memory Accesses” describes the behavior of direct byte, halfword, or word accesses to the bit-band

regions.

13.4.2.6 Memory Endianness

The processor views memory as a linear collection of bytes numbered in ascending order from zero. For exam ple,

bytes 0–3 hold the first stored word, and byte s 4–7 hold the second stored word. “Little-endian Format” describes

how words of data are stored in memory.

Little-endian Format

In little-endian format, the processor stores the least significant byte of a word at the lowest-nu mbered byte, and

the most significant byte at the highest-numbered byte . For example:

Figure 13-5. Little-endian Format

13.4.2.7 Synchronization Primitives

The Cortex-M4 instruction set includes pairs of synchronization primitives. These provide a non-blocking

mechanism that a thread or process can use to obta in exclusive access to a memory location. The software can

use them to perform a guaranteed read-modify-write memory update sequence, or for a semaphore mechanism.

A pair of synchronization primitives comprises:

A Load-exclusive Instruction, used to read the value of a memory location, requesting exclusive access to that

location.

A Store-Exclusive instruction, used to attempt to write to the same memory location, returning a status bit to a

0: It indicates that the thread or process gained exclusive access to the memory, and the write succeeds,

1: It indicates that the thread or process did no t gain exclusive access to the memory, and no write is

performed.

Memory Register

Address

A+1

lsbyte

msbyte

A+2

A+3

B0B1B3 B2

31 24 23 16 15 8 7 0

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The pairs of Load-Exclusive and Store-Exclusive instructions are:

The word instructions LDREX and STREX

The halfword instructions LDREXH and STREXH

The byte instructions LDREXB and STREXB.

The software mu st use a Load-Exclusive instr uc tio n with the corresponding Store-Exclusive instruction.

To perform an exclusive read-modify-write of a memory location, the software must:

1. Use a Load-Exclusive instruction to read the value of the location.

2. Update the value, as required.

3. Use a Store-Exclusive instruction to attempt to write the new value back to the memory location

4. Test the returned status bit. If this bit is:

0: The read-modify-write completed successfully.

1: No write was performed. This indicates that the value returned at step 1 might be out of date. The

software must retry the read-modify-write sequence.

The software can use the synchronization primitives to implement a semaphore as follows:

1. Use a Load-Exclusive instruction to read from the sema phore address to check whether the semaphore is

free.

2. If the semaphore is free, use a Store-Exclusive instruction to write the claim va lue to the semaphore

address.

3. If the returned status bit from step 2 indicates that the Store-Exclusive instruction succeeded then the

software has claimed the se ma p ho re . How ev er, if the Store-Exclusive instruction failed, another process

might have claimed the semaphore after the software performed the first step.

The Cortex-M4 includes an exclusive access monitor, that tags the fact that the processor has executed a Load-

Exclusive instruction. If the processor is part of a multiprocessor system, the system also globally tags the memory

locations addressed by exclusive accesses by each processor.

The processor removes its exclusive access tag if:

It executes a CLREX instruction

It executes a Store-Exclusive instruction, regardless of whether the write succeeds.

An exception occurs. This means that the pr ocessor can resolve semaphore conflicts between different

threads.

In a multiprocessor implementation:

Executing a CLREX instruction removes only the local exclusive access tag for the processor

Executing a Store-Exclusive instruction, or an exception, removes the local exclusive access tags, and all

global exclusive access tags for the processor.

For more information about the synchronization primitive instructions, see “LDREX and STREX” and “CLREX”.

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13.4.2.8 Programming Hints for the Synchronization Primitives

ISO/IEC C cannot directly generate the exclusive access instructions. CMSIS provides intrinsic functions for

generation of these instructions:

The actual exclusive access instruction generated depends on the data type of the pointer passed to the intrinsic

function. For example, the following C code generates the required LDREXB operation:

__ldrex((volatile char *) 0xFF);

13.4.3 Exception Model

This section describes the exception model.

13.4.3.1 Exception States

Each exception is in one of the following states:

Inactive

The exception is not active and not pending.

Pending

The exception is waiting to be serviced by the processor.

An interrupt request from a peripheral or from software can change the state of the corresponding interrupt to

pending.

Active

An exception is being serviced by the processor but has not completed.

An exception handler can interrupt the execution of another exception handler. In this case, both exceptions are in

the active state.

Active and Pending

The exception is being serviced by the processor and there is a pending exception from the same source.

13.4.3.2 Exception Types

The exception types are:

Reset

Reset is invoked on power up or a warm reset. The exception mode l treats reset as a special form of exce ption.

When reset is asserted, the operation of the processor stops, potentially at any point in an instruction. When reset

is deasserted, execution restarts from the address provided by the reset entry in the vec tor table. Execution

restarts as privileged execution in Thread mode.

Table 13-8. CMSIS Functions for Exclusive Access Instructions

Instruction CMSIS Function

LDREX uint32_t __LDREXW (uint32_t *addr)

LDREXH uint16_t __LDREXH (uint16_t *addr)

LDREXB uint8_t __LDREXB (uint8_t *addr)

STREX u int32_t __STREXW (uint32_t value, uint32_t *addr)

STREXH uint32_t __STREXH (uint1 6_t value, uin t16 _t *addr)

STREXB uint32_t __STREXB (uint8_t value, uint8_t *addr)

CLREX v oid __CLREX (void)

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Non Maskable Interrupt (NMI)

A non maskable interrupt (NMI) can be signalled by a peripheral or triggered by software. This is the highest

priority exception other than reset. It is permanently ena bled and has a fixed priority of -2.

NMIs cannot be:

Masked or prevented from activation by any other exception.

Preempted by an y exception other th an Reset.

Hard Fault

A hard fault is an exception that occurs because of an error during exception processing, or because an exception

cannot be managed by any othe r except ion me chanism . Hard Faults have a fixed priority of -1 , meani ng they have

higher priority than any exception with configurable priority.

Memory Management Fault (MemManage)

A Memory Ma nagem ent Fau lt is an ex cept ion that o ccurs becaus e of a m emo ry pr otec tion re late d fau lt. The MPU

or the fixed memory protection constraints determ ines this fault, fo r both instru ction and data m emory transactions.

This fault is used to a bort instruction accesses to Execute Never (XN) memory regions, even if the MPU is

disabled.

Bus Fault

A Bus Fault is an exception that occurs because of a memory related fault for an instruction or data memory

transaction. This might be from an error detected on a bus in the memory system.

Usage Fault

A Usage Fault is an exception that occurs because of a fault related to an instruction execution. This includes:

An undefined instruction

An illegal unaligned access

An invalid state on instruction exec ut ion

An error on exception return.

The following can cause a Usage Fault when the core is configured to report them:

An unaligned address on word and halfword memory access

A division by zero.

SVCall

A superviso r call (SVC) is a n exception that is triggered by the SVC instru ction. In an OS environment, applications

can use SVC instructions to access OS kernel functions and device drivers.

PendSV

PendSV is an interrupt-driven request for system-level service. In an OS environment, use PendSV for context

switching when no other exception is active.

SysTick

A SysTick exception is an exception the system timer generates when it reaches zero. Software ca n also gener ate

a SysTick exception. In an OS environment, the processor can use this exception as system tick.

Interrupt (IRQ)

A interrupt, or IRQ, is an exception signalled by a peripheral, or generated by a software request. All interrupts are

asynchronous to instruction execution. In the system, peripherals use interrupts to communicate with the

processor.

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Notes: 1. To simplify the software layer, the CMSIS only uses IRQ numbers and therefore uses neg ativ e values for exceptions other

than interrupts. The IPSR returns the Exception number, see “Interrupt Program Status Register”.

2. See “Vector Table” for more information

3. See “System Handler Priority Registers”

4. See “Interrupt Priority Registers”

5. Increasing in steps of 4.

For an asynchronous excep tion, other than re set, the processor can execute another instruction between wh en the

exception is triggered and when the processor enters the exception handler.

Privileged software can disable the exceptions that Table 13-9 shows as having co nfigurable priority, see:

“System Handler Control and State Register”

“Interrupt Clear-enable Registers”.

For more information about hard faults, memory ma nagement faults, bus faults, and usage faults, see “Fault

Handling”.

13.4.3.3 Exception Handlers

The processor handles exceptions using:

Interrupt Service Routines (ISRs)

Interrupts IRQ0 to IRQ49 are the exceptions handled by ISRs.

Fault Handlers

Hard fault, memory management fault, usage fault, bus fault are fault exceptions handled by the fault

handlers.

System Handlers

NMI, PendSV, SVCall SysTick, and the fault exceptions are all system exceptions that are handled by

system handlers.

Table 13-9. P roperties of the Different Excep tion Types

Exception

Number(1) Irq Number(1) Exception Type Priority Vector Address

or Offset(2) Activation

1 – Reset -3, the highest 0x00000004 Asynchronous

2 -14 NMI -2 0x00000008 Asynchronous

3 -13 Hard fault -1 0x0000000C –

4 -12 Memory

management fault Configurable(3) 0x00000010 Synchronous

5 -11 Bus fault Configurable(3) 0x00000014 Synchronous when precise,

asynchronous when imprecise

6 -10 Usage fault Co nfigurable(3) 0x00000018 Synchronous

7–10 – – – Reserved –

11 -5 SVCall Configurable(3) 0x0000002C Synchronous

12–13 – – – Reserved –

14 -2 PendSV Configurable(3) 0x00000038 Asynchronous

15 -1 SysTick Configurable(3) 0x0000003C Asynchronous

16 and above 0 and above Interrupt (IRQ) Configurable(4) 0x00000040 and above(5) Asynchronous

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13.4.3.4 Vector Table

The vector table contains the reset value of the stack pointer, and the start addresses, also called exception

vectors, for all exception handlers. Figure 13-6 shows the order of the exception vectors in the vector table. The

least-significant bit of each vector must be 1, indicating that the exception handler is Thumb code.

Figure 13-6. Vector Table

On system reset, the vector tab le is fixed at ad dre ss 0x00000 000. Privilege d software can write to the SCB_ VTOR

to relocate the vector table sta rt address to a different memory location, in the range 0x00000080 to 0x3FFFFF80,

see “Vector Table Offset Register”.

13.4.3.5 Exception Priorities

As Table 13-9 shows, all exceptions have an associated priority, with:

A lower priority value indicating a higher priority

Configurable priorities for all except ions except Reset, Hard fault and NMI.

If the software does not configure any priorities, then all exceptions with a configurable priority have a priority of 0.

For information about configuring exception priorities see “System Handler Priority Registers”, and “Interrupt

Priority Registers”.

Note: Configurable priority values are in the range 0–15. This means that the Reset, Hard fault, and NMI exceptions, with

fixed negative priority values, always have higher priority than any other exception.

For example, assigning a hig her prior ity value to IRQ[0] and a lower priority value to IRQ[1] means that IRQ[1] has

higher priority than IRQ[0]. If both IRQ[1] and IRQ[0] are asserted, IRQ[1] is processed before IRQ[0].

Initial SP value

Reset

Hard fault

NMI

Memory management fault

Usage fault

Bus fault

0x0000

0x0004

0x0008

0x000C

0x0010

0x0014

0x0018

Reserved

SVCall

PendSV

Reserved for Debug

SysTick

IRQ0

Reserved

0x002C

0x0038

0x003C

0x0040

OffsetException number

Vector

IRQ1

IRQ2

0x0044

IRQ239

17 0x0048

0x004C

255

0x03FC

IRQ number

-14

-13

-12

-11

-10

-5

-2

-1

239

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If multiple pending exceptio ns have the same priority, the pending excep tion with the lowest exception number

takes preced ence. For examp le, if both IRQ[0] and IRQ [1] are pending and have the same priority, then IRQ[0] is

processed before IRQ[1].

When the processor is executing an ex ception handler, the exception handler is preempted if a higher priority

exception occurs. If an exception occurs with the same priority as the exception being handled, the handler is not

preempted, irrespective of the exception number. However, the status of the new interrupt changes to pending.

13.4.3.6 Interrupt Priority Grouping

To increase priority control in systems with interrupts, the NVIC supports priority grouping. This divides each

interrupt priority register entry into two fields:

An upper field that defines the group priority

A lower field that defines a subpriority within the group.

Only the group priority determines preemption of interrupt exceptions. When the processor is executing an

interrupt ex ception ha ndler, an other int errupt with t he same gr oup priori ty as the inte rrupt be ing handled does no t

preempt the handler.

If multiple pending interrupts have the same group priority, the subpriority field determines the order in which they

are processed. If multiple pending interrupts have the same group priority and subpriority, the interrupt with the

lowest IRQ number is processed first.

For information about splitting the interrupt priority fields into group priority and subpriority, see “Application

Interrupt and Reset Control Register”.

13.4.3.7 Exception Entry and Return

Descriptions of exception handling use the following terms:

Preemption

When the processor is executing an exception handler, an exception can preempt the exception handler if its

priority is higher than the priority of the exception being handled. See “Interrupt Priority Grouping” for more

information about preemption by an interrupt.

When one exception preempts another, the exceptions are called nested exceptions. See “Exception Entry” more

information.

Return

This occurs when the exception handler is completed, and:

There is no pending exception with sufficient priority to be serviced

The completed exception handler was not handling a late-arriving exception.

The processor pops the stack and restores the processor state to the state it had before the interrupt occurred.

See “Exception Return” for more information.

Tail-chaining

This mechanism speeds up exception servicing. On completion of an exception handler, if there is a pending

exception that meets the requirements for exception entry, the stack pop is skipped and control transfers to the

new exception handler.

Late-arriving

This mechanism speeds up preemption. If a higher priority exception o ccurs during stat e saving for a previo us

exception, the processor switches to handle the higher pr iority exception and initiates the vector fetch for that

exception. State saving is not affe cted by late arrival because the state save d is the same for both exceptions.

Therefore the state saving continues uninterrupted. The processor can accept a late arriving exception until the

first instruction of the exception handler of the original exception enters the execute stage o f the processor. On

return from the exception handler of the late-arriving exception, the normal tail-chaining rules apply.

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Exception Entry

An Exception entry occurs when there is a pending exception with sufficient priority and either the processor is in

Thread mode, or the new exception is of a higher priority than the exception being handled, in which case the new

exception preempts the original exception.

When one exception preempts another, the exceptions are nested.

Sufficient priority means that the exception has more priority than any limits set by the mask registers, see

“Exception Mask Registers”. An exception with less priority than this is pending but is not handled by the

processor.

When the processor takes a n exception, un less the except ion is a tail-chained or a late-arriving exception, the

processor pushes information onto the current stack. This operation is referred as stacking and the structure of

eight data words is referred to as stack frame.

When using floating-p oint routines, the Cortex-M4 processor automatically stacks the architected floating-point

state on exception entry. Figure 13-7 shows the Cortex-M4 stack frame layout when floating-point state is

preserved on the stack as the result of an interrupt or an exception.

Note: Where stack space for floating-point state is not allocated, the stack frame is the same as that of ARMv7-M

implementations without an FPU. Figure 13-7 shows this stack frame also.

Figure 13-7. Exception Stack Frame

Immediately after stacking, the stack pointer indicates the lowest address in the stack frame. The alignment of the

stack frame is controlled via the STKALIGN bit of the Configurati on Control Register (CCR).

Pre-IRQ top of stack

xPSR

R12

{aligner}

IRQ top of stack

Decreasing

memory

address

xPSR

R12

FPSCR

S15

S14

S13

S12

S11

S10

{aligner}

IRQ top of stack

...

Exception frame with

floating-point storage

Exception frame without

floating-point storage

Pre-IRQ top of stack

...

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The stack frame includes the return address. This is the address of the next instruction in the interrupted program.

This value is restored to the PC at exception return so that the interrupted program resumes.

In parallel to the stacking operation, the processor performs a vector fetch that reads the exception handler sta rt

address from the vector table. When stacking is comple te, th e processor star ts executing the exce ption handler. At

the same time, the processor writes an EXC_RETURN value to the LR. This indicates which stack pointer

corresponds to the stack frame and what operation mode the processor was in before the entry occurred.

If no higher priority exception occurs during the exception entry, the pr ocessor starts executing the excep tion

handler and automatically changes the status of the corresponding pending interrupt to active.

If another higher priority exception occurs during the exception entry, the processor starts executing the exception

handler for this exception and does not change the pending status of the earlier exception. This is the late arrival

case.

Exception Return

An Exception return occurs when the processor is in Handler mode and executes one of the following instructions

to load the EXC_RETURN value into the PC:

An LDM or POP instruction that loads the PC

An LDR instruction with the PC as the destination.

A BX instruction using any register.

EXC_RETURN is the value loaded into the LR on exception entry. The exception mechanism relies on this value

to detect when the processor has completed an exception handler. The lowest five bits of this value provide

information on the return stack and processor mode. Table 13-10 shows the EXC_RETURN values with a

description of the exception return behavior.

All EXC_RETURN values have bits[31:5] set to one. When this value is loaded into the PC, it indicates to the

processor that the exception is complete, and the processor initiates the appropriate exception return sequence.

13.4.3.8 Fault Handling

Faults are a subset of the exceptions, see “Exception Model”. The following generate a fault:

A bus error on:

An instruction fetch or vector table load

A data access

An internally-detected error such as an undefined instruction

An attempt to execute an instruction from a memory region marked as Non-Executable (XN).

A privilege violation or an attempt to access an unmanaged region causing an MPU fa ult.

Table 13-10. Exception Return Behavior

EXC_RETURN[31:0] Description

0xFFFFFFF1 Return to Handler mode, exception return uses non-floating-point state from the MSP and

execution uses MSP after return.

0xFFFFFFF9 Return to Thread mode, exception return uses state from MSP and execution uses MSP after

return.

0xFFFFFFFD Return to Thread mode, exception return uses state from the PSP and execution uses PSP after

return.

0xFFFFFFE1 Return to Handler mode, exception return uses floating-point-state from MSP and execution uses

MSP after return.

0xFFFFFFE9 Return to Thread mode, exception return uses floating-point state from MSP and execution uses

MSP after return.

0xFFFFFFED Return to Thread mode, exception return uses floating-point state from PSP and execution uses

PSP after return.

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Fault Types

Table 13-11 shows th e types of fault, the h andler used for the f ault, the corr esponding fau lt status registe r, and th e

register bit that indicates that the fault has occurred. See “Configur able Fa ult Statu s Register” for mo re information

about the fault status registers.

Notes: 1. Occurs on an access to an XN region even if the processor does not include an MPU or the MPU is disabled.

2. Attempt to use an instruction set other than the Thumb instruction set, or return to a non load/store-multiple instruction with

ICI continuation.

3. Only present in a Cortex-M4F device

Table 13-11. Faults

Fault Handler Bit Name Fault Status Register

Bus error on a vector read Hard fault VECTTBL “Hard Fault Status Register”

Fault escalated to a hard fault FORCED

MPU or default memory map mismatch:

Memory

management

fault

––

on instruction access IACCVIOL(1)

“MMFSR: Memory Management Fault Status

Subregister”

on data access DACCVIOL(2)

during exception stacking MSTKERR

during exception unstacking MUNSTKERR

during lazy floating-point state preservation MLSPERR(3)

Bus error:

Bus fault

––

during exception stacking STKERR

“BFSR: Bus Fault Status Subregister”

during exception unstacking UNSTKERR

during instruction prefetch IBUSERR

during lazy floating-point state preservation LSPERR(3)

Precise data bus error PRE C ISERR

Imprecise data bus error IMPRECISERR

Attempt to access a coprocessor

Usage fault

NOCP

“UFSR: Usage Fault Status Subregister”

Undefined instruction UNDEFINSTR

Attempt to enter an invalid instruction set state INVSTATE

Invalid EXC_RETURN value INVPC

Illegal unaligned load or store UNALIGNED

Divide By 0 DIVBYZERO

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Fault Escalation an d Ha rd Faults

All faults exceptions except for hard fault have configurable exception priority, see “System Handler Priority

Registers”. The software can disable the execution of the handlers for these faults, see “System Handler Control

and State Register”.

Usually, the exception prio rity, together with the values of the exception mask registers, determ ines whether the

processor enters the fault handler, and whether a fault handler can preempt another fault handler, as described in

“Exception Model”.

In some situations, a fault with configurable priority is treated as a hard fault. This is called priority escalation, and

the fault is described as escalated to hard fault. Escalation to hard fault occurs when:

A fault handler causes the same kind of fault as the one it is servicing. This escalation to hard fault occurs

because a fault handler cannot preempt itself; it must have the same priority as the current priority level.

A fault handler caus es a fa ult with the sam e or lower pr ior ity as the fault it is servicing. This is because the

handler for the new fault cannot preempt the currently executing fault handler.

An exception handler causes a fault for which the priority is the same as or lower than the currently

executing exception.

A fault occurs and the handler for that fault is not enabled.

If a bus fault occurs during a stack push when entering a bus fault handler, the bus fault does not escalate to a

hard fault. This means that if a corrupted stack causes a fault, the fault handler executes even though the stack

push for the handler failed. The fault handler operates but the stack contents are corrupted.

Note: Only Reset and NMI can preempt the fixed priority hard fault. A hard fault can preempt an y exce p ti o n other than

Reset, NMI, or another hard fault.

Fault Status Registers and Fault Address Registers

The fault status registers indicate the cause of a fault. For bus faults and memory managem ent faults, the fault

address register indicates the address accessed by the operation that caused the fault, as shown in Table 13-12.

Lockup

The processor enters a lockup state if a hard fault occurs when executing the NMI or hard fault handlers. When the

processor is in lockup state, it does not execute any instructions. The processor remains in lockup state until

either:

It is reset

An NMI occurs

It is halted by a debugger.

Note: If the lockup state occurs from the NMI handler, a subsequent NMI does not cause the processor to leave the lockup

state.

Table 13-12. Fault Status and Faul t Address Registers

Handler Status Register

Name Address Register

Name Register Description

Hard fault SCB_HFSR – “Hard Fault Status Register”

Memory

management fault MMFSR SCB_MMFAR “MMFSR: Memory Management Fault Status Subregister”

“MemManage Fault Address Register”

Bus fault BFSR SCB_BFAR “BFSR: Bus Fault Status Subregister”

“Bus Fault Address Register”

Usage fault UFSR – “UFSR: Usage Fault Status Subregister”

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

13.5 Power Management

The Cortex-M4 processor sleep modes reduce the power consumption:

Sleep mode stops the processor clock

Deep sleep mode stops the system clock and switches off the PLL and flash memory.

The SLEEPDEEP bit of the SCR selects which sleep mode is used; see “System Control Register”.

This section describes the mechanisms for entering sleep mode, and the conditions for waking up from sleep

mode.

13.5.1 Entering Sleep Mode

This section describes the mechanisms software can use to put the processor into sleep mode.

The system can generate spurious wakeup events, for example a debug operation wakes up the processor.

Therefore, the software must be able to put the processor back into sleep mode after such an event. A program

might have an idle loop to put the processor back to sleep mode.

13.5.1.1 Wait for Interrupt

The wait for interrupt instruction , WFI, causes immediate entry to sleep mo de. When the processor executes a

WFI instruction it stops executing instructions and enters sleep mode. See “WFI” for more information.

13.5.1.2 Wait for Event

The wait for event instruction, WFE, causes entry to sleep mode conditional on the value of an one-bit event

If the register is 0, the processor stops executing instructions and enters sleep mode

If the register is 1, the processor clears the reg ister to 0 and continues executing instructions without

entering sleep mode.

See “WFE” for more information.

13.5.1.3 Sleep-on-exit

If the SLEEPONEXIT bit of the SCR is set to 1 when the processor completes the execution of an e xception

handler, it retu rns to Thread mode and im mediately enters sleep mo de. Use this mechanism in app lications that

only require the processor to run when an exception occurs.

13.5.2 Wakeup from Sleep Mode

The conditions for the processor to wake up depend on the mechanism th at cause it to enter sleep mode.

13.5.2.1 Wakeup from WFI or Sleep-on-exit

Normally, the processor wakes up only when it detects an exception with sufficient priority to cause exception

entry.

Some embedded systems might have to execute system restore tasks after the processor wakes up, and before it

executes an interrupt handler. To achieve this, set the PRIMASK bit to 1 and the FAULTMASK bit to 0. If an

interrupt arrives that is enabled and has a higher priority than the current exception priority, the processor wakes

up but does not execute the interrupt handler until the processor sets PRIMASK to zero. For more information

about PRIMASK and FAULTMASK, see “Exception Mask Registers”.

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13.5.2.2 Wakeup from WFE

The process or wake s up if:

It detects an exception with sufficient priority to cause an exception entry

It detects an external event signal. See “External Event Input”

In a multiprocessor system, another processor in the system executes an SEV instruction.

In addition, if the SEVONPEND bit in the SCR is set to 1, any new pending interrupt triggers an event and wakes

up the processor, even if the interrupt is disabled or has insufficient priority to cause an exception entry. For more

information about the SCR, see “System Control Register” .

13.5.2.3 External Event Input

The processor provides an external event input signal. Peripherals can drive this signal, either to wake the

processor fro m WFE, or to set the internal WFE ev ent register to 1 to in dicate that the processo r must not enter

sleep mode on a later WFE instruction. See “Wait for Event” for more information.

13.5.3 Power Management Programming Hints

ISO/IEC C cannot directly gene rate the WF I and WF E inst r uctions. The CMSIS provides the following functions for

these instructions:

void __WFE(void) // Wait for Event

void __WFI(void) // Wait for Interrupt

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13.6 Cortex-M4 Instruction Set

13.6.1 Instruction Set Summary

The processor implements a version of the Thumb instruction set. Table 13-13 lists the supported instructions.

Angle brackets, <>, enclose alternative forms of the operand

Braces, {}, enclose optional operands

The Operands column is not exhaustive

Op2 is a flexible second operand that can be either a register or a constant

Most instructions can use an optional condition code suffix.

For more information on the instructions and operands, see the instruction descriptions.

Table 13-13. Cortex-M4 Instructio ns

Mnemonic Operands Description Flags

ADC, ADCS {Rd,} Rn, Op2 Add with Carry N,Z,C,V

ADD, ADDS {Rd,} Rn, Op2 Add N,Z,C,V

ADD, ADDW {Rd,} Rn, #imm12 Add N,Z,C,V

ADR Rd, label Load PC-relative address –

AND, ANDS {Rd,} Rn, Op2 Logical AND N,Z,C

ASR, ASRS Rd, Rm, <Rs|#n> Arithmetic Shift Right N,Z,C

B label Branch –

BFC Rd, #lsb, #width Bit Field Clear –

BFI Rd, Rn, #lsb, #width Bit Field Insert –

BIC, BICS {Rd ,} Rn, Op 2 B it Clear N,Z,C

BKPT #imm Breakpoint –

BL label Branch with Link –

BLX Rm Branch indirect with Link –

BX Rm Branch indirect –

CBNZ Rn, label Compare and Branch if Non Zero –

CBZ Rn, label Compare and Branch if Zero –

CLREX – Clear Exclusive –

CLZ Rd, Rm Count lea ding zeros –

CMN Rn, Op2 Compare Negative N,Z,C,V

CMP Rn, Op2 Compare N,Z,C,V

CPSID i Change Processor State, Disable Interrupts –

CPSIE i Change Processor St ate, Enable Interrupt s –

DMB – Data Memory Barrier –

DSB – Data Synchronization Barrier –

EOR, EORS {Rd,} Rn, Op2 Exclusive OR N,Z,C

ISB – Instruction Synchronization Barrier –

IT – If-Then condition block –

LDM Rn{!}, reglist Load Multiple registers, increment after –

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LDMDB, LDMEA Rn{!}, reglist Load Multiple registers, decrement before –

LDMFD, LDMI A Rn{!}, reglist Load Multiple registers, increment after –

LDR Rt, [Rn, #offset] Load Register with word –

LDRB, LDRBT Rt, [Rn, #offset] Load Register with byte –

LDRD Rt, Rt2, [Rn, #offset] Load Register with two bytes –

LDREX Rt, [Rn, #offset] Load Register Exclusive –

LDREXB Rt, [Rn] Load Register Exclusive with byte –

LDREXH Rt, [Rn] Load Register Exclusive with halfword –

LDRH, LDRHT Rt, [Rn, #offset] Load Register with halfword –

LDRSB, DRSBT Rt, [Rn, #offset] Load Register with signed byte –

LDRSH, LDRSHT Rt, [Rn, #offset] Load Register with signed halfword –

LDRT Rt, [Rn, #offset] Load Register with word –

LSL, LSLS Rd, Rm, <Rs|#n> Logical Sh ift Left N,Z,C

LSR, LSRS Rd, Rm, <Rs|#n> Logical Shift Right N,Z,C

MLA Rd, Rn, Rm, Ra Multiply with Accumulate, 32-bit result –

MLS Rd, Rn, Rm, Ra Multiply and Subtract, 32-bit result –

MOV, MOVS Rd, Op2 Move N,Z,C

MOVT Rd, #imm16 Move Top –

MOVW, MOV Rd, #imm16 Move 16-bit constant N,Z,C

MRS Rd, spec_reg Move from special register to general register –

MSR spec_reg, Rm Move from general register to special register N,Z,C,V

MUL, MULS {Rd,} Rn, Rm Multiply, 32-bit result N,Z

MVN, MVNS Rd, Op2 Move NOT N,Z,C

NOP – No Operatio n –

ORN, ORNS {Rd,} Rn, Op2 Logical OR NOT N,Z,C

ORR, ORRS {Rd,} Rn, Op2 Logical OR N,Z,C

PKHTB, PKHBT {Rd,} Rn, Rm, Op2 Pack Halfword –

POP reglist Pop registers from stack –

PUSH reglist Pus h registers onto stack –

QADD {Rd,} Rn, Rm Saturating double and Add Q

QADD16 {Rd,} Rn, Rm Saturating Add 16 –

QADD8 {Rd,} Rn, Rm Saturating Add 8 –

QASX {Rd,} Rn, Rm Saturating Add and Subtract with Exchange –

QDADD {Rd,} Rn, Rm Saturating Add Q

QDSUB {Rd,} Rn, Rm Saturating double and Subtract Q

QSAX {Rd,} Rn, Rm Saturating Subtract and Add with Exchang e –

QSUB {Rd,} Rn, Rm Saturating Subtract Q

Table 13-13. Cortex-M4 Instructions (Continu ed )

Mnemonic Operands Description Flags

SAM G55 [DATASHEET]

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QSUB16 {Rd,} Rn, Rm Saturating Subtract 16 –

QSUB8 {Rd,} Rn, Rm Saturating Subtract 8 –

RBIT Rd, Rn Reverse Bits –

REV Rd, Rn Reverse byte order in a word –

REV16 Rd, Rn Reverse byte order in each halfword –

REVSH Rd, Rn Reverse byte order in bottom halfword and sign extend –

ROR, RORS Rd, Rm, <Rs|#n> Rotate Right N,Z,C

RRX, RRXS Rd, Rm Rotate Right with Extend N,Z,C

RSB, RSBS {Rd,} Rn, Op2 Reverse Subtract N,Z,C,V

SADD16 {Rd,} Rn, Rm Signed Add 16 GE

SADD8 {Rd,} Rn, Rm Signed Add 8 and Subtract with Exchange GE

SASX {Rd,} Rn, Rm Signed Add GE

SBC, SBCS {Rd,} Rn, Op 2 S ubtract with Carry N,Z,C,V

SBFX Rd, Rn, #lsb, #width Signed Bit Field Extract –

SDIV {Rd,} Rn, Rm Signed Divide –

SEL {Rd,} Rn, Rm Select bytes –

SEV – S end Event –

SHADD16 {Rd,} Rn, Rm Signed Halving Add 16 –

SHADD8 {Rd,} Rn, Rm Signed Halving Add 8 –

SHASX {Rd,} Rn, Rm Signed Halving Add and Subtract with Exchange –

SHSAX {Rd,} Rn, Rm Signed Halving Subtract and Add with Exchange –

SHSUB16 {Rd,} Rn, Rm Signed Halving Subtract 16 –

SHSUB8 {Rd,} Rn, Rm Signed Halving Subtract 8 –

SMLABB, SMLABT,

SMLATB, SMLATT Rd, Rn, Rm, Ra Signed Multiply Accumulate Long (halfwords) Q

SMLAD, SMLADX Rd, Rn, Rm, Ra Signed Multiply Accumulate Dual Q

SMLAL RdLo, RdHi, Rn, Rm Signed Multiply with Accumulate (32 × 32 + 64), 64-bit result –

SMLALBB, SMLALBT,

SMLALTB, SMLALT T RdLo, RdHi, Rn, Rm Signed Multiply Accumulate Long, halfwords –

SMLALD, SMLALDX RdLo, RdHi, Rn, Rm Signed Multiply Accumulate Long Dual –

SMLAWB, SMLAWT Rd, Rn, Rm, Ra Signed Multiply Accumulate, word by halfword Q

SMLSD Rd, Rn, Rm, Ra Signed Multiply Subtract Dual Q

SMLSLD RdLo, RdHi, Rn, Rm Signed Multiply Subtract Long Dual

SMMLA Rd, Rn, Rm, Ra Signed Most significant word Multiply Accumulate –

SMMLS, SMMLR Rd, Rn, Rm, Ra Signed Most significant word Multiply Subtract –

SMMUL, SMMULR {Rd,} Rn, Rm Signed Most significant word Multiply –

SMUAD {Rd,} Rn, Rm Signed dual Multiply Add Q

Table 13-13. Cortex-M4 Instructions (Continu ed )

Mnemonic Operands Description Flags

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SMULBB, SMULBT

SMULTB, SMULTT {Rd,} Rn, Rm Signed Multiply (halfwords) –

SMULL RdLo, RdHi, Rn, Rm Signed Multiply (32 × 32), 64-bit result –

SMULWB, SMULWT {Rd,} Rn, Rm Signed Multiply word by halfword –

SMUSD, SMUSDX {Rd,} Rn, Rm Signed dual Multiply Subtract –

SSAT Rd, #n, Rm {,shift #s} Signed Saturate Q

SSAT16 Rd, #n, Rm Signed Saturate 16 Q

SSAX {Rd,} Rn, Rm Signed Subtract and Add with Exchange GE

SSUB16 {Rd,} Rn, Rm Signed Subtract 16 –

SSUB8 {Rd,} Rn, Rm Signed Subtract 8 –

STM Rn{!}, reglist Store Multiple registers, increment after –

STMDB, STMEA Rn{!}, reglist Store Multiple registers, decrement before –

STMFD, STMIA Rn{!}, reglist Store Multiple registers, increment after –

STR Rt, [Rn, #offset] Store Register word –

STRB, STRBT Rt, [Rn, #offset] Store Register byte –

STRD Rt, Rt2, [Rn, #offset] Store Register two words –

STREX Rd, Rt, [Rn, #offset] Store Register Exclusive –

STREXB Rd, Rt, [Rn] Store Register Exclusive byte –

STREXH Rd, Rt, [Rn] Store Register Exclusive halfword –

STRH, STRHT Rt, [Rn, #offset] Store Register halfword –

STRT Rt, [Rn, #offset] Store Register word –

SUB, SUBS {Rd,} Rn, Op2 Subtract N,Z,C,V

SUB, SUBW {Rd,} Rn, #imm12 Subtract N,Z,C,V

SVC #imm Supervisor Call –

SXTAB {Rd,} Rn, Rm,{,ROR #} Extend 8 bits to 32 and add –

SXTAB16 {Rd,} Rn, Rm,{,ROR #} Dual extend 8 bits to 16 and add –

SXTAH {Rd,} Rn, Rm,{,ROR #} Extend 16 bits to 32 and add –

SXTB16 {Rd,} Rm {,ROR #n} Signed Extend Byte 16 –

SXTB {Rd,} Rm {,ROR #n} Sign extend a byte –

SXTH {Rd,} Rm {,ROR #n} Sign extend a halfword –

TBB [Rn, Rm] Table Branch Byte –

TBH [Rn, Rm, LSL #1] Table Branch Halfword –

TEQ Rn, Op2 Test Equivalence N,Z,C

TST Rn, Op2 Test N,Z,C

UADD16 {Rd,} Rn, Rm Unsign ed Add 16 GE

UADD8 {Rd,} Rn, Rm Unsigned Add 8 GE

USAX {Rd,} Rn, Rm Unsigned Subtract and Add with Exchange GE

Table 13-13. Cortex-M4 Instructions (Continu ed )

Mnemonic Operands Description Flags

SAM G55 [DATASHEET]

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UHADD16 {Rd,} Rn, Rm Unsigned Halving Add 16 –

UHADD8 {Rd,} Rn, Rm Unsign ed Halving Add 8 –

UHASX {Rd,} Rn, Rm Unsigned Halving Add and Subtract with Exchange –

UHSAX {Rd,} Rn, Rm Unsigned Halving Subtract and Add with Exchange –

UHSUB16 {Rd,} Rn, Rm Unsigned Halving Subtract 16 –

UHSUB8 {Rd,} Rn, Rm Unsigned Halving Subtract 8 –

UBFX Rd, Rn, #lsb, #width Unsigned Bit Field Extract –

UDIV {Rd,} Rn, Rm Unsigned Divide –

UMAAL RdLo, RdHi, Rn, Rm Unsigned Multiply Accumulate Accumulate Long (32 × 32 + 32 + 32),

64-bit result –

UMLAL RdLo, RdHi, Rn, Rm Unsigned Multipl y with Accumulate (32 × 32 + 64), 64-bit result –

UMULL RdLo, RdHi, Rn, Rm Unsigned Multiply (32 × 32), 64-bit result –

UQADD16 {Rd,} Rn, Rm Unsigned Saturating Add 16 –

UQADD8 {Rd,} Rn, Rm Unsigned Saturating Add 8 –

UQASX {Rd,} Rn, Rm Unsigned Saturating Add and Subtract with Exchange –

UQSAX {Rd,} Rn, Rm Unsigned Saturating Subtract and Add with Exchange –

UQSUB16 {Rd,} Rn, Rm Unsigned Saturating Subtract 16 –

UQSUB8 {Rd,} Rn, Rm Unsigned Saturating Subtract 8 –

USAD8 {Rd,} Rn, Rm Unsigned Sum of Absolute Differences –

USADA8 {Rd,} Rn, Rm, Ra Unsigned Sum of Absolute Differences and Accumulate –

USAT Rd, #n, Rm {,shift #s} Unsigned Saturate Q

USAT16 Rd, #n, Rm Unsigned Saturate 16 Q

UASX {Rd,} Rn, Rm Unsigned Add and Subtract with Exchange GE

USUB16 {Rd,} Rn, Rm Unsigned Subtract 16 GE

USUB8 {Rd,} Rn, Rm Unsigned Subtract 8 GE

UXTAB {Rd,} Rn, Rm,{,ROR #} Rotate, extend 8 bits to 32 and Add –

UXTAB16 {Rd,} Rn, Rm,{,ROR #} Rotate, dual extend 8 bits to 16 and Add –

UXTAH {Rd,} Rn, Rm,{,ROR #} Rotate, unsigned extend and Add Halfword –

UXTB {Rd,} Rm {,ROR #n} Zero extend a byte –

UXTB16 {Rd,} Rm {,ROR #n} Unsigned Extend Byte 16 –

UXTH {Rd,} Rm {,ROR #n} Zero extend a halfword –

VABS.F32 Sd, Sm Floating-point Absolute –

VADD.F32 {Sd,} Sn, Sm Floating-point Add –

VCMP.F32 Sd, <Sm | #0.0> Compare two floating-point registers, or one floating-point register

and zero FPSCR

VCMPE.F32 Sd, <Sm | #0.0> Compare two floating-point registers, or one floating-point register

and zero with Invalid Operation check FPSCR

VCVT.S32.F32 Sd, Sm Convert between floating-point and integer –

Table 13-13. Cortex-M4 Instructions (Continu ed )

Mnemonic Operands Description Flags

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

VCVT.S16.F32 Sd, Sd, #fbits Convert between floating-point and fixed point –

VCVTR.S32.F32 Sd, Sm Convert between floating-point and integer with rounding –

VCVT<B|H>.F32.F16 Sd, Sm Converts half-precision value to single-precisi on –

VCVTT<B|T>.F32.F16 Sd, Sm Converts single-precision register to half-precision –

VDIV.F32 {Sd,} Sn, Sm Floating-point Divide –

VFMA.F32 {Sd,} Sn, Sm Floating-point Fused Multiply Accumulate –

VFNMA.F32 {Sd,} Sn, Sm Floating-point Fused Negate Multiply Accumulate –

VFMS.F32 {Sd,} Sn, Sm Floating-point Fused Multiply Subtract –

VFNMS.F32 {Sd,} Sn, Sm Floating-point Fused Negate Multiply Subtract –

VLDM.F<32|64> Rn{!}, list Load Multiple extension registers –

VLDR.F<32|64> <Dd|Sd>, [Rn] Load an extension register from memory –

VLMA.F32 {Sd,} Sn, Sm Floating-point Multiply Accumulate –

VLMS.F32 {Sd,} Sn, Sm Floating-point Multiply Subtract –

VMOV.F32 Sd, #imm Floating-point Move immediate –

VMOV Sd, Sm Floating-point Move register –

VMOV Sn, Rt C opy ARM core register to single precision –

VMOV Sm, Sm1, Rt, Rt2 Copy 2 ARM core reg isters to 2 single precision –

VMOV Dd[x], Rt Copy ARM core register to scalar –

VMOV Rt, Dn[x] Copy scalar to ARM core register –

VMRS Rt, FPSCR Move FPSCR to ARM core register or APSR N,Z,C,V

VMSR FPSCR, Rt Move to FPSCR from ARM Core register FPSCR

VMUL.F32 {Sd,} Sn, Sm Floating-point Multiply –

VNEG.F32 Sd, Sm Floating-point Negate –

VNMLA.F32 Sd, Sn, Sm Floating-point Multiply and Add –

VNMLS.F32 Sd, Sn, Sm Floating-point Multiply and Subtract –

VNMUL {Sd,} Sn, Sm Floating-point Multiply –

VPOP list Pop extension registers –

VPUSH list Push extension registers –

VSQRT.F32 Sd, Sm Calculates floating-point Square Root –

VSTM Rn{!}, list Floating-point register Store Multiple –

VSTR.F<32|64> Sd, [Rn] Stores an extension register to memory –

VSUB.F<32|64> {Sd,} Sn, Sm Floating-point Subtract –

WFE – Wait For Event –

WFI – Wa it For Interrupt –

Table 13-13. Cortex-M4 Instructions (Continu ed )

Mnemonic Operands Description Flags

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13.6.2 CMSIS Functions

ISO/IEC cannot directly access some Cortex-M4 instructions. This section describes intrinsic functions that can

generate these instructions, provided by the CMIS and that might be provided by a C compiler. If a C compiler

does not support an appropriate intrinsic function , the user might have to use inline assembler to access some

instructions.

The CMSIS provides the following intrinsic functions to generate instructions that ISO/IEC C code cannot directly

access:

The CMSIS also provides a number of functions for accessing the special registers using MRS and MSR

instructions:

Table 13-14. CMSIS Functions to Generate some Cortex-M4 Instructio ns

Instruction CMSIS Function

CPSIE I void __enable_irq(void)

CPSID I void __disable_irq(void)

CPSIE F void __enable_fault_irq(void)

CPSID F void __disable_fault_irq(void)

ISB void __ISB(void)

DSB void __DSB(void)

DMB void __DMB(void)

REV uint32_t __REV(uint32 _t int value)

REV16 uint32_t __REV16(uint32_t int value)

REVSH uint32_t __REVSH(uint32_t int value)

RBIT uint32_t __RBIT(uint32_t int value)

SEV void __SEV(void)

WFE void __WFE(void)

WFI void __WFI(void)

Table 13-15. CMSIS Intrin sic Functions to Access the Special Reg isters

Special Register Access CMSIS Function

PRIMASK Read uint32_t __ge t_PRIMASK (void)

Write void __set_PRIMASK (uint32_t value)

FAULTMASK Read uint32_t __get_FAULTMASK (void

Write void __set_FAULTMASK (uint32_t value)

BASEPRI Read uint32_t __ge t_BASEPRI (void)

Write void __set_BASEPRI (uint32_t value)

CONTROL Read uint3 2_t __get_CONTROL (void)

Write void __set_CONTROL (uint32_t value)

MSP Read uint32_t __get_MSP (void)

Write void __set_MSP (uint32_t TopOfMainStack)

PSP Read uint32_t __get_PSP (void)

Write void __set_PSP (uint32_t TopOfProcStack)

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13.6.3 Instruction Descriptions

13.6.3.1 Operands

An instruction operand can be an ARM register, a constant, or another instructio n-spec ific parame ter. Inst ruction s

act on the operands and often store the result in a destination register. When there is a destination register in the

instruction, it is usually specified before the operands.

Operands in some instructions are flexible, can either be a register or a constant. See “Flexible Second Operand”.

13.6.3.2 Restrictions when Using PC or SP

Many instructions have restrictions on whether the Program Counter (PC) or Stack Pointer (SP) for the operands

or destination register can be used. See instruction descriptions for more information.

Note: Bit[0] of any address written to the PC with a BX, BLX, LDM, LDR, or POP instruction must be 1 for correct execution,

because this bit indicates the required instruction set, and the Cortex-M4 processor only supports Thumb instructions.

13.6.3.3 Flexible Second Operand

Many general data processing instructions have a flexible second operand. This is shown as Operand2 in the

descriptions of the syntax of each instruction.

Operand2 can be a:

“Constant”

“Register with Optional Shift”

Constant

Specify an Operand2 constant in the form:

#constant

where constant can be:

Any constant that can be produced by shifting an 8-bit value left by any number of bits within a 32-bit word

Any constant of the form 0x00XY00XY

Any constant of the form 0xXY00XY00

Any constant of the form 0xXYXYXYXY.

Note: In the constants shown above, X and Y are hexadecimal digits.

In addition, in a small number of instructions, constant can take a wider range o f values. These are described in

the individual instruction descriptions.

When an Operand2 constant is used with the instructions MOVS, MVNS, ANDS, ORRS, ORNS, EORS, BICS,

TEQ or TST, the carry flag is updated to bit[31] of the constant, if the constant is greater than 255 and can be

produced by shifting an 8-bit value. These instructions do not affect the carry flag if Operand2 is any other

constant.

Instruction Substitution

The assembler might be able to produce an equivalent instruction in cases where the user specifies a constant

that is not permitted. For example, an assembler might assemble the instruction CMP

, #0xFFFFFFFE as the

equivalent instruction CMN Rd, #0x2.

Specify an Operand2 register in the form:

Rm {, shift}

where:

Rm is the register holding the data for the second operand.

shift is an optional shift to be applied to Rm. It can be one of:

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ASR #narithmetic shift right n bits, 1 ≤ n ≤ 32.

LSL #nlogical shift left n bits, 1 ≤ n ≤ 31.

LSR #nlogical shift right n bits, 1 ≤ n ≤ 32.

ROR #nrotate right n bits, 1 ≤ n ≤ 31.

RRX rotate right one bit, with extend.

- if omitted, no shift occurs, equivalent to LSL #0.

If the user omits the shift, or specifies LSL #0, the instruction uses the value in Rm.

If the user specifies a shift, the shift is applied to the value in Rm, and the resulting 32-bit value is used by the

instruction. However, the contents in the register Rm remains unchanged. Specifying a register with shift also

updates the carry flag when used with certain instructions. For information on the shift operations and how they

affect the carry flag, see “Flexible Second Operand”.

13.6.3.4 Shift Operations

Directly by the instructions ASR, LSR, LSL, ROR, and RRX, and the re sult is written to a destination register

During the calculation of Operand2 by the instructions that specify the second operand as a register with

shift. See “Flexible Second Operand”. Th e result is used by the instruction.

The permitted shift lengths depend on the shift type and the instruction. If the shift length is 0, no shift occurs.

subsections describe the variou s shift operations and how they affect the carry flag. In these descriptions, Rm is

the register containing the value to be shifted, and n is the shift length.

ASR

Arithmetic shift right by n bits moves the left-hand 32-n bits of the register, Rm, to the right by n places, into the

right-hand 32-n bits of the result. And it copies the original bit[31] of the register into the left-hand n bits of the

result. See Figure 13-8.

The ASR #n operation can be used to divide the value in the register Rm by 2n, with the result being rounded

towards negative-infinity.

When the instruction is ASRS or when ASR #n is used in Operand2 with the instructions MOVS, MVNS, AND S,

ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[n-1], o f the

If n is 32 or more, then all the bits in the result are set to the value of bit[31] of Rm.

If n is 32 or more and the carry flag is updated, it is updated to the val ue of bit[31] of Rm.

Figure 13-8. ASR #3

LSR

Logical shift right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places, into the right-

hand 32-n bits of the result. And it sets the left-hand n bits of the result to 0. See Figure 13-9.



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The LSR #n operation can be used to divide the value in the register Rm by 2n, if the value is regarded as an

unsigned integer.

When the instruction is LSRS or when LSR #n is used in Operand2 with the instructions MOVS, MVNS, ANDS,

ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[n-1], of the

If n is 32 or more, then all the bits in the result are cleared to 0.

If n is 33 or more and the carry flag is updated, it is updated to 0.

Figure 13-9. LSR #3

LSL

Logical shift left by n bits moves the right-hand 32- n bits of the register Rm, to the left by n places, into the left-hand

32-n bits of the result; and it sets the right-hand n bits of the result to 0. See Figure 13-10.

The LSL #n operation can be used to multiply the value in the register Rm by 2n, if the value is regarde d as an

unsigned integer or a two’s complement signed integer. Overflow can occur without warning.

When the instruction is LSLS or when LSL #n, with non-zero n, is used in Operand2 with the instructions MOVS,

MVNS, ANDS, ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit shifted out, bit[32-

n], of the register Rm. These instructions do not affect the carry flag when used with LSL #0.

If n is 32 or more, then all the bits in the result are cleared to 0.

If n is 33 or more and the carry flag is updated, it is updated to 0.

Figure 13-10. LSL #3

ROR

Rotate right by n bits moves the left-hand 32-n bits of the register Rm, to the right by n places, into the right-hand

32-n bits of the result; and it moves the right-hand n bits of the register into the left-hand n bits of the result. See

Figure 13-11.

When the instruction is RORS or when ROR #n is used in Operand2 with the instructions MOVS, MVNS, ANDS,

ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to the last bit rotation, bit[n-1], of the register

Rm.

If n is 32, then the value of the result is same as the value in Rm, and if the carry fla g is updated, it is updated

to bit[31] of Rm.

ROR with shift length, n, more than 32 is the same as ROR with shift length n-32.

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

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Figure 13-11. ROR #3

RRX

Rotate right with extend moves the bits of the register Rm to the r ight by one bit; an d it copies the carry fla g into

bit[31] of the result. See Figure 13-12.

When the instruction is RRXS or when RRX is used in Operand2 with the instructions MOVS, MVN S, ANDS,

ORRS, ORNS, EORS, BICS, TEQ or TST, the carry flag is updated to bit[0] of the register Rm.

Figure 13-12. RRX

13.6.3.5 Address Alignment

An aligned access is an operation where a word-aligned address is used for a word, dual word, or multiple word

access, or where a halfword-aligned address is used for a halfword access. Byte accesses are always aligned.

The Cortex-M4 processor supports unaligned access only for the following instructions:

LDR, LDRT

LDRH, LDRHT

LDRSH, LDRSHT

STR, STRT

STRH, STRHT

All other load and store instructions gene rate a usage fault exception if they perform an unaligned access, and

therefore their accesses must be address-aligned. For more information about usage faults, see “Fault Handling”.

Unaligned accesses are usually slow er than aligned accesses. In addition, some memory regions might not

support unaligned accesses. Therefore, ARM re commends that prog rammers ensure that accesses are aligned.

To avoid accidental gene ration of unalig ned accesses, use the UNALIGN_TRP bit in the Configuration a nd Control

13.6.3.6 PC-relative Expressions

A PC-relative expression or label is a symbol that repr esents the address of an instr uction or literal data. It is

represented in the instruction as the PC value plus or minus a numeric offset. The assembler calculates the

required offset from the label and the address of the current instruction. If the offset is too big, the assembler

produces an error.

For B, BL, CBNZ, and CBZ instructions, the value of the PC is the address of the current instruction plus 4

bytes.

For all other instructions that use labels, the value of the PC is the address of the current instruction plus 4

bytes, with bit[1] of the result cleared to 0 to make it word-aligned.

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Your assembler might permit other syntaxes for PC-relative expressions, such as a label plus or minus a

number, or an expression of the form [PC, #number].

13.6.3.7 Conditional Execution

Most data proc essing instructions can optionally upda te the condition flags in the Application Program Status

instructions update all flags, and some only update a subset. If a flag is not updated, the original value is

preserved. See the instruction descriptions for the flags they affect.

An instruction can be exe cu ted con d ition a lly, ba se d on the condition flags set in another instruction, either:

Immediately after the instruction that updated the flags

After any number of intervening instructions that have not updated the flags.

Conditional execution is available by using conditional branches or by adding condition code suffixes to

instructions. See Table 13-16 for a list of the suffixes to add to instructions to make them conditional instructions.

The condition code suffix enables the processor to test a condition based on the flags. If the condition test of a

conditional instruction fails, the instruction:

Does not execute

Does not write any value to its destination register

Does not affect any of the flags

Does not generate any exception.

Conditional instructions, except for conditional branches, must be inside an If-Then instruction block. See “IT” for

more information and restrictions when using the IT instruction. Depending on the vendor, the assembler might

automatically insert an IT instruction if there are conditional instructions outside the IT block.

The CBZ and CBNZ instructions are used to compare th e value of a register again st zero and branch on the re sult.

This section describes:

“Condition Flags”

“Condition Code Suffixes”.

Condition Flags

The APSR contains the following condition flags:

N Set to 1 when the resu lt of th e op e ration was negative, cleared to 0 otherwise.

Z Set to 1 when the result of the operation was zero, cleared to 0 otherwise.

C Set to 1 when the operation resulted in a carry, cleared to 0 otherwise.

V Set to 1 when the operation caused overflow, cleared to 0 otherwise.

For more information about the APSR, see “Program Status Register”.

A carry occurs:

If the result of an addition is greater than or equal to 232

If the result of a subtraction is positive or zero

As the result of an inline barrel shifter operation in a move or logical instruction.

An overflow occurs when the sign of the result, in bit[31], does not match the sign of the result, had the operation

been performed at infinite precision, for example:

If adding two negative values results in a positive value

If adding two positive values results in a negative value

If subtracting a positive value from a negative value generates a positive value

If subtracting a negative value from a positive value generates a negative value.

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The Compare operations are identical to subtracting, for CMP, or adding, for CMN, except that the result is

discarded. See the instruction descriptions for more information.

Note: Most instructions update the status flags only if the S suffix is specified. See the instruction descriptions for more

information.

Condition Code Suffixes

The instructions that can be conditional have an optional condition code, shown in syntax descriptions as {cond}.

Conditional execution req uires a preceding IT instruction. An instruction with a conditio n code is only executed if

the condition code flags in the APSR meet the specified condition. Table 13-16 shows the condition codes to use.

A conditional execution can be used with the IT instruction to reduce the number of branch instructions in code.

Table 13-16 also shows the relationship between condition code suffixes and the N, Z, C, and V flags.

Absolute Value

The example below shows the use of a conditional instru ction to find the absolute value of a number. R0 =

ABS(R1). MOVS R0, R1 ; R0 = R1, setting flags

IT MI ; IT instruction for the negative condition

RSBMI R0, R1, #0 ; If negative, R0 = -R1

Compare and Up da te Value

The example below shows the use of conditional instructions to update the value of R4 if the signed values R0 is

greater than R1 and R2 is greater than R3.

CMP R0, R1 ; Compare R0 and R1, setting flags

ITT GT ; IT instruction for the two GT conditions

CMPGT R2, R3 ; If 'greater than', compare R2 and R3, setting flags

MOVGT R4, R5 ; If still 'greater than', do R4 = R5

Table 13-16. Condition Code Suffixes

Suffix Flags Meaning

EQ Z = 1 Equal

NE Z = 0 Not equal

CS or HS C = 1 Higher or same, unsigned ≥

CC or LO C = 0 Lower, unsigned <

MI N = 1 Negative

PL N = 0 Positive or zero

VS V = 1 Overflow

VC V = 0 No overflow

HI C = 1 and Z = 0 Higher, unsigned >

LS C = 0 or Z = 1 Lower or same, unsigned ≤

GE N = V Greater than or equal, signed ≥

LT N != V Less than, signed <

GT Z = 0 and N = V Greater than, signed >

LE Z = 1 and N != V Less than or equal, signed ≤

AL Can have any value Always. This is the default when no suffix is specified.

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13.6.3.8 Instruction Width Selection

There are many instructions that can generate either a 16-bit encoding or a 32-bit encoding depending on the

operands and destination register specified. For some of these instructions, the user can force a specific

instruction size by using an instruction width suffix. The .W suffix forces a 32-bit instruction encoding. The .N suffix

forces a 16-bit instruction encoding.

If the user specifie s an instruction width suffix and th e assembler cannot generate an instruction encoding of the

requested width, it generates an error.

Note: In some cases, it might be necessary to specify the .W suffix, for example if the operand is the label of an instruction or

literal data, as in the case of branch instructions. This is because the assembler might not automatically generate the

right size encoding.

To use an instruction width suffix, place it im mediately after the instruction m nemonic and condition cod e, if any.

The example below shows instructions with the instruction width suffix.

BCS.W label ; creates a 32-bit instruction even for a short

; branch

ADDS.W R0, R0, R1 ; creates a 32-bit instruction even though the same

; operation can be done by a 16-bit instruction

13.6.4 Memory Access Instructions

The table below shows the memory access instructions.

Table 13-17. Memo ry Access Instructions

Mnemonic Description

ADR Load PC-relative address

CLREX Clear Exclusive

LDM{mode} Load Multiple registers

LDR{type} Load Register using immediate offset

LDR{type} Load R eg i ste r usi n g re gi ster off se t

LDR{type}T Load Register with unprivileged access

LDR Load Register using PC-relative address

LDRD Load Register Dual

LDREX{type} Load Register Exclusive

POP Pop registers from stack

PUSH Push registers onto stack

STM{mode} Store Multiple registers

STR{type} Store Register using immediate offset

STR{type} Store Register using register offset

STR{type}T Store Register with unprivileged access

STREX{type} Store Register Exclusive

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13.6.4.1 ADR

Load PC-relative address.

Syntax ADR{cond} Rd, label

where:

cond is an optional condition code, see “Conditional Execution”.

Rd is the destination regist er .

label is a PC-relative ex pr es sio n. See “PC-relative Expressions”.

Operation

ADR determines the address by adding an immediate value to the PC, and writes the result to the destination

ADR produces position-independent code, because the address is PC-relative.

If ADR is used to generate a targ et address for a BX or BLX in struction, ensu re that bit[0 ] of the addre ss gene rated

is set to 1 for correct execution.

Values of label must be within the range of −4095 to +4095 from the address in the PC.

Note: The user might have to use the .W suffix to get the maximum offset range or to generate addresses that are not word-

aligned. See “Instruction Width Selection”.

Restrictions

Rd must not be SP and must not be PC.

Condition Flags

This instruction does not change the flags.

Examples

ADR R1, TextMessage ; Write address value of a location labelled as

; TextMessage to R1

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13.6.4.2 LDR and STR, Immediate Offset

Load and Store with imm edi at e of fse t, pr e- in de xe d imm ediate offset, or post-indexed immediate offset.

Syntax op{type}{cond} Rt, [Rn {, #offset}] ; immediate offset

op{type}{cond} Rt, [Rn, #offset]! ; pre-indexed

op{type}{cond} Rt, [Rn], #offset ; post-indexed

opD{cond} Rt, Rt2, [Rn {, #offset}] ; immediate offset, two words

opD{cond} Rt, Rt2, [Rn, #offset]! ; pre-indexed, two words

opD{cond} Rt, Rt2, [Rn], #offset ; post-indexed, two words

where:

op is one of:

LDR Load Register.

STR Store Register.

type is one of:

B unsigned byte, zero extend to 32 bits on loads.

SB signed byte, sign extend to 32 bits (LDR only) .

H unsigned halfword, zero extend to 32 bits on loads.

SH signed halfword, sign extend to 32 bits (LDR only).

- omit, for word.

cond is an optional condition code, see “Conditional Execution”.

Rt is the re gis t er to lo a d or stor e.

Rn is the register on which the memory address is based.

offset is an offset from Rn. If offset is omitted, the address is the contents of Rn.

Rt2 is the additional register to load or store for two-word operations.

Operation

LDR instructions load one or two registers with a value from memory.

STR instructions store one or two register values to memory.

Load and store instructions with immediate offset can use the following ad dressing modes:

Offset Addressing

The offset value is ad ded to or subtracted from the address o btained from the r egister Rn. The result is used as the

address for the memory access. The register Rn is unaltered. The assembly language synta x for this mode is:

[Rn, #offset]

Pre-indexed Addressing

The offset value is ad ded to or subtracted from the address o btained from the r egister Rn. The result is used as the

address for the me mory access and written b ack into the re gister Rn. The assembly language syn tax for this mode

is: [Rn, #offset]!

Post-indexed Addressing

The address obtained from the register Rn is used as the address for the memory access. The offset value is

added to or subtracted from the address, and written back into the register Rn. The assembly language syntax for

this mode is:

[Rn], #offset

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The value to load or store can be a byte, halfword, word, or two words. Bytes and halfwords can either be signed

or unsigned. See “Address Alignment”.

The table below shows the ranges of offset for immediate, pre-indexed and post-indexed forms.

Restrictions

For load instructions:

Rt can be SP or PC for word loads only

Rt must be different from Rt2 for two-word loads

Rn must be different from Rt and Rt2 in the pre-indexed or post-indexed forms.

When Rt is PC in a word load instruction:

Bit[0] of the loaded value must be 1 for correct execution

A branch occurs to the address created by changing bit[0] of the loaded value to 0

If the instruction is conditional, it must be the last instruction in the IT block.

For store instructions:

Rt can be SP for word stores only

Rt must not be PC

Rn must not be PC

Rn must be different from Rt and Rt2 in the pre-indexed or post-indexed forms.

Condition Flags

These instructions do not change the flags.

Examples

LDR R8, [R10] ; Loads R8 from the address in R10.

LDRNE R2, [R5, #960]! ; Loads (conditionally) R2 from a word

; 960 bytes above the address in R5, and

; increments R5 by 960.

STR R2, [R9,#const-struc] ; const-struc is an expression evaluating

; to a constant in the range 0-4095.

STRH R3, [R4], #4 ; Store R3 as halfword data into address in

; R4, then increment R4 by 4

LDRD R8, R9, [R3, #0x20] ; Load R8 from a word 32 bytes above the

; address in R3, and load R9 from a word 36

; bytes above the address in R3

STRD R0, R1, [R8], #-16 ; Store R0 to address in R8, and store R1 to

; a word 4 bytes above the address in R8,

; and then decrement R8 by 16.

Table 13-18. Offs et Ranges

Instruction Type Immediate Offset Pre-indexed Post-indexed

Word, halfword, signed

halfword, byte, or signed byte -255 to 4095 -255 to 255 -255 to 255

Two w ords multiple of 4 in the range

-1020 to 1020 multiple of 4 in the range

-1020 to 1020

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100

13.6.4.3 LDR and STR, Register Offset

Load and Store with register offset.

Syntax op{type}{cond} Rt, [Rn, Rm {, LSL #n}]

where:

op is one of:

LDR Load Register.

STR Store Register.

type is one of:

B unsigned byte, zero extend to 32 bits on loads.

SB signed byte, sign extend to 32 bits (LDR only) .

H unsigned halfword, zero extend to 32 bits on loads.

SH signed halfword, sign extend to 32 bits (LDR only).

- omit, for word.

cond is an optional condition code, see “Conditional Execution”.

Rt is the re gis t er to lo a d or stor e.

Rn is the register on which the memory address is based.

Rm is a register containing a value to be used as the of fse t.

LSL #nis an optional shift, with n in the range 0 to 3 .

Operation

LDR instructions load a register with a value from me m or y.

STR instructions store a register value into memory.

The memory address to load from or store to is at an offset from the register Rn. The offset is specified by the

The value to load or store can be a byte, halfword, or word. For load instructions, bytes and halfwords can either

be signed or unsigned. See “Address Alignment”.

Restrictions

In these instructions:

Rn must not be PC

Rm must not be SP and must not be PC

Rt can be SP only for word loads and word stores

Rt can be PC only for word loads.

When Rt is PC in a word load instruction:

Bit[0] of the loaded value must be 1 for correct execution, and a branch occurs to this halfword-aligned

address

If the instruction is conditional, it must be the last instruction in the IT block.

Condition Flags

These instructions do not change the flags.

101

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Examples

STR R0, [R5, R1] ; Store value of R0 into an address equal to

; sum of R5 and R1

LDRSB R0, [R5, R1, LSL #1] ; Read byte value from an address equal to

; sum of R5 and two times R1, sign extended it

; to a word value and put it in R0

STR R0, [R1, R2, LSL #2] ; Stores R0 to an address equal to sum of R1

; and four times R2

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13.6.4.4 LDR and STR, Unprivileged

Load and Store with unprivileged access.

Syntax op{type}T{cond} Rt, [Rn {, #offset}] ; immediate offset

where:

op is one of:

LDR Load Register.

STR Store Register.

type is on e of:

B unsigned byte, zero extend to 32 bits on loads.

SB signed byte, sign extend to 32 bits (LDR only) .

H unsigned halfword, zero extend to 32 bits on loads.

SH signed halfword, sign extend to 32 bits (LDR only).

- omit, for word.

cond is an optional condition code, see “Conditional Execution”.

Rt is the re gis t er to lo a d or stor e.

Rn is the register on which the memory address is based.

offset is an offset from Rn and can be 0 to 255.

If offset is omitted, the address is the value in Rn.

Operation

These load and store instructions perform the same function as the memory access instructio ns with immediate

offset, see “LDR and STR, Immediate Offset”. The diffe rence is that these instructions have on ly unprivileged

access even when used in privileged software.

When used in unprivileged so ftware, these instruction s behave in exactly the same way as normal memory access

instructions with immediate offset.

Restrictions

In these instructions:

Rn must not be PC

Rt must not be SP and must not be PC.

Condition Flags

These instructions do not change the flags.

Examples

STRBTEQ R4, [R7] ; Conditionally store least significant byte in

; R4 to an address in R7, with unprivileged access

LDRHT R2, [R2, #8] ; Load halfword value from an address equal to

; sum of R2 and 8 into R2, with unprivileged access

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13.6.4.5 LDR, PC-relative

Load register from memory.

Syntax LDR{type}{cond} Rt, label

LDRD{cond} Rt, Rt2, label ; Load two words

where:

type is one of:

B unsigned byte, zero extend to 32 bits.

SB signed byte, sign extend to 32 bits.

H unsigned halfword, zero extend to 32 bits.

SH signed halfword, sign extend to 32 bits.

- omit, for word.

cond is an optional condition code, see “Conditional Execution”.

Rt is the re gis t er to lo a d or stor e.

Rt2 is the second register to load or store.

label is a PC-relative ex pr es sio n. See “PC-relative Expressions”.

Operation

LDR loads a register with a value from a PC-relative me mory address. The mem ory address is sp ecified by a label

or by an offset from the PC.

The value to load or store can be a byte, halfword, or word. For load instructions, bytes and halfwords can either

be signed or unsigned. See “Address Alignment”.

label must be within a limited range of the current instruction. The table below shows the possible offsets between

label and the PC.

The user might have to use the .W suffix to get the maximum offset range. See “Instruction Width Selection”.

Restrictions

In these instructions:

Rt can be SP or PC only for word loads

Rt2 must not be SP and must not be PC

Rt must be different from Rt2.

When Rt is PC in a word load instruction:

Bit[0] of the loaded value must be 1 for correct execution, and a branch occurs to this halfword-aligned

address

If the instruction is conditional, it must be the last instruction in the IT block.

Condition Flags

These instructions do not change the flags.

Table 13-19. Offs et Ranges

Instruction Type Offset Range

Word, halfword, signed halfword, byte, signed byte -4095 to 4095

Two words -1020 to 1020

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Examples

LDR R0, LookUpTable ; Load R0 with a word of data from an address

; labelled as LookUpTable

LDRSB R7, localdata ; Load a byte value from an address labelled

; as localdata, sign extend it to a word

; value, and put it in R7

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13.6.4.6 LDM and STM

Load and Store Multiple registers.

Syntax op{addr_mode}{cond} Rn{!}, reglist

where:

op is one of:

LDM Load Multiple registers.

STM Store Multiple registers.

addr_mode is any one of the follow i ng :

IA Increment address After each access. This is the default.

DB Decrement address Before each access.

cond is an optional condition code, see “Conditional Execution”.

Rn is the register on which the memory addresses are based.

! is an optional writeback suffix.

If ! is present, the final address, that is loaded from or stored to, is written back into Rn.

reglist is a list of one or more registers to be loaded or stored, enclosed in braces. It

can contain register ranges. It must be comma separated if it contains more

than one register or register range, see “Examples”.

LDM and LDMFD are synonyms for LDMIA. LDMFD refers to its use for popping data from Full Descending

stacks.

LDMEA is a synonym for LDMDB, and refers to its use for popping data from Empty Ascending stacks.

STM and STMEA are synonyms for STMIA. STMEA refers to its use for pushing data onto Empty Ascending

stacks.

STMFD is s synonym for STMDB, and refers to its use for pushing data onto Full Descending stacks

Operation

LDM instructions load the registers in reglist with word values from memory addresses based on Rn.

STM instructions store the word values in the registers in reglist to memory addresses based on Rn.

For LDM, LDM IA, LDMFD, STM, STMIA, and STME A the m emory add resses use d for the acce sses are at 4-byte

intervals rang ing fro m Rn to Rn + 4 * (n-1), where n is the number of registers in reglist. The accesses happens in

order of increasing register numbers, with the lowest numbered register using the lowest memory address and the

highest number register using the highest memory address. If the writeback suffix is specified, the value of Rn + 4

* (n-1) is written back to Rn.

For LDMDB, LDMEA, STMDB, and STMFD the memory addresses used for the accesses are at 4-byte intervals

ranging from Rn to Rn - 4 * (n-1), where n is the nu mber of registers in reglist. The accesses ha ppen in order of

decreasing register numbers, with the highest nu mbered register using the highest memory address and the

lowest number register using the lowest memory address. If the writeback suffix is specified, the value of Rn - 4 *

(n-1) is written back to Rn.

The PUSH and POP instructions can be expressed in this form. See “PUSH and POP”for details.

Restrictions

In these instructions:

Rn must not be PC

reglist must not contain SP

In any STM instruction, reglist must not contain PC

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In any LDM instruction, reglist must not contain PC if it contains LR

reglist must not contain Rn if the writeback suffix is specified.

When PC is in reglist in an LDM instruction:

Bit[0] of the value loaded to the PC must be 1 for correct execution, and a branch occurs to this halfword-

aligned address

If the instruction is conditional, it must be the last instruction in the IT block.

Condition Flags

These instructions do not change the flags.

Examples

LDM R8,{R0,R2,R9} ; LDMIA is a synonym for LDM

STMDB R1!,{R3-R6,R11,R12}

Incorrect Examples

STM R5!,{R5,R4,R9} ; Value stored for R5 is unpredictable

LDM R2, {} ; There must be at least one register in the list

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13.6.4.7 PUSH and POP

Push registers onto, and pop registers off a full-descending stack.

Syntax PUSH{cond} reglist

POP{cond} reglist

where:

cond is an optional condition code, see “Conditional Execution”.

reglist is a non-empty list of registers, enclosed in braces. It can contain register

ranges. It must be comma separated if it contains more than one register or

PUSH and POP are synonyms for STMDB and LDM (or LDMIA) with the memory addresses for the access based

on SP, and with the final address for the access written back to the SP. PUSH and POP are the preferred

mnemonics in these cases.

Operation

PUSH stores registers on the stack in order of decreasing the register numbers, with the highest numbered

POP loads registers from the stack in order of increasing register numbers, with the lowest numbered register

using the lowest memo ry ad d re ss an d th e hig he st numbered register using the highest memory address.

See “LDM and STM” for more information.

Restrictions

In these instructions:

reglist must not contain SP

For the PUSH instruction, reglist must not contain PC

For the POP instruction, reglist must not contain PC if it contains LR.

When PC is in reglist in a POP instruction:

Bit[0] of the value loaded to the PC must be 1 for correct execution, and a branch occurs to this halfword-

aligned address

If the instruction is conditional, it must be the last instruction in the IT block.

Condition Flags

These instructions do not change the flags.

Examples PUSH {R0,R4-R7}

PUSH {R2,LR}

POP {R0,R10,PC}

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13.6.4.8 LDREX and STREX

Load and Store Register Exclusive.

Syntax LDREX{cond} Rt, [Rn {, #offset}]

STREX{cond} Rd, Rt, [Rn {, #offset}]

LDREXB{cond} Rt, [Rn]

STREXB{cond} Rd, Rt, [Rn]

LDREXH{cond} Rt, [Rn]

STREXH{cond} Rd, Rt, [Rn]

where:

cond is an optional condition code, see “Conditional Execution”.

Rd is the destination register for the returned status.

Rt is the re gis t er to lo a d or stor e.

Rn is the register on which the memory address is based.

offset is an optional offset applied to the value in Rn.

If offset is omitted, the address is the value in Rn.

Operation

LDREX, LDREXB, and LDREXH load a word, byte, and ha lfw or d re sp ec tive ly fro m a mem or y ad dr e ss.

STREX, STREXB, and STREXH attempt to store a word, byte, and halfword respectively to a memory address.

The address used in any Store-Exclusive instruction must be the same as the address in the most recently

executed Load-exclusive instruction. The value stored by the Store-Exclusive instruction must also have the same

data size as the value loaded by the preceding Loa d-exclusive instruction. This means software must always use a

Load-exclusive instruction and a matching Store-Exclusive instruction to perform a synchronization operation, see

“Synchronization Primitives”.

If an Store-Exclusive instruction performs the store, it writes 0 to its destination register. If it does not perform the

store, it writes 1 to its destination register. If the Store-Exclusive instruction writes 0 to the destination register, it is

guaranteed that no other p rocess in the system has accessed the memory location between the Load-exclusive

and Store-Exclusive instructions.

For reasons of performance, keep the number of instructions betwe en corresponding Load-Exclusive and Store-

Exclusive instruction to a minimum.

The result of exe cu tin g a S tor e -Exc lus ive instr u ctio n to an ad dr es s th at is diffe r en t fr om th at u se d in the pr ece d ing

Load-Exclusive instruction is unpredictable.

Restrictions

In these instructions:

Do not use PC

Do not use SP for Rd and Rt

For STREX, Rd must be diffe rent from both Rt and Rn

The value of offset must be a multiple of four in the range 0–1020.

Condition Flags

These instructions do not change the flags.

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Examples MOV R1, #0x1 ; Initialize the ‘lock taken’ value try

LDREX R0, [LockAddr] ; Load the lock value

CMP R0, #0 ; Is the lock free?

ITT EQ ; IT instruction for STREXEQ and CMPEQ

STREXEQ R0, R1, [LockAddr] ; Try and claim the lock

CMPEQ R0, #0 ; Did this succeed?

BNE try ; No – try again

.... ; Yes – we have the lock

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13.6.4.9 CLREX

Clear Exclusive.

Syntax CLREX{cond}

where:

cond is an optional condition code, see “Conditional Execution”.

Operation

Use CLREX to make the next STREX, STREXB, or STREXH instruction write a 1 to its destination register and fail

to perform the store. It is use ful in exce ption handler code to force the failure of the store exclusive if the exception

occurs between a load exclusive instruction and the matching store exclusive instruction in a synchronization

operation.

See “Synchronization Primitives” for more information.

Condition Flags

These instructions do not change the flags.

Examples

CLREX

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13.6.5 General Data Processing Instructions

The table below shows the data processing instructions.

Table 13-20. Data Processing Instruction s

Mnemonic Description

ADC Add with Carry

ADD Add

ADDW Add

AND Logical AND

ASR Arithmetic Shift Right

BIC Bit Clear

CLZ Coun t leading zeros

CMN Compare Negative

CMP Compare

EOR Exclusive OR

LSL Logical Shift Left

LSR Logical Shift Right

MOV Move

MOVT Move Top

MOVW Move 16-bit constant

MVN Move NOT

ORN Logical OR NOT

ORR Logical OR

RBIT Reverse Bits

REV Reverse byte order in a word

REV16 Reverse byte order in each halfword

REVSH Reverse byte order in bottom halfword and sign extend

ROR Rotate Right

RRX Rotate Right with Extend

RSB Reverse Subtract

SADD16 Signed Add 16

SADD8 Signed Add 8

SASX Signed Add and Subtract with Exchange

SSAX Signed Subtract and Add with Exchange

SBC Subtract with Carry

SHADD16 Signed Halving Add 16

SHADD8 Signed Halving Add 8

SHASX Signed Halving Add and Subtract with Exchange

SHSAX Signed Halving Subtract and Add with Exch ange

SHSUB16 Signed Halving Subtract 16

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SHSUB8 Signed Halving Subtract 8

SSUB16 Signed Subtract 16

SSUB8 S igned Subtract 8

SUB Subtract

SUBW Subtract

TEQ Test Equivalence

TST Test

UADD16 Unsigned Add 16

UADD8 Unsign ed Add 8

UASX Unsigned Add and Subtract with Exchange

USAX Unsigned Subtract and Add with Exchange

UHADD16 Unsigned Halving Add 16

UHADD8 Unsigned Halving Add 8

UHASX Unsigned Halving Add and Subtract with Exchange

UHSAX Unsigned Halvi ng Subtract and Add with Exchange

UHSUB16 Unsigned Halving Subtract 16

UHSUB8 Unsigned Halving Subtract 8

USAD8 Unsigned Sum of Absolute Differences

USADA8 Unsigned Sum of Absolute Differences and Accumulate

USUB16 Unsigned Subtract 16

USUB8 Unsigned Subtract 8

Table 13-20. Data Processing Instructions (Continued)

Mnemonic Description

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13.6.5.1 ADD, ADC, SUB, SBC, and RSB

Add, Add with carry, Subtract, Subtract with carry, and Reverse Subtract.

Syntax op{S}{cond} {Rd,} Rn, Operand2

op{cond} {Rd,} Rn, #imm12 ; ADD and SUB only

where:

op is one of:

ADD Add.

ADC Add with Carry.

SUB Subtract.

SBC Subtract with Carry.

RSB Reverse Subtract.

S is an optional suffix. If S is specified, the condition code flags are updated on the result

of the operation, see “Conditional Execution”.

cond is an optional condition code, see “Conditional Execution”.

Rd is the destination regist er. If Rd is omitted, the destination register is Rn.

Rn is the register holdin g th e firs t oper an d.

Operand2 is a flexible second operand. See “F lexible Second Operand” for details of the

options.

imm12 is any value in the range 0–4095.

Operation

The ADD instruction adds the value of Operand2 or imm12 to the value in Rn.

The ADC instruction adds the values in Rn and Operand2, together with the carry flag.

The SUB instruction subtracts the value of Operand2 or imm12 from the value in Rn.

The SBC instruction subtracts the value of Operand2 from the value in Rn. If the carry flag is clear, the result is

reduced by one.

The RSB instruction subtracts the value in Rn from the value of Operand2. This is useful because of the wide

range of options for Operand2.

Use ADC and SBC to synthesize multiword arithmetic, see Multiword arithmetic examples on.

See also “Big-endian memory”.

Load/store architecture A processor architectu re whe re da ta-processing operations only operate on register contents, not

directly on memory contents.

Memory Protection Unit

(MPU) Hardware that controls access permissions to blocks of memory. An MPU does not perform any

address translation.

Prefetching In pipelined processors, the process of fetching instructions from memory to fill up the pipeline before

the preceding instructions have finished executing. Prefetching an i nstruction does not mean that the

instruction has to be executed.

Preserved Preserved by writing the same value back that has been previously read from the same field on the

same processor.

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Read Reads are defined as memory operations that have the semantics of a load. Reads include the Thumb

instructions LDM, LDR, LDRSH, LDRH, LDRSB, LDRB, and POP.

Region A partition of memory space.

Reserved A field in a control register or instruction format is reserved if the field is to be defined by the

implementation, or produces Unpredictable results if the contents of the field are not zero. These fields

are reserved for use in future extensions of the architecture or are implementation-specific. All

reserved bits not used by the implementation must be written as 0 and read as 0.

Thread-safe In a multi-tasking environment, thread-safe functions use safeguard mechanisms when accessing

shared resources, to ensure correct operation without the risk of shared access conflicts.

Thumb instruction One or two halfwords that specify an operation for a processor to perform. Thumb instructions must be

halfword-aligned.

Unaligned A data item stored at an address that is not divisible by the number of bytes that defines the data size

is said to be unaligned. For example, a word stor ed at an address that is not divisible by four.

Undefined Indicates an instruction that generates an Undefined instruction exception.

Unpredictable One cannot rely on the behavior. Unpredictable behavior must not represent security holes.

Unpredictable behavior must not halt or hang the processor, or any parts of the system.

Warm reset Also known as a core reset. Initializes the majority of the processor excluding the debug controller and

debug logic. This type of reset is useful if debugging features of a processor.

WA See “Write-allocate (WA)”.

WB See “Write-back (WB)”.

Word A 32-bit data item.

Write Writes are defined as operations that have the semantics of a store. Writes include the Thumb

instructions STM, STR, STRH, STRB, and PUSH.

Write-allocate (WA) In a write-allocate cache, a cache miss on storing data causes a cache line to be allocated into the

cache.

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Write-back (WB) In a write-back cache, data is only written to main memory when it is forced out of the cache on line

replacement following a cache miss. Otherwise, writes by the processor only update the cache. This is

also known as copyback.

Write buffer A block of high-speed memory, arranged as a FIFO buffer, between the data cache and main memory ,

whose purpose is to optimize stores to main memory.

Write-through (WT) In a write-through cache, data is written to main memory at the same time as the cache is updated.

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14. Cortex-M Cache Controller (CMCC)

14.1 Description

The Cortex-M Cache Controller (CMCC) is a 4-Way set associative unified cache controller. It integrates a

controller, a tag directory, data memory, metadata memory and a configu ration interface.

14.2 Embedded Characteristics

Physically addressed and physically tagged

CMCC memory size set to 8KB

L1 data cache set up to 8 Kbytes

L1 Tightly Coupled Memory RAM (TCM) up to 16KB

L1 cache line size set to 16 Bytes

L1 cache integrates 32 bus master interface

Software-allocated RAM resource between cache and TCM

Unified direct mapped cache architecture

Unified 4-Way set associative cache architecture

Write accesses forwarded, cache state not modified. Allocate on read.

Round Robin victim selection policy

Event Monitoring, with one programmable 32-bit counter

Configuration registers accessible through Cortex-M Private Peripheral Bus (PPB)

Cache interface includes cache maintenance operations registers

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14.3 Block Diagram

Figure 14-1. Block Diagram

14.4 Functional Description

14.4.1 Cache Operation

On reset, the cache controller data entries are all invalidated and the cache is disabled. The cache is transparent

to processor operations. The cache controller is activated with its configuration registers. The configuration

interface is memory-mapped in the private peripher al bus.

Use the following sequence to enable the cache controller:

1. Verify that the cache controller is disabled by reading the value of the CSTS (Cache Controller Status) bit of

the Status register (CMCC_SR).

2. Enable the cache controller by writing a one to the CEN (Cache Enable) bit of the Control register

(CMCC_CTRL).

The cache controller integrates three memory areas, selectable through address decoding:

A cacheable memory ar ea—allo ws software e xecution with cod e located in slow me mory (em bedded Flash )

A TCM area—provides fast and predictable code execution and data access

A non-cacheable memory area—permits data and instruction access to system-level shared memory or

peripheral

The total amount of RAM is shared between the cache controller and the TCM. If the application requires a large

amount of TCM, the cache can be disabl ed an d its me mor y r eused . If the a pp licatio n r equir es only cache me mor y,

the TCM is reallocated to the cache memory. The size of the RAM allocated to the cache is defined in the

Cache

Controller

META INFO RAM

DATA RAM

TAG RAM

RAM

Interface

Cortex-M interface

Memory Interface

Registers

Interface

Cortex-M

PPB

Cortex-M Memory Interface Bus

System Memory Bus

TCM RAM

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PRGCSIZE field of the CMCC_CFG register. The d ifference between the cach e size and the tota l CMCC RAM

size is automatically allocated as TCM.

14.4.2 Cache Maintenance

If the contents seen by the cache have chan ged, the user must invalidate the cache entries. This can be done line-

by-line or for all cache entries.

14.4.2.1 Cache Invalidate-by-Line Operation

When an invalidate-by-line command is issued, the cache controller resets the valid bit information of the decoded

cache line. As the line is no longer valid, the replacement counte r points to that line.

Use the following sequence to invalidate one line of cache:

1. Disable the cache controller by clearing the CEN bit of CMCC_CTRL.

2. Check the CSTS bit of CMCC_SR to verify that the cache is successfully disabled .

3. Perform an invalidate-by-line by configuring the bits INDEX and WAY in the Maintenance Register 1

(CMCC_MAINT1).

4. Enable the cache controller by writing a one the CEN bit of the CMCC_CTRL.

14.4.2.2 Cache Invalidate All Operation

To invalidate all cache entries, write a one to the INVALL bit of the Maintenance Register 0 (CMCC_MAINT0).

14.4.3 Cache Performance Monitoring

The Cortex-M ca che co ntro ller include s a prog ram mab le 32- bit monito r coun ter. The monit or can be configu red to

count the number of clock cycles, the number of data hits or the numb er of instruction hits.

Use the following sequence to activate the counter:

1. Configure the monitor counter by writing to the MODE field of the Monitor Configuration register

(CMCC_MCFG).

2. Enable the counter by writing a one to the MENABLE bit of the Monitor Enable register (CMCC_MEN).

3. If required, clear the counter by writing a one to the SWRST bit of the Monitor Control register

(CMCC_MCTRL).

4. Check the value of the monitor counter by reading the EVENT_CNT field of the CMCC_MSR.

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14.5 Cortex-M Cache Controller (CMCC) User Interface

Table 14-1. Register Mapping

Offset Register Name Access Reset

0x00 Cache Controller Type Register CMCC_TYPE Read-only 0X000013D7

0x04 Cache Controller Configuration Register CMCC_CFG Read/Write 0x00000020

0x08 Cache Controller Control Register CMCC_CTRL Write-only –

0x0C Cache Controller Status Register CMCC_SR Read-only 0X00000000

0x10–0x1C Reserved – – –

0x20 Cache Controller Maintenance Register 0 CMCC_MAINT0 Write-only –

0x24 Cache Controller Maintenance Register 1 CMCC_MAINT1 Write-only –

0x28 Cache Controller Monitor Configuration Register CMCC_MCFG Read/Write 0x00000000

0x2C Cache Controller Monitor Enable Register CMCC_MEN Read/Write 0x00000000

0x30 Cache Controller Monitor Control Register CMCC_MCTRL Write-only –

0x34 Cache Controller Monitor Status Register CMCC_MSR Rea d-only 0x00000000

0x38–0xFC Reserved – – –

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14.5.1 Cache Controller Type Register

Name: CMCC_TYPE

Address: 0x4003C000

Access: Read-only

• AP: Access Port Access Allowed

0: Access Port Access is disabled.

1: Access Port Access is enabled.

• GCLK: Dynamic Clock Gating Supported

0: Cache controller does not support clock gating.

1: Cache controller uses dynamic clock gating.

• RANDP: Random Selection Policy Supported

0: Random victim selection is not supported.

1: Random victim selection is supported.

• LRUP: Least Recently Used Policy Supported

0: Least Recently Used Policy is not supported.

1: Least Recently Used Policy is supported.

• RRP: Random Selection Policy Supported

0: Random Selection Policy is not supported.

1: Random Selection Policy is supported.

• WAYNUM: Number of Ways

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–CLSIZECSIZE

76543210

LCKDOWN WAYNUM RRP LRUP RANDP GCLK AP

Value Name Description

0 DMAPPED Direct Mapped Cache

1 ARCH2WAY 2-way set associ ative

2 ARCH4WAY 4-way set associ ative

3 ARCH8WAY 8-way set associ ative

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• LCKDOWN: Lockdown Supported

0: Lockdown is not supported.

1: Lockdown is supported.

• CSIZE: Data Cache Size

• CLSIZE: Cache LIne Size

Value Name Description

0 CSIZE_1KB Data cache size is 1 Kbyte

1 CSIZE_2KB Data cache size is 2 Kbytes

2 CSIZE_4KB Data cache size is 4 Kbytes

3 CSIZE_8KB Data cache size is 8 Kbytes

Value Name Description

0 CLSIZE_1KB Cache line size is 4 bytes

1 CLSIZE_2KB Cache line size is 8 bytes

2 CLSIZE_4KB Cache line size is 16 bytes

3 CLSIZE_8KB Cache line size is 32 bytes

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14.5.2 Cache Controller Configuration Register

Name: CMCC_CFG

Address: 0x4003C004

Access: Read/Write

• GCLKDIS: Disable Clock Gating

0: Clock gating is activated.

1: Clock gating is disabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– PRGCSIZE – DCDIS ICDIS GCLKDIS

• ICDIS: Instruction Caching Disable

0: Instruction caching enabled.

1: Instruction caching disabled.

• DCDIS: Data Caching Disable

0: Data caching enabled.

1: Data caching disabled.

• PRGCSIZE: Programmable Cache Size

Value Name Description

0-Reserved

1 PRGCSIZE_2KB Programmabl e cache size is 2 Kbytes

2 PRGCSIZE_4KB Programmabl e cache size is 4 Kbytes (defau lt value)

3 PRGCSIZE_8KB Programmabl e cache size is 8 Kbytes

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14.5.3 Cache Controller Control Register

Name: CMCC_CTRL

Address: 0x4003C008

Access: Write-only

• CEN: Cache Controller Enable

0: The cache controller is disabled.

1: The cache controller is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––CEN

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14.5.4 Cache Controller Status Register

Name: CMCC_SR

Address: 0x4003C00C

Access: Read-only

• CSTS: Cache Controller Status

0: The cache controller is disabled.

1: The cache controller is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––CSTS

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14.5.5 Cache Controller Maintenance Register 0

Name: CMCC_MAINT0

Address: 0x4003C020

Access: Write-only

• INVALL: Cache Controller Invalidate All

0: No effect.

1: All cache entries are invalidated.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––INVALL

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14.5.6 Cache Controller Maintenance Register 1

Name: CMCC_MAINT1

Address: 0x4003C024

Access: Write-only

• INDEX: Invalidate Index

This field indicates the cache line that is being invalidated.

The size of the INDEX field depends on the cache size:

For example:

– for 2 Kbytes: 5 bits

– for 4 Kbytes: 6 bits

– for 8 Kbytes: 7 bits

• WAY: Invalidate Way

31 30 29 28 27 26 25 24

WAY ––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––––––INDEX

76543210

INDEX ––––

Value Name Description

0 WAY0 Way 0 is selection for index invalidation

1 WAY1 Way 1 is selection for index invalidation

2 WAY2 Way 2 is selection for index invalidation

3 WAY3 Way 3 is selection for index invalidation

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14.5.7 Cache Controller Monitor Configuration Register

Name: CMCC_MCFG

Address: 0x4003C028

Access: Read/Write

• MODE: Cache Controller Monitor Counter Mode

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––– MODE

Value Name Description

0 CYCLE_COUNT Cycle counter

1 IHIT_COUNT Instruction hit counter

2 DHIT_COUNT Data hit counter

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14.5.8 Cache Controller Monitor Enable Register

Name: CMCC_MEN

Address: 0x4003C02C

Access: Read/Write

• MENABLE: Cache Controller Monitor Enable

0: The monitor counter is disabled.

1: The monitor counter is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––MENABLE

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14.5.9 Cache Controller Monitor Control Register

Name: CMCC_MCTRL

Address: 0x4003C030

Access: Write-only

• SWRST: Monitor

0: No effect.

1: Resets the event counter register.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––SWRST

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14.5.10 Cache Controller Monitor Status Register

Name: CMCC_MSR

Address: 0x4003C034

Access: Read-only

• EVENT_CNT: Monitor Event Counter

31 30 29 28 27 26 25 24

EVENT_CNT

23 22 21 20 19 18 17 16

EVENT_CNT

15 14 13 12 11 10 9 8

EVENT_CNT

76543210

EVENT_CNT

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15. Bus Matrix (MATRIX)

15.1 Description

The Bus Matrix (MATRIX) implements a mu lti-layer AHB that enable s parallel access paths between multiple AHB

masters and slaves in a system, thus increasing overall bandwidth. The Bus Matrix interconnects three AHB

masters to four AHB slaves. The no rmal latency to conn ect a master to a slave is one cycle. The exception is the

default master of the accessed slave which is connected directly (zero cycle latency).

The Bus Matrix user interface also provides a System I/O Configuration user interface with registers that support

application-sp ecific features.

15.2 Embedded Characteristics

One Decoder for Each Master

Support for Long Bursts of 32, 64 and 128 Beats and Up to the 256-be at Word Burst AHB Limit

Enhanced Programmable Mixed Arbitration for Each Slave

Round-robin

Fixed Priority

Latency Quality of Service

Programmable Default Master for Each Slave

No Default Master

Last Accessed Default Master

Fixed Default Master

Deterministic Maximum Access Latency for Masters

Zero or One Cycle Arbitration Latency for the First Access of a Burst

Bus Lock Forwar d ing to Slaves

Master Number Forwarding to Slaves

Automatic clock-off mode for power reduction

Register Write Protection

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15.3 Master/Slave Management

15.3.1 Matrix Masters

The Bus Matrix manages five masters. Each master can perform an access concurrently with others to an

available slave.

Each master has its own specifically-defined decoder. In order to simplify the addressing, all the masters have the

same decoding.

15.3.2 Matrix Slaves

The Bus Matrix manages five slaves. Each slave has its own arbiter, providing a diff erent arbitration per slave

15.3.3 Master to Slave Access

Table 15-3 gives valid paths for master to slave access. The paths shown as “–” are forbidden or not wired, e.g.,

access from the processor I/D bus to internal SRAM.

Table 15-1. List of Bus Matrix Masters

Master No. Name

0 Processor Instruction/Data Bus

1 Processor System Bus

2 P eripheral DMA Controller (PDC)

3 CRC Calculation Unit (CRCCU)

4 U SB Host DMA

Table 15-2. List of Bus Matrix Slaves

Slave No. Name

0 Internal SRAM

1 Internal ROM

2 Internal Flash

3 Peripheral Bridge

4 USB Host Register

Table 15-3. Master to Slave Access

Slaves

Masters

01234

Processor

I/D Bus Processor

System Bus PDC CRCCU USB Host DMA

0 Internal SRAM –XXXX

1 Internal RO M X–X––

2 Internal Flash X–XX–

3 Peripheral Bridge –XX––

4 USB Host Register –X–––

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15.4 Memory Mapping

The Bus Matrix provides one decoder for every AHB master interface. The decoder offers each AHB master

several memory mappings. Depending on the product, each memory area may be assigned to several slaves.

Thus it is possible to boot at the same address while using different AHB slaves.

15.5 Special Bus Granting Techniques

The Bus Matrix provides some speculative bus granting techniques in order to anticipate access req uests from

some masters, reducing latency at the first access of a burst or single transfer. The bus granting technique sets a

default mast er for ev er y slave.

At the end of the current access, if no other request is pending, the slave remains connected to its associated

default master. A slave can be associated with three kinds of default masters:

No default master

Last access master

Fixed default master

15.5.1 No Default Master

At the end of the current access, if no other request is pending, the slave is disconnected from all masters. This is

suitable when the device is in low-power mode.

15.5.2 Last Access Master

At the end of th e current access, if no oth er request is pending, the slave remains connected to the last master that

performed an access request.

15.5.3 Fixed Default Master

At the end of the current access, if no other request is pending , the slave connects to its fixed default master.

Unlike the last access master, the fixed master does not change un less the user modifies it by software (field

FIXED_DEFMSTR of the related MATRIX_SCFG).

To change from one kind of default master to another, the Bus Matrix user interface provides the Slave

Configuration registers (MATRIX_SCFGx), one for each slave, used to set a default master for each slave.

MATRIX_SCFGx contain the fields DEFMSTR_TYPE and FIXED_DEFMSTR. The 2-bit DEFMSTR_TYPE field

selects the default master type (no default, last access master, fixed default master) whereas the 4-bit

FIXED_DEFMSTR field selects a fixed default master, provided that DEFMSTR_TYPE is set to fixed default

master. Refer to the Section 15.9 “Bus Matrix (MATRIX) User Interface”.

15.6 Arbitration

The Bus Matrix provides an arbitration technique that reduces latency when conflicting cases occur; for example,

when two or m ore ma sters try to access the same slave a t the sam e time. O ne arbite r per AHB sla ve is prov ided,

so that each slave can be arbitrated differently.

The Bus Matrix provides the user with two types of arbitration for ea ch slave:

Round-robin arbitration (default)

Fixed priority arbitration

Each algorithm may be complemented by selecting a default master configuration for each slave.

When a re-arbitration must be done, specific conditions apply. See Section 15 .6.1 “Arbitration Rules”.

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15.6.1 Arbitration Rules

Each arbiter has the ability to arbitrate between requests from two or more masters. To avoid burst breaking and to

provide the maximum throughput for slave interfaces, arbitration should take place during the following cycles:

Idle cycles: When a slave is not connected to any master or is connected to a master which is not currently

accessing it.

Single cycles: When a slave is currently doing a single access.

End of Burst cycles: When the current cycle is the last cycle of a burst transfer. For a defined bu rst length,

predicted end of burst matches the size of the tran sfer but is man aged di fferently for undefined le ng th b urst.

See Section 15.6.1.1 “Undefined Length Burst Arbitration”.

Slot cycle limit: When the slot cycle counter has reached the limit value indicating that the current master

access is too long and mu st be br ok en . S ee Section 15.6.1.2 “Slot Cycle Limit Arbitration”.

15.6.1.1 Undefined Length Burst Arbitration

In order to prevent long AHB burst lengths th at can lock the access to the slave for an excessive period of time, the

user can trigger the re-arbitration before the end of the incremental bursts. The re-arbitration period can be

selected from the following Undefined Length Burst Type (ULBT) possibilities:

Unlimited: no predetermined end of burst is generated. This value enables 1 Kbyte burst lengths.

4-beat bursts: predetermined end of burst is generated at the end of each 4-beat boundary during INCR

transfer.

8-beat bursts: predetermined end of burst is generated at the end of each 8-beat boundary during INCR

transfer.

16-beat bursts: predetermined end of burst is generated at the end of each 16-beat boundary during INCR

transfer.

This selection is made through the ULBT field of the Master Configura tion re gisters (MATRIX_M CF G ).

15.6.1.2 Slot Cycle Limit Arbitration

The Bus Matrix contains specific logic to break long accesses, such as very long bursts on a very slow slave (e.g.,

an external low speed memory). At th e be ginning of the burst access, a counter is loaded with the value previously

written in the SLOT_CYCLE field of the related MATRIX_SCFG and decreased at each clock cycle. When the

counter reaches zero, the arbiter has the ability to re-arbitrate at the end of the current byte, half-word or word

transfer.

15.6.1.3 Round-Robin Arbitration

The Bus Matrix arbiters use the round-robin algorithm to dispatch the requests from different masters to the same

slave. If two or m ore maste rs make a r equest a t the same time, the master with the lowe st number is serviced firs t.

The others are then serviced in a round-robin manner.

Three round-robin algorithms are implemented:

Round-robin arbitration without defa ult master

Round-robin arbitration with last access master

Round-robin arbitration with fixed default master

Round-robin arbitration without default master

Round-robin arbitration without default master is the main algorithm used by Bus Matrix arbiters. Using this

algorithm, the Bus Matrix dispatches requests from different masters to the same slave in a pure round-robin

manner. At the end of the current access, if no other request is pending, the slave is disconnected from all

masters. This configuration incurs one latency cycle for the first access of a burst. Arbitration without default

master can be used for masters that perform significant bursts.

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Round-robin arbitration with last access master

Round-robin arbitration with last access master is a biased round-robin al gorithm used by Bus Matrix arbiter s to

remove one latency cycle for the last master that accessed the slave. At the end of the current transfer, if no other

master request is pend ing, the slave remains connect ed to the last master that performs the ac cess. Other non-

privileged masters still get one latency cycle if they attempt to access the same slave. This technique can be used

for masters that mainly perform single accesses.

Round-robin arbitration with fixed default master

Round-robin arb itratio n with fixed de fa ult m aster is an alg orith m use d by th e Bus Matr ix ar biters to remo ve the on e

latency cycle for the fixed default master per slave. At the end of the c urrent acc ess, the slave remains connected

to its fixed default master. Every request attempted by this fixed default master will not cause any latency whereas

other non-privileged masters will still get one latency cy cle. This technique can be used for masters that mainly

perform single accesses.

15.6.1.4 Fixed Priority Arbitration

The fixed priority algorithm is used by the Bus Matrix arbiters to dispatch the requests from different masters to the

same slave by using the fixed priority defined by the user. If requests from two or more masters are active at the

same time, the master with the highest priority number is serviced first. If requests from two or more master with

the same priority are active at the same time, the master with the highest number is serviced first.

For each slave, the priority of each master may be defined through the Priority registers for slaves

(MATRIX_PRAS).

15.7 System Configuration

The System I/O Configuration register (CCFG_SYSIO) configures I/O lines in system I/O mode (such as JTAG,

ERASE, USB I/Os, etc.) or as general-purpose I/O lines. Enabling or disabling the corresponding I/O lines in

peripheral mode or in PIO mode (PIO_PER or PIO_PDR registers) in the PIO controller has no effect. However,

the direction (input or output), pull-up, pull-down and other mode control is still managed by the PIO controller.

The USB Management register (CCFG_USBMR) configures the USB transceiver and selects the USB mode (Host

or Device).

The I2S Clock Source Selection register (CCFG_I2SCLKSEL) configures the I2S peripheral to provide a clock

source independent of the processor clock.

The Dynamic Clock Gati ng re gister (CCFG_DYNCKG) optimizes the power consumption for specific applications.

When enabled, the system bus circuitry is only driven by th e clock when necessary (transfer in prog ress, access to

peripheral, etc.).

15.8 Register Write Protection

To prevent any single software error from corrupting MATRIX behavior, certain registers in the address space can

be write-protected by setting the WPEN bit in the “Bus Matrix Write Protection Mode Register” (MATRIX_WPMR).

If a write access to a write-protected register is detected, the WPVS flag in the “Bus Matrix Write Protection Status

been attempted.

The WPVS flag is reset by writing the MATRIX_WPMR with the appropriate access key WPKEY.

The following registers can be write-protected:

“Bus Matrix Master Configuration Registers”

“Bus Matrix Slave Co nf igu ratio n Re gisters”

“Bus Matrix Priority Registers A For Slaves”

“System I/O Configuration Register”

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15.9 Bus Matrix (MATRIX) User Interface

Note: 1. This default reset value must not be modifi ed.

Table 15-4. Register Mapping

Offset Register Name Access Reset

0x0000 Master Configuration Register 0 MATRIX_MCFG0 Read/Write 0x00000000

0x0004 Master Configuration Register 1 MATRIX_MCFG1 Read/Write 0x00000000

0x0008 Master Configuration Register 2 MATRIX_MCFG2 Read/Write 0x00000000

0x000C Master Configuration Register 3 MATRIX_MCFG3 Read/Write 0x00000000

0x0010 Master Configuration Register 4 MATRIX_MCFG4 Read/Write 0x00000000

0x0014–0x003C Reserved – – –

0x0040 Slave Configuration Register 0 MATRIX_SCFG0 Read/Write 0x00010010

0x0044 Slave Configuration Register 1 MATRIX_SCFG1 Read/Write 0x00050010

0x0048 Slave Configuration Register 2 MATRIX_SCFG2 Read/Write 0x00000010

0x004C Slave Configuration Register 3 MATRIX_SCFG3 Read/Write 0x00000010

0x0050 Slave Configuration Register 4 MATRIX_SCFG4 Read/Write 0x00000010

0x0054–0x007C Reserved – – –

0x0080 Priority Register A for Slave 0 MATRIX_PRAS0 Read/Write 0x00000000

0x0084 Reserved – – –

0x0088 Priority Register A for Slave 1 MATRIX_PRAS1 Read/Write 0x00000000

0x008C Reserved – – –

0x0090 Priority Register A for Slave 2 MATRIX_PRAS2 Read/Write 0x00000000

0x0094 Reserved – – –

0x0098 Priority Register A for Slave 3 MATRIX_PRAS3 Read/Write 0x00000000

0x009C Reserved – – –

0x00A0 Priority Register A for Slave 4 MATRIX_PRAS4 Read/Write 0x00000000

0x00A4–0x010C Reserved – – –

0x0110 Reserved – – 0x22222224(1)

0x0114 System I/O Configuration Register CCFG_SYSIO Read/Write 0x0000_0C00

0x0118 Dynamic Clock Gating Register CC FG_DYNCKG Read/Write 0x00000007

0x011C I2S Clock Source Selection Register CCFG_I2SCLKSEL Read/Write 0x00000000

0x0120 USB Management Register CCFG_USBMR Read/Write 0x00000000

0x0124–0x01E0 Reserved – – –

0x1E4 Write Protection Mode Register MATRIX_WPMR Read/Write 0x0

0x1E8 Write Protection Status Register MATRIX_WPSR Read-only 0x0

0x01EC–0x01FC Reserved – – –

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15.9.1 Bus Matrix Master Configuration Registers

Name: MATRIX_MCFGx [x = 0..4]

Address: 0x400E0200

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the Bus Matrix Write Protection Mode Register.

• ULBT: Undefined Length Burst Type

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––– ULBT

Value Name Description

0UNLIMITEDNo predicted end of burst is generated and therefore INCR bursts coming from this master cannot be

broken.

1SINGLE The undefined length burst is treated as a succession of single access allowing rearbitration at each beat

of the INCR burst.

2 4_BEAT The undefined length burst is split into a 4-beat bursts allowing rearbitration at each 4-beat burst end.

3 8_BEAT The undefined length burst is split into 8-beat bursts allowing rearbitration at each 8-beat burst end.

4 16_BEAT The undefined length burst is split into 16-beat bursts allowing rearbitration at each 16 -beat burst end.

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15.9.2 Bus Matrix Slave Configuration Registers

Name: MATRIX_SCFGx [x = 0..4]

Address: 0x400E0240

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the Bus Matrix Write Protection Mode Register.

• SLOT_CYCLE: Maximum Number of Allowed Cycles for a Burst

When SLOT_CYCLE AHB clock cycles have elapsed since the la st a rb itr ation , a new a rb itr ation takes pl ace to le t ano th er

master access this slave. If another master is requesting the slave bus, then the current master burst is broken.

If SLOT_CYCLE = 0, the slot cycle limit feature is disabled and bursts always complete unless broken according to the

ULBT.

This limit has been placed in order to enforce arbitration so as to meet potential latency constraints of masters wa iting for

slave access.

This limit must not be too small. Unreasonably small values break every burst and the Bus Matrix arbitrates without per-

forming any data transfer. The default maximum value is usually an optimal conservative choice.

In most cases, this feature is not needed and should be disabled for power saving.

See Section 15.6.1.2 “Slot Cycle Limit Arbitration ” for details.

• DEFMSTR_TYPE: Default Master Type

• FIXED_DEF MST R : Fixe d De fa ul t Ma s te r

The number of th e de fa ult mas te r for this sla ve. Only us ed if DEFM ST R_ TY PE is 2. Spec ifyin g th e nu m be r of a mast er

which is not connected to the selected slave is equivalent to setting DEFMSTR_TYPE to 0.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – – FIXED_DEFMSTR DEFMSTR_TYPE

15 14 13 12 11 10 9 8

––––––––

76543210

SLOT_CYCLE

Value Name Description

0 NO_DEFAULT At the end of current slave access, if no other master request is pending, the slave is disconnected from all

masters.

This results in having a one cycle latency for the first access of a burst transfer or for a single access.

1 LAST At the end of current slave access, if no other master request is pending, the slave stays connected to the

last master having accessed it.

This results in not having the one cycle latency when the last master tries to access the slave again.

2 FIXED At the end of the current slave access, if no other master request is pending, the slave connects to the

fixed master the number that has been written in the FIXED_DEF MSTR field.

This results in not having the one cycle latency when the fixed master tries to access the slave again.

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15.9.3 Bus Matrix Priority Registers A For Slaves

Name: MATRIX_PRAS0..MATRIX_PRAS4

Address: 0x400E0280 [0], 0x400E0288 [1], 0x400E0290 [2], 0x400E0298 [3], 0x400E02A0 [4]

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the Bus Matrix Write Protection Mode Register.

• MxPR: Master x Priority

Fixed priority of master x to access the selected slave. The higher the number, the higher the priority.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––––– M4PR

15 14 13 12 11 10 9 8

–– M3PR –– M2PR

76543210

–– M1PR –– M0PR

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15.9.4 System I/O Configuration Register

Name: CCFG_SYSIO

Address: 0x400E0314

Access Read/Write

This register can only be written if the WPEN bit is cleared in the Bus Matrix Write Protection Mode Register.

• SYSIO4: PB4 or TDI Assignment

0: TDI function selected.

1: PB4 function selected.

• SYSIO5: PB5 or TDO/TRACESWO Assignment

0: TDO/TRACESWO function selected.

1: PB5 function selected.

• SYSIO6: PB6 or TMS/SWDIO Assignment

0: TMS/SWDIO function selected.

1: PB6 function selected.

• SYSIO7: PB7 or TCK/SWCLK Assignment

0: TCK/SWCLK function selected.

1: PB7 function selected.

• SYSIO10: PA21 or DM Assignment

0: DM function selected.

1: PA21 function selected.

• SYSIO11: PA22 or DP Assignment

0: DP function selected.

1: PA22 function selected.

• SYSIO12: PB12 or ERASE Assignment

0: ERASE function selected.

1: PB12 function selected.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

– – – SYSIO12 SYSIO11 SYSIO10 – –

76543210

SYSIO7 SYSIO6 SYSIO5 SYSIO4 ––––

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15.9.5 Dynamic Clock Gating Register

Name: CCFG_DYNCKG

Address: 0x400E0318

Access Read/Write

Note: Clearing all the bits provides the optimal energy reduction for the system bus circuitry.

• MAT CKG: MATRIX Dynamic Clock Gating

0: MATRIX Dynamic Clock Gating Enabled. The MATRIX circuitry is driven by the clock only when a transfer to a periph-

eral is being performed. The energy consumption is optimized.

1: MATRIX Dynamic Clock Gating Disabled. The MATRI X circuitry is always driven by the clock in Active mode.

• BRIDCKG: Bridge Dynamic Clock Gating Enable

0: Bridge Dynamic Clock Gating Enabled. The Peripheral Bridge circuitry is driven by the clock only when a transfer

to/from any peripheral located on the APB bus is being performed. The energy consumption is optimized.

1: Bridge Dynamic Clock Gating Disabled. The Peripheral Bridge circuitry is always driven by the clock in Active mode.

• EFCCKG: EFC Dynamic Clock Gating Enable

0: EFC Dynamic Clock Gating Enabled. The Embedded Flash Controller circuitry is driven by the clock only when an

access to the Flash memory is being performed. The energy consumption is optimized.

1: EFC Dynamic Clock Gating Disabled. The Embedded Flash Controller is always driven by the clock in Active mode.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––EFCCKGBRIDCKGMATCKG

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15.9.6 I2S Clock Source Selection Register

Name: CCFG_I2SCLKSEL

Address: 0x400E031C

Access Read/Write

• CLKSEL0: I2S0 Clock Source

0: Peripheral Clock selected (same frequency as processor clock)

1: PMC PCK4 selected (independent of processor clock)

• CLKSEL1: I2S1 Clock Source

0: Peripheral Clock selected (same frequency as processor clock)

1: PMC PCK4 selected (independent of processor clock)

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––CLKSEL1CLKSEL0

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15.9.7 USB Management Register

Name: CCFG_USBMR

Address: 0x400E0320

Access Read/Write

• USBMODE: USB Mode Selection

The USB transceiver is shared by the USB Host and the USB device. The selection is done through the USBMODE bit.

0: USB Host selected

1: USB Device selected

• USBHTSSC: USB Transceiver Suspend Software Control

0: USB Host Transceiver active

1: USB Host Transceiver in Suspend mode

• USBHTSC: USB Host Transceiver Suspend Control

0: USB Host transceiver is controlled by the USB Host (OHCI)

1: USB Host transceiver is controlled by the USBHTSSC bit

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – – USBHTSC USBHTSSC USBMODE

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15.9.8 Bus Matrix Write Protection Mode Register

Name: MATRIX_WPMR

Address: 0x400E03E4

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x4D4154 (“MAT” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x4D4154 (“MAT” in ASCII).

See Section 15.8 “Register Write Protection“ for the list of registers that can be write-protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x4D4154 PASSWD Writing any other value in this field aborts the write operation of the WPEN bit. Always reads as 0.

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15.9.9 Bus Matrix Write Protection Status Register

Name: MATRIX_WPSR

Address: 0x400E03E8

Access: Read-only

• WPVS: Write Protection Violation Status

0: No write protec tion v iola tio n ha s occ ur r ed since the last write of the MATRIX_WPMR.

1: A write protection violation has occurred since the last write of the MATRIX_W PM R. If this violation is an unauthorized

attempt to write a protected register, the associated violation is reported into field WPVSRC.

• WPVSRC: Write Protection Vi olation Source

When WPVS = 1, WPVSRC indicates the register address offset at which a write access has been attempted.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

WPVSRC

15 14 13 12 11 10 9 8

WPVSRC

76543210

–––––––WPVS

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16. Parallel Input/Output Controller (PIO)

16.1 Description

The Parallel Input/Output Controller (PIO) manages up to 32 fully programmable input/output lines. Each I/O line

may be dedicated as a general-purpose I/O or be assigned to a function of an embedded peripheral . This ensures

effective optimization of the pins of the product.

Each I/O line is associated with a bit number in all of the 32-bit registers of the 32-bit wide user interface.

Each I/O line of the PIO Controller features:

An input change interrupt enabling level change detection on any I/O line.

Additional Interrupt modes enabling rising edge, falling edge, low-level or high-level detection on any I/O

line.

A glitch filter providing rejection of glitches lower than one-half of peripheral clock cycle.

A debouncing filter providing rejection of unwanted pulses from key or push button operations.

Multi-drive capability similar to an open drain I/O line.

Control of the pull-up and pull-down of the I/O line.

Input visibility and output control.

The PIO Controller also features a synchronous output providing up to 32 bits of data output in a single write

operation.

16.2 Embedded Characteristics

Up to 32 Programmable I/O Lines

Fully Programmable through Set/Clear Registers

Multiplexing of Four Peripheral Functions per I/O Line

For each I/O Line (Whether Assigned to a Peripheral or Used as General Purpose I/O)

Input Change Interrupt

Programmable Glitch Filter

Programmable Debouncing Filter

Multi-drive Option Enables Driving in Open Drain

Programmable Pull-Up on Each I/O Line

Pin Data Status Register, Supplies Visibility of the Level on the Pin at Any Time

Additional Interrupt Modes on a Programmable Event: Rising Edge, Falling Edge, Low-Level or High-

Level

Synchronous Output, Provides Set and Clear of Several I/O Lines in a Single Write

Register Write Protection

Programmable Schmitt Trigger Inputs

Programmable I/O Drive

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16.3 Block Diagram

Figure 16-1. Block Diagram

16.4 Product Dependencies

16.4.1 Pin Multiplexing

Each pin is configurable, depending on the product, as either a general-purpose I/O line only, or as an I/O line

multiplexed with one or two peripheral I/Os. As the multiplexing is hardware defined and thus product-dependent,

the hardware designer and programmer must carefully determine the conf iguration of the PIO Controllers required

by their application. When an I/O line is general-purpose only, i.e., not multiplexed with any peripheral I/O,

programming of the PIO Controller regarding the assignment to a peripheral has no effect and only the PIO

Controller can control how the pin is driven by the product.

16.4.2 External Interrupt Lines

When the WKUPx input pins must be used as external interrupt lines, the PIO Controller must be configured to

disable the peripheral control on these IOs, and the corresponding IO lines must be set to Input mode.

Embedded

Peripheral

Embedded

Peripheral

PIO Interrupt

PIO Controller

PMC

Up to x

peripheral IOs

Up to x

peripheral IOs

Peripheral Clock

APB

Interrupt Controller

Data, Enable

PIN x-1

PIN 1

PIN 0

Data, Enable

x is an integer representing the maximum number

of IOs managed by one PIO controller.

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16.4.3 Power Management

The Power Management Controller controls the peripheral clock in order to save power. Writing any of the

registers of the user interface does not require the peripheral clock to be enabled. This means that the

configuration of the I/O lines does not require the peripheral clock to be enabled.

However, when the clock is disabled, not all of the features of the PIO Controller are available, including glitch

filtering. Note that th e inpu t chan ge inter rupt, th e inte rrupt modes on a progr ammabl e event an d the r ead of th e pin

level require the cloc k to be valid at ed .

After a hardware reset, the peripheral clock is disabled by default.

The user must configure the Power Management Controller before any access to the input line information.

16.4.4 Interrupt Sources

For interrupt handling, the PIO Controllers are considered as user peripherals. This means that the PIO Controller

interrupt lines are connected among the interrupt sources. Refer to the PIO Controller peripheral identifier in the

Peripheral Identifiers table to identify the interrupt sources dedicated to the PIO Controllers. Using the PIO

Controller requires the Interrupt Controller to be programmed first.

The PIO Controller interrupt can be generated only if the peripheral clock is enabled.

Table 16-1. Peripheral IDs

Instance ID

PIOA 11

PIOB 12

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16.5 Functional Description

The PIO Controller features up to 32 fully-programmable I/O lines. Most of the control logic associated to each I/O

is represented in Figure 16-2. In this description each signal shown represents one of up to 32 possible indexes.

Figure 16-2. I/O Line Control Logic

16.5.1 Pull-up and Pull-down Resistor Control

Each I/O line is designed with an embedded pull-up resistor and an embedded pull-down resistor. The pull-up

resistor can be enabled or disabled by writing to the Pull-up Enable Register (PIO_PUER) or Pull-up Disable

the Pull-up Status Register (PIO_PUSR). Reading a one in PIO_PUSR means the pull-up is disabled and reading

a zero means the pull-up is enabled. T he pull-down resistor can be enabled or disabled by writing the Pull-down

Enable Register (PIO_PPDER) or the Pull-down Disable Register (PIO_PPDDR), respectively. Writing in these

DQ DQ

DFF

Programmable

Glitch

Debouncing

Filter

PIO_PDSR[0] PIO_ISR[0]

PIO_IDR[0]

PIO_IMR[0]

PIO_IER[0]

PIO Interrupt

(Up to 32 possible inputs)

PIO_ISR[31]

PIO_IDR[31]

PIO_IMR[31]

PIO_IER[31]

Pad

PIO_PUDR[0]

PIO_PUSR[0]

PIO_PUER[0]

PIO_MDDR[0]

PIO_MDSR[0]

PIO_MDER[0]

PIO_CODR[0]

PIO_ODSR[0]

PIO_SODR[0]

PIO_PDR[0]

PIO_PSR[0]

PIO_PER[0]

PIO_ABCDSR1[0]

PIO_ODR[0]

PIO_OSR[0]

PIO_OER[0]

Peripheral Clock

Resynchronization

Stage

Peripheral A Input

Peripheral D Output Enable

Peripheral A Output Enable

EVENT

DETECTOR

DFF

PIO_IFDR[0]

PIO_IFSR[0]

PIO_IFER[0]

Peripheral Clock

Clock

Divider

PIO_IFSCSR[0]

PIO_IFSCER[0]

PIO_IFSCDR[0]

PIO_SCDR

Slow Clock

Peripheral B Output Enable

Peripheral C Output Enable

Peripheral D Output

Peripheral A Output

Peripheral B Output

Peripheral C Output

PIO_ABCDSR2[0]

Peripheral B Input

Peripheral C Input

Peripheral D Input

PIO_PPDDR[0]

PIO_PPDSR[0]

PIO_PPDER[0]

VDD

GND

Integrated

Pull-Down

Resistor

Integrated

Pull-Up

Resistor

div_slck

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registers results in setting or clearing the corresponding bit in the Pull-down Status Register (PIO_PPDSR).

Reading a one in PIO_PPDSR means the pull-up is disable d and reading a zero means the pull-down is enabled.

Enabling the pull-down resistor while th e pull-up resistor is still enabled is not possible. In this case, the write of

PIO_PPDER for the relevant I/O line is discarded. Likewise, enabling the pull-up resistor while the pull-down

resistor is still enabled is not possible. In this case, the write of PIO_PUER for the relev ant I/O line is discarded.

Control of the pull-up resistor is possible regardless of the configuration of the I/O line.

After reset, depending on the I/O, pull-up or pull-down can be set.

16.5.2 I/O Line or Peripheral Function Selection

When a pin is multiplexed with one or two peripheral functions, the selection is controlled with the Enable Register

(PIO_PER) and the Disable Registe r (PIO_PDR) . The Status Register (PIO_PSR) is the result of the set and clear

registers and indicates whether the pin is controlled by the corresponding peripheral or by the PIO Controller. A

value of zero indicates that the pin is controlled by the corresponding on-chip peripheral selected in the Peripheral

ABCD Select registers (PIO_ABCDSR1 and PIO_ABCDSR2). A value of one indicates the pin is controlled by the

PIO Controller.

If a pin is used as a general-purpose I/O line (not multiplexed with an on-chip peripheral), PIO_PER and PIO_PDR

have no effect and PIO_PSR returns a one for the corresponding bit.

After reset, th e I/O lines are controlled by the PI O Controller, i.e., PIO_PSR reset s at one. However, in some

events, it is important th at PIO lines are controlle d by the periphera l (as in the case of memory chip sele ct lines that

must be driven inactive after reset, or for address lines that must be driven low for booting out of an external

memory). Thus, the reset value of PIO_PSR is defined at the pr oduct level and depends on the multiplexing of the

device.

16.5.3 Peripheral A or B or C or D Selection

The PIO Controller provides multiplexing of up to four peripheral functions on a single pin. The selection is

performed by writing PIO_ABCDSR1 and PIO_ABCDSR2.

For each pin:

The corresponding bit at level zero in PIO_ABCDSR1 and the corresponding bit at level zero in

PIO_ABCDSR2 means peripheral A is selected.

The corresponding bit at level one in PIO_ABCDSR1 and the corresponding bit at level zero in

PIO_ABCDSR2 means peripheral B is selected.

The correspo nd ing bit at level zero in PIO_ABCDSR 1 an d th e cor re sp o ndi ng bit at level on e in

PIO_ABCDSR2 means peripheral C is selected.

The correspo nd ing bit at level on e in PIO _ABCDSR1 and the corresponding bit at level one in

PIO_ABCDSR2 means peripheral D is selected.

Note that multiplexing of peripheral lines A, B, C and D only affects the output line. The peripheral input lines are

always connec te d to th e pin input (se e Figure 16-2).

Writing in PIO_ABCDSR1 and PIO_ABCDSR2 manages the multiplex ing regardless of the config uration of the

pin. However, assignment of a pin to a peripheral function requires a write in PIO_ABCDSR1 and PIO_ABCDSR2

in addition to a write in PIO_PDR.

After reset, PIO_ABCDSR1 and PIO_ABCDSR2 are zero, thus indicating that all the PIO lines are configured on

peripheral A. However, peripheral A generally does not drive the pin as the PIO Controller resets in I/O line mode.

If the software selects a peripheral A, B, C or D which does not exist for a pin, no alternate functions are enabled

for this pin and the selection is taken into account. The PIO Controller does not carry out checks to prevent

selection of a peripheral which does not exist.

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16.5.4 Output Control

When the I/O line is assigned to a peripher al function, i.e., the corre sponding bit in PIO_PSR is a t zero, the drive of

the I/O line is controlled by the peripheral. Peripheral A or B or C or D depending on the value in PIO_ABCDSR1

and PIO_ABCDSR2 determines whether the pin is driven or not.

When the I/O line is controlled by th e PIO Controller, the p in can be configured to be drive n. This is done by writing

the Output Enable Register (PIO_OER) and Output Disa ble Register (PIO_ODR). Th e results of these write

operations are detected in the Output Status Register (PIO_OSR). When a bit in this register is at zero, the

corresponding I/O line is used as an input only. When the bit is at one, the corresponding I/O line is driven by the

PIO Controller.

The level driven on an I/O line can be determined by writing in the Set Output Data Register (PIO_SODR) and the

Clear Output Data Register (PIO_CODR). These write operations, respectively, set and clear the Output Data

Status Register (PIO_ODSR), which represents the data driven on the I/O lines. Writing in PIO_OER and

PIO_ODR manages PIO_OSR whether the pin is configured to be controlled by the PIO Controller or assigned to

a peripheral function. This enables configuration of the I/O line prior to setting it to be managed by the PIO

Controller.

Similarly, writing in PIO_SODR and PIO_CODR affects PIO_ODSR. This is important as it defines the first level

driven on the I/O line.

16.5.5 Synchronous Data Output

Clearing one or more PIO line(s) and setting another one or more PIO line(s) synchronously cannot be done by

using PIO_SODR and PIO_CODR. It requires two successive write operations into two different registers. To

overcome this, the PIO Controller offers a direct control of PIO outputs by single write access to PIO_ODSR. Only

bits unmasked by the Outp ut Write Stat us Register (PIO_OWSR) are written. The mask bits in PIO_OWSR are set

by writing to the Output Write Enable Register (PIO_OWER) and cleared by writing to the Output Write Disable

After reset, the synchronous data output is disabled on all the I/O lines as PIO_OWSR resets at 0x0.

16.5.6 Multi-Drive Control (Open Drain)

Each I/O can be independently programmed in open drain by using the multi-drive feature. This feature permits

several drivers to be connected on the I/O line which is driven low only by each device. An external pull-up resistor

(or enabling of the internal one) is generally required to guarantee a high level on the line.

The multi-drive feature is controlled by the Multi-driver Enable Register (PIO_MDER) and the Multi-driver Disable

assigned to a peripheral function. The Multi-driver Status Register (PIO_MDSR) indicates the pins that are

configured to support external drivers.

After reset, the multi-drive feature is disabled on all pins, i.e., PIO_MDSR resets at value 0x0.

16.5.7 Output Line Timings

Figure 16-3 shows how the outputs are driven either by writing PIO_SODR or PIO_CODR, or by directly writing

PIO_ODSR. This last case is valid only if the corresponding bit in PIO_OWSR is set. Fi gure 1 6-3 also shows when

the feedback in the Pin Data Status Register (PIO_PDSR) is available.

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Figure 16-3. Output Line Timings

16.5.8 Inputs

The level on each I/O line can be read through PIO_PDSR. This register indicates the level of the I/O lines

regardless of the ir configuration, whether uniquely a s an input, or driven by the PIO Controller, o r driven by a

peripheral.

Reading the I/O line levels requires the clock of the PIO Controller to be enabled, otherwise PIO_PDSR reads the

levels present on the I/O line at the time the cloc k was disab le d.

16.5.9 Input Glitch and Debouncing Filters

Optional input glitch and debouncing filters are independently programmable on each I/O line.

The glitch filter can filter a glitch with a duration of less than 1/2 pe rip her al clock a nd the de bouncing filter can filter

a pulse of less than 1/2 period of a programmable divide d slow clock.

The selection between glitch filtering or debounce filtering is done by writing in the PIO Input Filter Slow Clock

Disable Register (PIO_IFSCDR) and the PIO Input Filter Slow Clock Enable Register (PIO_IFSCER). Writing

PIO_IFSCDR and PIO_IFSCER, respectively, sets and clears bits in the Input Filter Slow Clock Status Register

(PIO_IFSCSR).

The current sele ctio n statu s ca n be che cke d by rea ding th e PIO_IFSCSR.

If PIO_IFSCSR[i] = 0: The glitch filter can filter a glitch with a duration of less than 1/2 master clock period.

If PIO_IFSCSR[i] = 1: The debouncing filter can filter a pulse with a duration of less than 1/2 programmable

divided slow clock period.

For the debouncing filter, the period of the d ivided slow clock is define d by writ ing in the DIV field of the Slow Clock

Divider Debouncing Register (PIO_SCDR):

tdiv_slck = ((DIV + 1) × 2) × tslck

When the glitch or debo uncing filter is enabled, a glitch or p ulse with a duration of less than 1/2 se lected clock

cycle (selected clock represents peripheral clock or divided slow clock depending on PIO_IFSCDR and

PIO_IFSCER programming) is automatically rejected, while a pulse with a duration of one selected clock

(peripheral clock or divided slow clock) cycle or more is accepted. For pulse durations between 1/2 selecte d cloc k

cycle and one selected clock cycle, the pulse may or may not be taken into account, depending on the precise

timing of its occurrence. Thus for a pulse to be visible, it must exceed one selected clock cycle, whereas for a glitch

to be reliably filtered out, its duration must not exceed 1/2 selected clock cycle.

The filters also introduce some latencies, illustrated in Figure 16-4 and Figure 16-5.

2 cycles

APB Access

2 cycles

APB Access

Peripheral clock

Write PIO_SODR

Write PIO_ODSR at 1

PIO_ODSR

PIO_PDSR

Write PIO_CODR

Write PIO_ODSR at 0

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The glitch filters are controlled by the Input Filter Enable Register (PIO _IFER), the Input Filter Disable Register

(PIO_IFDR) and the Inpu t Filter Status Register (PIO_IFSR). Writing PIO_IFER and PIO_IFDR respectively sets

and clears bits in PIO_IFSR. This last register enables the glitch filter on the I/O lines.

When the glitch and/or debouncing filter is enabled, it does not modify the behavior of the inputs on the

peripherals. It acts only on the value re ad in PIO_PDSR and on th e input change inte rrupt detection. The glitch and

debouncing filters require that the peripheral clock is enabled.

Figure 16-4. Input Glitch Filter Timing

Figure 16-5. Input Debouncing Filter Timing

16.5.10 Input Edge/Level Interrupt

The PIO Controller can be programmed to generate an interrupt when it detects an edge or a level on an I/O line.

The Input Edge/Level interrupt is controlled by writing the Interrupt Enable Register (PIO_IER) and the Interrupt

Disable Register (PIO_IDR), which enable and disable the input change interrupt respectively by setting and

clearing the corr esponding bit in the In terrupt Mask Regi ster (PIO_IMR). As input ch ange detection is possible only

by comparing two successive samplings of the input of the I/O line, the peripheral clock must be enabled. The

Input Change interrupt is available regardless of the configuration of the I/O line, i.e., configured as an input only,

controlled by the PIO Controller or assigned to a peripheral function.

By default, the interrupt can be generated at any time an edge is detected on the input.

Some addition al interrupt modes c an be enabled/disable d by writing in the Ad ditional Interrupt Mod es Enable

selection can be read through the Additional Interrupt Modes Mask Register (PIO_AIMMR).

Peripheral clcok

Pin Level

PIO_PDSR

if PIO_IFSR = 0

PIO_PDSR

if PIO_IFSR = 1

1 cycle 1 cycle 1 cycle

up to 1.5 cycles

2 cycles

up to 2.5 cycles up to 2 cycles

1 cycle

PIO_IFCSR = 0

Divided Slow Clock

(div_slck)

Pin Level

PIO_PDSR

if PIO_IFSR = 0

PIO_PDSR

if PIO_IFSR = 1

1 cycle tdiv_slck

up to 1.5 cycles tdiv_slck

1 cycle tdiv_slck

up to 2 cycles tperipheral clock up to 2 cycles tperipheral clock

up to 2 cycles tperipheral clock

up to 1.5 cycles tdiv_slck

PIO_IFCSR = 1

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These additional modes are:

Rising edge detection

Falling edge detection

Low-level detection

High-level detection

In order to select an additional interrupt mode:

The type of event detection (edge or level) must be selected by writing in the Edge Select Register

(PIO_ESR) and Level Select Register (PIO_LSR) which select, respectively, the edge and level detection.

The current status of this sele ct ion is acce ssib le th ro ug h th e Edg e /L eve l Status Register (PIO_ELS R) .

The polarity of the event detection (rising/falling edge or high/low-level) must be selected by writing in the

Falling Edge/Low-Level Select Register (PIO_FELLSR) and Rising Edge/High-Level Select Register

(PIO_REHLSR) which allow to select falling or rising edge (if edge is selected in PIO_ELSR) edge or high-

or low-level detection (if level is selected in PIO_ELSR). The current status of this selection is accessible

through the Fall/Rise - Low/High Status Register (PIO_FRLHSR).

When an input edge or level is detected on an I/O line, the corresponding bit in the Interrupt Status Register

(PIO_ISR) is set. If the corresponding bit in PIO_IMR is set, the PIO Controller interrupt line is asserted.The

interrupt signals of the 32 channels are ORed-wired together to generate a single interrupt signal to the interrupt

controller.

When the software reads PIO_ISR, all the interrupts are automatically cleared. This signifies that all the interrupts

that are pending when PIO_ISR is read m ust be han dled. Wh en an In terrup t is enab led on a “level” , th e inte rrupt is

generated as long as the interrupt source is not cleared, even if some read accesses in PIO_ISR are performed.

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Figure 16-6. Event Detector on Input Lines (Figure Represen ts Line 0)

Example of interrupt generation on following lines:

Rising edge on PIO line 0

Falling edge on PIO line 1

Rising edge on PIO line 2

Low-level on PIO line 3

High-level on PIO line 4

High-level on PIO line 5

Falling edge on PIO line 6

Rising edge on PIO line 7

Any edge on the othe r line s

Table 16-2 provides the required configuration for this example.

Event Detector

Edge

Detector

Falling Edge

Detector

Rising Edge

Detector

PIO_FELLSR[0]

PIO_FRLHSR[0]

PIO_REHLSR[0]

Low Level

Detector

High Level

Detector

PIO_ESR[0]

PIO_ELSR[0]

PIO_LSR[0]

PIO_AIMDR[0]

PIO_AIMMR[0]

PIO_AIMER[0]

Event detection on line 0

Resynchronized input on line 0

Table 16-2. Configuration for Example Interrupt Generation

Configuration Description

Interrupt Mode All the interrup t so urces are enable d by writing 32’hFFFF_FFFF in PIO_ IER .

Then the additional interrupt mode is enabled for lines 0 to 7 by writing 32’h0000_00FF in

PIO_AIMER.

Edge or Level Detection

Lines 3, 4 and 5 are configured in level detection by writing 32’h0000_0038 in PIO_LSR.

The other lines are configured in edge detection by default, if they have not been previously

configured. Otherwise, lines 0, 1, 2, 6 and 7 must be configured in edge detection by writing

32’h0000_00C7 in PIO_ESR.

Falling/Rising Edge or Low/High-Level

Detection

Lines 0, 2, 4, 5 and 7 are configured in rising edge or high-level detection by writing

32’h0000_00B5 in PIO_REHLSR.

The other lines are configured in falling edge or low-level detection by default if they have

not been previously configured. Otherwise, lines 1, 3 and 6 must be configured in falling

edge/low-level detecti on by writ ing 32’h0000_004A in PIO_FELL SR.

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Figure 16-7. Input Change Interrupt Timings When No Additional Interrupt Modes

16.5.11 Programmable I/O Drive

It is possible to configure the I/O drive for pads -. Refer to the section “Electrica l Characteristics”.

16.5.12 Programmable Schmitt Trigger

It is possible to configure each in put for the Schmitt trigge r. By default the Schmitt tri gger is active. Disabling the

Schmitt trigger is requested when using the QTouch® Library.

Peripheral clock

Pin Level

Read PIO_ISR APB Access

PIO_ISR

APB Access

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16.5.13 I/O Lines Programming Example

The programming example shown in Table 16-3 is used to obtain the following configuration:

4-bit output port on I/O lines 0 to 3 (should be written in a single write operation), open-drain, with pull-up

resistor

Four output signals on I/O lines 4 to 7 (to drive LEDs for example), driven high and low, no pull-up resistor,

no pull-down resistor

Four input signals on I/O lines 8 to 11 (to read push-button states for example), with pull-up resistors, glitch

filters and input change interrupts

Four input signals on I/O line 12 to 15 to read an external device status (polled, thus no input change

interrupt), no pull-up resistor, no glitch filter

I/O lines 16 to 19 assigned to peripheral A functions with pull-up resistor

I/O lines 20 to 23 assigned to peripheral B functions with pull-down resistor

I/O lines 24 to 27 assigned to peripheral C with input change interrupt, no pull-up resistor and no pull-down

resistor

I/O lines 28 to 31 assigned to peripheral D, no pull-up resistor and no pull-down resistor

Table 16-3. Programming Example

PIO_PER 0x0000_FFFF

PIO_PDR 0xFFFF_0000

PIO_OER 0x0000_00FF

PIO_ODR 0xFFFF_FF00

PIO_IFER 0x0000_0F00

PIO_IFDR 0xFFFF_F0FF

PIO_SODR 0x0000_0000

PIO_CODR 0x0FFF_FFFF

PIO_IER 0x0F00_0F00

PIO_IDR 0xF0FF_F0FF

PIO_MDER 0x0000_000F

PIO_MDDR 0xFFFF_FFF0

PIO_PUDR 0xFFF0_00F0

PIO_PUER 0x000F_FF0F

PIO_PPDDR 0xFF0F_FFFF

PIO_PPDER 0x00F0_0000

PIO_ABCDSR1 0xF0F0_0000

PIO_ABCDSR2 0xFF00_0000

PIO_OWER 0x0000_000F

PIO_OWDR 0x0FFF_ FFF0

347

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.5.14 Register Write Protection

To prevent any single software error from corrupting PIO behavior, certain registers in the address space can be

write-protected by setting the WPEN bit in the PIO Write Protection Mode Register (PIO_WPMR).

If a write access to a write-protected register is detected, the WPVS flag in the PIO Write Protection Status

attempted.

The WPVS bit is automatically cleared after reading the PIO_WPSR.

The following registers can be write-protected:

PIO Enable Register

PIO Disable Register

PIO Output Enable Register

PIO Output Disab le Re gist er

PIO Input Filter Enable Register

PIO Input Filter Disable Register

PIO Multi-driver Enable Register

PIO Multi-driver Disable Register

PIO Pull-Up Disable Register

PIO Pull-Up Enable Register

PIO Peripheral ABCD Select Register 1

PIO Peripheral ABCD Select Register 2

PIO Output Write Enable Register

PIO Output Write Disable Register

PIO Pad Pull-Down Disable Register

PIO Pad Pull-Down Enable Register

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

348

16.6 Parallel Input/Output Controller (PIO) User Interface

Each I/O line controlled by the PIO Controller is associated with a bit in each of the PIO Controller User Interface

registers. Each register is 32-bit wide. If a parallel I/O line is not defined, writing to the corresponding bits has no

effect. Undefined bits read zero. If the I/O line is not multiplexed with any peripheral, the I/O line is controlled by the

PIO Controller and PIO_PSR returns one systematically.

Table 16-4. Register Mapping

Offset Register Name Access Reset

0x0000 PIO Enable Register PIO_PER Write-only –

0x0004 PIO Disable Register PIO_PDR Write-only –

0x0008 PIO Status Register PIO_PSR Read-only (1)

0x000C Reserved – – –

0x0010 Output Enable Register PIO_OER Write-only –

0x0014 Output Disable Register PIO_ODR Write-only –

0x0018 Output Status Register PIO_OSR Read-only 0x00000000

0x001C Reserved – – –

0x0020 Glitch Input Filter Enable Register PIO_IFER Write-only –

0x0024 Glitch Input Filter Disable Register PIO_IFDR Write-only –

0x0028 Glitch Input Filter Status Register PIO_IFSR Read-only 0x00000000

0x002C Reserved – – –

0x0030 Set Output Data Register PIO_SODR Write-only –

0x0034 Clear Output Data Register PIO_CODR Write-only

0x0038 Output Data Status Register PIO_ODSR Read-only

or(2)

Read/Write –

0x003C Pin Data Status Register PIO_PDSR Read-only (3)

0x0040 Interrupt Enable Register PIO_IER Write-only –

0x0044 Interrupt Disable Register PIO_IDR Write-only –

0x0048 Interrupt Mask Register PIO_IMR Read-only 0x00000000

0x004C Interrupt Status Register(4) PIO_ISR Read-only 0x00000000

0x0050 Multi-driver Enable Regi ster PIO_MDER Write-only –

0x0054 Multi-driver Disable Register PIO_MDDR Write-only –

0x0058 Multi-driver Status Register PIO_MDSR Read-only 0x00000000

0x005C Reserved – – –

0x0060 Pull-up Disable Register PIO_PUDR Write-only –

0x0064 Pull-up Enable Register PIO_PUER Write-only –

0x0068 Pad Pull-up Status Register PIO_PUSR Read-only (1)

0x006C Reserved – – –

0x0070 Peripheral ABCD Select Register 1 PIO_ABCDSR1 Read/Write 0x00000000

0x0074 Peripheral ABCD Select Register 2 PIO_ABCDSR2 Read/Write 0x00000000

0x0078–0x007C Reserved – – –

349

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Notes: 1. Reset value depends on the product implementation.

2. PIO_ODSR is Read-only or Read/Write depending on PIO_OWSR I/O lines.

3. Reset value of PIO_PDSR depends on the level of the I/O lines. Reading the I/O line levels requires the clock of the PIO

Controller to be enabled, otherwise PIO_PDSR reads the levels present on the I/O line at the time the clock was disabled.

4. PIO_ISR is reset at 0x0. However, the first read of the register may read a different value as input changes may have

occurred.

5. If an offset is not listed in the table it must be considered as reserved.

0x0080 Input Filter Slow Clock Disable Register PIO_IFSCDR Write-only –

0x0084 Input Filter Slow Clock Enable Register PIO_IFSCER Write-only –

0x0088 Input Filter Slow Clock Status Register PIO_IFSCSR Read-only 0x00000000

0x008C Slow Clock Divider Debouncing Register PIO_SCDR Read/Write 0x0000000 0

0x0090 Pad Pull-down Disable Register PIO_PPDDR Write-only –

0x0094 Pad Pull-down Enable Register PIO_PPDER Write-only –

0x0098 Pad Pull-down Status Register PIO_PPDSR Read-only (1)

0x009C Reserved – – –

0x00A0 Output Write Enable PIO_OWER Write-only –

0x00A4 Output Write Disable PIO_OWDR Write-only –

0x00A8 Output Write Status Register PIO_OWSR Read-only 0x00000000

0x00AC Reserved – – –

0x00B0 Additional Interrupt Modes Enable Register PIO_AIMER Write-only –

0x00B4 Additional Interrupt Modes Disable Register PIO_AIMDR Write-only –

0x00B8 Additional Interrupt Modes Mask Register PIO_AIMMR Read-only 0x00000000

0x00BC Reserved – – –

0x00C0 Ed ge Select Register PIO_ESR Write-only –

0x00C4 Level Select Register PIO_LSR Write-only –

0x00C8 Edge/Level Status Register PIO_ELSR Read-only 0x00000000

0x00CC Reserved – – –

0x00D0 Falling Edge/Low-Level Select Register PIO_FELLSR Write-only –

0x00D4 R ising Edge/High-Level Select Register PIO_REHLSR Write-only –

0x00D8 Fall/Rise - Low/High Status Register PIO_FRLHSR Read-only 0x00000000

0x00DC Reserved – – –

0x00E0 Reserved – – –

0x00E4 Write Protection Mode Register PIO_WPMR Read/Write 0x00000000

0x00E8 Write Protection Status Register PIO_WPSR Read-only 0x00000000

0x00EC–0x00FC Reserved – – –

0x0100 Schmitt T rigger Register PIO_SCHMITT Read/Write 0x00000000

0x0104–0x010C Reserved – – –

0x0110 I/O Drive Register PIO_DRIVER Read/Write 0x00000000

0x0114–0x011C Reserved – – –

0x0120–0x014C Reserved – – –

Table 16-4. Register Mapping (Continued)

Offset Register Name Access Reset

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

350

16.6.1 PIO Enable Register

Name: PIO_PER

Address: 0x400E0E00 (PIOA), 0x400E1000 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: PIO Enable

0: No effect.

1: Enables the PIO to control the corresponding pin (disables peripheral control of the pin).

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

351

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.2 PIO Disable Register

Name: PIO_PDR

Address: 0x400E0E04 (PIOA), 0x400E1004 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: PIO Disa b le

0: No effect.

1: Disables the PIO from controlling the corresponding pin (enables peripheral control of the pin).

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

352

16.6.3 PIO Status Register

Name: PIO_PSR

Address: 0x400E0E08 (PIOA), 0x400E1008 (PIOB)

Access: Read-only

• P0–P31: PIO Status

0: PIO is inactive on the corresponding I/O line (peripheral is active).

1: PIO is active on the corresponding I/O line (peripheral is inactive).

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

353

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.4 PI O Output Enable Register

Name: PIO_OER

Address: 0x400E0E10 (PIOA), 0x400E1010 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Output Enable

0: No effect.

1: Enables the output on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

354

16.6.5 PIO Output Disable Register

Name: PIO_ODR

Address: 0x400E0E14 (PIOA), 0x400E1014 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Output Disable

0: No effect.

1: Disables the output on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

355

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.6 PIO Output Status Register

Name: PIO_OSR

Address: 0x400E0E18 (PIOA), 0x400E1018 (PIOB)

Access: Read-only

• P0–P31: Output Status

0: The I/O line is a pure input.

1: The I/O line is enabled in output.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

356

16.6.7 PIO Input Filter Enable Register

Name: PIO_IFER

Address: 0x400E0E20 (PIOA), 0x400E1020 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Input Filter Enable

0: No effect.

1: Enables the input glitch filter on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

357

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.8 PI O Input Filter Disable Register

Name: PIO_IFDR

Address: 0x400E0E24 (PIOA), 0x400E1024 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Input Filter Disable

0: No effect.

1: Disables the input glitch filter on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

358

16.6.9 PI O Input Filter Status Register

Name: PIO_IFSR

Address: 0x400E0E28 (PIOA), 0x400E1028 (PIOB)

Access: Read-only

• P0–P31: Input Filter Status

0: The input glitch filter is disabled on the I/O line.

1: The input glitch filter is enabled on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

359

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.10 PIO Set Output Data Register

Name: PIO_SODR

Address: 0x400E0E30 (PIOA), 0x400E1030 (PIOB)

Access: Write-only

• P0–P31: Set Output Data

0: No effect.

1: Sets the data to be driven on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

360

16.6.11 PIO Clear Output Data Register

Name: PIO_CODR

Address: 0x400E0E34 (PIOA), 0x400E1034 (PIOB)

Access: Write-only

• P0–P31: Clear Output Data

0: No effect.

1: Clears the data to be driven on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

361

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.12 PIO Output Data Status Register

Name: PIO_ODSR

Address: 0x400E0E38 (PIOA), 0x400E1038 (PIOB)

Access: Read-only or Read/Write

• P0–P31: Ou t pu t Data Status

0: The data to be driven on the I/O line is 0.

1: The data to be driven on the I/O line is 1.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

362

16.6.13 PIO Pin Data Status Register

Name: PIO_PDSR

Address: 0x400E0E3C (PIOA), 0x400E103C (PIOB)

Access: Read-only

• P0–P31: Ou t pu t Data Status

0: The I/O line is at level 0.

1: The I/O line is at level 1.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

363

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.14 PIO Interrupt Enable Register

Name: PIO_IER

Address: 0x400E0E40 (PIOA), 0x400E1040 (PIOB)

Access: Write-only

• P0–P31: Input Change Interrupt Enable

0: No effect.

1: Enables the input change interrupt on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

364

16.6.15 PIO Interrupt Disable Register

Name: PIO_IDR

Address: 0x400E0E44 (PIOA), 0x400E1044 (PIOB)

Access: Write-only

• P0–P31: Input Change Interrupt Disable

0: No effect.

1: Disables the input change interrupt on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

365

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.16 PIO Interrupt Mask Register

Name: PIO_IMR

Address: 0x400E0E48 (PIOA), 0x400E1048 (PIOB)

Access: Read-only

• P0–P31: Input Change Interrupt Mask

0: Input change interrupt is disabled on the I/O line.

1: Input change interrupt is enabled on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

366

16.6.17 PIO Interrupt Status Register

Name: PIO_ISR

Address: 0x400E0E4C (PIOA), 0x400E104C (PIOB)

Access: Read-only

• P0–P31: Input Change Interrupt Status

0: No input change has been detected on the I/O line since PIO_ISR was last read or since reset.

1: At least one input change has been detected on the I/O line since PIO_ISR was last read or since reset.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

367

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.18 PIO Multi-driver Enable Register

Name: PIO_MDER

Address: 0x400E0E50 (PIOA), 0x400E1050 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0-P31: Multi-drive Enable

0: No effect.

1: Enables multi-drive on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

368

16.6.19 PIO Multi-driver Disable Register

Name: PIO_MDDR

Address: 0x400E0E54 (PIOA), 0x400E1054 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Multi-drive Disable

0: No effect.

1: Disables multi-drive on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

369

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.20 PIO Multi-driver Status Register

Name: PIO_MDSR

Address: 0x400E0E58 (PIOA), 0x400E1058 (PIOB)

Access: Read-only

• P0–P31: Multi-drive Status

0: The multi-drive is disabled on the I/O line. The pin is driven at high- and low-level.

1: The multi-drive is enabled on the I/O line. The pin is driven at low-level only.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

370

16.6.21 PIO Pull-Up Disable Register

Name: PIO_PUDR

Address: 0x400E0E60 (PIOA), 0x400E1060 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Pull-Up Disable

0: No effect.

1: Disables the pull-up resistor on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

371

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.22 PIO Pull-Up Enable Register

Name: PIO_PUER

Address: 0x400E0E64 (PIOA), 0x400E1064 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Pull-Up Enable

0: No effect.

1: Enables the pull-up resistor on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

372

16.6.23 PIO Pull-Up Status Register

Name: PIO_PUSR

Address: 0x400E0E68 (PIOA), 0x400E1068 (PIOB)

Access: Read-only

• P0–P31: Pull-Up Status

0: Pull-up resistor is enabled on the I/O line.

1: Pull-up resistor is disabled on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

373

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.24 PIO Peripheral ABCD Select Register 1

Name: PIO_ABCDSR1

Address: 0x400E0E70 (PIOA), 0x400E1070 (PIOB)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Peripheral Select

If the same bit is set to 0 in PIO_ABCDSR2:

0: Assigns the I/O line to the Peripheral A function.

1: Assigns the I/O line to the Peripheral B function.

If the same bit is set to 1 in PIO_ABCDSR2:

0: Assigns the I/O line to the Peripheral C function.

1: Assigns the I/O line to the Peripheral D function.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

374

16.6.25 PIO Peripheral ABCD Select Register 2

Name: PIO_ABCDSR2

Address: 0x400E0E74 (PIOA), 0x400E1074 (PIOB)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Peripheral Select

If the same bit is set to 0 in PIO_ABCDSR1:

0: Assigns the I/O line to the Peripheral A function.

1: Assigns the I/O line to the Peripheral C function.

If the same bit is set to 1 in PIO_ABCDSR1:

0: Assigns the I/O line to the Peripheral B function.

1: Assigns the I/O line to the Peripheral D function.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

375

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.26 PIO Input Filter Slow Clock Disable Register

Name: PIO_IFSCDR

Address: 0x400E0E80 (PIOA), 0x400E1080 (PIOB)

Access: Write-only

• P0–P31: Peripheral Clock Glitch Filtering Select

0: No effect.

1: The glitch filter is able to filter glitches with a duration < tperipheral clock/2.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

376

16.6.27 PIO Input Filter Slow Clock Enable Register

Name: PIO_IFSCER

Address: 0x400E0E84 (PIOA), 0x400E1084 (PIOB)

Access: Write-only

• P0–P31: Slow Clock Debouncing Filtering Select

0: No effect.

1: The debouncing filter is able to filter pulses with a duration < tdiv_slck/2.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

377

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.28 PIO Input Filter Slow Clock Status Register

Name: PIO_IFSCSR

Address: 0x400E0E88 (PIOA), 0x400E1088 (PIOB)

Access: Read-only

• P0–P31: Glitch or Debouncing Filter Selection Status

0: The glitch filter is able to filter glitches with a duration < tperipheral clock/2.

1: The debouncing filter is able to filter pulses with a duration < tdiv_slck/2.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

378

16.6.29 PIO Slow Clock Divider Debouncing Register

Name: PIO_SCDR

Address: 0x400E0E8C (PIOA), 0x400E108C (PIOB)

Access: Read/Write

• DIV: Slow Clock Divider Selection for Debouncing

tdiv_slck = ((DIV + 1) × 2) × tslck

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–– DIV

76543210

DIV

379

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.30 PIO Pad Pull-Down Disable Register

Name: PIO_PPDDR

Address: 0x400E0E90 (PIOA), 0x400E1090 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Pull-Down Disable

0: No effect.

1: Disables the pull-down resistor on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

380

16.6.31 PIO Pad Pull-Down Enable Registe r

Name: PIO_PPDER

Address: 0x400E0E94 (PIOA), 0x400E1094 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Pull-Down Enable

0: No effect.

1: Enables the pull-down resistor on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

381

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.32 PIO Pad Pull-Down Status Register

Name: PIO_PPDSR

Address: 0x400E0E98 (PIOA), 0x400E1098 (PIOB)

Access: Read-only

• P0–P31: Pull-Down Status

0: Pull-down resistor is enabled on the I/O line.

1: Pull-down resistor is disabled on the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

382

16.6.33 PIO Output Write Enable Register

Name: PIO_OWER

Address: 0x400E0EA0 (PIOA), 0x400E10A0 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Output Write Enable

0: No effect.

1: Enables writing PIO_ODSR for the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

383

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.34 PIO Output Write Disable Register

Name: PIO_OWDR

Address: 0x400E0EA4 (PIOA), 0x400E10A4 (PIOB)

Access: Write-only

This register can only be written if the WPEN bit is cleared in the PIO Write Protection Mode Register.

• P0–P31: Output Write Disable

0: No effect.

1: Disables writing PIO_ODSR for the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

384

16.6.35 PIO Output Write Status Register

Name: PIO_OWSR

Address: 0x400E0EA8 (PIOA), 0x400E10A8 (PIOB)

Access: Read-only

• P0–P31: Ou tput Write Stat u s

0: Writing PIO_ODSR does not affect the I/O line.

1: Writing PIO_ODSR affects the I/O line.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

385

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.36 PIO Additional Interrupt Modes Enable Register

Name: PIO_AIMER

Address: 0x400E0EB0 (PIOA), 0x400E10B0 (PIOB)

Access: Write-only

• P0–P31: Additional Interrupt Modes Enable

0: No effect.

1: The interrupt source is the event described in PIO_ELSR and PIO_FRLHSR.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

386

16.6.37 PIO Additional Interrupt Modes Disable Register

Name: PIO_AIMDR

Address: 0x400E0EB4 (PIOA), 0x400E10B4 (PIOB)

Access: Write-only

• P0–P31: Additional Interrupt Modes Disable

0: No effect.

1: The interrupt mode is set to the default interrupt mode (both-edge detection).

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

387

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.38 PIO Additional Interrupt Modes Mask Register

Name: PIO_AIMMR

Address: 0x400E0EB8 (PIOA), 0x400E10B8 (PIOB)

Access: Read-only

• P0–P31: IO Line Index

Selects the IO event type triggering an interrupt.

0: The interrupt source is a both-edge detection event.

1: The interrupt source is described by the registers PIO_ELSR and PIO_FRLHSR.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

388

16.6.39 PIO Edge Select Register

Name: PIO_ESR

Address: 0x400E0EC0 (PIOA), 0x400E10C0 (PIOB)

Access: Write-only

• P0–P31: Edge Interrupt Selection

0: No effect.

1: The interrupt source is an edge-detection event.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

389

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.40 PIO Level Select Register

Name: PIO_LSR

Address: 0x400E0EC4 (PIOA), 0x400E10C4 (PIOB)

Access: Write-only

• P0–P31: Level Interrupt Selection

0: No effect.

1: The interrupt source is a level-detection event.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

390

16.6.41 PIO Edge/Level Status Register

Name: PIO_ELSR

Address: 0x400E0EC8 (PIOA), 0x400E10C8 (PIOB)

Access: Read-only

• P0–P31: Edge/Level Interrupt Source Selection

0: The interrupt source is an edge-detection event.

1: The interrupt source is a level-detection event.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

391

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.42 PIO Falling Edge/Low-Level Select Register

Name: PIO_FELLSR

Address: 0x400E0ED0 (PIOA), 0x400E10D0 (PIOB)

Access: Write-only

• P0–P31: Falling Edge/Low-Level Interrupt Selection

0: No effect.

1: The interrupt source is set to a falling edge detection or low-level detection eve nt, depending on PIO_ELSR.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

392

16.6.43 PIO Rising Edge/High-Level Select Register

Name: PIO_REHLSR

Address: 0x400E0ED4 (PIOA), 0x400E10D4 (PIOB)

Access: Write-only

• P0–P31: Rising Edge/High-Level Interrupt Selection

0: No effect.

1: The interrupt source is set to a rising edge detection or high-leve l detection event, depending on PIO_ELSR.

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

393

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.44 PIO Fall/Rise - Low/High Status Register

Name: PIO_FRLHSR

Address: 0x400E0ED8 (PIOA), 0x400E10D8 (PIOB)

Access: Read-only

• P0–P31: Edge/Level Interrupt Source Selection

0: The interrupt source is a falling edge detection (if PIO_ELSR = 0) or low-level detection event (if PIO_ELSR = 1).

1: The interrupt source is a rising edge detection (if PIO_ELSR = 0) or high-level detection event (if PIO_ELSR = 1).

31 30 29 28 27 26 25 24

P31 P30 P29 P28 P27 P26 P25 P24

23 22 21 20 19 18 17 16

P23 P22 P21 P20 P19 P18 P17 P16

15 14 13 12 11 10 9 8

P15 P14 P13 P12 P11 P10 P9 P8

76543210

P7 P6 P5 P4 P3 P2 P1 P0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

394

16.6.45 PIO Write Protection Mode Registe r

Name: PIO_WPMR

Address: 0x400E0EE4 (PIOA), 0x400E10E4 (PIOB)

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x50494F (“PIO” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x50494F (“PIO” in ASCII).

See Section 16.5.14 “Register Write Protection” for the list of registers that can be protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x50494F PASSWD Writing any other value in this field aborts the write operation of the WPEN bit.

Always reads as 0.

395

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.46 PIO Write Protection Status Register

Name: PIO_WPSR

Address: 0x400E0EE8 (PIOA), 0x400E10E8 (PIOB)

Access: Read-only

• WPVS: Write Protection Violation Status

0: No write protec tion v iola tio n ha s occ u rred since the last read of the PIO_WPSR.

1: A write protection violation has occurred since the last read of the PIO_WPSR. If this violation is an unauthorized

attempt to write a protected register, the associated violation is reported into field WPVSRC.

• WPVSRC: Write Protection Vi olation Source

When WPVS = 1, WPVSRC indicates the register address offset at which a write access has been attempted.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

WPVSRC

15 14 13 12 11 10 9 8

WPVSRC

76543210

–––––––WPVS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

396

16.6.47 PIO Schmitt Trigger Register

Name: PIO_SCHMITT

Address: 0x400E0F00 (PIOA), 0x400E1100 (PIOB)

Access: Read/Write

• SCHMITTx [x=0..31]: Schmitt Trigger Control

0: Schmitt trigger is enabled.

1: Schmitt trigger is disabled.

31 30 29 28 27 26 25 24

SCHMITT31 SCHMITT30 SCHMITT29 SCHMITT28 SCHMITT27 SCHMITT26 SCHMITT25 SCHMITT24

23 22 21 20 19 18 17 16

SCHMITT23 SCHMITT22 SCHMITT21 SCHMITT20 SCHMITT19 SCHMITT18 SCHMITT17 SCHMITT16

15 14 13 12 11 10 9 8

SCHMITT15 SCHMITT14 SCHMITT13 SCHMITT12 SCHMITT11 SCHMITT10 SCHMITT9 SCHMITT8

76543210

SCHMITT7 SCHMITT6 SCHMITT5 SCHMITT4 SCHMITT3 SCHMITT2 SCHMITT1 SCHMITT0

397

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

16.6.48 PIO I/O Drive Register

Name: PIO_DRIVER

Address: 0x400E0F10 (PIOA), 0x400E1110 (PIOB)

Access: Read/Write

• LINEx [x=0..31]: Drive of PIO Li ne x

31 30 29 28 27 26 25 24

LINE31 LINE30 LINE29 LINE28 LINE27 LINE26 LINE25 LINE24

23 22 21 20 19 18 17 16

LINE23 LINE22 LINE21 LINE20 LINE19 LINE18 LINE17 LINE16

15 14 13 12 11 10 9 8

LINE15 LINE14 LINE13 LINE12 LINE11 LINE10 LINE9 LINE8

76543210

LINE7 LINE6 LINE5 LINE4 LINE3 LINE2 LINE1 LINE0

Value Name Description

0 LOW_DRIVE Lowest drive

1 HIGH_DRIVE Highest drive

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

398

17. Clock Generator

17.1 Description

The Clock Generator user interface is embedded within the Power Management Controller and is described in

Section 18.20 ”Power Management Controller (PMC) User Interface”. However, the Clock Generator registers are

named CKGR_.

17.2 Embedded Characteristics

The Clock Generator is made up of:

A low-power 32768 Hz crystal oscillator with Bypass mode

A low-power embedded 32 kHz (typical) RC oscillator

A 3 to 20 MHz crystal or ceramic resonator-based oscillator, which can be bypassed.

A factory-trimmed embedded RC oscillator. Three output frequencies can be selected: 8/16/24 MHz. By

default 8 MHz is selected.

Two programmable PLLs, (PLLA input from 20 to 300 KHz, output clock range 48 to 120 MHz and PLLB

input from 20 to 100KHz, output clock range 24 to 48MHz), capable of providing the clock MCK to the

processor and to the peripherals.

It provides the following clocks:

SLCK, the slow clock, which is the only permanent clock within the system.

MAINCK is the output of the main clock oscillator selection: either the crystal or ceramic resonator-based

oscillator or 8/16/24 MHz RC oscillator.

PLLACK is the output of the 48 to 120 MHz programmable PLL (PLLA).

PLLBCK is the output of the 24 to 48MHz programmable PLL (PLLB).

399

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

17.3 Block Diagram

Figure 17-1. Clock Generator Block Diagram

PLLA Clock

PLLACK

3–20 MHz

Crystal

Ceramic

Resonator

Oscillator

Embedded

8/16/24 MHz

RC Oscillator

PLLB Clock

PLLBCK

ControlStatus

MOSCSEL

XIN

XOUT

XIN32

XOUT32

32768 Hz

Crystal

Oscillator

or external

oscillator

Embedded

32 kHz

RC Oscillator

Clock Generator

XTALSEL (SUPC_CR)

Slow Clock

SLCK

Main Clock

MAINCK

Power

Management

Controller

CKGR_MOR

OSCBYPASS (SUPC_MR)

PLLA and

Divider/2

PLLADIV2

PMC_MCKR

PLLB and

Divider/2

PLLBDIV2

PMC_MCKR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

400

17.4 Slow Clock

The Supply Controller embeds a slow clock generator that is supplied with the VDDIO power supply. As soon as

VDDIO is supplied, both the 32768 Hz crystal oscillator and the embedded 32 kHz (typical) RC oscillator are

powered up, but only the RC oscillator is enabled. This allows the slow clock to be valid in a short time (about

100 µs).

The slow clock is generated either by the 32768 Hz crystal oscillator or by the embedded 32 kHz (typical) RC

oscillator.

The selection of the slow clock source is made via the XTALSEL bit in the Supply Contr oller Control Register

(SUPC_CR).

The OSCSEL bit of the Supply Controller Status Register (SUPC_SR) and the OSCSELS bit of the PMC Status

when the switch se qu en ce initia te d by a ne w value written in SUPC_CR.XTALSEL is done.

17.4.1 Embedded 32 kHz (typical) RC Oscillator

By default, the embedded 32 kHz (typical) RC oscillator is enabled an d selected. The user has to take into ac count

the possible drifts of this oscillator. More details are given in the section “DC Characteristics”.

This oscillator is disabled by clearing the SUPC_CR.XTALSEL.

17.4.2 32768 Hz Crystal Oscillator

The Clock Generator integrates a low-power 32768 Hz crystal oscillator. To u se this oscillator, the XIN32 and

XOUT32 pins must be connecte d to a 32768 Hz crysta l. Two externa l capacito rs must be wired a s shown in Figure

17-2. More details are given in the section “DC Characteristics”.

Note that the user is not obliged to use the 32768 Hz crystal oscillator and can use the 32 kHz (typical) RC

oscillator instead.

Figure 17-2. Typical 32768 Hz Crystal Oscillator Connection

The 32768 Hz crystal oscillator provides a more accurate frequency than the 32 kHz (typical) RC oscillator.

To select the 32768 Hz crystal oscillator as the source of the slow clock, the bit SUPC_CR.XTALSEL must be set.

This results in a sequence which first configures the PIO lines multiplexed with XIN32 and XOUT32 to be drive n by

the slow clock oscillator, then enables the 32768 Hz crystal oscillator and then disables the 32 kHz (typical) RC

oscillator to save power. The switch of the slow clock source is glitch-free.

Reverting to the 32 kHz (typical) RC oscillator is only possible by shutting down the VDDIO power supply. If the

user does not need the 32768 Hz crystal oscillator, the XIN32 and XOUT32 pins can be left unconnected since by

default the XIN32 and XOUT32 system I/O pins are in PIO input mode with pull-up after reset.

The user can also set the 32768 Hz crystal oscillator in Bypass mode instead of connecting a crystal. In this case,

the user must provide the external clock signa l on XIN32. The input characteristics of the XIN32 pin are give n in

the section “Electrical Characteristics”. To enter Bypass mode, the OSCBYPASS bit of the Supply Controller Mode

XIN32 XOUT32 GND

32768 Hz

Crystal

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17.5 Main Clock

Figure 17-3 shows the main clock block diagram.

Figure 17-3. Main Clock Bloc k Diagram

The main clock has two sources:

A 8/16/24 MHz RC oscillator with a fast start-up time and that is selected by default to start the system

A 3 to 20 MHz crystal or ceramic resonator-based oscillator which can be bypassed

XIN

XOUT

MOSCXTEN

MOSCXTST

MOSCXTS

Main Clock

Frequency

Counter

MAINF

SLCK

Slow Clock

3–20 MHz

Crystal

Ceramic Resonator

Oscillator

3–20 MHz

Oscillator

Counter

MOSCRCEN

Fast RC

Oscillator

MOSCRCS

MOSCRCF

MOSCRCEN

MOSCXTEN

MOSCSEL

MOSCSEL MOSCSELS

MAINCK

Main Clock

MAINCK

Main Clock

Ref.

RCMEAS

CKGR_MCFR

CKGR_MOR CKGR_MOR

CKGR_MOR

PMC_SR

CKGR_MOR

CKGR_MCFR

PMC_SR

CKGR_MCFR

MAINFRDY

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17.5.1 Embedded 8/16/24 MHz RC Oscillator

After reset, the 8/16/24 MHz RC oscillator is enabled with the 8 MHz frequency selected. This oscillator is selected

as the source of MAINCK. MAINCK is the default clock selected to start the system.

The 8/16/24 MHz RC oscillator freq uencies are calibrate d in production e xcept for the lowe st frequency which is

not calibrated.

Refer to the section “DC Characteristics”.

The software can disable or enable the 8/16/24 MHz RC oscillator with the MOSCRCEN bit in the Clock Generator

Main Oscillator Register (CKGR_MOR).

The output frequency of the RC oscillator can be se lected among 8/16/24 MHz. The selection is done via the

CKGR_MOR.MOSCRCF field. When changing the frequency selection, the MOSCRCS bit in the Power

Management Controller Status Register (PMC_SR) is automatically cleared and MAINCK is stopped until the

oscillator is stabilized. Once the oscillator is stabilized, MAINCK restarts and PMC_SR.MOSCRCS is set.

When disabling the main clock by clearing the CKGR_MOR.MOSCRCEN bit, the PMC_SR.MOSCRCS bit is

automatically cleared, indicating the main clock is off.

Setting the MOSCRCS bit in the Power Management Controller Interrupt Enable Register (PMC_IER) can trigger

an interrupt to the processor.

When main clock (MAINCK) is not used to drive the processor and frequency monitor (SLCK or PLLACK or

PLLBCK is used instead), it is recommend ed to disable the 8/16/24 MHz RC oscillator and 3 to 20 MHz crystal

oscillator.

The CAL8, CAL16 and CAL24 values in the PMC Oscillator Calibration Register (PMC_OCR) are the default

values set by Atmel during production. These values are stored in a specific Flash memory area different from the

memory plane for code. These values cannot be modified by the user and cannot be erased by a Flash erase

command or by the ERASE pin. Values written by the user application in PMC_OCR are reset after each power up

or peripheral reset.

17.5.2 8/16/24 MHz RC Oscillator Clock Frequency Adjustment

It is possible for the user to adjust the 8/16/24 MHz RC oscillator frequency throug h PMC_OCR. By default,

SEL8/16/24 bits are cleared, so the RC oscillator wi ll be driven with Flash calibration bits which are programmed

during chip production.

The user can adjust the trimming of the 8/16/24 MHz RC oscillator through this register. This can be used to

compensate derating factors such as temperature and voltage, thus providing greater accuracy.

In order to calibrate the RC oscillator lower frequency, SEL8 bit must be set to 1 and a frequency value must be

configured in the field CAL8. Likewise, SEL16/24 bit must be set to 1 and a trim value must be configur ed in the

field CAL16/24 in order to adjust the other frequencies of the RC oscillator.

It is possible to adjust the RC oscillator frequency while operating from this clock. For example, when running on

lowest frequency it is possible to change the CAL8 value if PMC_OCR.SEL8 bit is set.

At any time, it is possible to restart a measurement of the frequency of the selected clock via the RCMEAS bit in

Main Clock Frequency Register (CKGR_MCFR). Thus, when CKGR_MCFR.MAINFRDY reads 1, another read

access on CKGR_MCFR provides an image of the frequency on CKGR_MCFR.MAINF field. The software can

calculate the error with an expected frequency and correct the CAL8 (or CAL16/CAL2 4) field accordingly. This

may be used to compensate frequency drift due to derating fa ctors such as temperature and/or voltage.

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17.5.3 3 to 20 MHz Crystal or Ceramic Resonator-b ased Oscillator

After reset, the 3 to 20 MHz crystal or ceramic resonator-based oscillator is disabled and is not selected as the

source of MAINCK.

As the source of MAINCK, the 3 to 20 MHz crystal or ceramic reso nator-based oscillator provides a very precise

frequency. The software enables or disables this oscillator in order to reduce power consumption via

CKGR_MOR.MOSCXTEN.

When disabling this oscillator by cl earing the CKGR_MOR.MOSCXTEN, PMC_SR.MOSCXTS is automatically

cleared, indicating the 3 to 20 MHz crystal oscillator is off.

When enabling this oscillator, the user must initiate the start-up time counter. The start-up time depends on the

characteristics of the external device connecte d to this oscillator.

When CKGR_MOR.MOSCXTEN and CKGR_MOR.MOSCXTST are written to enable this oscillator, the XIN and

XOUT pins are automatically switched into Oscillator mode. PMC_SR.MOSCXTS is cleared and the counter starts

counting down on the slow clock divided by 8 from the CKGR_MOR.MOSCXTST value. Since the

CKGR_MOR.MOSCXTST value is coded with 8 bits, the maximum start-up time is about 62 ms.

When the start-up time counter reaches 0, PMC_SR.MOSCXTS is set, indicating that the 3 to 20 M Hz crystal

oscillator is stabilized. Setting the MOSCXTS bit in the Interrupt Mask Register (PMC_IMR) can trigger an interrupt

to the processor.

17.5.4 Main Clock Source Selection

The user can select the source of the main clock from either the 8/16/24 MHz RC oscillator, the 3 to 20 MHz crystal

oscillator or the ceramic resonator-based oscillator.

The advantage of the 8/16/24 MHz RC oscillator is its fast start-up time. By default, this oscillator is selected to

start the system and when entering Wait mode.

The advantage of the 3 to 20 MHz crystal oscillator or ceramic resonator-based oscillator is its precise frequency.

The selection of the oscillator is made by writing CKGR_MOR.MOSCSEL. The switch of the main clock source is

glitch-free, so there is no need to run out of SLCK, PLLACK in order to change the selection.

PMC_SR.MOSCSELS indicates when the switch sequen ce is done.

Setting PMC_IMR.MOSCSELS triggers an interrupt to the processor.

Enabling the 8/16/24 MHz RC oscillator (MOSCRCEN = 1) and changing its frequency (MOSCCRF) at the same

time is not allowed.

This oscillator must be enabled first and its frequency changed in a second step.

17.5.5 Bypassing the 3 to 20 MHz Crystal Oscillator

Prior to bypassing the 3 to 20 MHz crystal oscillator, the external clock frequency provided on the XIN pin must be

stable and within the values specified in the XIN Clock characteristics in the section “Ele ctr ical Characteristics”.

The sequence is as follows:

1. Ensure that an external clock is connected on XIN.

2. Enable the bypass by writing a 1 to CKGR_MOR.MOSCXTBY.

3. Disable the 3 to 20 MHz crystal oscillator by writing a 0 to bit CKGR_MOR.MOSCXTEN.

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17.5.6 Main Clock Frequency Counter

The frequency counter is managed by CKGR_MCFR.

During the measurement period, the frequency counter increments at the main clock speed.

A measurement is started in the following cases:

When the RCMEAS bit of CKGR_MCFR is written to 1.

When the 8/16/24 MH z RC oscillator is selected as the source of main clock and when this oscillator

becomes stable (i.e., when the MOSCRCS bit is set)

When the 3 to 20 MHz crystal or ceramic resonator-based oscillator is selected as the source of main clock

and when this oscillator becomes stable (i.e., when the MOSCXTS bit is set)

When the main clock source selection is modified

The measurement period ends at the 16th falling edge of slow clock, the MAINFRDY bit in CKGR_MCFR is set

and the counter stop s co unting . Its valu e can be re ad in the MAINF field of CKGR_MCFR and g ives the num ber of

clock cycles during 16 periods of slow clock, so that the frequency of the 8/16/24 MHz RC oscillator or 3 to 20 MHz

crystal or ceramic resonator-based oscillator can be determined.

17.5.7 Switching Main Clock between the RC Oscillator and the Crystal Oscillator

When switching the source of the main clock between the RC oscillator and the crystal oscillator, both oscillators

must be enabled. After completion of the switch, the unused oscillator can be disabled.

If switching to the crystal oscillator, a check mus t be carried out to ensure that the oscillator is present and that its

frequency is valid. Follow the sequence below:

1. Select the slow clock as MCK by configuring bit CSS = 0 in the Master Clock Register (PMC_MCKR)).

2. Wait for PMC_SR.MCKRDY flag in PMC_SR to rise.

3. Enable the crystal oscillator by setting CKGR_MOR.MOSCXTEN. Configure the CKGR_MOR. MOSCXTST

field with the crystal oscillator start-up time as defined in the section “Electrical Characteristics”.

4. Wa it for PMC_SR.MOSCXTS flag to rise, indicating the end of a start-up period of the crystal oscillator.

5. Select the crystal oscillator as the source of the main clock by setting CKGR_MOR.MOSCSEL.

6. Read CKGR_MOR.MOSCSEL until its value equals 1.

7. Check the status of PMC_SR.MOSCSELS flag:

If MOSCSELS = 1: There is a crystal oscillator connected.

a. Initiate a new frequency measurement by setting CKGR_MCFR.RCMEAS.

b. Read CKGR_MCF R.MAINFRDY until its value equals 1.

c. Read CKGR_MCFR.MAINF and compute the value of the crystal frequency.

d. If the MAINF value is valid, the main clock can be switched to the crystal oscillator.

If MOSCSELS = 0:

a. There is no crystal oscillator connected or the crystal oscillator is out of specification.

b. Select the RC oscillator as the source of the main clock by clearing CKGR_MOR.MOSCSEL.

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17.6 Divider and PLL Block

The device features two PLL blocks that permit a wide range of frequencies to be selected on either the master

clock, the processor clock or th e pr og rammab l e clock outputs. A 48 MHz clock signal is provided to the e mbedde d

USB device port regardless of the frequency of the main clo ck.

Figure 17-4 shows the block diagram of the divider and PLL blocks.

Figure 17-4. PLL Block Diagram

17.6.1 Phase Lock Loop Programming

The PLLs (PLLA, PLLB) allow multiplic ation of the SLCK clock source. The PLL clock signal has a frequency that

depends on the respective source signal frequency and MUL (MULA) and PLLEN (PLLAEN, PLLBEN). The factor

applied to the source signal fr equency is MUL + 1. When MUL is written to 0 or PLLEN = 0, the PLL is disabled and

its power consumption is saved. Note that there is a delay of two SLCK clock cycles between the disable

command and the real disable of the PLL. Re-enabling the PLL can be performed by writing a value higher than 0

in the MUL field and PLLA(B)EN higher than 0.

Whenever the PLL is re-enabled or one of its param eter s is ch ang ed, th e LOCK (LOCKA, LOCKB) bit in PMC_SR

is automatically cleared. The values written in the PLLCOUNT field (PLLACOUNT, PLLBCOUNT) in CKGR_PLLR

(CKGR_PLLAR, CKGR_PLLBR) are loaded in the PL L coun ter . T he PLL cou nter th en decre men ts at the spee d of

the slow clock until it reaches 0. At this time, the LOCK bit is set in PMC_SR and can trigger an interrupt to the

processor. The user has to load the number of slow clock cycles required to cover the PLL transient time into the

PLLCOUNT field.

The PLL clock can be divided by 2 by writing the PLLDIV2 (PLLADIV2, PLLBDIV2) bit in PMC_MCKR.

To avoid programming the PLL with a multiplication factor that is too high, the use r can saturat e the multiplic ation

factor value sent to the PLL by se ttin g th e PLLA_MMAX and PLLB_MMAX fields in PMC_PMMR.

It is prohibited to change the frequency of the 8/16/24 MHz RC oscillator or to change the source of the main clock

in CKGR_MOR while the mast er clock source is the PLL.

PLLA

MULA

PLLACOUNT

LOCKA

PLLACK

PLLA

Counter

SLCK

CKGR_PLLAR

PMC_SR

CKGR_PLLAR

PLLB

MULB

PLLBCOUNT

LOCKB

PLLBCK

PLLB

Counter

CKGR_PLLBR

PMC_SR

CKGR_PLLBR

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406

The user must:

1. Switch on the 8/16/24 MHz RC oscillator by writing a 1 to the CSS field of PMC_MCKR.

2. Change the frequency (MOSCRCF) or oscillator selection (MOSCSEL) in CKGR_MOR.

3. Wait for MOSCRCS (if frequency changes) or MOSCSELS (if oscillator selection changes) in PMC_SR.

4. Disable and then enable the PLL.

5. Wait for the LOCK flag in PMC_SR.

6. Switch back to the PLL by writing the appropriate value to the CSS field of PMC_MCKR.

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18. Power Management Controller (PMC)

18.1 Description

The Power Management Controller (PMC) optimizes power consumption by controlling all system and user

peripheral clocks. The PMC en ables/disables the clock inputs to many of the pe ripherals and the Cortex-M4

processor.

The Supply Controller selects either the embedded 32 kHz RC oscillator or the 32768 Hz crystal oscillator. The

unused oscillator is disabled automatically so that power consumption is optimized.

By default, at startup, the chip runs out of the master clock using the 8/16/24 MHz RC oscillator running at 8 MHz.

The user can trim the 16 and 24 MHz RC oscillator frequencies by software.

18.2 Embedded Characteristics

The PMC provides the following clocks:

MCK, the Master Clock, programmable from a few hundred Hz to the maximum operating frequency of the

device. It is available to the modules running permanently, such as the Enhanced Embedded Flash

Controller.

Processor Clock (HCLK) , automatically switched off when entering the processor in Sleep Mode

Free-running processor Clock (FCLK)

The Cortex-M4 SysTick external clock

Peripheral Clocks, provided to the embedded peripherals (USART, SPI, TWI, TC, etc.) and independently

controllable. Some of the peripherals can be configured to be driven by MCK divided by 2, 4, 8.

Programmable Clock Outputs (PCKx), selected from the clock generator outputs to drive the device PCK

pins

Clock sources independ ent of MCK and HCLK, provided by internal PCKx for FLEXCOM (USART/SPI/TWI),

Timer, ADCC and PDMIC

The PMC also provides the following features on clocks:

A 3 to 20 MHz crystal oscillator clock failure detector

A 32768 Hz crystal oscillator frequency monitor

A frequency counter on main clock

An on-the-fly adjustable 8/16/24 MHz RC oscillator frequency

Asynchronous partial wakeup (SleepWalking) for FLEXCOM0-7, ADC

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18.3 Block Diagram

Figure 18-1. General Clock Block Diagram

MCK

periph_clk[..]

int

SLCK

MAINCK

PLLACK

Prescaler

/1,/2,/3,/4,/8,

/16,/32,/64

HCLK

Processor

Clock

Controller

Sleep Mode

Master Clock Controller

(PMC_MCKR)

Clock Controller

(PMC_PCERx) ON/OFF

Prescaler

/1 to /256

granularity=1 pck[..]

ON/OFF

FCLK

SysTick

Divider

SLCK

MAINCK

PLLACK

Processor clock

Free Running Clock

Master Clock

Programmable Clock Controller

(PMC_PCKx)

PRES

PRESCSS

CSS

MCK

Peripherals

PLLBCK

UDPCK

Divider

/1, /2, /3,... /16

USB Clock Controller (PMC_USB)

PLLBCK

USBDIV

USBS

PLLACK ON/OFF

UHPCK

(PMC_SCER/SCDR)

PLLA Clock

PLLACK

3–20 MHz

Crystal

Ceramic

Resonator

Oscillator

Embedded

8/16/24 MHz

RC Oscillator

PLLB Clock

PLLBCK

ControlStatus

MOSCSEL

XIN

XOUT

XIN32

XOUT32

32768 Hz

Crystal

Oscillator

or external

oscillator

Embedded

32 kHz

RC Oscillator

Clock Generator

XTALSEL (SUPC_CR)

Slow Clock

SLCK

Main Clock

MAINCK

Power

Management

Controller

CKGR_MOR

OSCBYPASS (SUPC_MR)

PLLA and

Divider/2

PLLADIV2

PMC_MCKR

PLLB and

Divider/2

PLLBDIV2

PMC_MCKR

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Figure 18-2. Peripheral Clock Divider Block Diagra m

18.4 Master Clock Controller

The Master Clock Controller provi des selection and di vision of the master clock (MCK) . MCK is the source clock of

the peripheral clocks. The master clock is selected from one of the clocks provided by the Clock Generator.

Selecting the slow clock provides a slow clock signal to the whole device. Selecting the main clock saves power

consumption of the PLL. The Master Clock Controller is made up of a clock selector and a prescaler.

The master clock selection is made by writing the CSS field (Clock Source Selection) in PMC_MCKR.

The prescaler supports the division by a power of 2 of the selected clock between 1 and 64, and the division by 3.

The PRES field in PMC_MCKR programs the prescaler.

Each time PMC_MCKR is written to define a new master clock, the MCKRDY bit is cleared in PMC_SR. It reads 0

until the master clock is established. Then, the MCKRDY bit is set and can trigger an interrupt to the processor.

This feature is useful wh en switching from a high-speed clock to a lower one to inform the software when the

change is actually done.

Figure 18-3. Master Clock Contro ller

18.5 Processor Clock Controller

The PMC features a Processor Clock Controller (HCLK) that implements the processor Sleep mode. These

processor clock can be disabled by executing the WFI (WaitForInterrupt) or the WFE (WaitForEvent) processor

instruction while the LPM bit is at 0 in the PMC Fast Startup Mode Register (PMC_FSMR).

MCK

periph_clk[n]

int

SLCK

MAINCK

PLLACK

Prescaler

/1,/2,/3,/4,/8,

/16,/32,/64

HCLK

Processor

Clock

Controller

Sleep Mode

Master Clock Controller

(PMC_MCKR)

Peripherals

Clock Controller

(PMC_PCERx)

Peripherals

Clock Controller

(PMC_PCR)

PLLBCK

Processor Clock

Master Clock

PRESCSS ON/OFF

ON/OFF

periph_clk[n+1]

periph_clk[n+2]

DIV(PID = n+1)

DIV(PID = n+2)

Divider

/2,/4,/8,

MCK

div8

div4

div2

div8

div4

div2

div8

div4

div2

SLCK

Master Clock

Prescaler To the MCK Divider

PRESCSS

MAINCK

PLLACK

PLLBCK To the Processor

Clock Controller (PCK)

PMC_MCKR PMC_MCKR

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The Processor Clock Controller HCLK is enabled after a reset and is automatically re-enabled by any enabled

interrupt. The processor Sleep mode is entered by disabling the processor clock, which is automatically re-enabled

by any enabled fast or normal interrupt, or by the reset of the product.

When processor Sleep mode is entered, the current instruction is finished before the clock is stopped, but this

does not prevent data transfers from other masters of the system bus.

18.6 SysTick Clock

The SysTick calibration value is fixed to 12500 which allows the generation of a time base of 1 ms with SysTick

clock to the maximum frequency on MCK divided by 8.

18.7 USB Clock Controller

The user can select the PLLA or the PLLB output as the USB source clock by writing the USBS bit in

PMC_USB.If using the USB, the user must program the PLL to generate an appropriate frequency depending on

the USBDIV bit in the USB Clock Register (PMC_USB).

When the PLL output is stable, i.e., the LOCK bit is set, the USB device and host FS clocks can be enabled by

setting the UDP, UHP, bits in the System Clock Enable Register (PMC_SCER). To save power on this peripheral

when it is not used, the user can set the UDP, UHP, bits in the System Clock Disable Register (PMC_SCDR). The

UDP, UHP, bits in the System Clock Status Register (PMC_SCSR) gives the activity of this clock. The USB device

and host ports require both the 48 MHz signal and the peripheral clock. The USB peripheral clock may be

controlled by means of the Master Clock Controller.

Figure 18-4. USB Clock Controller

18.8 Peripheral Clock Controller

The PMC controls the clocks of each embedded peripheral by means of the Peripheral Clock Controller. The user

can individually enable and disable the clock on the peripherals.

The user can also enable and disable these clocks by writing Peripheral Clock Enable 0 (PMC_PCER0),

Peripheral Clock Disable 0 (PMC_PCDR0), Peripheral Clock Enable 1 (PM C_PCER1) and Peripheral Clock

Disable 1 (PMC_PCDR1) registers. The status of the peripheral clock activity can be read in the Peripheral Clock

Status Register (PMC_PCSR0) and Peripheral Clock Status Register (PMC_PCSR1).

When a peripheral clock is disabled, the clock is immediately stopped. The peripheral clocks are automatically

disabled after a reset.

To stop a peripheral, it is recommended that the system software wait until the peripheral has executed its last

programmed operat ion before disabling the clock. This is to avoid data corru ption or erroneous behavior of the

system.

USB

Source

Clock

UDP Clock (UDPCK)

UDP

USBDIV

Divider

/1,/2,/3,.../16

UHP Clock (UHPCK)

UHP

PMC_USB PMC_SCER,

PMC_SDER

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The bit number within the Peripheral Clock Control registers (PMC_PCER0–1, PMC_PCDR0–1, and

PMC_PCSR0–1) is the Peripheral Identifier defined at the product level. The bit number corresponds to the

interrupt source number assigned to the peripheral.

In order to reduce power consumption, the clock of FLEXCOM0-7, PDMIC, TC0-5, ADC peripherals can be MCK

divided by a division factor of 1, 2, 4, 8.

The divisor is defined in PMC_PCR. To apply a division factor, PID, CMD and DIV must be written in a single

operation. The target peripheral clock is defined by the PID field. The divisor value is defined by DIV and the bit

CMD must be set. To read the current division factor associated with a peripheral clock, two separate operations

must be performed:

1. Write a one to the bit CMD and configure PID for the target peripheral clock. DIV is not significant for this

operation.

2. Read the PMC_PCR. The value of DIV is the divisor applied on the peripheral clock defined by PID.

DIV must not be changed while peripheral is in use or when the peripheral clock is enabled. To change the clock

division factor (DIV) of a peripheral, its clock must first be disabled by writing either EN to 0 for the corresponding

PID (DIV must be kept the same if this me thod is used), or writing to the PMC_PCDR. Then, the secon d write must

be performed in the PMC_PCR with the new value of DIV and the third write must be performed to enable the

peripheral clock (by using either the PMC_PCR or PMC_PCER).

18.9 Asynchronous Partial Wakeup (SleepWalking)

18.9.1 Description

The asynchronous partial wakeup (SleepWalking) wake s up a periphe ral in a fully asynchronous wa y when activity

is detected on the communication line. Moreover, under some user configurable conditions, the asynchronous

partial wakeup can trigger an exit of the system from Wait mode (full system wakeup).

The asynchronous partial wakeup function automatically manages the peripheral clock. It improves the overall

power consumption of the system by clocking peripherals only when needed.

Only the following peripherals can be configured with asynchronous partial wakeup: FLEXCOM0-7, ADC.

The peripheral selected for asynchronous partial wakeup must be first configured so that its clock is enabled by

setting the appropriate PIDx bit in PMC_PCERx.

When the system is in Wait mode, all clocks of the system (except SLCK) are stopped. When an asynchronous

clock request from a peripheral occurs, the PMC partially wakes up the system to feed the clock only to this

peripheral. The rest of the system is not fed with the clock, thus optimizing power consumption. Finally, depending

on user-configurable conditions, the peripheral either wakes up the whole system if these conditions are met or

stops the peripheral clock until the next clock request. If a wakeup request occurs, the Asynchronous Partial

Wakeup mode is automatically disabled until the user instructs the PMC to enable asynchronous partial wakeup.

This is done by setting PIDx in the PMC SleepWalking Enable Register (PMC_SLPWK_ER).

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Figure 18-5. SleepWalking During Wait Mode

When the system is in Active mode, peripherals enabled for asynchronous partial wakeup have their respective

clocks stoppe d until the periph erals request a cloc k. When a peripheral requests the clock, the PMC provides the

clock without CPU intervention.

The triggering of the peripheral clock request depends on conditions which can be configured for each peripheral.

If these conditions are met, the peripheral asserts a request to the PMC. Th e PMC disables the Asynchronous

Partial Wakeup mode of the peripheral and provides the clock to the peripher al un til the user instru cts th e PM C to

re-enable partial wakeup on the peripheral. This is done by setting PIDx in the PMC_SLPWK_ER.

If the conditions are not met, the peripheral clears the clock request and PMC stops the peripheral clock until the

clock request is re-asserted by the peripheral.

Figure 18-6. SleepWalking During Active Mode

system_clock

peripheral_clock

peripheral

clock request

peripheral

wakeup request

peripheral

sleepwalking status

The wakeup request wakes up the system

and resets the sleepwalking status of the

peripheral

The system is in wait mode. No clock is fed to the system.

system_clock

peripheral_clock

peripheral

clock request

peripheral

wakeup request

peripheral

sleepwalking status

The wakeup request resets the

sleepwalking status of the peripheral

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18.9.2 Configuration Procedure

Before configuring the asynchronous partial wakeup (SleepWalking) function of a peripheral, check that the PIDx

bit in the PMC Peripheral Clock Status Register (PMC_PCSR) is set. This ensures that the peripheral clock is

enabled.

To enable the asynchronous partial wakeup (SleepWalking) function of a peripheral, follow the steps below:

1. Check that the co rr espo ndi ng PIDx bit in the PMC SleepWalking Activity Status Register

(PMC_SLPWK_ASR) is cleared. This ensures that the peripheral has no activity in progress.

2. Enable the asynchronous partial wakeup function of the peripheral by writing a one to the corresponding

PIDx bit in the PMC_SLPWK_ER.

3. Check that the corresponding PIDx bi t in PMC_SLPWK_ASR is cleared. This ensures that no activity has

started during the enab le pha se .

4. In the PMC_SLPWK_ASR, if the corresponding PIDx bit is set, the asynchronous partial wakeup function

must be immediately disabled by writing a one to the PIDx bit in the PMC SleepWalking Disable Register

(PMC_SLPWK_DR). Wait for the end of peripheral activity before reinitializing the procedure.

If the corresponding PIDx bit is cleared, the peripheral clock is disabled and the system can now be placed

in Wait mode.

Note: When asynchronous partial wakeup (SleepWalking) of a peripheral is enabled and the core is running (system not in

Wait mode), the peripheral must not be accessed before a wakeup of th e peripheral is performed.

18.10 Free-Running Processor Clock

The free-running processor clock (FCLK)used for sampling interrupts and clocking debug b locks ensures that

interrupts can be sampled, and sleep events can be traced, while the processor is sleeping. It is connected to

master clock (MCK).

18.11 Programmable Clock Output Controller

The PMC controls three signals to be output on external pins, PCKx. Each signal can be independently

programmed via the Programmable Clock Registers (PMC_PCKx) .

PCKx can be independently selected between th e slow clock (SLCK), the main clock (MAINCK), the PLLA clock

(PLLACK), the PLLB clock (PLLBCK),and the master clock (MCK) by writing the CSS field in PMC_PCKx. Each

output signal can also be divided by a power of 2 between 1 and 64 by writing the PRES (Prescaler) field in

PMC_PCKx.

Each output signal can be enabled and disabled by writing a 1 to the corresponding PCKx bit of PMC_SCER and

PMC_SCDR, respectively. Status of the active programmable output clocks are given in the PCKx bits of

PMC_SCSR.

The PCKRDYx status flag in PMC_SR indicates that the programmable clock is actually what has been

programmed in the programmable clock registers.

As the Program mable Clock Controller d oes not mana ge with glitch prevention when switching clocks, it is strongly

recommended to disa ble the programmable clock before any configu ration change and to re-enable it after the

change is actually performed.

18.12 Core and Bus Independent Clocks for Peripherals

The USART/UART/SPI/TWI/TIMER/PDMIC/ADCC can operate while the core, bus and peripheral clock

frequencies are modified, thus providing communications at a rate which is independent for the

core/bus/peripheral clock. This mode of operation is possible by using the internally generated independent clock

sources PCK3 to PCK7.

Before entering Wait mode, check that all the PIDx bits in PMC_SLPWK_ASR are cleared.

This ensures that none of the peripherals has any activity in progress.

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PCK3 to PCK7 internal clocks can be independently selected between the slow clock (SLCK), the main clock

(MAINCK), any available PLL clo ck, and the master clock (MCK) by writing the C SS field in the Programmable

Clock Registers (PMC_PCK3 to PMC_PCK7). The independent clock sources can be also divided by writing the

field PRES.

Each internal clock signal (PCKx) can be enabled and disabled by writing a one to the corresponding PCKx bit of

PMC_SCER and PMC_SCDR, respectively. The status of the internal clocks are given in the PCKx bits of

PMC_SCSR.

The PCKRDYx status flag in PMC_SR indicates that the programmable internal clock has been programmed in

the programmable clock registers.

The independent clock source must also be selected in each peripheral

(USART/UART/SPI/TWI/TIMER/PDMIC/ADCC) to oper ate communication s, timings, etc without influence of the

frequency of the core/bus/peripherals (except frequency limitations listed in each peripheral).

18.13 Fast Startup

At exit from Wait mode, the device allows the processor to restart in less than 10 microseconds only if the C-code

function that manages the Wait mode entry and exit is linked to and executed from on-chip SRAM.

The fast startup time cannot be achieved if the first instruction after an exit is located in the embedded Flash.

If fast startup is not required, or if the fir st instruction after a Wait mode exit is located in embe dded Flash, see

Section 18.14 ”Startup from Embedded Flash”.

Prior to instructing the device to enter Wait mode:

1. Select the 8/16/24 MHz RC oscillator as the master clock source (the CSS field in PMC_MCKR must be

written to 1).

2. Disable the PLL if enabled.

3. Wait for two SLCK clock cycles.

4. Clear the internal wakeup sources.

5. Verify that none of the enabled external wakeup inputs (WKUP) hold an active po larity

The system enters Wait mode either by setting the WAITMODE bit in CKGR_MOR, or by executing the

WaitForEvent (WFE) instruction of th e processor while the LPM bit is at 1 in PMC_FSMR. Immed iately after settin g

the WAITMODE bit or using the WFE instruction, wait for the MCKRDY bit to be set in PMC_SR.

A fast startup is enabled upon th e detection of a pr ogrammed level on o ne the wake up input pin s WKUPx (up to 16

inputs, see Peripheral Signal Multiplexing on I/O Lines section for exact number) or upon an active alarm from the

RTC, RTT and USB Controller. The polarity of each wake-up input is programmable by writing the PMC Fast

Startup Polarity Register (PMC_FSPR).

WARNING: The duration of the WKUPx pins active level must be greater than four main clock cycles.

Table 18-1. Clock Assig nment

Clock Name Peripheral

PCK3 TC

PCK4 PDMIC, I2SC0/1

PCK5 ADCC

PCK6 FLEXCOM0/1/2/3 (USART/SPI/TWI)

PCK7 FLEXCOM4/5/6/7 (USART/SPI/TWI)

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The fast startup circuitry, as shown in Figure 18-7, is fully asynchronous and provides a fast startup signal to the

PMC. As soon as the fast startup signal is asserted, the embedded 8/16/24 MHz RC oscillator restarts

automatically.

When entering Wait mode, the embedded Flash can be placed in one of the Low-power m odes (Deep-power-

down or Standby modes) depending on the configuration of the FLPM field in the PMC_FSMR. The FLPM field

can be programmed at anytime and its value will be applied to the next Wait mode period.

The power consumption reduction is optimal when configuring 1 (Deep-power-down mode) in field FLPM. If 0 is

programmed (Standby mode), the power consumption is slig htly higher than in Deep-power-down mode.

When programming 2 in field FLPM, the Wait mode Flash power consumption is equivalent to that of the Active

mode when there is no read access on the Flash.

Figure 18-7. Fast Startup Circuitry

Each wakeup input pin and alarm can be enabled to generate a fast startup event by setting the corresponding bit

in PMC_FSMR.

The user inte rface does not pr ovide any statu s for fast startup, bu t the user can ea sily recover this infor mation by

reading the PIO Controller and the status registers of the RTC, RTT and USB Controller.

18.14 Startup from Embedded Flash

The inherent start-up time of the embedded Flash cannot provide a fast startup of the system.

If system fast start-up time is not required, the first instruction after a Wait mode exit can be located in the

embedded Flash. Under these conditions, prior to entering Wait mode, the Flash controller must be programmed

to perform access in 0 wait-state. Refer to the section “Enhanced Embedded Flash Controller (EEFC)”.

fast_restart

WKUP15

FSTT15

FSTP15

WKUP1

FSTT1

FSTP1

WKUP0

FSTT0

FSTP0

RTTAL

RTCAL

USBAL

RTT Alarm

RTC Alarm

USB Alarm

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If the 8/16/24 MHz RC oscillator is configured to generate 16 MHz or 24 MHz (MOSCRCF = 1 or 2 in

CKGR_MOR), th e first instruction after an exit mu st not be located in the embedded Flash and the fast startup

procedure must be used (see Section 18.13 ”Fast Startup”). If this RC oscillator is configured to generate 8 MHz

(MOSCRCF = 0 in CKGR_MOR), the instructions mana ging start-up time can be located in any on-chip memory.

The procedure and conditions to enter Wait mode and the circuitry to exit Wait mode are strictly the same as fast

startup (s ee Section 18.13 ”Fast Startup”).

18.15 Main Clock Failure Detector

The clock failure detector monitors the 3 to 20 MHz crystal oscillator or ceramic resonator-based oscillator to

identify a failure of this oscillator when selected as main clock.

The clock failure detector can be enabled or disabled by bit CFDEN in CKGR_MOR. After a VDDCORE reset, t he

detector is disabled. However, if the oscillator is disabled (MOSCXTEN = 0), the detector is also disabled.

A failure is detected by means of a counter incrementing on the main clock and detection logic is triggered by the

32 kHz (typical) RC oscillator which is automatically enabled when CFDEN=1.

The counter is cleared when the 32 kHz (typical) RC oscillator clock signal is low and enabled when the signal is

high. Thus, the failure detection time is one RC oscillator period. If, during the high level period of the 32 kHz

(typical) RC oscillator clock signal, less than eight 3 to 20 MHz cry stal oscillator clock periods have been counted,

then a failure is reported.

If a failure of the main clock is detected, bit CFDEV in PMC_SR indicates a failure event and generates an

interrupt if the corresponding interrupt source is enabled. The interrupt remains active until a read occurs in

PMC_SR. The user can know the status of the clock failure detection at any time by reading the CFDS bit in

PMC_SR.

Figure 18-8. Clock Failure Detectio n (Example)

If the 3 to 20 MHz crystal oscillator or ceramic resonator-based oscillator is selected as the source clock of

MAINCK (MOSCSEL in CKGR_MOR = 1), and if MCK source is PLLACK or PLLBCK (CSS = 2), a clock failure

detection automatically forces MAINCK to be the source clock for MCK. Then, regardless of the PMC

configuration, a clock failure dete ction automatically forces the 8 /16/24 MHz RC o scillator to be the source clock

for MAINCK. If this oscillator is disabled when a clock failure detection occurs, it is automatically re-enabled by the

clock failure detection mechanism.

It takes two 32 kHz (typical) RC oscilla tor clock cyc les to detect and switc h from the 3 to 20 MHz crystal oscillator,

to the 8/16/24 MHz RC oscillator if the source master clock (MCK) is main clock (MAINCK), or three 32 kHz

(typical) RC oscillator clock cycles if the source of MCK is PLLACK or PLLBCK.

The user can know the status of the clock failure detector at any time by reading the FOS bit in PMC_SR.

This fault output remains active until the defe ct is detected and until it is cleared by the bit FOCLR in the PM C Fault

Output Clear Register (PMC_FOCR).

Main Crytal Clock

SLCK

Note: ratio of clock periods is for illustration purposes only

CDFEV

CDFS

Read PMC_SR

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18.16 32768 Hz Crystal Oscillator Frequency Monitor

The frequency of the 32768 Hz crystal oscillator can be monitored by means of logic driven by the 8/16/24 MHz

RC oscillator known as a reliable clock source. This function is enabled b y configuring the XT32KFME bit of

CKGR_MOR. The SEL4/SEL8/SEL12 bits of PMC_OCR must be cleared.

An error flag (XT32KERR in PMC_SR) is asse rted when the 32768 Hz crystal oscillator freq uency is out of the

±60% nominal frequency value (i.e., 32768 Hz). The error flag can be cleared only if the slow clock frequency

monitoring is disabled.

The monitored clock fre quency is declared invalid if at least fo ur consecutive clock period measur ement results are

over the nominal period ±60%.

Due to the possible frequency variation of the embedded 8/16/24 MHz RC oscillator acting as reference clock for

the monitor logic, any 32768 Hz crystal oscillator frequency deviation over ±60% of the nominal frequency is

systematically reported as an error by the XT32KERR bit in PMC_SR. Between -1% and -60% and +1% and

+60%, the error is not systematically report ed .

Thus only a crystal running at 32768 Hz frequency ensures that the error flag will not be asserted. The permitted

drift of the crystal is 10000 ppm (1%), which allows any standard crystal to be used.

If the 8/16/24 MHz RC frequency needs to be changed while the slow clock frequency monitor is operating, the

monitoring must be stopped prior to changing the 8/16/24 MHz RC frequency. It can then be re-enabled as soon

as MOSCRCS is set in PMC_SR.

The error flag can be defined as an interrupt source of the PMC by setting the XT32KERR bit of PMC_IER.

18.17 Programming Sequence

1. If the 3 to 20 MHz crystal oscillator is not required, the PLL and divider can be directly configured (Step 6.)

else this oscillator must be started (Step 2.).

2. Enable the 3 to 20 MHz crystal oscillator by setting the MOSCXTEN field in CKGR_MOR:

The user can define a start-up time. This is done by writing a value in the MOSCXTST field in CKGR_MOR.

Once this register has been correctly configured, the user must wait for MOSCXTS field in PMC_SR to be

set. This is done either by polling MOSCXTS in PMC_SR, or by waiting for the interrupt line to be raised if

the associated interrupt source (MOSCXTS) has been enabled in PMC_IER.

3. Switch the MAINCK to the 3 to 20 MHz crystal oscillator by setting MOSCSEL in CKGR_MOR.

4. Wait for the MOSCSELS to be set in PMC_SR to ensure the switch is complete.

5. Check the main clock frequency:

This main clock frequency can be measured via CKGR_MCFR.

Read CKGR_MCFR until the MAINFRDY field is set, after which the user can read the MAINF field in

CKGR_MCFR by performing an additional read. This provides the number of main clock cycles that have

been counted during a period of 16 slow clock cycles.

If MAINF = 0, switch the MAINCK to the 8/16/24 MHz RC Oscillator by clearing MOSCSEL in CKGR_MOR.

If MAINF ≠ 0, proceed to Step 6.

6. Set PLLx and Divider (if not required, proceed to Step 7.):

In the names PLLx, DIVx, MULx, LOCKx, PLLxCOUNT, an d CKGR _PLLxR, ‘x’ represents Aor B.

All parameters needed to configure PLLx and the divider are located in CKGR_PLLxR.

The DIVx field is used to control the divider itself. This parameter can be programmed between 0 and 127.

Divider output is divider input divided by DIVx parameter. By default, DIVx field is cle ared which means that

the divider and PLLx are turned off.

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The MULx field is the PLLx multiplier factor. This parameter can be programmed between 0 and 7500. If

MULx is cleared, PLLx will be turned off, otherwise the PLLx output frequency is PLLx input frequency

multiplied by (MULx + 1).

The PLLxCOUNT fi eld specifies the numb er of slow clock cycles before the LOCKx bit is set in the PMC_SR

after CKGR_PLLxR has been written.

Once CKGR_PLLxR has been written, the user must wait for the LOCKx bit to be set in the PMC_SR. This

can be done either by polling LOCKx in PMC_SR or by waiting for the interrupt line to be raised if the

associated interrupt source (LOCKx) has been enabled in PMC_IER. All fields in CKGR_PLLxR can be

programmed in a single write operation. If at some stage one of the following parameters, MULx or DIVx is

modified, the LOCKx bit goes low to indicate that PLLx is not yet ready. When PLLx is locked, LOCKx is set

again. The user must wait for the LOCKx bit to be set before using the PLLx output clock.

7. Select the maste r clo ck an d pr oc essor clock

The master clock and the processor clock are configurable via PMC_MCKR.

The CSS field is used to select the clock source of the master clock and pr ocessor clock dividers. By default,

the selected clock source is the main clock.

The PRES field is used to define the processor clock and master clock prescaler. The user can ch oose

between different values (1, 2, 3, 4, 8, 16, 32, 64). Prescaler output is the selected clock source frequency

divided by the PRES value.

Once the PMC_M CKR has bee n writ te n, the us er mus t wait for the MCKRDY bit to be set in the PMC_SR.

This can be done ei ther by pol ling MCKRDY in PMC_SR o r by waiting for the interrupt line to be raised if the

associated interrupt source (MCKRDY) has been enabled in PMC_IER. PMC_MCKR mu st not be

programmed in a single write operation. The programming seq uence for PMC_MCKR is as follows:

If a new value for CSS field corresponds to PLL clock,

Program the PRES field in PMC_MCKR.

Wait for the MCKRDY bit to be set in PMC_SR.

Program the CSS field in PMC_MCKR.

Wait for the MCKRDY bit to be set in PMC_SR.

If a new value for CSS field corresponds to main clock or slow clock,

Program the CSS field in PMC_MCKR.

Wait for the MCKRDY bit to be set in the PMC_SR.

Program the PRES field in PMC_MCKR.

Wait for the MCKRDY bit to be set in PMC_SR.

If at some stage, parameters CSS or PRES are modified, the MCKRDY bit goes low to indicate that the

master clock and the processo r clock ar e no t yet read y. The user must wa it for MCKRDY bi t to be set aga in

before using the master and processor clocks.

Note: IF PLLx clock was selected as the master clock and the user decides to modify it by writing in CKGR_PLLxR, the

MCKRDY flag will go low while PLLx is unlocked. Once PLLx is locked aga in, LOCKx goes high an d MCKRDY is set.

While PLLx is unlocked, the master clock selection is automatically changed to slow clock for PLLA and main clock for

PLLB. For further information, see Section 18.18.2 ”Clock Switching Waveforms”.

Code Example:

write_register(PMC_MCKR,0x00000001)

wait (MCKRDY=1)

write_register(PMC_MCKR,0x00000011)

wait (MCKRDY=1)

The master clock is main clock divided by 2.

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8. Select the programmable clocks

Programmable clocks are controlled via registers, PMC_SCER, PMC_SCDR and PMC_SCSR.

Programmable clocks can be enabled and/or dis abled via PMC_SCER and PMC_SCDR. Three

programmable clocks can b e used. PMC_SCSR indica tes wh ich prog rammable clock is en abled. By de fault

all programmable clocks are disabled.

PMC_PCKx registers are used to configure programmable clo cks.

The CSS field is used to select the programmable clock divider source. Several clock options are available:

main clock, slow clock, master clock, PLLACK, PLLBCK. The slow clock is the default clock source.

The PRES field is used to control the programmable clock prescaler. It is possible to choose between

different values (1, 2, 4, 8, 16, 32, 64). Programmable clock output is prescaler input divided by PRES

parameter. By default, the PRES value is cleared which means that PCKx is equal to slow clock.

Once PMC_PCKx register has been configured, the corresponding progra mmable clock must be enabled

and the user is constr ained to wait for the PCKRDYx bi t to be set in the PMC_ SR. This can be done either by

polling PCKRDYx in PMC_SR or by waiting for the interrupt line to be raised if the associated interrupt

source (PCKRDYx) has been enab led in PMC_IER. All para meters in PMC_PCKx ca n be progr ammed in a

single write oper a tion .

If the CSS and PRES parameters are to be modified, the corresponding programmable clock must be

disabled first. The parameters can then be modified. Once this has been done, the user must re-enable the

programmable clock and wait for the PCKRDYx bit to be set.

9. Enable the peripheral clocks

Once all of the previous steps have been completed, the peripheral clocks can be enabled and/or disabled

via registers PMC_PCER0, PMC_PCER, PMC_PCDR0 and PMC_PCDR.

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18.18 Clock Switching Details

18.18.1 Master Clock Switching Timings

Table 18-2 and Table 18-3 give the worst case timings required for the master clock to switch from one selected

clock to another one. This is in the event that the prescaler is de-activated. When the prescaler is activated, an

additional time of 64 clock cycles of the newly selected clock has to be added.

Notes: 1. PLL designates either the PLLA or the PLLB Clock.

2. PLLCOUNT designates either PLLACOUNT or PLLBCOUNT.

Table 18-2. Clock Switching Timing s (Worst Case)

From Main Clock SLCK PLL Clock

Main Clock – 4 x SLCK +

2.5 x Main Clock

3 x PLL Clock +

4 x SLCK +

1 x Main Clock

SLCK 0.5 x Main Clock +

4.5 x SLCK –3 x PLL Clock +

5 x SLCK

PLL Clock

0.5 x Main Clock +

4 x SLCK +

PLLCOUNT x SLCK +

2.5 x PLLx Clock

2.5 x PLL Clock +

5 x SLCK +

PLLCOUNT x SLCK

2.5 x PLL Clock +

4 x SLCK +

PLLCOUNT x SLCK

Table 18-3. Clock Switching Timing s between Two PLLs (Wo r st Case)

From PLLA Clock PLLB Clock

PLLA Clock 2.5 x PLLA Clock +

4 x SLCK +

PLLACOUNT x SLCK

3 x PLLA Clock +

4 x SLCK +

1.5 x PLLA Clock

PLLB Clock 3 x PLLB Clock +

4 x SLCK +

1.5 x PLLB Clock

2.5 x PLLB Clock +

4 x SLCK+

PLLBCOUNT x SLCK

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18.18.2 Clock Switching Wa veforms

Figure 18-9. Switch Master Clock from Slow Clock to PLLx Clock

Figure 18-10. Switch Master Clock from Main Clock to Slow Clock

Slow Clock

LOCK

MCKRDY

Master Clock

Write PMC_MCKR

PLLx Clock

Slow Clock

Main Clock

MCKRDY

Master Clock

Write PMC_MCKR

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Figure 18-11. Change PLLx Programming

Figure 18-12. Programmable Clock Output Programming

Slow Clock

PLLx Clock

LOCKx

MCKRDY

Master Clock

Write CKGR_PLLxR

PLLx Clock

PCKRDY

PCKx Output

Write PMC_PCKx

Write PMC_SCER

Write PMC_SCDR PCKx is disabled

PCKx is enabled

PLL Clock is selected

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18.19 Register Write Protection

To prevent any single software error from corrupting PMC behavior, certain registers in the address space can be

write-protected by setting the WPEN bit in the “PMC Write Protection Mode Register” (PMC_WPMR).

If a write access to a write-protected register is detected, the WPVS flag in the “PMC Write Protection Status

attempted.

The WPVS bit is automatically cleared after reading the PMC_WPSR.

The following registers can be write-protected:

“PMC System Clock Enable Register”

“PMC System Clock Disable Register”

“PMC Peripheral Clock Enable Register 0”

“PMC Peripheral Clock Disable Register 0”

“PMC Clock Generator Main Oscillator Register”

“PMC Clock Generator Main Clock Frequency Register”

“PMC Clock Generator PLLA Register”

“PMC Clock Generator PLLB Register”

“PMC Master Clock Register”

“PMC USB Clock Register”

“PMC Programmable Clock Register”

“PMC Fast Startup Mode Register”

“PMC Fast Startup Polarity Register”

“PMC Peripheral Clock Enable Register 1”

“PMC Peripheral Clock Disable Register 1”

“PMC Oscillator Calibration Register”

“PMC SleepWalking Enable Register 0”

“PMC SleepWalking Disable Register 0”

“PLL Maximum Multiplier Value Register”

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18.20 Power Management Controller (PMC) User Interface

Table 18-4. Register Mapping

Offset Register Name Access Reset

0x0000 System Clock Enable Register PMC_SCER Write-only –

0x0004 System Clock Disable Register PMC_SCDR Write-only –

0x0008 System Clock S tatus Register PMC_SCSR Read-only 0x0000_0001

0x000C Reserved – – –

0x0010 Peripheral Clock Enable Register 0 PMC_PCER0 Write-only –

0x0014 Peripheral Clock Disable Register 0 PMC_PCDR0 Write-only –

0x0018 Peripheral Clock Status Register 0 PMC_PCSR0 Rea d-only 0x0000_0000

0x0020 Main Oscillator Register CKGR_MOR Read/Write 0x0000_0008

0x0024 Main Clock Frequency Register CKGR_MCFR Read/Write 0x0000_0000

0x0028 PLLA Register CKGR_PLLAR Read/W rite 0x0000_3F00

0x002C PLLB Register CKGR_PLLBR Read/Write 0x0000_3F00

0x0030 Master Clock Register PMC_MCKR Rea d/Write 0x0000_0001

0x0034 Reserved – – –

0x0038 USB Clock Register PMC_USB Read/Write 0x0000_0000

0x003C Reserved – – –

0x0040 Programmable Clock 0 Register PMC_PCK0 Read/Write 0x0000_0000

0x0044 Programmable Clock 1 Register PMC_PCK1 Read/Write 0x0000_0000

0x0048 Programmable Clock 2 Register PMC_PCK2 Read/Write 0x0000_0000

0x004C Programmable Clock 3 Register PMC_PCK3 Read/Write 0x0000_0000

0x0050 Programmable Clock 4 Register PMC_PCK4 Read/Write 0x0000_0000

0x0054 Programmable Clock 5 Register PMC_PCK5 Read/Write 0x0000_0000

0x0058 Programmable Clock 6 Register PMC_PCK6 Read/Write 0x0000_0000

0x005C Programmable Clock 7 Register PMC_PCK7 Read/Write 0x0000_0000

0x0060 Interrupt Enable Register PMC_IER Write-only –

0x0064 Interrupt Disable Register PMC_IDR Write-only –

0x0068 Status Register PMC_SR Read-only 0x0003_0008

0x006C Interrupt Mask Register PMC_IMR Rea d-only 0x0000_0000

0x0070 Fast Startup Mode Regi ster PMC_FSMR Read/Write 0x0000_0000

0x0074 Fast Startup Polarity Register PMC_FSPR Rea d/Write 0x0000_0000

0x0078 Fault Output Clear Register PMC_FOCR Write-only –

0x007C–0x00E0 Reserved – – –

0x00E4 Write Protection Mode Register PMC_WPMR Read/Write 0x0000_0000

0x00E8 Write Protection Status Register PMC_WPSR Read-only 0x0000_0000

0x00EC–0x00FC Reserved – – –

0x0100 Peripheral Clock Enable Register 1 PMC_PCER1 Write-only –

425

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Note: If an offset is not listed in the table it must be considered as “reserved”.

0x0104 Peripheral Clock Disable Register 1 PMC_PCDR1 Write-only –

0x0108 Peripheral Clock Status Register 1 PMC_PCSR1 Rea d-only 0x0000_0000

0x010C Peripheral Control Register PMC_PCR Read/Write 0x0000_0000

0x0110 Oscillator Calibration Register PMC_OCR Read/Write 0x0040_4040

0x0114 SleepWalking Enable Register 0 PMC_SLPWK_ER0 Write-only –

0x0118 SleepWalking Disable Regist er 0 PMC_SLPWK_DR0 Write-only –

0x011C SleepWalking Status Register 0 PMC_SLPWK_SR0 Read-only 0x00 00_0000

0x0120 SleepWalking Activity Status Register 0 PMC_SLPWK_ASR0 Read-Only –

0x0130 PLL Maximum Multiplier Value Register PMC_PMMR Read/Write 0x07F F_07FF

Table 18-4. Register Mapping (Continued)

Offset Register Name Access Reset

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

426

18.20.1 PMC System Clock Enable Regis ter

Name: PMC_SCER

Address: 0x400E0400

Access: Write-only

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• UHP: USB Host Port Clock Enable

0: No effect.

1: Enables the 48 MHz clock (UHPCK) of the USB Host Port.

• UDP: USB Device Port Clock Enable

0: No effect.

1: Enables the 48 MHz clock (UDPCK) of the USB Device Port.

• PCKx: Programmable Clock x Output Enable

0: No effect.

1: Enables the corresponding Programmable Clock output.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

PCK7 PCK6 PCK5 PCK4 PCK3 PCK2 PCK1 PCK0

76543210

UDPUHP –––––

427

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.2 PMC System Clock Disable Register

Name: PMC_SCDR

Address: 0x400E0404

Access: Write-only

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• UHP: USB Host Port Clock Disable

0: No effect.

1: Disables the 48 MHz clock (UHPCK) of the USB Host Port.

• PCKx: Programmable Clock x Output Disable

0: No effect.

1: Disables the corresponding Programmable Clock output.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

PCK7 PCK6 PCK5 PCK4 PCK3 PCK2 PCK1 PCK0

76543210

UDPUHP –––––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

428

18.20.3 PMC System Clock Status Register

Name: PMC_SCSR

Address: 0x400E0408

Access: Read-only

• UHP: USB Host Port Clock Status

0: The 48 MHz clock (UHPCK) of the USB Device Port is disabled.

1: The 48 MHz clock (UHPCK) of the USB Host Port is enabled.

• PCKx: Programmable Clock x Output Status

0: The corresponding Programmable Clock output is disabled.

1: The corresponding Programmable Clock output is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

PCK7 PCK6 PCK5 PCK4 PCK3 PCK2 PCK1 PCK0

76543210

UDPUHP –––––

429

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.4 PMC Peripheral Clock Enable Register 0

Name: PMC_PCER0

Address: 0x400E0410

Access: Write-only

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PIDx: Peripheral Clock x Enable

0: No effect.

1: Enables the corresponding peripheral clock.

Note: PIDx refers to identifiers defined in the section “Peripheral Identifiers”. Other peripherals can be enabled in PMC_PCER1 (Section

18.20.23 ”PMC Peripheral Clock Enabl e Register 1”).

Note: Programming the control bits of the Peripheral ID that are not implemented has no effect on the behavior of the PMC.

31 30 29 28 27 26 25 24

– – PID29 PID28 PID27 PID26 PID25 PID24

23 22 21 20 19 18 17 16

PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16

15 14 13 12 11 10 9 8

PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8

76543210

––––––––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

430

18.20.5 PMC Peripheral Clock Disable Register 0

Name: PMC_PCDR0

Address: 0x400E0414

Access: Write-only

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PIDx: Peripheral Clock x Disable

0: No effect.

1: Disables the corresponding peripheral clock.

Note: PIDx refers to identifiers defined in the section “Peripheral Identifiers”. Other peripherals can be disabled in PMC_PCDR1

(Section 18.20.24 ”PMC Peripheral Clock Disable Register 1”).

31 30 29 28 27 26 25 24

– – PID29 PID28 PID27 PID26 PID25 PID24

23 22 21 20 19 18 17 16

PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16

15 14 13 12 11 10 9 8

PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8

76543210

––––––––

431

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.6 PMC Peripheral Clock Status Register 0

Name: PMC_PCSR0

Address: 0x400E0418

Access: Read-only

• PIDx: Peripheral Clock x Status

0: The corresponding peripheral clock is disabled.

1: The corresponding peripheral clock is enabled.

Note: PIDx refers to identifiers define d i n th e se cti o n “Per ipheral Identifi e r s”. Othe r pe ri p he ra l s status can be rea d in PMC_PC SR1

(Section 18.20.25 ”PMC Peripheral Clock Status Register 1”).

31 30 29 28 27 26 25 24

– – PID29 PID28 PID27 PID26 PID25 PID24

23 22 21 20 19 18 17 16

PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16

15 14 13 12 11 10 9 8

PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8

76543210

––––––––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

432

18.20.7 PMC Clock Generator Main Osc illator Register

Name: CKGR_MOR

Address: 0x400E0420

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• MOSCXTEN: 3 to 20 MHz Crystal Oscillator Enable

A crystal must be connected between XIN and XOUT.

0: The 3 to 20 MHz crystal oscillator is disabled.

1: The 3 to 20 MHz crystal oscillator is enabled. MOSCXTBY must be cleared.

When MOSCXTEN is set, the MOSCXTS flag is set once the crystal oscillator start-up time is achieved.

• MOSCXTBY: 3 to 20 MHz Crystal Oscillator Bypass

0: No effect.

1: The 3 to 20 MHz crystal oscillator is bypassed. MOSCXTEN must be cleared. An external clock must be connected on

XIN.

When MOSCXTBY is set, the MOSCXTS flag in PMC_SR is automatically set.

Clearing MOSCXTEN and MOSCXTBY bits resets the MOSCXTS flag.

Note: When the crystal oscillator bypass is disabled (MOSCXTBY = 0), the MOSCXTS flag must be read at 0 in PMC_SR before

enabling the crystal oscillator (MOSCXTEN = 1).

• WAITMODE: Wait Mode Command (Write-only)

0: No effect.

1: Puts the device in Wait mode.

• MOSCRCEN: 8/16/24 MHz RC Oscillator Enable

0: The 8/16/24 MHz RC oscillator is disabled.

1: The 8/16/24 MHz RC oscillator is enabled.

When MOSCRCEN is set, the MOSCRCS flag is set once the RC oscillator start-up time is achieved.

31 30 29 28 27 26 25 24

–––––XT32KFMECFDENMOSCSEL

23 22 21 20 19 18 17 16

KEY

15 14 13 12 11 10 9 8

MOSCXTST

76543210

– MOSCRCF MOSCRCEN WAITMODE MOSCXTBY MOSCXTEN

433

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• MOSCRCF: 8/16/24 MHz RC Oscillator Frequency Selection

At startup, the RC oscillator frequency is 8 MHz.

Note: MOSCRCF must be changed only if MOSCRCS is set in the PMC_SR. Therefore MOSCRCF and MOSCRCEN ca nnot be

changed at the same time.

• MOSCXTST: 3 to 20 MHz Crystal Oscillator Start-up Time

Specifies the number of slow clock cycles multiplied by 8 for the crystal oscillator start-up time.

• KEY: Write Access Password

• MOSCSEL: Main Clock Oscillator Selection

0: The 8/16/24 MHz RC oscillator is selected.

1: The 3 to 20 MHz crystal oscillator is selected.

• CFDEN: Clock Failure Detector Enable

0: The clock failure detector is disabled.

1: The clock failure detector is enabled.

Note: 1. The 32 kHz (typical) RC oscillator is automatically enabled when CFDEN=1.

• XT32KFME: 32768 Hz Crystal Oscillator Frequency Monitoring Enable

0: The 32768 Hz crystal oscillator frequency monitoring is disabled.

1: The 32768 Hz crystal oscillator frequency monitoring is enabled.

Value Name Description

0 8_MHz The RC oscillator frequency is at 8 MHz (default)

1 16_MHz The RC oscillator frequency is at 16 MHz

2 24_MHz The RC oscillator frequency is at 24 MHz

Value Name Description

0x37 PASSWD Writing any other value in this field aborts the write operation.

Always reads as 0.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

434

18.20.8 PMC Clock Generator Main Cloc k Frequency Register

Name: CKGR_MCFR

Address: 0x400E0424

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• MAINF: Main Clock Frequency

Gives the number of main clock cycles within 16 slow clock periods. To calculate the frequency of the measured clock:

fMAINCK = (MAINF × fSLCK) / 16

where frequency is in MHz.

• MAINFRDY: Main Clock Frequency Measure Ready

0: MAINF value is not valid or the measured oscillator is disabled or a measure has just been started by means of

RCMEAS.

1: The measured oscillator has been enabled previously and MAINF value is available.

Note: To ensure that a correct value is read on the MAINF field, the MAINFRDY flag must be read at 1 then another read access must

be performed on the register to get a stable value on the MAINF field.

• RCMEAS: Restart Main Clock Source Frequency Measure (write-only)

0: No effect.

1: Restarts measuring of the frequency of the main clock source. MAINF will carry the new frequency as soon as a low to

high transition occurs on the MAINFRDY flag.

The measure is performed on the main frequency (i.e. not limited to RC oscillator only), but if the main clock frequency

source is the 3 to 20 MHz crystal oscillator, the restart of measuring is not needed because of the well known stability of

crystal oscillators.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––RCMEAS–––MAINFRDY

15 14 13 12 11 10 9 8

MAINF

76543210

MAINF

435

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.9 PMC Clock Generator PLLA Register

Name: CKGR_PLLAR

Address: 0x400E0428

Access: Read/Write

Possible limitations on PLLA input frequencies and multiplier factors should be checked before using the PMC.

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PLLAEN: PLLA Control

0: PLLA is disabled

1: PLLA is enabled

2–255: Forbidden

• PLLACOUNT: PLLA Counter

Specifies the number of Slow Clock cycles before the LOCKA bit is set in PMC_SR after CKGR_PLLAR is written.

• MULA: PLLA Multiplier

0: The PLLA is deactivated (PLLA also disabled if DIVA = 0).

8 up to 7500 = The PLLA Clock frequency is the PLLA input frequency multiplied by MULA + 1.

Unlisted values are forbidden.

• ZERO: Must Be Written to 0

Bit 29 must always be writ te n to 0 when pro g ra mmi ng th e CKG R _P LL AR.

31 30 29 28 27 26 25 24

––ZERO MULA

23 22 21 20 19 18 17 16

MULA

15 14 13 12 11 10 9 8

– – PLLACOUNT

76543210

PLLAEN

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

436

18.20.10 PMC Clock Generator PLLB Register

Name: CKGR_PLLBR

Address: 0x400E042C

Access: Read/Write

Possible limitations on PLLB input frequencies and multiplier factors should be checked before using the PMC.

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PLLBEN: PLLB Control

0: PLLB is disabled

1: PLLB is enabled

2–255: Forbidden

• PLLBCOUNT: PLLB Counter

Specifies the number of Slow Clock cycles before the LOCKB bit is set in PMC_SR after CKGR_PLLBR is written.

• MULB: PLLB Multiplier

0: The PLLB is deactivated (PLLB also disabled if DIVB = 0).

8 up to 2400: The PLLB Clock frequency is the PLLB input frequency multiplied by MULB + 1.

Unlisted values are forbidden.

• ZERO: Must Be Written to 0

31 30 29 28 27 26 25 24

––ZERO–– MULB

23 22 21 20 19 18 17 16

MULB

15 14 13 12 11 10 9 8

– – PLLBCOUNT

76543210

PLLBEN

437

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.11 PMC Master Clock Regist er

Name: PMC_MCKR

Address: 0x400E0430

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• CSS: Master Clock Source Selection

• PRES: Processor Clock Prescaler

• PLLADIV2: PLLA Divisor by 2

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––PLLBDIV2PLLADIV2––––

76543210

–PRES––CSS

Value Name Description

0 SLOW_CLK Slow Clock is selected

1 MAIN_CLK Main Clock is selected

2 PLLA_CLK PLLA Clock is selected

3 PLLB_CLK PLLB Clock is selected

Value Name Description

0 CLK_1 Selected clock

1 CLK_2 Selected clock divid ed by 2

2 CLK_4 Selected clock divid ed by 4

3 CLK_8 Selected clock divid ed by 8

4 CLK_16 Selected clock divided by 16

5 CLK_32 Selected clock divided by 32

6 CLK_64 Selected clock divided by 64

7 CLK_3 Selected clock divid ed by 3

PLLADIV2 PLLA Clock Division

0 PLLA clock frequency is divided by 1.

1 PLLA clock frequency is divided by 2.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

438

• PLLBDIV2: PLLB Divisor by 2

PLLBDIV2 PLLB Clock Division

0 PLLB clock frequency is divided by 1.

1 PLLB clock frequency is divided by 2.

439

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.12 PMC USB Clock Register

Name: PMC_USB

Address: 0x400E0438

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• USBS: USB Input Clock Selection

0: USB Clock Input is PLLA.

1: USB Clock Input is PLLB

• USBDIV: Divider for USB Clock

USB Clock is Input clock divided by USBDIV + 1.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––– USBDIV

76543210

–––––––USBS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

440

18.20.13 PMC Programmable Clock Register

Name: PMC_PCKx

Address: 0x400E0440

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• CSS: Master Clock Source Selection

• PRES: Programmable Clock Prescaler

0–255: Selected clock is divided by PRES + 1.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––– PRES

76543210

PRES – CSS

Value Name Description

0 SLOW_CLK Slow Clock is selected

1 MAIN_CLK Main Clock is selected

2 PLLA_CLK PLLA Clock is selected

3 PLLB_CLK PLLB Clock is selected

4 MCK Master Clock is selected

441

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.14 PMC Interrupt Enable Register

Name: PMC_IER

Address: 0x400E0460

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Enables the corresponding interrupt.

• MOSCXTS: 3 to 20 MHz Crystal Oscillator Status Interrupt Enable

• LOCKA: PLLA Lock Interrupt Enable

• LOCKB: PLLB Lock Interrupt Enable

• MCKRDY: Master Clock Ready Interrupt Enable

• PCKRDYx: Programmable Clock Ready x Interrupt Enable

• MOSCSELS: Main Clock Source Oscillator Selection Status Interrupt Enable

• MOSCRCS: 8/16/24 MHz RC Oscillator Status Interrupt Enable

• CFDEV: Clock Failure Detector Event Interrupt Enable

• XT32KERR: 32768 Hz Crystal Oscillator Error Interrupt Enable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – XT32KERR – – CFDEV MOSCRCS MOSCSELS

15 14 13 12 11 10 9 8

PCKRDY7 PCKRDY6 PCKRDY5 PCKRDY4 PCKRDY3 PCKRDY2 PCKRDY1 PCKRDY0

76543210

––––MCKRDYLOCKBLOCKAMOSCXTS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

442

18.20.15 PMC Interrupt Disable Register

Name: PMC_IDR

Address: 0x400E0464

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Disables the corresponding interrupt.

• MOSCXTS: 3 to 20 MHz Crystal Oscillator Status Interrupt Disable

• LOCKA: PLLA Lock Interrupt Disable

• LOCKB: PLLB Lock Interrupt Disable

• MCKRDY: Master Clock Ready Interrupt Disable

• PCKRDYx: Programmable Clock Ready x Interrupt Disable

• MOSCSELS: Main Clock Source Oscillator Selection Status Interrupt Disable

• MOSCRCS: 8/16/24 MHz RC Oscillator Status Interrupt Disable

• CFDEV: Clock Failure Detector Event Interrupt Disable

• XT32KERR: 32768 Hz Oscillator Error Interrupt Disable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – XT32KERR – – CFDEV MOSCRCS MOSCSELS

15 14 13 12 11 10 9 8

PCKRDY7 PCKRDY6 PCKRDY5 PCKRDY4 PCKRDY3 PCKRDY2 PCKRDY1 PCKRDY0

76543210

––––MCKRDYLOCKBLOCKAMOSCXTS

443

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.16 PMC Status Register

Name: PMC_SR

Address: 0x400E0468

Access: Read-only

• MOSCXTS: 3 to 20 M Hz C rys tal Oscillator Status

0: 3 to 20 MHz crystal oscillator is not stabilized.

1: 3 to 20 MHz crystal oscillator is stabilized.

• LOCKA: PLLA Lock Status

0: PLLA is not locked

1: PLLA is locked.

• LOCKB: PLLB Lock Status

0: PLLB is not locked

1: PLLB is locked.

• MCKRDY: Master Clock Status

0: Master Clock is not ready.

1: Master Clock is ready.

• OSCSELS: Slow Clock Oscillator Selection

0: Embedded 32 kHz RC oscillator is selected.

1: 32768 Hz crystal oscillator is selected.

• PCKRDYx: Programmable Clock Ready Status

0: Programmable Clock x is not ready.

1: Programmable Clock x is ready.

• MOSCSELS: Main Clock Source Oscillator Selection Status

0: Selection is in progress.

1: Selection is done.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – XT32KERR FOS CFDS CFDEV MOSCRCS MOSCSELS

15 14 13 12 11 10 9 8

PCKRDY7 PCKRDY6 PCKRDY5 PCKRDY4 PCKRDY3 PCKRDY2 PCKRDY1 PCKRDY0

76543210

OSCSELS – – – MCKRDY LOCKB LOCKA MOSCXTS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

444

• MOSCRCS: 8/16/24 MHz RC Oscillator Status

0: 8/16/24 MHz RC oscillator is not stabilized.

1: 8/16/24 MHz RC oscillator is stabilized.

• CFDEV: Clock Failure Detector Event

0: No clock failure detection of the 3 to 20 MHz crystal oscillator has occurred since the last read of PMC_SR.

1: At least one clock failure detection of the 3 to 20 MHz crystal oscillator has occurred since the last read of PMC_SR.

• CFDS: Clock Failure Detector Status

0: A clock failure of the 3 to 20 MHz crystal oscillator is not detected.

1: A clock failure of the 3 to 20 MHz crystal oscillator is detected.

• FOS: Clock Failure Detector Fault Output Status

0: The fault output of the clock failure detector is inactive.

1: The fault output of the clock failure detector is active.

• XT32KERR: 32768 Hz Crystal Oscillator Error

0: The frequency of the 32768 Hz crystal oscillator is correct (32768 Hz +/- 1%) or the monitoring is disabled.

1: The frequency of the 32768 Hz crystal oscillator is incorrect or has been incorrect for an elapsed period of time since the

monitoring has been enabled.

445

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.17 PMC Interrupt Mask Register

Name: PMC_IMR

Address: 0x400E046C

Access: Read-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Enables the corresponding interrupt.

• MOSCXTS: 3 to 20 MHz Crystal Oscillator Status Interrupt Mask

• LOCKA: PLLA Lock Interrupt Mask

• LOCKB: PLLB Lock Interrupt Mask

• MCKRDY: Master Clock Ready Interrupt Mask

• PCKRDYx: Programmable Clock Ready x Interrupt Mask

• MOSCSELS: Main Clock Source Oscillator Selection Status Interrupt Mask

• MOSCRCS: 8/16/24 MHz RC Oscillator Status Interrupt Mask

• CFDEV: Clock Failure Detector Event Interrupt Mask

• XT32KERR: 32768 Hz Oscillator Error Interrupt Mask

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – XT32KERR – – CFDEV MOSCRCS MOSCSELS

15 14 13 12 11 10 9 8

– PCKRDY6 PCKRDY5 PCKRDY4 PCKRDY3 PCKRDY2 PCKRDY1 PCKRDY0

76543210

––––MCKRDYLOCKBLOCKAMOSCXTS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

446

18.20.18 PMC Fast Startup Mode Register

Name: PMC_FSMR

Address: 0x400E0470

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• FSTT0–FSTT15: Fast Startup Input En able 0 to 15

0: The corresponding wakeup input has no effect on the PMC.

1: The corresponding wakeup input enables a fast restart signal to the PMC.

• RTTAL: RTT Alarm Enable

0: The RTT alarm has no effect on the PMC.

1: The RTT alarm enables a fast restart signal to the PMC.

• RTCAL: RTC Alarm Enable

0: The RTC alarm has no effect on the PMC.

1: The RTC alarm enables a fast restart signal to the PMC.

• USBAL: USB Alarm Enable

0: The USB alarm has no effect on the PMC.

1: The USB alarm enables a fast restart signal to the PMC.

• LPM: Low-power Mode

0: The WaitForInterrupt (WFI) or the WaitForEvent (WFE) instruction of the processor makes the processor enter Sleep

mode.

1: The WaitForEvent (WFE) instruction of the processor makes the system to enter Wait mode.

• FFLPM: Force Flash Low-power Mode

0: The Flash Low-power mode, defined in the FLPM field, is automatically applied when in Wait mode and released when

going back to Active mode.

1: The Flash Low-power mode is user defined by the FLPM field and immediately app lied.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

FFLPM FLPM LPM – USBAL RTCAL RTTAL

15 14 13 12 11 10 9 8

FSTT15 FSTT14 FSTT13 FSTT12 FSTT11 FSTT10 FSTT9 FSTT8

76543210

FSTT7 FSTT6 FSTT5 FSTT4 FSTT3 FSTT2 FSTT1 FSTT0

447

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• FLPM: Flash Low-power Mode

Value Name Description

0 FLASH_STANDBY Flash is in Standby Mode when system enters Wait Mode

1 FLASH_DEEP_POWERDOWN Flash is in Deep-power-down mode when system enters Wait Mode

2 FLASH_IDLE Idle mode

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

448

18.20.19 PMC Fast Startup Polarity Register

Name: PMC_FSPR

Address: 0x400E0474

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• FSTPx: Fast Startup Input Polarityx

Defines the active polarity of the corresponding wakeup input. If the corresponding wakeup input is enabled and at the

FSTP level, it enables a fast restart signal.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

FSTP15 FSTP14 FSTP13 FSTP12 FSTP11 FSTP10 FSTP9 FSTP8

76543210

FSTP7 FSTP6 FSTP5 FSTP4 FSTP3 FSTP2 FSTP1 FSTP0

449

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.20 PMC Fault Output Clear Register

Name: PMC_FOCR

Address: 0x400E0478

Access: Write-only

• FOCLR: Fault Output Clear

Clears the clock failure detector fault output.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––FOCLR

SAM G55 [DATASHEET]

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450

18.20.21 PMC Write Protection Mode Register

Name: PMC_WPMR

Address: 0x400E04E4

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x504D43 (“PMC” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x504D43 (“PMC” in ASCII).

See Section 18.19 ”Register Write Protection” for the list of registers that can be write-protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x504D43 PASSWD Writing any other value in this field aborts the write operation of the WPEN bit. Always

reads as 0.

451

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.22 PMC Write Protection S tatus Register

Name: PMC_WPSR

Address: 0x400E04E8

Access: Read-only

• WPVS: Write Protection Violation Status

0: No write protec tion v iola tio n ha s occ u rred since the last read of the PMC_WPSR.

1: A write protection violation has occurred since th e last read of the PMC_WPSR. If this violation is an unauthorized

attempt to write a protected register, the associated violation is reported into field WPVSRC.

• WPVSRC: Write Protection Vi olation Source

When WPVS = 1, WPVSRC indicates the register address offset at which a write access has been attempted.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

WPVSRC

15 14 13 12 11 10 9 8

WPVSRC

76543210

–––––––WPVS

SAM G55 [DATASHEET]

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452

18.20.23 PMC Peripheral Clock Enable Register 1

Name: PMC_PCER1

Address: 0x400E0500

Access: Write-only

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PIDx: Peripheral Clock x Enable

0: No effect.

1: Enables the corresponding peripheral clock.

Notes: 1. The values for PIDx are defined in the section “Peripheral Identifiers”.

2. Programming the control bits of the Peripheral ID that are not implemented has no effect on the behavior of the PMC.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––PID49PID48

15 14 13 12 11 10 9 8

PID47–––––––

76543210

––––––––

453

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.24 PMC Peripheral Clock Disable Register 1

Name: PMC_PCDR1

Address: 0x400E0504

Access: Write-only

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PIDx: Peripheral Clock x Disable

0: No effect.

1: Disables the corresponding peripheral clock.

Note: The values for PIDx are defined in the section “Peripheral Identifiers”.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––PID49PID48

15 14 13 12 11 10 9 8

PID47–––––––

76543210

––––––––

SAM G55 [DATASHEET]

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454

18.20.25 PMC Peripheral Clock Status Register 1

Name: PMC_PCSR1

Address: 0x400E0508

Access: Read-only

• PIDx: Peripheral Clock x Status

0: The corresponding peripheral clock is disabled.

1: The corresponding peripheral clock is enabled.

Note: The values for PIDx are defined in the section “Peripheral Identifiers”.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––PID49PID48

15 14 13 12 11 10 9 8

PID47–––––––

76543210

––––––––

455

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.26 PMC Peripheral Control Register

Name: PMC_PCR

Address: 0x400E050C

Access: Read/Write

• PID: Peripheral ID

Peripheral ID selection from PID2 to PID63.

PID2 to PID63 refer to identifiers as defined in the section “Peripheral Identifiers”.

Not all PID can be configured with divided clock.

Only the following PID can be configured with divided clock: FLEXCOM0-7, PDMIC, TC0-5, ADC.

•CMD: Command

0: Read mode.

1: Write mode.

• DIV: Divisor Value

DIV must not be changed while peripheral is in use or when the peripheral clock is enabled.

• EN: Enable

0: Selected Peripheral clock is disabled.

1: Selected Peripheral clock is enabled.

31 30 29 28 27 26 25 24

–––EN––––

23 22 21 20 19 18 17 16

–––––– DIV

15 14 13 12 11 10 9 8

–––CMD––––

76543210

–– PID

Value Name Description

0 PERIPH_DIV_MCK Peripheral clock is MCK

1 PERIPH_DIV2_MCK Peripheral clock is MCK/2

2 PERIPH_DIV4_MCK Peripheral clock is MCK/4

3 PERIPH_DIV8_MCK Peripheral clock is MCK/8

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

456

18.20.27 PMC Oscillator Calibration Register

Name: PMC_OCR

Address: 0x400E0510

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• CAL8: RC Oscillator Calibration bits for 8 MHz

Calibration bits applied to the RC Oscillator when SEL8 is set.

• SEL8: Selection of RC Oscillator Calibration bits for 8 MHz

0: Default value stored in Flash memory.

1: Value written by user in CAL8 field of this register.

• CAL16: RC Os ci lla to r Calibration bits for 16 MHz

Calibration bits applied to the RC Oscillator when SEL16 is set.

• SEL16: Selection of RC Oscillator Calibration bits for 16 MHz

0: Factory-determined value stored in Flash me mory.

1: Value written by user in CAL16 field of this register.

• CAL24: RC Os ci lla to r Calibration bits for 24 MHz

Calibration bits applied to the RC Oscillator when SEL24 is set.

• SEL24: Selection of RC Oscillator Calibration bits for 24 MHz

0: Factory-determined value stored in Flash me mory.

1: Value written by user in CAL24 field of this register.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

SEL24 CAL24

15 14 13 12 11 10 9 8

SEL16 CAL16

76543210

SEL8 CAL8

457

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.28 PMC SleepWalking Enable Register 0

Name: PMC_SLPWK_ER0

Address: 0x400E0514

Access: Write-only

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PIDx: Peripheral x SleepWalking Enable

0: No effect.

1: The asynchronous partial wakeup (SleepWalking) function of the corresponding peripheral is enabled.

Not all PIDs can be configured with asynchronous partial wakeup.

Only the following PID can be configured with asynchronous partial wakeup: FLEXCOM0-7, ADC.

The clock of the peripheral must be enabled before using its asynchronous partial wakeup (SleepWalking) function (its

associated PIDx field in “PMC Peripheral Clock Status Register 0” is set to ‘1’).

Note: The values for PIDx are defined in section “Peripheral Identifiers”.

31 30 29 28 27 26 25 24

– – PID29 PID28 PID27 PID26 PID25 PID24

23 22 21 20 19 18 17 16

PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16

15 14 13 12 11 10 9 8

PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8

76543210

––––––––

SAM G55 [DATASHEET]

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458

18.20.29 PMC SleepWalking Disable Register 0

Name: PMC_SLPWK_DR0

Address: 0x400E0518

Access: Write-only

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PIDx: Peripheral x SleepWalking Disable

0: No effect.

1: The asynchronous partial wakeup (SleepWalking) function of the corresponding peripheral is disabled.

Not all PIDs can be configured with asynchronous partial wakeup.

Only the following PIDs can be configured with asynchronous partial wakeup: FLEXCOM0-7, ADC.

Note: The values for PIDx are defined in the section “Peripheral Identifiers”.

31 30 29 28 27 26 25 24

– – PID29 PID28 PID27 PID26 PID25 PID24

23 22 21 20 19 18 17 16

PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16

15 14 13 12 11 10 9 8

PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8

76543210

––––––––

459

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.30 PMC SleepWalking Status Register 0

Name: PMC_SLPWK_SR0

Address: 0x400E051C

Access: Read-only

• PIDx: Peripheral x SleepWalking Status

0: The asynchronous partial wakeup (SleepWalking) function of the peripheral is currently disabled or the peripheral

enabled for asynchronous partial wakeup (SleepWalking) cleared the PIDx bit upon detection of a wakeup condition.

1: The asynchronous partial wakeup (SleepWalking) function of the peripheral is currently enabled.

Not all PIDs can be configured with asynchronous partial wakeup.

Only the following PIDs can be configured with asynchronous partial wakeup: FLEXCOM0-7, ADC.

Note: The values for PIDx are defined in the section “Peripheral Identifiers”.

31 30 29 28 27 26 25 24

– – PID29 PID28 PID27 PID26 PID25 PID24

23 22 21 20 19 18 17 16

PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16

15 14 13 12 11 10 9 8

PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8

76543210

––––––––

SAM G55 [DATASHEET]

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460

18.20.31 PMC SleepWalking Activity Status Register 0

Name: PMC_SLPWK_ASR0

Address: 0x400E0520

Access: Read-only

• PIDx: Peripheral x Activity Status

0: The peripheral x is not presently active. The asynchronous partial wakeup (SleepWalking) function can be activated.

1: The peripheral x is presently active. The asynchronous partial wakeup (SleepWalking) function must not be activated.

Only the following PIDs can be configured with asynchronous partial wakeup: FLEXCOM0-7, ADC.

All other PIDs are always read at 0.

Note: The values for PIDx are defined in the section “Peripheral Identifiers”.

31 30 29 28 27 26 25 24

– – PID29 PID28 PID27 PID26 PID25 PID24

23 22 21 20 19 18 17 16

PID23 PID22 PID21 PID20 PID19 PID18 PID17 PID16

15 14 13 12 11 10 9 8

PID15 PID14 PID13 PID12 PID11 PID10 PID9 PID8

76543210

––––––––

461

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

18.20.32 PLL Maximum Multiplier Value Register

Name: PMC_PMMR

Address: 0x400E0530

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “PMC Write Protection Mode Register” .

• PLLA_MMAX: PLLA Maximum Allowed Multiplier Value

Defines the maximum value of multiplication factor that can be sent to PLLA. Any value of the MULA field (see “PMC Clock

Generator PLLA Register” ) above PLLA_MMAX is saturated to PLLA_M MAX. PLLA_MMAX write operation is cancelled in

the following cases:

• The value of MULA is currently saturated by PLLA_MMAX

• The user is trying to write a value of PLLA_MMAX that is smaller than the current value of MULA

• PLLB_MMAX: PLLB Maximum Allowed Multiplier Value

Defines the maximum value of multiplication factor that can be sent to PLLB. Any value of the MULB field (see “PMC Clock

Generator PLLB Register” ) above PLLB_MMAX is saturated to PLLB_M MAX. PLLB_MMAX write operation is cancelled in

the following cases:

• The value of MULB is currently saturated by PLLB_MMAX.

• The user is trying to write a value of PLLB_MMAX that is smaller than the current value of MULB .

31 30 29 28 27 26 25 24

––––– PLLB_MMAX

23 22 21 20 19 18 17 16

PLLB_MMAX

15 14 13 12 11 10 9 8

––––– PLLA_MMAX

76543210

PLLA_MMAX

SAM G55 [DATASHEET]

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462

19. Reset Controller (RSTC)

19.1 Description

The Reset Controller (RSTC), driven by power-on reset (POR) cells, software, external reset pin and peripheral

events, handles a ll the r esets of the system with out any external components. It reports which reset occurred last.

The RSTC also dri ves indepen dently or simultaneou sly the extern al reset and the pe ripheral and p rocessor resets.

19.2 Embedded Characteristics

Driven by Embedded Power-on Reset, Software, External Reset Pin and Peripheral Events

Management of All System Resets, Including

External Devices through the NRST Pin

Processor

Peripheral Set

Reset Source Status

Status of the Last Re se t

Either VDDCORE and VDDIO POR Reset, Sof tware Reset, User Reset, W atchdog Reset, 32.768 kHz

Crystal Oscillator Failure Detection Reset

External Reset Signal Control and Shaping

19.3 Block Diagram

Figure 19-1. Reset Controller Block Diagram

NRST Pin

Processor

reset line

wd_fault

Peripherals

reset line

SLCK

Reset

State

Manager

Reset Controller

RSTC

interrupt line

NRST

Manager exter_nreset

nrst_out

WDT_MR.WDRPROC

user_reset

POR

Backup

From

watchdog

Backup area reset

SUPC

VDDCORE reset

Backup

POR

VDDCORE

BOD

VDDCORE

463

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19.4 Functional Description

19.4.1 Overview

The RSTC is made up of an NRST manager and a reset state manager. It runs at SLCK frequency and generates

the following reset signals:

proc_nreset: Processor reset line (also resets the Watchdog Timer)

periph_nreset: Affects the whole set of embedded peripherals

nrst_out: Drives the NRST pin

These reset signals are asserted by the RSTC, either on events generated by peripherals, even ts o n NRST pin, o r

on software action. The reset state manager controls the generation of reset signals and provides a signal to the

NRST manager when an assertion of the NRST pin is required.

The NRST manager shapes the NRST assertion during a programmable time, thus controlling external device

resets.

The RSTC Mode register (RSTC_MR), used to configure the RSTC, is powered with VDDIO, so that its

configuration is saved as long as VDDIO is on.

19.4.2 NRST Manager

The NRST manager samples the NRST input pin and drives this pin low when required by the reset state

manager. Figure 19-2 shows the block diagram of the NRST manager.

Figure 19-2. NRST Manager

19.4.2.1 NRST Signal or Interrupt

The NRST manager samples the NRST pin at SLCK speed. When the NRST line is low for more than three clock

cycles, a User Reset is reported to the reset state manager. The NRST pin must be asserted for at least 1 SLCK

clock cycle to ensure execution of a user reset.

However, the NRST manager can be programmed to not trigger a reset when an assertion of NRST occurs.

Writing a ‘0’ to RSTC_MR.URSTEN disables the User Reset trigger.

The level of th e pin NR ST can be read at an y time in the bit NRSTL in the RSTC Status Register (RSTC_SR). As

soon as the NRST pin is asserted, RSTC_SR. URSTS is written to ‘1’. This bit is cleared only when the RSTC_SR

is read.

The RSTC can also be programmed to generate an interrupt instead of generating a reset. To do so,

RSTC_MR.URSTIEN must be set.

External Reset Timer

URSTS

URSTEN

ERSTL

exter_nreset

URSTIEN

RSTC_MR

RSTC_SR

NRSTL

nrst_out

NRST

Other

interrupt

sources

user_reset

RSTC

Interrupt line

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

464

19.4.2.2 NRST External Reset Control

The reset state manager asserts the signal exter_nreset to assert the NRST pin. When this occurs, the “nrst_out”

signal is driven low by the NRST manager for a time programmed by RSTC_MR.ERSTL. This assertion duration,

named External Reset Le ngth, lasts 2(ERSTL+1) SLCK cycles. This gives the approximate duration of an assertion

between 60 µs and 2 seconds. Note that ERSTL at ‘0’ defines a two-cycle duration for the NRST pulse.

This feature allows the RSTC to shape the NRST pin level, and thus to guarantee that the NRST line is driven low

for a time compliant with potential external devices connected on the system reset.

RSTC_MR is backed up, making it possible to use the value of ERSTL to shape the system powerup reset for

devices requiring a longer startup time than that of the MCU.

19.4.3 Reset States

The reset state manager ha ndles the different re se t sour ces and ge nerates the intern al rese t signals. It repor ts the

reset status in RSTTYP of the Status Register (RSTC_SR). The update of RSTC_SR.RSTTYP is performed when

the processor reset is released.

465

SAM G55 [DATASHEET]

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19.4.3.1 General Reset

A general reset occurs when a VDDIO power-on-reset is detected, a brownout or a voltage regulation loss is

detected by the Supply Controller. The vddcore_nreset signal is asserted by the Supply Controller when a general

reset occurs.

All the reset signals are released and RSTC_SR.RSTTYP reports a general reset. As the RSTC_MR is written to

‘0’, the NRST line rises two cycles after the vddcore_nreset, as ERSTL defaults at value 0x0.

Figure 19-3 shows how the general reset affects the reset signals.

Figure 19-3. General Reset Timing Diagram

19.4.3.2 Backup Reset

A backup reset occurs when the chip exits from Backup mode. While exiting Backup mode, the vddcore_nreset

signal is asserted by the Supply Controller.

Field RSTC_SR.RSTTYP is updated to report a backup reset.

SLCK

Processor

Reset Line

NRST

(nrst_out)

3 SLCK cycles

MCK

VDDIO POR

Output

Any

Freq.

RSTTYP XXX 0x0 = General Reset XXX

6.5 SLCK cycles + 2 Main RC cycles

Peripheral

Reset Line

Inactive

VDDCORE POR

Output

Regulator Startup

Power Supply

Activation

5 Main RC cycles

Backup Logic

Reset

5 SLCK

cycles

Main RC

Oscillator

Active

2 SLCK cycles

Active

Inactive

SAM G55 [DATASHEET]

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466

19.4.3.3 32.768 kHz Crystal Oscillator Failure Detection Reset

The 32.768 kHz crystal oscillator failure detection reset is done when th e 32.768 kHz crystal oscillator frequency

monitoring circuitry in the PMC detects a failure an d RSTC_MR.SCKSW is written to '1'. This reset lasts three slow

clock cycles.

When RSTC_MR.SCKSW is written to ‘0’, the 32.768 kHz crystal oscillator fault has no impact on the RSTC.

During the 32.768 kHz crystal oscillator failure dete ction reset, the processor reset and the peripheral reset are

asserted. The NRST line is also asserted, depending on the value of RSTC_MR.ERSTL.

When the 32.768 kHz crystal oscillator failure generates a VDDCORE reset, PMC_SR.XT32KERR is automatically

cleared by the peripheral and core reset.

Figure 19-4. 32.768 kHz Crystal Oscillator Failure Detection Reset Timing Diagram

0x7 = XTAL Fail Reset

SLCK

Processor and

Peripherals

Reset Line

NRST

(nrst_out)

MCK

Any

Frequency.

RSTTYP XXX

Main RC

Oscillator

3 SLCK cycles + 2 MCK cycles

Active

Inactive

Any

Frequency.

Inactive

32K Crystal

Clock Fail

Min = 2 SLCK cycles if ERSTL=0 (e.g. 8 if ERSTL=2)

467

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19.4.3.4 Watchdog Reset

The watchdog reset is entered when a watchdog fault occurs. This reset lasts three SLCK cycles.

When in watchdog reset, assertion of the reset signals depends on the value of WDT_MR.WDRPROC:

If WDRPROC = 0, the processor reset and the periphera l reset are asserted. The NRST line is also

asserted, depending on how field RSTC_MR.ERSTL is programmed. However, the resulting low level on

NRST does not result in a user reset state.

If WDRPROC = 1, only the processor reset is asserted.

The Watchdog Timer is reset by the proc_nreset signal. As the watchdog fault always causes a processor reset if

WDT_MR.WDRSTEN is written to ‘1’, the Watchdog Timer is always reset after a watchdog reset, and the

Watchdog is enabled by default and with a period set to a maximum.

When WDT_MR.WDRSTEN is written to ‘0’, the watchdog fault has no impact on the RSTC.

After a watchdog overflow occurs, the report on the RSTC_SR.RSTTYP may differ (either WDT_RST or

USER_RST) depending on the exte rn al comp onents driving th e NRST pin. For example, if the NRST line is driven

through a resistor and a capacitor (NRST pin debouncer), the reported value is USER_RST if the low to high

transition is greater than one SLCK cycle.

Figure 19-5. Watchdog Reset Timing Dia gram

Only if

WDT_MR.WDRPROC = 0

0x2 = Watchdog Reset

SLCK

Processor

Reset Line

NRST

(nrst_out)

MCK

Any

Frequency.

RSTTYP XXX

Main RC

Oscillator

3 SLCK cycles + 2 MCK cycles

Active

Inactive

Any

Frequency.

Inactive

WDT Fault

Min = 2 SLCK cycles if ERSTL=0 (e.g. 8 if ERSTL=2)

Active Inactive

Inactive

Peripherals

Reset Line

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

468

19.4.3.5 Software Reset

The RSTC offers commands to assert the different reset signals. These commands are perform ed by writing the

Control register (RSTC_CR) with the following bits at ‘1’:

RSTC_CR.PROCRST: Writing a ‘1’ to PROCRST resets the processor and the watchdo g timer.

RSTC_CR.PERRST: Writing a ‘1’ to PERRST resets all the embedded peripherals including the memory

system, and, in particular, the Remap Command. The Peripheral Reset is generally used for debug

purposes.

Except for debug purposes, PERRST must always be used in conjunction with PROCRST (PERRST and

PROCRST set both at 1 simultaneously).

RSTC_CR.EXTRST: Writing a ‘1’ to EXTRST asserts low the NRST pin during a time defined by the field

RSTC_MR.ERSTL.

The software reset is entered if at least one of these bits is written to ‘1’ by the software. All these commands can

be performed independently or simultaneously. The software reset lasts three SLCK cycles.

The internal reset signals are asserted as soon as the register write is performed. This is detected on the Master

Clock (MCK). They are released when the software reset has ended, i.e., synchronously to SLCK.

If EXTRST is written to ‘1’, the nrst_out signal is asserted depending on the configuration of RSTC_MR.ERSTL.

However, the resulting falling edge on NRST does not lead to a user reset.

If and only if the RSTC_CR.PROCRST is written to ‘1’, the RSTC reports the software status in field

RSTC_SR.RSTTYP. Other software resets are not reported in RSTTYP.

As soon as a software operation is detected, RSTC_SR.SRCMP is written to ‘1’. SRCMP is cleared at the end of

the software reset. No other software reset can be performed while SRCMP is written to ‘1’, and writing any value

in the RSTC_CR has no effect.

Figure 19-6. Software Reset Timing Diagram

Write RSTC_CR

NRST

(nrst_out)

if EXTRST=1

0x3 = Software Reset

SLCK

Processor

Reset Line

MCK Any

Frequency.

RSTTYP XXX

Main RC

Oscillator

3 SLCK cycles + 2 MCK cycles

Active

Inactive

Any

Frequency.

Inactive

Min = 2 SLCK cycles if ERSTL=0 (e.g. 8 if ERSTL=2)

Up to 1 SLCK cycle

Peripherals

Reset Line Active Inactive

Inactive

RSTC_SR.SRCMP

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19.4.3.6 User Reset

A user reset is generated when a low level is detected on the NRST pin and RSTC_MR.URST EN is at ‘1’. The

NRST input signal is resynchronized with SLCK to ensure proper behavior of the system. Thus, the NRST pin

must be asserted for at least 1 SLCK clock cycle to ensure execution of a user reset.

The user reset is triggered 2 SLCK cycles after a low level is detected on NRST. The processor reset and the

peripheral reset are asserted.

The user reset ends when NRST rises, after a two-cycle resynchronization time and a three-cycle processor

startup. The processor clock is reenabled as soon as NRST is confirmed high.

When the processor rese t signal is released, RSTC_SR.RSTTYP is loaded with the valu e ‘4’, indicating a user

reset.

The NRST manager guarantees that the NRST line is asserted for External Reset Length SLCK cycles, as

configured in RSTC_MR.ERST L. H owever, if NRST does not ris e after E xternal Reset Length because it is driven

low externally, the internal reset lines remain asserted until NRST actually rises.

Figure 19-7. User Reset Timing Diagram

SLCK

Processor

Reset Line

NRST

(nrst_out)

MCK

Any

Frequency.

RSTTYP XXX

Main RC

Oscillator

Active

Inactive

Any

Frequency.

Inactive

NRST pin

Min = 2 SLCK cycles if ERSTL=0 (e.g. 8 if ERSTL=2)

0x4 = User Reset

2 SLCK cycles

6 SLCK cycles

Active InactiveInactive

Peripherals

Reset Line

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19.4.4 Reset State Priorities

The reset state manager manages the pr iorities among the di fferent reset sources. The resets are listed in order of

priority as follows:

1. General reset

2. Backup reset

3. 32.768 kHz Crystal Failure Detection reset

4. Watchdog reset

5. Software reset

6. User reset

Specific cases are listed below:

When in user reset:

A watchdog event is impossible because the W atchdog T imer is being reset by the proc_nrese t signal.

A software reset is impossible, since the processor reset is being activated.

When in software reset:

A watchdog event ha s pr ior ity over the current state.

The NRST has no effect.

When in watchdog reset:

The processor reset is active and so a software reset cannot be programmed.

A user reset cann ot be ente re d.

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19.5 Reset Controller (RSTC) User Interface

Note: 1. This value assumes that a general reset has been performed, subj ect to change if other types of reset are generated.

Table 19-1. Register Mapping

Offset Register Name Access Reset

0x00 Control Register RSTC_CR Write-only –

0x04 Status Register RSTC_SR Read-only 0x0000_0000(1)

0x08 Mode Register RSTC_MR Read/Write 0x0000 0001

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19.5.1 RSTC Control Register

Name: RSTC_CR

Address: 0x400E1400

Access: Write-only

• PROCRST: Processor Reset

0: No effect.

1: If KEY = 0xA5, resets the processor.

• PERRST: Peripheral Reset

0: No effect.

1: If KEY = 0xA5, resets the peripherals.

• EXTRST: External Reset

0: No effect.

1: If KEY = 0xA5, asserts the NRST pin.

• KEY: System Reset Key

31 30 29 28 27 26 25 24

KEY

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––EXTRSTPERRST–PROCRST

Value Name Description

0xA5 PASSWD Writing any other value in this field aborts the write operation.

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19.5.2 RSTC Status Register

Name: RSTC_SR

Address: 0x400E1404

Access: Read-only

• URSTS: User Reset Status

A high-to-low transition of the NRST pin sets the URSTS. This transition is also detected on the MCK rising edge. If the

user reset is disabled (URSTEN = 0 in RSTC_MR) and if the inte rrupt is enabled by RSTC_MR.URSTIEN, URSTS triggers

an interrupt. Reading the RSTC_SR resets URSTS and clears the interrupt.

0: No high-to-low edge on NRST happened since the last read of RSTC_SR.

1: At least one high-to-low transition of NRST has been detected since the last read of RSTC_SR.

• RSTTYP: Reset Type

This field reports the cause of the last processor reset. Reading this RSTC_SR does not reset this field.

• NRSTL: NRST Pin Level

Registers the NRST pin level sampled on each MCK rising edge.

• SRCMP: Software Reset Command in Progress

When set, this bit indicates that a software reset command is in progress and that no further software reset should be per-

formed until the end of the current one. This bit is automatically cleared at the end of the current software reset.

0: No software command is being performed by the RSTC. The RSTC is ready for a software command .

1: A software reset command is being performed by the RSTC. The RSTC is busy.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––SRCMPNRSTL

15 14 13 12 11 10 9 8

––––– RSTTYP

76543210

–––––––URSTS

Value Name Description

0 GENERAL_RST First powerup reset

1 BACKUP_RST Return from Backup mode

2 WDT_RST Watchdog fault occurred

3 SOFT_RST Processor reset required by the software

4 USER_RST NRST pin detected low

5– Reserved

6– Reserved

7 SLCK_XTAL_RST 32.768 kHz crystal failure detection fault occurred

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19.5.3 RSTC Mode Register

Name: RSTC_MR

Address: 0x400E1408

Access: Read/Write

This register can on ly be writte n if the W PEN bit is clea re d in the Syst em Con trolle r Writ e Pro te ctio n M od e Register

(SYSC_WPMR).

• URSTEN: User Reset Enable

0: The detection of a low level on the NRST pin does not generate a user reset.

1: The detection of a low level on the NRST pin triggers a user reset.

• SCKSW: Slow Clock Switching

0: The detection of a 32.768 kHz crystal failure has no effect.

1: The detection of a 32.768 kHz crystal failure resets the logic supplied by VDDCORE.

• URSTIEN: User Reset Interrupt Enable

0: RSTC_SR.USRTS at ‘1’ has no effect on the RSTC interrupt line.

1: RSTC_SR.USRTS at ‘1’ asserts the RSTC interrupt line if URSTEN = 0.

• ERSTL: Exte rna l Rese t Le n g th

This field defines the external reset length. The external reset is asserted during a time of 2(ERSTL+1) SLCK cycles. This

allows assertion duration to be programmed between 60 µs and 2 seconds. Note that synchronization cycles must also be

considered when calculating the actual reset length as previously described.

• KEY: Write Access Password

31 30 29 28 27 26 25 24

KEY

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––– ERSTL

76543210

– – – URSTIEN – – SCKSW URSTEN

Value Name Description

0xA5 PASSWD Writing any other value in this field aborts the write operatio n.

Always reads as 0.

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20. Watchdog Timer (WDT)

20.1 Description

The Watchdog Timer (WDT) is used to prevent system lock-up if the software becomes trapp ed in a deadlock. It

features a 12-bit down counter that allows a watchdog period of up to 16 second s (slow clock around 32 kHz). It

can generate a general reset or a processor reset only. In addition, it can be stopped while the processor is in

Debug mode or Sleep mode (Idle mode).

20.2 Embedded Characteristics

12-bit Key-protected Programmable Counter

Watchdog Clock is Independent from Processor Clock

Provides Reset or Interrupt Signals to the System

Counter May Be Stopped while the Processor is in Debug State or in Idle Mode

20.3 Block Diagram

Figure 20-1. Watchdog Timer Block Diagra m

= 0

set

reset

read WDT_SR

reset

wdt_fault

(to Reset Controller)

set

reset

WDFIEN

wdt_int

WDT_MR

SLCK

1/128

12-bit Down

Counter

Current

Value

WDD

WDT_MR

<= WDD

WDV

WDRSTT

WDT_MR

WDT_CR

reload

WDUNF

WDERR

reload

write WDT_MR

WDT_MR

WDRSTEN

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20.4 Functional Description

The Watchdog Timer is used to prevent system lock-up if the software becomes trapped in a deadlock. It is

supplied with VDDCORE. It restarts with initial values on processor reset.

The watchdog is built around a 12-bit down counter, which is loaded with the value defined in the field WDV of the

Mode Register (WDT_MR). The Watchdog Tim er uses the slow clock divided by 128 to establish the maximum

watchdog period to be 16 seconds (with a typical slow clock of 32.768 kHz).

After a processor reset, the value of WDV is 0xFFF, corresponding to the maximum value of the counter with the

external reset generation enable d (field WDRSTEN at 1 after a ba ckup re se t) . This means that a d efault watchdo g

is running at reset, i.e., at power-up. The user can either disable the WDT by setting bit WDT_MR.WDDIS or

reprogram the WDT to meet the maximum watchdog period the application requires.

When setting the WDDIS bit, and wh ile it is set, th e field s WDV and WDD m ust not be modif i ed.

If the watchdog is restarted by writing into the Control Register (WDT_CR), WDT_MR must not be programmed

during a period of time of three slow clock periods following the WDT_CR write access. In any case, programming

a new value in WDT_MR automatically initiates a restart instruction.

WDT_MR can be written only once. Only a processor reset resets it. Writing WDT_MR reloads the timer with the

newly programmed mode paramete rs.

In normal operation, the user reloads the watchdog at regular intervals before the timer underflow occurs, by

setting bit WDT_CR.WDRSTT. The watchdog counter is then immediately reloaded from WDT_MR and restarted,

and the slow clock 128 divider is reset and restarted. WDT_CR is write-protected. As a result, writing WDT_CR

without the correct hard-coded key has no effect. If an underflow does occur, the “wdt_fault” signal to the Reset

Controller is asserted if bit WDT_MR.WDRSTEN is set. Moreover, the bit WDUNF is set in the Status Register

(WDT_SR).

The reload of the watchdog must occur while th e watchdog coun ter is within a win dow be tween 0 and WDD. WDD

is defined in WDT_MR.

Any attempt to restart the watchdog while the watchdog counter is between WDV and WDD results in a watchdog

error, even if the watchdog is disabled. The bit WDT_SR.WDERR is updated and the “wdt_fault” signal to the

Reset Controller is asserted.

Note that this feature can be disabled by progr amming a WDD value greater than or equal to the WDV value. In

such a configuration, restarting the Watchdog Timer is permitted in the whole range [0; WDV] and does not

generate an error. This is the default configuration on reset (the WDD and WDV values are equal).

The status bits WDUNF (Watch dog Unde rflow) and WDERR ( Watch dog Erro r) trigger an inter rupt, provide d the bit

WDT_MR.WDFIEN is set. The signal “wdt_fault” to the Reset Controller causes a watchdog reset if the

WDRSTEN bit is set as already explained in the Reset Controller documentation. In this case, the processor and

the Watchdog Timer are reset, and the WDERR and WDUNF flags are reset.

If a reset is generated or if WDT_SR is read, the status bits are reset, the interrupt is cleared, and the “wdt_fault”

signal to the reset controller is deasserted.

Writing WDT_MR reload s an d re sta r ts the dow n co un ter.

While the processor is in debug state or in Sleep mode, the counter may be stopped depending on the value

programmed for the bits WDIDLEHLT and WDDBGHLT in WDT_MR.

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Figure 20-2. Watchdog Behavior

WDV

WDD

WDT_CR.WDRSTT=1

Watchdog

Fault

Normal behavior

Watchdog Error Watchdog Underflow

FFF

if WDRSTEN is 1

if WDRSTEN is 0

Forbidden

Window

Permitted

Window

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20.5 Watchdog Timer (WDT) User Interface

Table 20-1. Register Mapping

Offset Register Name Access Reset

0x00 Control Register WDT_CR Write-only –

0x04 Mode Register WDT_MR Read/Write Once 0x3FFF_2FFF

0x08 Status Register WDT_SR Read-only 0x0000_0000

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20.5.1 Watchdog Timer Control Register

Name: WDT_CR

Address: 0x400E1450

Access: Write-only

Note: The WDT_CR register values must not be modifie d within three slow clock periods following a restart of the watchdog performed

by a write access in WDT_CR. Any modification will cause the wa tchdog to trigger an end of period earlier than expected.

• WDRSTT: Watchdog Restart

0: No effect.

1: Restarts the watchdog if KEY is written to 0xA5.

• KEY: Password

31 30 29 28 27 26 25 24

KEY

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––WDRSTT

Value Name Description

0xA5 PASSWD Writing any other value in this fi eld aborts the write operation.

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20.5.2 Watchdog Timer Mode Register

Name: WDT_MR

Address: 0x400E1454

Access: Read/Write Once

Notes: 1. The first write access prevents any further modification of the value of this register. Read accesses remain possible.

2. The WDT_MR register values must not be modified within three slow clock periods following a restart of the watchdog

performed by a write access in WDT_CR. Any modification will cause the watchdog to trigger an end of period earlier than

expected.

• WDV: Watchdog Counter Value

Defines the value loaded in the 12-bit watchdog counter.

• WDFIEN: Watchdog Fault Interrupt Enable

0: A watchdog fault (underflow or error) has no effect on interrupt.

1: A watchdog fault (underflow or error) asserts interrupt.

• WDRSTEN: Watchdog Reset Enable

0: A watchdog fault (underflow or error) has no effect on the resets.

1: A watchdog fault (underflow or error) triggers a watchdog reset.

• WDRPROC: Watchdog Reset Processor

0: If WDRSTEN is 1, a watchdog fault (underflow or error) activates all resets.

1: If WDRSTEN is 1, a watchdog fault (underflow or error) activates the processor reset.

• WDDIS: Watchdog Disable

0: Enables the Watchdog Timer.

1: Disables the Watchdog Timer.

Note: When setting the WDDIS bit, and while it is set, the fields WDV and WDD must not be modified.

• WDD: Watchdog Delta Value

Defines the permitted range for reloading the Watchdog Timer.

If the Watchdog Timer value is less than or equal to WDD, setting bit WDT_CR.WDRSTT restarts the timer.

If the Watchdog Timer value is greater than WDD, setting bit WDT_CR.WDRSTT causes a watchdog error.

31 30 29 28 27 26 25 24

––

WDIDLEHLT WDDBGHLT WDD

23 22 21 20 19 18 17 16

WDD

15 14 13 12 11 10 9 8

WDDIS WDRPROC WDRSTEN WDFIEN WDV

76543210

WDV

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• WDDBGHLT: Watchdog Debug Halt

0: The watchdog runs when the processor is in debug state.

1: The watchdog stops when the processor is in debug state.

• WDIDLEHLT: Watchdog Idle Halt

0: The watchdog runs when the system is in idle state.

1: The watchdog stops when the system is in idle state.

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20.5.3 Watchdog Timer Status Register

Name: WDT_SR

Address: 0x400E1458

Access Read-only

• WDUNF: Watchdog Underflow (cleared on read)

0: No watchdog underflow occurred since the last read of WDT_ SR.

1: At least one watchdog underflow occurred since the last read of WDT_SR.

• WDERR: Watchdog Error (cleared on read)

0: No watchdog error occurred since the last rea d of WDT_SR.

1: At least one watchdog error occurred since the last read of WDT_SR.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––WDERRWDUNF

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21. Peripheral DMA Controller (PDC)

21.1 Description

The Peripheral DMA Controller (PDC) transfers data between on-chip serial peripherals and the target memories.

The link between the PDC and a serial peripheral is operated by the AHB to APB bridge.

The user interface of each PDC channel is integrated into the user interface of the peripheral it serves. The u ser

interface of mono-direction al channels (receive- only or tr ansmit-only) contains two 32-bit memory pointers and two

16-bit counters , one set (pointer, counter) fo r the current transfer and one s et (pointer, counter) for the nex t

transfer. The bidirectional channel user interface contains four 32-bit memory pointers and four 16-bit counters.

Each set (pointer, counter) is used by the current transmit, next transmit, current receive and next receive.

Using the PDC decreases processor overhead by reducing its intervention during the transfer. This lowers

significantly the number of clock cycles required for a data transfer, improving microcontroller performance.

To launch a transfer, the peripheral triggers its associated PDC channels by using transmit and receive signals.

When the programmed data is transferred, an end of transfer interrupt is generated by the peripheral itself.

21.2 Embedded Characteristics

Performs Transfers to/from APB Communication Serial Peripherals

Supports Half-duplex and Full-duplex Peripherals

Automatic Circular Buffer Mode

Transfer Bus Error Report

21.3 Peripheral DMA Controller Channels

The Peripheral DMA Controller handles transfer requests from the channel according to the following priorities

(CH0 is high priority):

Table 21-1. Peripheral DMA Controller

Instance Name Channel T/R Channel Nu mber

USART7 Transmit 29

SPI7 Transmit 29

TWI7 Transmit 29

MEM2MEM Transmit 28

SPI5 Transmit 27

USART5 Transmit 27

TWI5 Transmit 27

TWI4 Transmit 26

USART4 Transmit 26

SPI4 Transmit 26

TWI6 Transmit 25

USART6 Transmit 25

SPI6 Transmit 25

USART0 Transmit 24

TWI0 Transmit 24

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SPI0 Transmit 24

USART1 Transmit 23

TWI1 Transmit 23

SPI1 Transmit 23

USART2 Transmit 22

TWI2 Transmit 22

SPI2 Transmit 22

I2SC1 Transmit 21, 20

I2SC0 Transmit 19, 18

USART3 Transmit 17

SPI3 Transmit 17

TWI3 Transmit 17

USART7 Receive 16

SPI7 Receive 16

TWI7 Receive 16

MEM2MEM Receive 15

TC0::TC0 Receive 14

SPI5 Receive 13

USART5 Receive 13

TWI5 Receive 13

TWI4 Receive 12

USART4 Receive 12

SPI4 Receive 12

TWI6 Receive 11

USART6 Receive 11

SPI6 Receive 11

USART0 Receive 10

TWI0 Receive 10

SPI0 Receive 10

USART1 Receive 9

TWI1 Receive 9

SPI1 Receive 9

USART2 Receive 8

TWI2 Receive 8

SPI2 Receive 8

PDMIC1 Receive 7

PDMIC0 Receive 6

Table 21-1. Peripheral DMA Controller (Continued)

Instance Name Channel T/R Channe l Nu mber

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21.4 Block Diagram

Figure 21-1. Block Diagram

I2SC1 Receive 4,5

I2SC0 Receive 2,3

ADC Receive 1

USART3 Receive 0

SPI3 Receive 0

TWI3 Receive 0

Table 21-1. Peripheral DMA Controller (Continued)

Instance Name Channel T/R Channel Nu mber

PDC

FULL DUPLEX

PERIPHERAL

THR

RHR

PDC Channel A

PDC Channel B

Control

Status & Control

Control

PDC Channel C

HALF DUPLEX

PERIPHERAL

THR

Status & Control

RECEIVE or TRANSMIT

PERIPHERAL

RHR or THR

Control

RHR

PDC Channel D

Status & Control

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21.5 Functional Description

21.5.1 Configuration

The PDC channel user interface enables the user to configure and control data transfers for each channel. The

user interface of each PDC channel is integrated into the associated pe ripheral user interface.

The user interface of a serial pe ripheral, whether it is full- or half-duplex, contains four 32-bit pointers (RPR,

RNPR, TPR, TNPR) and four 16-bit counter registers (RCR, RNCR, TCR, TNCR). However, the transmit and

receive parts of each type are programmed differently: the transmit and receive parts of a full-duplex peripheral

can be programmed at the same time, whereas only one part (transmit or receive) of a half-duplex peripheral can

be programmed at a time.

32-bit pointers define the access location in memory for the current and next transfer, whether it is for read

(transmit) or write (receive). 16-bit counters define the size of the current and next transfers. It is possible, at any

moment, to read the number of transfers remaining for each chann el.

The PDC has dedicated status registers which indicate if the transfer is ena bled or disabled for each channel. The

status for each channel is located in the associated peripheral status register . Transfers can be enabled and/or

disabled by setting TXTEN/TXTDIS and RXTEN/RXTDIS in the peripheral’s Transfer Control register.

At the end of a transfer, the PDC channel sends status flags to its associated peripheral. These flags are visible in

the peripheral Status register (ENDRX, ENDTX, RXBUFF, and TXBUFE). Refer to Section 21.5.3 and to the

associated peripheral user interface.

The peripheral where a PDC transfer is configured must have its peripheral clock enabled. The peripheral clock

must be also enabled to access the PDC register set associated to this peripheral.

21.5.2 Memory Pointers

Each full-duplex peripheral is connected to the PDC by a receive channel and a transmit channel. Both channels

have 32-bit memory pointers that po int to a receive area and to a transmit area, resp ectively, in the target memor y.

Each half-duplex peripheral is con nected to the PDC by a bidirectional channel. This channel has two 32-bit

memory pointers, one for current transfer and the other for next transfer. These pointers point to transmit or

receive data depending on the operating mode of the peripheral.

Depending on the type of transfer (byte, half-word or word), the memo ry pointer is in cremented respective ly by 1,

2 or 4 bytes.

If a memory pointer address changes in the middle of a transfer, the PDC channel continues operating using the

new address.

21.5.3 Transfer Counters

Each channel has two 16-bit counters, one for the current transfer and the one for the next transfer. These

counters define the size of data to be transferred by the channel. The current transfer counter is decremented first

as the data addressed by the current memory po inter starts to be transferred. When the current transfer counter

reaches zero, the channel checks its next transfer counter. If the value of the next counter is zero, the channel

stops transferring data and sets the appropriate flag. If the next counter value is greater than zero, the values of

the next pointer/next c ounter are copied into the current poin ter/current counter and the channe l resumes the

transfer, whereas next pointe r/next counter get zero/zero as values. Whe n the Circular buffer mode is activated,

the register set {next counter, next pointer} is not reset when the next counter value is copied to the curr ent

counter, both next and current registers must be written to the same value. At the end of this transfer, the PDC

channel sets th e ap pr opr i at e flag s in the Per iph er a l Statu s reg ist er .

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The following list gives an overview of how status register flags behave depending on the counters’ value s:

ENDRX flag is set when the PDC Receive Counter Register (PERIPH_RCR) reaches zero.

RXBUFF flag is set when both PERIPH_RCR and the PDC Receiv e Next Counter Register

(PERIPH_RNCR) reach zero.

ENDTX flag is set when the PDC Transmit Counter Register (PERIPH_TCR) reaches zero.

TXBUFE flag is set when both PERIPH_TCR and the PDC Transmit Next Counter Register

(PERIPH_TNCR) reach zero.

These status flags are described in the Transfer Status Register (PERIPH_PTSR).

21.5.4 Data Transfers

The serial peripheral triggers its associated PDC channels’ transfers using transmit enable (TXEN) and receive

enable (RXEN) flags in the transfer control register integrated in the peripheral’s user interface.

When the peripheral receives external data, it sends a Receive Ready signal to its PDC receive channel which

then requests access to the Matrix. When access is granted, the PDC receive channel starts reading the

peripheral Receive Holding register (RHR). The read data are stored in an internal buffer and then written to

memory.

When the peripheral is about to send data, it sends a Transmit Ready to its PDC transmit channel which then

requests access to the Matrix. When access is granted, the PDC tra nsmit channel reads data from mem ory and

transfers the data to the Transmit Holding register (THR) of its associated peripheral. The same peripheral sends

data depending on its mechanism.

In case of invalid memory address resulting from a badly programmed PDC transmit or receive pointer, the bus

matrix does not perform the requested access an d signals a bus error to the PDC. This transfer bus error drives

the PERIPH_PTSR.ERR bit high to flag the error in the Transf er Statu s Reg ist er .

21.5.5 PDC Flags and Peripheral Status Register

Each peripheral connected to the PDC sends out receive ready and tra nsmit ready flags and the PDC re turns flags

to the peripheral. All these flags are only visible in the peripheral’s Status register.

Depending on whether the peripheral is half- or full-duplex, the flags belong to either one single channel or two

different channels.

21.5.5.1 Receive Transfer End

The receive transfer end flag is set when PERIPH_RCR reaches zero and the last data has been transferred to

memory.

This flag is reset by writing a non-zero value to PERIPH_RCR or PERIPH_RNCR.

21.5.5.2 Transmit Transfer End

The transmit transfer end flag is set when PERIPH_TCR reaches zero and the last data has been written to the

peripheral THR.

This flag is reset by writing a non-zero value to PERIPH_TCR or PERIPH_TNCR.

21.5.5.3 Receive Buffer Full

The receive buffer full flag is set when PERIPH_RCR reaches zero, with PERIPH_RNCR also s et to zero and the

last data transferred to memory.

This flag is reset by writing a non-zero value to PERIPH_TCR or PERIPH_TNCR.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

488

21.5.5.4 Transmit Buffer Empty

The transmit buffer em pty flag is se t when PERIPH_T CR reache s zero, with PERI PH_TNCR a lso set to zero and

the last data written to peripheral THR.

This flag is reset by writing a non-zero value to PERIPH_TCR or PERIPH_TNCR.

489

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

21.6 Peripheral DMA Controller (PDC) User Interface

Note: 1. PERIPH: Ten registers are mapped in the peripheral memory space at the same offset. These can be configured by the user

depending on the function and the desired perip heral.

Table 21-2. Register Mapping

Offset Register Name(1) Access Reset

0x00 Receive Pointer Register PERIPH_RPR Read/Write 0

0x04 Receive Counter Register PERIPH_RCR Read/Write 0

0x08 Transmit Pointer Register PERIPH_TPR R ead/Write 0

0x0C Transmit Counter Register PERIPH_TCR Read/Write 0

0x10 Receive Next Pointer Register PERIPH_RN PR Read/Write 0

0x14 Receive Next Counter Register PERIPH_RNCR Read/Write 0

0x18 Transmit Next Pointer Register PERIPH_TNPR Read/Write 0

0x1C Transmit Next Counter Register PERIPH_TNCR Read/Write 0

0x20 Transfer Control Register PERIPH_PTCR Write-only –

0x24 Transfer Status Register PERIPH_PTSR Read-only 0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

490

21.6.1 Receive Pointer Register

Name: PERIPH_RPR

Access: Read/Write

• RXPTR: Receive Pointer Register

RXPTR must be set to receive buffer address.

When a half-duplex peripheral is connected to the PDC, RXPTR = TXPTR.

31 30 29 28 27 26 25 24

RXPTR

23 22 21 20 19 18 17 16

RXPTR

15 14 13 12 11 10 9 8

RXPTR

76543210

RXPTR

491

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

21.6.2 Receive Counter Register

Name: PERIPH_RCR

Access: Read/Write

• RXCTR: Receive Counter Register

RXCTR must be set to receive buffer size.

When a half-duplex peripheral is connected to the PDC, RXCTR = TXCTR.

0: Stops periph er al data transfer to the receiver.

1–65535: Starts peripheral data transfer if the corresponding channel is ac tive.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

RXCTR

76543210

RXCTR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

492

21.6.3 Transmit Pointer Register

Name: PERIPH_TPR

Access: Read/Write

• TXPTR: Transmit Counter Register

TXPTR must be set to transmit buffer address.

When a half-duplex peripheral is connected to the PDC, RXPTR = TXPTR.

31 30 29 28 27 26 25 24

TXPTR

23 22 21 20 19 18 17 16

TXPTR

15 14 13 12 11 10 9 8

TXPTR

76543210

TXPTR

493

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

21.6.4 Transmit Counter Register

Name: PERIPH_TCR

Access: Read/Write

• TXCTR: Transmit Counter Register

TXCTR must be set to transmit buffer size.

When a half-duplex peripheral is connected to the PDC, RXCTR = TXCTR.

0: Stops periph er al data transfer to the transmitter.

1–65535: Starts peripheral data transfer if the corresponding channel is ac tive.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

TXCTR

76543210

TXCTR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

494

21.6.5 Receive Next Pointer Register

Name: PERIPH_RNPR

Access: Read/Write

• RXNPTR: Receive Next Point er

RXNPTR contains the next receive buffer addre ss.

When a half-duplex peripheral is connected to the PDC, RXNPTR = TXNPTR.

31 30 29 28 27 26 25 24

RXNPTR

23 22 21 20 19 18 17 16

RXNPTR

15 14 13 12 11 10 9 8

RXNPTR

76543210

RXNPTR

495

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

21.6.6 Receive Next Counter Register

Name: PERIPH_RNCR

Access: Read/Write

• RXNCTR: Receive Next Counter

RXNCTR contains the next receive buffer size.

When a half-duplex peripheral is connected to the PDC, RXNCTR = TXNCTR.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

RXNCTR

76543210

RXNCTR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

496

21.6.7 Transmit Next Pointer Register

Name: PERIPH_TNPR

Access: Read/Write

• TXNPTR: Transmit Next Pointer

TXNPTR contains the next transmit buffer address.

When a half-duplex peripheral is connected to the PDC, RXNPTR = TXNPTR.

31 30 29 28 27 26 25 24

TXNPTR

23 22 21 20 19 18 17 16

TXNPTR

15 14 13 12 11 10 9 8

TXNPTR

76543210

TXNPTR

497

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

21.6.8 Transmit Next Counter Register

Name: PERIPH_TNCR

Access: Read/Write

• TXNCTR: Transmit Counter Next

TXNCTR contains the next transmit buffer size.

When a half-duplex peripheral is connected to the PDC, RXNCTR = TXNCTR.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

TXNCTR

76543210

TXNCTR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

498

21.6.9 Transfer Control Register

Name: PERIPH_PTCR

Access: Write-only

• RXTEN: Receiver Transfer Enable

0: No effect.

1: Enables PDC receiver channel requests if RXTDIS is not set.

When a half-duplex per ipheral is conn ected to the PDC, ena bling the r eceiver cha nnel r equests automa tically di sables th e

transmitter channel requests. It is forbidden to set both TXTEN and RXTEN for a half-duplex peripheral.

• RXTDIS: Receiver Transfer Disable

0: No effect.

1: Disables the PDC receiver channel requests.

When a half-duplex p eriphe ral is connecte d to the PDC, d isablin g th e receiver chan nel requests also disables the tra nsmit-

ter channel requests.

• TXTEN: Transmitter Transfer Enable

0: No effect.

1: Enables the PDC transmitter channel requests.

When a half-duplex peripheral is connected to the PDC, it enables the transmitter channel requests only if RXTEN is not

set. It is forbidden to set both TXTEN and RXTEN for a half-duplex peripheral.

• TXTDIS: Transmitter Transfer Disable

0: No effect.

1: Disables the PDC transmitter channel requests.

When a half-duplex peripheral is connected to the PDC, disabling the transmitter channel requests disables the receiver

channel requests.

• RXCBEN: Receiver Circular Buffer Enable

0: No effect.

1: Enables the PDC circular buffer for the receiver operation.

• RXCBDIS: Receiver Circular Buffer Disable

0: No effect.

1: Disables the PDC circular buffer for the receiver operation.

31 30 29 28 27 26 25 24

–––––––ERRCLR

23 22 21 20 19 18 17 16

––––TXCBDISTXCBENRXCBDISRXCBEN

15 14 13 12 11 10 9 8

––––––TXTDISTXTEN

76543210

––––––RXTDISRXTEN

499

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• TXCBEN: Transmitter Circular Buffer Enable

0: No effect.

1: Enables the PDC circular buffer for the transmitter operation.

• TXCBDIS: Transmitter Circular Buffer Disable

0: No effect.

1: Enables the PDC circular buffer for the transmitter operation.

• ERRCLR: Transfer Bus Error Clear

0: No effect.

1: Clears the transfer bus error status bit.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

500

21.6.10 Transfer Status Register

Name: PERIPH_PTSR

Access: Read-only

• RXTEN: Receiver Transfer Enable

0: PDC receiver channel requests are disabled.

1: PDC receiver channel requests are enabled.

• TXTEN: Transmitter Transfer Enable

0: PDC transmitter channel requests are disabled.

1: PDC transmitter channel requests are enabled.

• RXCBEN: Receiver Circular Buffer Enable

0: PDC Receiver circular buffer mode is disabled.

1: PDC Receiver circular buffer mode is enabled.

• TXCBEN: Transmitter Circular Buffer Enable

0: PDC Transmitter circular buffer mode is disabled.

1: PDC Transmitter circular buffer mode is enabled.

• ERR: Transfer Bus Error

0: PDC accesses are performed on valid memory address since the last write of ERRCLR bit in PERIPH_PTCR.

1: PDC transmit or receive pointer (or next pointer) is programmed with an invalid memory address since the last write of

ERRCLR bit in PERIPH_PTCR.

31 30 29 28 27 26 25 24

–––––––ERR

23 22 21 20 19 18 17 16

–––––TXCBEN–RXCBEN

15 14 13 12 11 10 9 8

–––––––TXTEN

76543210

–––––––RXTEN

501

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

22. Memory to Memory (MEM2MEM)

22.1 Description

The Memory to Memory (MEM2MEM) module allows the Peripheral DMA Controller (PDC) to perform memory to

memory transfer without CPU intervention. The tra nsfer size can be configured in byte, half-word or word. Two

PDC channels are requir ed to perform the transfer; one channel defines the sourc e of the transfer and the other

defines the destination.

22.2 Embedded Characteristics

Allows PDC to perform memory to memory transfer

Supports byte, half-word and word transfer

Interrupt for End of Transfer

22.3 Block Diagram

Figure 22-1. Memory to Memory Block Diagram

22.4 Product Dependencies

22.4.1 Power Management

The MEM2MEM is not continuously clocked. The user must first configure the Power Management Controller

(PMC) to enable the MEM2MEM clock.

22.4.2 Interrupt Sources

The MEM2MEM interface has an interrupt line connected to the Interrupt Controller.

Handling the MEM2MEM interrupt requires programming the Interrupt Controller before configuring the

MEM2MEM.

MEM2MEM

Transmit

Channel

User Interface

APB

Interrupt

Controller

PMC

THR

peripheral clock

PDC

MEM2MEM

Receive

Channel

Control Logic

RXEND

RXBUFF

Table 22-1. Peripheral IDs

Instance ID

MEM2MEM 15

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

502

22.5 Functional Description

The memory to memory transfer requires two operations.

The PDC receive channel associated to the MEM2M EM module must be configured with the transfer destination

address and buffer size.

The PDC transmit channel associated to the MEM2MEM module must be configured with the source address and

buffer size. The transmit channel buffer size must be equal to the receive channel buffer size.

The two PDC channels exchange data through the Memory to Memory Transfer Holding Register

(MEM2MEM_THR) which appears fully transparent from configuration. This register can be used as a general

purpose register in case the memory to memory transfer capability is not used.

The size of each element of the data buffer can be configured in byte, half-word or word by writing TSIZE field in

the Memory to Memory Mode Register (MEM2MEM_MR). Word transfer (32-bit) is the default size.

The transfer ends when either RXEND rises and/or RXBUFF rises in the Memory to Memory Interrupt Status

An interrupt can be triggered at the end of transfe r by configur ing the Memory to Memor y Interrupt Enable Registe r

(MEM2MEM_IER). Refer to the PDC section of the pro du ct da ta sh ee t fo r detaile d info rm at ion .

503

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

22.6 Memory to Memory (MEM2MEM) User Interface

Table 22-2. Register Mapping

Offset Register Name Access Reset

0x00 Memory to Memory Transfer Holdi ng Register MEM2MEM_THR Read/Write 0x0000_0000

0x04 Memory to Memory Mode Register MEM2MEM_MR Read/Write 0x0000_0002

0x08 Memory to Memory Interrupt Enable Register MEM2MEM_IER Write-only –

0x0C Memory to Memory Interrupt Disable Register MEM2MEM_IDR Write-only –

0x10 Memory to Memory Interrupt Mask Register MEM2MEM_IMR Read-only 0x0000_0000

0x14 Memory to Memory Interrupt Status Register MEM2MEM_ISR Read-only 0x0000_0000

0x18–0xFC Reserved – – –

0x100–0x124 Reserved for PDC Registers – – –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

504

22.6.1 Memory to Memory Transfer Hol d in g Re gi st er

Name: MEM2MEM_THR

Address: 0x40028000

Access: Read/Write

• THDATA: Transfer Holding Data

Must be written by the PDC transmit channel and read by the PDC receive channel.

31 30 29 28 27 26 25 24

THDATA

23 22 21 20 19 18 17 16

THDATA

15 14 13 12 11 10 9 8

THDATA

76543210

THDATA

505

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

22.6.2 Memory to Memory Mode Register

Name: MEM2MEM_MR

Address: 0x40028004

Access: Read/Write

• TSIZE: Transfer Size

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––– TSIZE

Value Name Description

0x0 T_8BIT The buffer size is defined in byte.

0x1 T_16BIT The buffer size is defined in half-word (16-bit).

0x2 T_32BIT The buffer size is defined in word (32-bit). Default value.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

506

22.6.3 Memory to Memory Interrupt Enable Register

Name: MEM2MEM_IER

Address: 0x40028008

Access: Write-only

• RXEND: End of Transfer Interrupt Enable

0: No effect

1: Enables the corresponding interrupt.

• RXBUFF: Buffer Full Interrupt Enable

0: No effect

1: Enables the corresponding interrupt.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––RXBUFFRXEND

507

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

22.6.4 Memory to Memory Interrupt Disable Register

Name: MEM2MEM_IDR

Address: 0x4002800C

Access: Write-only

• RXEND: End of Transfer Interrupt Disable

0: No effect

1: Disables the corresponding interrupt.

• RXBUFF: Buffer Full Interrupt Disable

0: No effect

1: Disables the corresponding interrupt.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––RXBUFFRXEND

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

508

22.6.5 Memory to Memory Interrupt Mask Register

Name: MEM2MEM_IMR

Address: 0x40028010

Access: Read-only

• RXEND: End of Transfer Inte rrupt Mask

0: The corresponding interrupt is not enabled.

1: The corresponding interrupt is enabled.

• RXBUFF: Buffer Full Interrupt Mask

0: The corresponding interrupt is not enabled.

1: The corresponding interrupt is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––RXBUFFRXEND

509

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

22.6.6 Memory to Memory Interrupt Status Register

Name: MEM2MEM_ISR

Address: 0x40028014

Access: Read-only

• RXEND: End of Transfer

0: The End of Transfer signal from the PDC receive channel is inactive.

1: The End of Transfer signal from the PDC receive channel is active.

• RXBUFF: Buffer Full

0: The signal Buffer Full from the PDC receive channel is inactive.

1: The signal Buffer Full from the PDC receive channel is active.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––RXBUFFRXEND

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

510

23. Enhanced Embedded Flash Controller (EEFC)

23.1 Description

The Enhanced Embedded Flas h Controller (EEFC) pr ovides the interface o f the Flash block with the 32-bit internal

bus.

Its 128-bit or 64-bit wide memory interface increases performance. It also manages the programming, erasing,

locking and unlockin g sequences of the Flash u sing a full set of commands. One of the commands returns the

embedded Flash descriptor definition that informs the system about the Flash organization, thus making the

software generic.

23.2 Embedded Characteristics

Increases Performance in Thumb-2 Mode with 128-bit or 64-bit-wide Memory Interface up to 96 MHz

Code Loop Optimization

64 Lock Bits, Each Protecting a Lock Region

8 General-purpose GPNVM Bits

One-by-one Lock Bit Programming

Commands Protected by a Keyword

Erase the Entire Fl as h

Erase by Plane

Erase by Sector

Erase by Page

Provides Unique Identifier

Provides 512-byte User Signature Area

Supports Erasing before Programming

Locking and Un loc king Op er at ion s

Supports Read of the Calibration Bits

Register Write Protection

23.3 Product Dependencies

23.3.1 Power Management

The Enhanced Embedded Flash Controller (EEFC) is continuously clocked. The Power Management Controller

has no effect on its behavior.

23.3.2 Interrupt Sources

The EEFC interrupt lin e is connected to the interrupt contro ller. Using the EEFC interrupt requires the interrupt

controller to be programmed first. The EEFC interrupt is generated only if the value of EEFC_FMR.FRDY is ‘1’.

Table 23-1. Peripheral IDs

Instance ID

EFC 6

511

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

23.4 Functional Description

23.4.1 Embedded Flash Organization

The embedded Flash interfaces directly with the internal bus. The embedded Flash is composed of:

One memory plane organized in several pages of the same size for the code

A separate 2 x 512-byte memory area which includes the unique chip identifier

A separate 512-byte memory area for the user signature

Two 128-bit or 64-bit read buffers used for code read optimization

One 128-bit or 64-bit read buffer used for data read optimization

One write buf fer that manage s page programming. The write buf fer size is equal to the pag e size. This buffer

is write-only and accessible all along the 1 Mbyte address space, so that each word can be written to its final

address.

Several lock bits used to protect write/erase operation on several pages (lock region). A lock bit is

associated with a lock region composed of several pages in the memory plane.

Several bits that may be set and cleared through the EEFC interface, called general-purpose non-volatile

memory bits (GPNVM bits)

The embedded Flash size, the page size, the organization of lock regions and the definition of GPNVM bits are

specific to the device. The EEFC returns a descriptor of the Flash controller after a ‘Get Flash Descriptor’

command has been issued by the application (see Section 23.4.3.1 ”Get Flash Descriptor Command”).

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

512

Figure 23-1. Flash Memory Areas

@FBA+0x000

User Signature Area

Unique Identifier Area

Unique Identifier

Code Area

@FBA+0x1FF

@FBA+0x000

@FBA+0x3FF

@FBA+0x000

Write “Start Unique Identifier”

(Flash Command STUI)

Write “Start User Signature”

(Flash Command STUS)

@FBA+0x010

Write “Stop Unique Identifier”

(Flash Command SPUI)

Write “Stop User signature”

(Flash Command SPUS)

FBA = Flash Base Address

513

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 23-2. Organization of Embedded Flash for Code

23.4.2 Read Operations

An optimized controller manage s embedded Flash reads, thus increasing perfor mance when the processor is

running in Thumb-2 mode by means of the 128- or 64-bit-wide memory interface.

The Flash memory is accessible through 8-, 16- and 32-bit reads.

As the Flash block size is smaller than the address space rese rved for the internal memory area, the embedded

Flash wraps around the address space and appears to be repeated within it.

The read operations can be performed with or without wait states. Wait states must be programmed in the field

FWS in the Flash Mode register (EEFC_FMR). Defining FWS as 0 enables the single-cycle access of the

embedded Flash. For more details, refer to the section “Electrical Characteristics” of this datasheet.

23.4.2.1 128- or 64-bit Access Mode

By default, the read acce sses of the Flash are perform ed through a 128-bit wide memory interface. It improves

system performance especially when two or three wait states are needed.

For system s re quiring only 1 wait state, or to focus on current consumption rather than performance, the user can

select a 64-bit wide memory access via the bit EEFC_FMR.FAM.

For more details, refer to the section “Electrical Characteristics” of this datasheet.

23.4.2.2 Code Read Optimization

Code read optimization is enabled if the bit EEFC_FMR.SCOD is cleared.

A system of 2 x 128-bit or 2 x 64-bit buffers is added in order to optimize sequential code fetch.

Note: Immediate consecutive code read accesses are not mandatory to benefit from this optimization.

The sequentia l code read op timization is enab led by def ault. If the bit EEFC_FMR.SCOD is set, these buffers are

disabled and the sequential code read is no longer optimized.

Start Address

Page 0

Lock Region 0

Lock Region 1

Memory Plane

Page (m-1)

Lock Region (n-1)

Page (n*m-1)

Start Address + Flash size -1

Lock Bit 0

Lock Bit 1

Lock Bit (n-1)

Another system of 2 x 128-bit or 2 x 64-bit buffers is added in order to optimize loop code fetch. Refer to Section 23.4.2.3 ”Code

Loop Optimization” for more details.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

514

Figure 23-3. Code Read Optimization for FWS = 0

Note: When FWS is equal to 0, all the accesses are performed in a single-cycle access.

Figure 23-4. Code Read Optimization for FWS = 3

Note: When FWS is between 1 and 3, in case of sequential reads, the first access takes (FWS + 1) cycles. The following accesses take

only one cycle.

23.4.2.3 Code Loop Optimization

Code loop optimization is enabled when the bit EEFC_FMR.CLOE is set.

When a backw ard jump is inse rted in the co de, the p ipeline of the s equentia l optimiz ation is broken and b ecomes

inefficient. In this case, the loop code read optimization takes over from the sequential code read optimization to

prevent the insertion of wait states. The loop co de read op timization is enabled by default. In EEFC_FMR, if the bit

CLOE is reset to 0 or the bit SCOD is set, these buffers are disabled and the loop code read is not optimized.

When code loop optimization is enabled, if inner loop body instructio ns L0 to Ln are positioned from th e 128-bit

Flash memory cell Mb0 to the memory cell Mp1, after recognition of a first backward branch, the first two Flash

memory ce lls Mb0 and Mb1 targeted by this branch are cached for fast access from the processor at the next loop

iteration.

Flash Access

Buffer 0 (128 bits)

Master Clock

ARM Request

(32-bit)

XXX

Data to ARM

Bytes 0–15 Bytes 16–31 Bytes 32–47

Bytes 0–15

Buffer 1 (128 bits)

Bytes 32–47

Bytes 0–3 Bytes 4–7 Bytes 8–11 Bytes 12–15 Bytes 16–19 Bytes 20–23 Bytes 24–27

XXX

XXX Bytes 16–31

@ 0 @+4 @ +8 @+12 @+16 @+20 @+24 @+28 @+32

Bytes 28–31

anticipation of @16-31

Flash Access

Buffer 0 (128 bits)

Master Clock

ARM Request

(32-bit)

Data to ARM

Buffer 1 (128 bits)

0–3

XXX

Bytes 16–31

@ 0 @+4 @+8

Bytes 0–15 Bytes 16–31 Bytes 32–47 Bytes 48–6

Bytes 0–15

4–7 8–11 12–15

@+12 @+16 @+20

24–27 28–31 32–35 36–3916–19 20–23 40–43 44–47

@+24 @+28 @+32 @+36 @+40 @+44 @+48 @+52

Bytes 32–47

48–51

anticipation of @16-31 anticipation of @32-47

wait 3 cycles before

128-bit data is stable @0/4/8/12 are ready @16/20/24/28 are ready

515

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Then by combining the sequential prefetch (described in Section 23.4.2.2 ”Code Read Optimization”) through the

loop body with the fast read access to the loop entry cache, th e entire loop can be iterated with no wait state.

Figure 23-5 illustrates code loop optimization.

Figure 23-5. Code Loop Optimization

23.4.2.4 Data Read Optimization

The organization of the Flash in 128 bits or 64 bits is associated with two 128-bit or 64-bit prefetch buffers and one

128-bit or 64-bit data read buffer, thus providing maximum system performance. This buffer is added in order to

store the requested data plus all th e data co ntained in the 128-bit or 64- bit aligned data. This spe eds up sequential

data reads if, for example, F WS is equal to 1 ( see Figu re 2 3-6). The da ta read optimization is enab led by default. If

the bit EEFC_FMR.SCOD is set, this buffer is disabled and the data read is no longer optimized.

Note: No consecutive data read accesses are mandatory to benefit from this optimization .

Figure 23-6. Data Read Optimization for FWS = 1

23.4.3 Flash Commands

The EEFC offers a set of commands to manage programm ing the Flash memory, locking and unlocking lock

regions, consecutive programming, locking and full Flash erasing, etc.

n-1

n-2

n-3

n-4

n-5

2×128-bit loop entry

cache 2×128-bit prefetch

buffer

Loop Entry instruction

Loop End instruction

Flash Memory

128-bit words

Branch Cache 0

Branch Cache 1

Prefetch Buffer 0

Prefetch Buffer 1

Backward address jump

Flash Access

Buffer (128 bits)

Master Clock

ARM Request

(32-bit)

XXX

Data to ARM

Bytes 0–15 Bytes 16–31

Bytes 0–15

Bytes 0–3 4–7 8–11 12–15 16–19 20–23

XXX

Bytes 16–31

@Byte 0 @ 4 @ 8 @ 12 @ 16 @ 20 @ 24 @ 28 @ 32 @ 36

XXX Bytes 32–47

24–27 28–31 32–35

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The commands are listed in the following table.

In order to execute one of these commands, select the required command using the FCMD field in the Flash

Command register (EEFC_FCR). As soon as EEFC_FCR is written, the FRDY flag and the FVALUE field in the

Flash Result register (EEFC_FRR) are au tomatically cleared. Once the current com mand has completed, the

FRDY flag is automatically set. If an interrupt has been enabled by setting the bit EEFC_FMR.FRDY, the

corresponding interrupt line o f the interrupt controller is activated. (Note that this is true for all commands excep t

for the STUI command. The FRDY flag is not set when the STUI command has completed.)

All the commands are protected by the same keyword, which must be written in the eight highest bits of

EEFC_FCR.

Writing EEFC_FCR with data that does not contain the correct key and/or with an invalid command has no effect

on the whole memory plane, but the FCMDE flag is set in the Flash Status register (EEFC_FSR). This flag is

automatically cleared by a read access to EEFC_FSR.

When the current command writes or erases a page in a locked region, the command has no effect on the whole

memory plane, but the FLOC KE flag is set in EEFC_FSR. This flag is automatically cleared by a read access to

EEFC_FSR.

Table 23-2. Set of Commands

Command Value Mnemonic

Get Flash descriptor 0x00 GETD

Write page 0x01 WP

Write page and lock 0x02 WPL

Erase page and write page 0x03 EWP

Erase page and write page then lock 0x04 EWPL

Erase all 0x05 EA

Erase pages 0x07 EPA

Set lock bit 0x08 SLB

Clear lock bit 0x09 CLB

Get lock bit 0x0A GLB

Set GPNVM bit 0x0B SGPB

Clear GPNVM bit 0x0C CGPB

Get GPNVM bit 0x0D GGPB

Start read unique identifier 0x0E STUI

St op read unique identifier 0x0F SPUI

Get CALIB bit 0x10 GCALB

Erase sector 0x11 ES

Write user signature 0x12 WUS

Erase user signature 0x13 EUS

Start read user signature 0x14 STUS

Stop read user signature 0x15 SPUS

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Figure 23-7. Command Stat e Chart

23.4.3.1 Get Flash Descriptor Command

This command provides the system with information on the Flash organization. The system can take full

advantage of this information. For instance, a device could be replaced by one with more Flash capacity, and so

the software is able to adapt itself to the new configuration.

To get the embedded Fla sh descrip tor, the app lication wr ites the GETD command in EEFC_FCR. The first word of

the descriptor can be read by the software application in EEFC_FRR as soon as the FRDY flag in EEFC_FSR

rises. The next reads of EEFC_FRR provide the following word of the descriptor. If extra read operations to

EEFC_FRR are done after the last word of the descriptor has been returned, the EEFC_FRR value is 0 until the

next valid command.

Check if FRDY flag Set No

Yes

Read Status: EEFC_FSR

Write FCMD and PAGENB in Flash Command Register

Check if FLOCKE flag Set

Check if FRDY flag Set No

Read Status: EEFC_FSR

Yes

Yes Locking region violation

Check if FCMDE flag Set Yes

Bad keyword violation

Command Successful

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23.4.3.2 Write Commands

Several commands are used to program the Flash.

Only 0 values can be programmed using Flash technology; 1 is the erased value. In order to program words in a

page, the page must firs t be erase d. Commands are available to er ase the fu ll memory plane or a given number of

pages. With the EWP and EWPL commands, a page erase is done automatically before a page programming.

After programming, the page (the entire lock region) can be locked to prevent miscellaneous write or erase

sequences. The lock bit can be automatically set after page programming usin g WPL or EWPL commands.

Data to be programmed in the Flash must be written in an internal latch buffer before writing the programming

command in EEFC_FCR. Data can be written at their final destination address, as the latch buffer is mapped into

the Flash memory address space and wraps around within this Flash address space.

Byte and half-word AHB accesses to the latch buffer are not allowed. Only 32-bit word accesses are supported.

32-bit words must be written continuously, in either as cending or descending order. Writing the latch buffer in a

random order is not permitted. This prevents mapping a C-co de structure to the latch buffer an d accessing the

data of the structure in any order. It is instead recommended to fill in a C-code structure in SRAM and copy it in the

latch buffer in a continuous order.

Write operations in the latch buffer are performed with the number of wait states programmed for reading the

Flash.

The latch buffer is automatically re-initialized, i.e., written with logical ‘1’, after execution of each programming

command.

The programming sequence is the following:

1. Write the data to be programmed in the latch buffer.

2. Write the programming command in EEFC_FCR. This automatically clears the bit EEFC_FSR.FRDY.

3. When Flash programming is completed, the bit EEFC_FSR.FRDY rises. If an interrupt has been ena bled by

setting the bit EEFC_FMR.FRDY, the interrupt line of the EEFC is activated.

Three errors can be detected in EEF C_F SR after a program ming sequ e nc e:

Command Error: A bad keyword has been written in EEFC_FCR.

Lock Error: The page to be programmed belongs to a locked region. A command must be run previously to

unlock the corresponding region.

Flash Error: When programming is completed, the WriteVerify test of the Flash memory has failed.

Only one page can be programmed at a time. It is possible to program all the bits of a page (full page

programming) or only some of the bits of the page (partial pag e pr og ra m ming).

Table 23-3. Fla sh Descriptor Definition

Symbol Word Index Description

FL_ID 0 F lash interface description

FL_SIZE 1 Flash size in bytes

FL_PAGE_SIZE 2 Page size in bytes

FL_NB_PLANE 3 Number of planes

FL_PLANE[0] 4 Number of bytes in the plane

FL_NB_LOCK 4 + FL_NB_PLANE Number of lock bits. A bit is associated with a lock region. A lock bit is used

to prevent write or erase operations in the lock region.

FL_LOCK[0] 4 + FL_NB_PLANE + 1 Number of bytes in the first lock region

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Depending on the number of bits to be programmed within the page, the EEFC adapts the write operations

required to program the Flash.

When a ‘Write Page’ (WP) command is issued, the EEFC starts the pro grammin g sequen ce and all the bits written

at 0 in the latch buffer are cleared in the Flash memory array.

During programming, i.e., until EEFC_FSR.FDRY rises, access to the Flash is not allowed.

Full Page Programming

To program a full page, all the bits of the page must be erased before writing the latch buffer and issuing the WP

command. The latch buffer must be written in ascending order, starting fro m the first address of the page. See

Figure 23-8 "Full Page Programming".

Partial Page Programming

To program only part of a page using the WP command, the following constraints must be respected:

See Figure 23-9 "Partial Page Programming".

Optimized Partial Page Programming

The EEFC automatically detects the number of 128-bit words to be programmed. If only one 128-bit aligned word

is to be programmed in the Flash array, the process is optimized to reduce the time neede d for programming.

If several 128-bit words are to be programmed, a standard pag e programming operation is performed.

See Figure 23-10 "Optimized Partial Page Programming".

Programming Bytes

Individual bytes can be programmed using the Partial page prog ramming mode.

Refer to Figure 23-11 "Programming Bytes in the Flash".

Data to be programmed must be contained in integer multiples of 64-bit address-aligned words.

64-bit words can be programmed only if all the corresponding bits in the Flash array are erased (at logical

value ‘1’).

In this case, an area of 64 bits must be reserved for each byte.

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Figure 23-8. Full Page Programming

FF FF FF FF

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

Before programming: Unerased page in Flash array

CA FE CA FE

Step 1: Flash array after page erase

FF FF FF FF

address space

for

Page N

address space

for

latch buffer

Step 2: Writing a page in the latch buffer

DE CA DE CA

CA FE CA FE

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

address space

for

Page N

Step 3: Page in Flash array after issuing

WP command and FRDY=1

DE CA DE CA

FF FF FF FF

32 bits wide 32 bits wide

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Figure 23-9. Partial Page Programming

32 bits wide 32 bits wide

FF FF FF FF

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

Step 2: Flash array after programming

64-bit at address 0xX08 (write latch buffer + WP)

CA FE CA FE

FF FF FF FF

address space

for

Page N

FF FF FF FF

Step 1: Flash array after page erase

A FE

A F

A FE

A F

32 bits wide

FF FF FF FF

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

Step 3: Flash array after programming

a second 64-bit data at address 0xX00

(write latch buffer + WP)

CA FE CA FE

FF FF FF FF FF FF FF FF

FF FF FF FF

CA FE CA FE

32 bits wide

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

Step 4: Flash array after programming

a 128-bit data word at address 0xX10

(write latch buffer + WP)

CA FE CA FE

FF FF FF FF

CA FE CA FE

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Figure 23-10. Optimized Partial Page Programming

32 bits wide

FF FF FF FF

32 bits wide

FF FF FF FF

Case 2: 2 x 32 bits modified, not crossing 128-bit boundary

User programs WP, Flash Controller sends Write Word

=> Only 1 word programmed => programming period reduced

FF FF FF FF

CA FE FF FF

FF FF CA FE

A FE FF F

F FF

A F

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

32 bits wide

FF FF FF FF

Case 3: 4 x 32 bits modified across 128-bit boundary

User programs WP, Flash Controller sends WP

=> Whole page programmed

FF FF FF FF

32 bits wide

FF FF FF FF

Case 4: 4 x 32 bits modified, not crossing 128-bit boundary

User programs WP, Flash Controller sends Write Word

=> Only 1 word programmed => programming period reduced

FF FF FF FF

CA FE CA FE

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

CA FE CA FE

FF FF FF FF

CA FE CA FE

Case 1: 2 x 32 bits modified, not crossing 128-bit boundary

User programs WP, Flash Controller sends Write Word

=> Only 1 word programmed => programming period reduced

CA FE CA FE FF FF FF FF

FF FF FF FF

4 x 32 bits

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Figure 23-11. Programmin g By tes in the Flash

23.4.3.3 Erase Commands

Erase commands are allowed only o n u nlocked re gion s. Depend ing on th e Flash memor y, several comm and s can

be used to erase the Flash:

Erase All Memory (EA): All memory is erased. The processor must not fetch code from the Flash memory.

Erase Pages (EPA): 8 or 16 pages are erased in the Flash sector selected. The first page to be erased is

specified in the FARG[15:2] field of the EEFC_FCR. The first page numbe r must be a multiple of 8 , 16 or 32

depending on the number of pages to erase at the same time.

Erase Sector (ES): A full memory sector is erased. Sector size depends on the Flash memory.

EEFC_FCR.FARG must be set with a page number that is in the sector to be erased.

If the processor is fetching code from the Flash memory while the EPA or ES command is being executed, the

processor accesses are stalled until the EPA command is completed. To avoid stalling the processor, the code can

be run out of intern al S RAM .

32 bits wide

FF FF FF FF

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

FF FF FF FF

address space

for

Page N

Step 1: Flash array after programming first byte (0xAA)

64-bit used at address 0xX00 (write latch buffer + WP)

FF FF FF FF

xx xx xx xx

xx xx xx AA

32 bits wide

FF FF FF FF

0xX00

0xX04

0xX08

0xX0C

0xX10

0xX14

0xX18

0xX1C

FF FF FF FF

xx xx xx xx

xx xx xx AA

Step 2: Flash array after programming second byte (0x55)

64-bit used at address 0xX08 (write latch buffer + WP)

xx xx xx xx

xx xx xx 55

Note: The byte location shown here is for example only, it can be any byte location within a 64-bit word.

4 x 32 bits =

1 Flash word

4 x 32 bits =

1 Flash word

Note: Note: If one subsector is locked within the first sector, the Erase Sector (ES) command cannot be processed on non-

locked subsectors of the first sector . All the lock bits of the first sector must be cleared prior to issuing an ES command

on the first sector. After the ES command has been issued, the first sector lock bits must be reverted to the state

before clearin g them.

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The erase seq u enc e is the follo win g :

1. Erase starts as soon as one of the er as e co mm a nd s an d th e FARG field are written in EEFC_F CR.

For the EPA command, the two lowest bit s of the FARG field define the number of pa ges to be er ased

(FARG[1:0]):

2. When erasing is completed, the bit EEFC_FSR.FRDY rises. If an interrupt has been enabled by setting the

bit EEFC_FMR.FRDY, the interrupt line of the interrupt controller is activated.

Three errors can be detected in EEF C_F SR after an erasing se quen ce :

Command Error: A bad keyword has been written in EEFC_FCR.

Lock Error: At least one page to be erased belongs to a locked region. The erase command has been

refused, no page has been erased. A command must be run previously to unlock the corresponding region.

Flash Error: At the end of the erase period, the EraseVerify test of the Flash memory has failed.

23.4.3.4 Lock Bit Protection

Lock bits are associated with several pages in the embed ded Flash memo ry plane. This defines lock re gions in the

embedded Fla sh me mo ry pl an e. Th ey pr ev en t writing/erasing pr ot ec te d pa ge s.

The lock sequence is the following:

1. Execute the ‘Set Lock Bit’ command by writing EEFC_FCR.FCMD with the SLB command and

EEFC_FCR.FARG with a page number to be protected.

2. When the locking completes, the bit EEFC_FSR.FRDY rises. If an interrupt has been enabled by setting the

bit EEFC_FMR.FRDY, the interrupt line of the interrupt controller is activated.

3. The result of the SLB command can be checked running a ‘Get Lock Bit’ (GLB) command.

Note: The value of the FARG argument passed together with SLB command must not exceed the higher lock bit index

available in the product.

Two errors can be detected in EEFC_FSR after a programming sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

Flash Error: At the end of the programming, the EraseVerify or WriteVerify test of the Flash memory has

failed.

It is possible to clear lock bits previously set. After the lock bits are cleared, the locked region can be erased or

programmed. The unlock sequence is the following:

1. Execute the ‘Clear Lock Bit’ command by writing EEFC_FCR.FCMD with the CLB command and

EEFC_FCR.FARG with a page number to be unprotected.

2. When the unlock completes, the bit EEFC_FSR.FRDY rises. If an interrupt has been enabled by setting the

bit EEFC_FMR.FRDY, the interrupt line of the interrupt controller is activated.

Note: The value of the FARG argument passed together with CLB command must not excee d the higher lock bit index

available in the product.

Two errors can be detected in EEFC_FSR after a programming sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

Flash Error: At the end of the programming, the EraseVerify or WriteVerify test of the Flash memory has

failed.

Table 23-4. EEFC_FCR.FARG Field for EPA Command

FARG[1:0] Number of pages to be erased with EPA command

0 4 pages (only valid for small 8 KB sectors)

1 8 pages (only valid for small 8 KB sectors)

2 16 pages

3 32 pages (not valid for small 8 KB sectors)

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The status of lock bits can be returned by the EEFC. The ‘Get Lock Bit’ sequence is the following:

1. Execute the ‘Get Lock Bit’ command by writing EEFC_FCR.FCMD with the GLB command. Field

EEFC_FCR.FARG is meaningless.

2. Lock bits can be read by the software application in EEFC_FRR. The first word read corresponds to the 32

first lock bits, next reads providing the next 32 lock bits as long as it is meaningful. Extra reads to

EEFC_FRR return 0.

For example, if the third bit of the first word read in EEFC_FRR is set, the third lock region is locked.

Two errors can be detected in EEFC_FSR after a programming sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

Flash Error: At the end of the programming, the EraseVerify or WriteVerify test of the Flash memory has

failed.

Note: Access to the Flash in read is permitted when a ‘Set Lock Bit’, ‘Clear Lock Bit’ or ‘Get Lock Bit’ command is executed.

23.4.3.5 GPNVM Bit

GPNVM bits do not interfere with the embedded Flash memory plane. For more details, refer to the section

“Memories” of this datasheet.

The ‘Set GPNVM Bit’ sequence is the following:

1. Execute the ‘Set GPNVM Bit’ command by writing EEFC_FCR.FCMD with the SGPB command and

EEFC_FCR.FARG with the number of GPNVM bits to be set.

2. When the GPNVM bit is set, the bit EEFC_FSR.FRDY rises. If an interrupt was enabled by setting the bit

EEFC_FMR.FRDY, the interrupt line of the interrupt controller is activated.

3. The result of the SGPB command can be checked by running a ‘Get GPNVM Bit’ (GGPB) command.

Note: The value of the FARG argument passed together with SGPB command must not exceed the higher GPNVM index

available in the product. Flash data content is not altered if F ARG exceeds the limit. Command Error is detected only if

FARG is greater than 8.

Two errors can be detected in EEFC_FSR after a programming sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

Flash Error: At the end of the programming, the EraseVerify or WriteVerify test of the Flash memory has

failed.

It is possible to clear GPNVM bits previously set. The ‘Clear GPNVM Bit’ sequence is the following:

1. Execute the ‘Clear GPNVM Bit’ command by writing EEFC_FCR.FCMD with the CGPB command and

EEFC_FCR.FARG with the number of GPNVM bits to be cleared.

2. When the clear completes, the bit EEFC_FSR.FRDY rise s. If an interrupt has been enabled by setting the b it

EEFC_FMR.FRDY, the interrupt line of the interrupt controller is activated.

Note: The value of the FARG argument passed together with CGPB command must not exceed the higher GPNVM inde x

available in the product. Flash data content is not altered if F ARG exceeds the limit. Command Error is detected only if

FARG is greater than 8.

Two errors can be detected in EEFC_FSR after a programming sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

Flash Error: At the end of the programming, the EraseVerify or WriteVerify test of the Flash memory has

failed.

The status of GPNVM bits can be returned by the EEFC. The sequence is the following:

1. Execute the ‘Get GPNVM Bit’ command by writing EEFC_FCR.FCMD with the GGPB command. Field

EEFC_FCR.FARG is meaningless.

2. GPNVM bits can be read by the software application in EEFC_FRR. The first word read corresponds to the

32 first GPNVM bit s, following read s provide the next 3 2 GPNVM bit s as long as it is m eaningful. Extra rea ds

to EEFC_FRR return 0.

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For example, if the third bit of the first word read in EEFC_FRR is set, the third GPNVM bit is active.

One error can be detected in EEFC_FSR after a programming sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

Note: A ccess to the Flas h in read is permi tted when a ‘Set GP NVM Bit’, ‘Clear GPNVM Bit’ or ‘Get GPNVM Bit’ command is

executed.

23.4.3.6 Calibration Bit

Calibration bits do not interfere with the embedded Flash memory plane.

The calibration bits cannot be modified.

The status of calibration bits are returned by the EEFC. The sequence is the following:

1. Execute the ‘Get CALIB Bit’ command by writing EEFC_FCR.FCMD with the GCALB command. Field

EEFC_FCR.FARG is meaningless.

2. Calibration bits can be read by the software application in EEFC_FRR. The first word read corresponds to

the first 32 calibration bit s. The following reads provide the next 32 calibra tion bits as long as it is meaningful.

Extra reads to EEFC_FRR return 0.

The 16/24 MHz internal RC os cillator is calibrated in production. This calibration can be read through the GCALB

command. Table 23-5 shows the bit implementation.

The RC calibration for the 8 MHz is set to ‘1000000’.

Note: 1. Refer to bits SUPC_PWMR.LPOWER0–3 in the section “Suppl y Controller (SUPC)”.

23.4.3.7 Security Bit Protection

When the security bit is enabled, access to the Flash through the SWD interface or through the Fast Flash

Programming interface is forbidden. This ensures the confidentiality of the code programmed in the Flash.

The security bit is GPNVM0 .

Disabling the security bit can only be achieved by asserting the ERASE pin at ‘1’, and after a full Flash erase is

performed. When the security bit is deactivated, all accesses to the Flash are permitted.

23.4.3.8 Unique Identifier Area

Each device is programmed with a 2*512-bytes unique identifier area . See Figure 23-1 "Flash Memory Areas".

The sequence to read the unique identifier area is the following:

1. Execute the ‘Start Read Unique Identifie r’ command by writing EEFC_FCR.FCMD with the STUI command.

Field EEFC_FCR.FARG is meaningless.

2. Wait until the bit EEFC_FSR.FRDY falls to read the unique identifier area. The unique identifier field is

located in the first 128 bits of the Flash memory mapping. The ‘Start Read Unique Identifier’ command

reuses some addresses of the memory plane for code, but the unique identifier area is physically different

from the memory plane for code.

3. To stop reading the unique identifier area, execute the ‘Stop Read Unique Identifier’ command by writing

EEFC_FCR.FCMD with the SPUI command. Field EEFC_FCR.FARG is meaningless.

4. When the SPUI command has been executed, the bit EEFC_FSR.FRDY rises. If an interrupt was enabled

by setting the bit EEFC_FMR.FRDY, the interrupt line of the interrupt controller is activated.

Note that durin g the se quence, the software cannot be fetched from the Flash.

Table 23-5. Calibr ation Bit Indexes

Description EEFC_FRR Bits

Low-power regulator trimming value (1) [117–114]

16 MHz RC calibration output [28–22]

24 MHz RC calibration output [38–32]

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23.4.3.9 User Signature Area

Each product contains a user signature area of 512-bytes. It can be used for storage. Read, wr ite and erase of this

area is allowed.

See Figure 23-1 "Flash Memory Areas".

The sequence to read the user signature area is the following:

1. Execute the ‘Start Read User Signature’ command by writing EEFC_FCR.FCMD with the STUS command.

Field EEFC_FCR.FARG is meaningless.

2. Wait until the bit EEFC_FSR.FRDY falls to read the user signature area. The user signature area is located

in the first 512 bytes of the Flash memory mapping. The ‘S tart Read User Sign ature’ command reuses som e

addresses of the memory plane but the user signature area is physically different from the memory plane

3. To stop reading the user signature area, execute the ‘Stop Read User Signature’ command by writing

EEFC_FCR.FCMD with the SPUS command. Field EEFC_FCR.FARG is meaningless.

4. When the SPUI command has been executed, the bit EEFC_FSR.FRDY rises. If an interrupt was enabled

by setting the bit EEFC_FMR.FRDY, the interrupt line of the interrupt controller is activated.

Note that during the sequence, the software cannot be fetched from the Flash or from the second plane in case of

dual plane.

One error can be detected in EEFC_FSR after this sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

The sequence to write the user signature area is the following:

1. Write the full page, at any page address, within the internal memory area address space.

2. Execute the ‘Write User Signature ’ command by writing EEFC_FCR.FCMD with the WUS command. Field

EEFC_FCR.FARG is meaningless.

3. When prog ra m m ing is comp le te d, th e bit EEFC_F SR.F R DY rises. If an interrupt has been enabled by

setting the bit EEFC_FMR.FRDY, the corresponding interrupt line of the interrupt controller is activated.

Two errors can be detected in EEFC_FSR after this sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

Flash Error: At the end of the programming, the WriteVerify test of the Flash memory has failed.

The sequence to erase the user signature area is the following:

1. Execute the ‘Erase User Signature’ command by writing EEFC_FCR.FCMD with the EUS command. Field

EEFC_FCR.FARG is meaningless.

2. When prog ra m m ing is comp le te d, th e bit EEFC_F SR.F R DY rises. If an interrupt has been enabled by

setting the bit EEFC_FMR.FRDY, the corresponding interrupt line of the interrupt controller is activated.

Two errors can be detected in EEFC_FSR after this sequence:

Command Error: A bad keyword has been written in EEFC_FCR.

Flash Error: At the end of the programming, the EraseVerify test of the Flash memory has failed.

23.4.4 Register Write Protection

To prevent any single software error from corrupting EEFC behavior, certain registe rs in the addr ess space can b e

write-protected by setting the WPEN bit in the “EEFC Write Protection Mode Register” (EEFC_WPMR).

The following register can be write-protected:

“EEFC Flash Mode Register”

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528

23.5 Enhanced Embedded Flash Controller (EEFC) User Interface

The User Interface of the Embedded Flash Controller (EEFC) is integ rated within the System Controller with base address

0x400E0800.

Table 23-6. Register Mapping

Offset Register Name Access Reset St ate

0x00 EEFC Flash Mode Register EEFC_FMR Read/Write 0x0400_0000

0x04 EEFC Flash Command Register EEFC_FCR Write-only –

0x08 EEFC Flash Status Register EEFC_FSR Read-only 0x0000_0001

0x0C EEFC Flash Result Register EEFC_FRR Read-only 0x0

0x10–0x14 Reserved – – –

0x18–0xE0 Reserved – – –

0xE4 Write Protection Mode Register EEFC_WPMR Read/Write 0x0

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23.5.1 EEFC Flash Mode Register

Name: EEFC_FMR

Address: 0x400E0A00

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the “EEFC Write Protection Mode Register” .

• FRDY: Flash Ready Interrupt Enable

0: Flash ready does not generate an interrupt.

1: Flash ready (to ac ce pt a ne w com m a nd ) ge ne rate s an inte rr up t.

• FWS: Flash Wait State

This field defines the number of wait states for read and wr ite operations:

FWS = Number of cycles for Read/Write operations - 1

• SCOD: Sequential Code Optimization Disable

0: The sequential code optimization is enabled.

1: The sequential code optimization is disabled.

No Flash read should be done during change of this field.

• FAM: Flash Access Mode

0: 128-bit access in Read mode only to enhance access speed.

1: 64-bit access in Read mode only to enhance power consumption.

No Flash read should be done during change of this field.

• CLOE: Code Loop Optimization Enable

0: The opcode loop optimization is disabled.

1: The opcode loop optimization is enabled.

No Flash read should be done during change of this field.

31 30 29 28 27 26 25 24

–––––CLOE–FAM

23 22 21 20 19 18 17 16

–––––––SCOD

15 14 13 12 11 10 9 8

–––– FWS

76543210

–––––––FRDY

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530

23.5.2 EEFC Flash Command Register

Name: EEFC_FCR

Address: 0x400E0A04

Access: Write-only

• FCMD: Flash Command

31 30 29 28 27 26 25 24

FKEY

23 22 21 20 19 18 17 16

FARG

15 14 13 12 11 10 9 8

FARG

76543210

FCMD

Value Name Description

0x00 GETD Get Flash descriptor

0x01 WP Write page

0x02 WPL Write page and lock

0x03 EWP Erase page and write page

0x04 EWPL Erase page and write page then lock

0x05 EA Erase all

0x07 EPA Erase pages

0x08 SLB Set lock bit

0x09 CLB Clear lock bit

0x0A GLB Get lock bit

0x0B SGPB Set GPNVM bit

0x0C CGPB Clear GPNVM bit

0x0D GGPB Get GPNVM bit

0x0E STUI Start read unique identifier

0x0F SPUI Stop read unique identifier

0x10 GCALB Get CALIB bit

0x11 ES Erase sector

0x12 WUS Write user signature

0x13 EUS Erase user signature

0x14 STUS Start read user signature

0x15 SPUS Stop read user signature

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• FARG: Flash Command Argument

• FKEY: Flash Writing Protection Key

GETD, GLB,

GGPB, STUI,

SPUI, GCALB,

WUS, EUS, STUS,

SPUS, EA

Commands

requiring no

argument, including

Erase all command

FARG is meaningless, must be written with 0

ES Erase sector

command FARG must be written with any page number within the sector to be erased

EPA Erase pages

command

FARG[1:0] defines the number of pages to be erased

The start page must be written in FARG[15:2].

FARG[1:0] = 0: Four pages to be erased. FARG[15:2] = Page_Number / 4

F A RG[1:0] = 1: Eight pages to be erased. F ARG[15:3] = Page_Number / 8, FARG[2] = 0

FARG[1:0] = 2: Sixteen pages to be erased. FARG[15:4] = Page_Number / 16,

FARG[3:2] = 0

FARG[1:0] = 3: Thirty-two pages to be erased. FARG[15:5] = Page_Number / 32,

FARG[4:2] = 0

Refer to Table 23-4 “EEFC_FCR.FARG Field for EPA Command”.

WP, WPL, EWP,

EWPL Programming

commands FARG must be written with the page number to be programmed

SLB, CLB Lock bit commands FARG defines the page number to be locked or unlocked

SGPB, CGPB GPNVM co mmands FARG defines the GPNVM number to be pro g r a mme d

Value Name Description

0x5A PASSWD The 0x5A value enables the command defined by the bits of the register . If the field is written with a

different value, the write is not performed and no action is started.

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23.5.3 EEFC Flash Status Register

Name: EEFC_FSR

Address: 0x400E0A08

Access: Read-only

• FRDY: Flash Ready Status (cleared when Flash is busy)

0: The EEFC is busy.

1: The EEFC is ready to start a new command.

When set, this flag triggers an interrupt if the FRDY flag is set in EEFC_FMR.

This flag is automatically cleared when the EEFC is busy.

• FCMDE: Flash Command Error Status (cleared on read or by writing EEFC_FCR)

0: No invalid commands and no bad keywords were written in EEFC_FMR.

1: An invalid command and/or a bad keyword was/were written in EEFC_FMR.

• FLOCKE: Flash Lock Error Status (cleared on read)

0: No programming/erase of at least one locked region has happened since the last read of EEFC_FSR.

1: Programming/erase of at least one locked region has happened since the last read of EEFC_FSR.

This flag is automatically cleared when EEFC_FSR is read or EEFC_FCR is written.

• FLERR: Flash Error Status (cleared when a programming operation starts)

0: No Flash memory error occurred at the end of programming (EraseVerify or WriteVerify test has passed).

1: A Flash memory error occurred at the end of programming (EraseVerify or WriteVerify test has failed).

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––FLERRFLOCKEFCMDEFRDY

533

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23.5.4 EEFC Flash Result Register

Name: EEFC_FRR

Address: 0x400E0A0C

Access: Read-only

• FVALUE: Flash Result Value

The result of a Flash command is returned in this reg ister. If the size of the result is greater than 32 bits, the next resulting

value is accessible at the next register read.

31 30 29 28 27 26 25 24

FVALUE

23 22 21 20 19 18 17 16

FVALUE

15 14 13 12 11 10 9 8

FVALUE

76543210

FVALUE

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23.5.5 EEFC Write Protection Mode Register

Name: EEFC_WPMR

Address: 0x400E0AE4

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x454643 (EFC in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x454643 (EFC in ASCII).

See Section 23.4.4 ”Register Write Protection” for the list of registers that can be protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x454643 PASSWD Writing any other value in this field aborts the write operation.

Always reads as 0.

535

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24. Timer Counter (TC)

24.1 Description

A Timer Counter (TC) module includes three identical TC channels. The number of implemented TC modules is

device-specific.

Each TC channel can be independently programmed to perform a wide range of functions including frequency

measurement, event counting, interval measurement, pulse generation, delay timing and pulse width modulation.

Each channel has three external clock inputs, five internal clock inputs and two multi-purpose input/output signals

which can be configured by the user. Each cha nnel drive s an internal inter rupt signal which can be progra mmed to

generate processor interrupts.

The TC block has two global registers which act upon all TC channels:

Block Control Register (TC_BCR)—allows channels to be started simultaneou sly with the same instruction

Block Mode Register (TC_BMR)—defines the external clock inputs for each channel, allowing them to be

chained

24.2 Embedded Characteristics

Total number of TC channels implemented on this device: 6

TC channel size: 16-bit

Wide range of functions including:

Frequency measurement

Event counting

Interval measurement

Pulse generation

Delay timing

Pulse Width Modulation

Up/down capabilities

2-bit Gray up/down count for stepper motor

Each channel is user-configurable and contains:

Three exte rn al cloc k inp uts

Five Internal clock inputs

Two multi-purpose input/output signals acting as trigger event

Internal interrupt signal

Read of the Capt ur e re gis te rs by the PDC

Register Write Protection

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24.3 Block Diagram

Figure 24-1. Timer Counter Block Diagram

Table 24-1. Timer Counter Clock Assignment

Name Definition

TIMER_CLOCK1 MCK/2

TIMER_CLOCK2 MCK/8

TIMER_CLOCK3 MCK/32

TIMER_CLOCK4 MCK/128

TIMER_CLOCK5 PCK3

Table 24-2. Channel Signal Description

Signal Name Description

XC0, XC1, XC2 External Clock Inputs

TIOAx Capture Mode: Timer Counter Input

Waveform Mode: Timer Counter Output

TIOBx Capture Mode: Timer Counter Input

Waveform Mode: Timer Counter Input/Output

INT Interrupt Signal Output (internal signal)

SYNC Synchronization Input Signal (from configuration register)

Timer/Counter

Channel 0

Timer/Counter

Channel 1

Timer/Counter

Channel 2

SYNC

Parallel I/O

Controller

TC1XC1S

TC0XC0S

TC2XC2S

INT0

INT1

INT2

TIOA0

TIOA1

TIOA2

TIOB0

TIOB1

TIOB2

XC0

XC1

XC2

XC0

XC1

XC2

XC0

XC1

XC2

TCLK0

TCLK1

TCLK2

TCLK0

TCLK1

TCLK2

TCLK0

TCLK1

TCLK2

TIOA1

TIOA2

TIOA0

TIOA2

TIOA0

TIOA1

Interrupt

Controller

TCLK0

TCLK1

TCLK2

TIOA0

TIOB0

TIOA1

TIOB1

TIOA2

TIOB2

Timer Counter

TIOA

TIOB

TIOA

TIOB

TIOA

TIOB

SYNC

TIMER_CLOCK2

TIMER_CLOCK3

TIMER_CLOCK4

TIMER_CLOCK5

TIMER_CLOCK1

537

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24.4 Pin List

24.5 Product Dependencies

24.5.1 I/O Lines

The pins used for interfacing the compliant external devices may be multiplexed with PIO lines. The programmer

must first program the PIO controllers to assign the TC pins to their peripheral functions.

24.5.2 Power Management

The TC is clocked through the Power Management Controller (PMC), thus the programmer must first configure the

PMC to enable the Timer Counter clock of each channel.

24.5.3 Interrupt Sources

The TC has an interrupt line per channel connected to the interrupt controller. Handling the TC interrupt requires

programming the interrupt controller before configuring the TC.

Table 24-3. Pin List

Pin Name Description Type

TCLK0–TCLK2 External Clock Input I nput

TIOA0–TIOA2 I/O Line A I/O

TIOB0–TIOB2 I/O Line B I/O

Table 24-4. I/O Lines

Instance Signal I/O Line Peripheral

TC0 TCLK0 PA2 A

TC0 TCLK1 PA19 A

TC0 TCLK2 PA20 A

TC0 TIOA0 PA0 B

TC0 TIOA1 PA23 B

TC0 TIOA2 PA21 A

TC0 TIOB0 PA1 B

TC0 TIOB1 PA16 B

TC0 TIOB2 PA22 A

Table 24-5. Peripheral IDs

Instance ID

TC0 23

TC1 24

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538

24.6 Functional Description

24.6.1 Description

All channels of the Timer Counter are independent and identical in operation. The registers for channel

programming are listed in Table 24-6 “Register Mapping”.

24.6.2 16-bit Counter

Each 16-bit channel is org ani ze d a round a 16 -bit co un ter. The value of the counter is increme nted at each po sitive

edge of the selected clock. When the counter has reached the value 216-1 and passes to zero, an ove r flow occurs

and the COVFS bit in the TC Status Register (TC_SR) is set.

The current value of the counter is accessible in real time by reading the TC Cou nter Value Register (TC_CV). The

counter can be reset by a trigge r. In this case, the counter value passes to zero on the next valid edge of the

selected clock.

24.6.3 Clock Selection

At block level, input clock signals of each channel can be connected either to the external inputs TCLKx, or to the

internal I/O signals TIOAx for c haining(1) by programming the TC Block Mode Register (TC_BMR). See Figure 24-

Each channel can independently select an internal or external clock source for its counter(2):

External clock signals: XC0, XC1 or XC2

Internal clock signals: MCK/2, MCK/8, MCK/32, MCK/128, PCK3

This selection is made by the TCCLKS bits in the TC Channel Mode Register (TC_CMR).

The selected clock can be inverted with the CLKI bit in the TC_CMR. This allows counting on the opposite edges

of the clock.

The burst function allows the clock to be validated when an external signal is high. The BURST parameter in the

TC_CMR defines this signal (none, XC0, XC1, XC2). See Figure 24-3.

Notes: 1. In Waveform mode, to chain two timers, it is mandatory to initialize some parameters:

- Configure TIOx outputs to 1 or 0 by writing the re qu i re d val u e to TC_C MR .ASWTRG.

- Bit TC_BCR.SYNC must be written to 1 to start the channels at the same time.

2. In all cases, if an external clock or asynchronous internal clock PCK3 is used, the duration of each of its levels

must be longer than the peripheral clock period, so the clock frequency will be at least 2.5 times lower than the

peripheral clock.

539

SAM G55 [DATASHEET]

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Figure 24-2. Clock Chaining Selection

Figure 24-3. Clock Selection

Timer/Counter

Channel 0

SYNC

TC0XC0S

TIOA0

TIOB0

XC0

XC1 = TCLK1

XC2 = TCLK2

TCLK0

TIOA1

TIOA2

Timer/Counter

Channel 1

SYNC

TC1XC1S

TIOA1

TIOB1

XC0 = TCLK0

XC1

XC2 = TCLK2

TCLK1

TIOA0

TIOA2

Timer/Counter

Channel 2

SYNC

TC2XC2S

TIOA2

TIOB2

XC0 = TCLK0

XC1 = TCLK1

XC2

TCLK2

TIOA0

TIOA1

TIMER_CLOCK1

TIMER_CLOCK2

TIMER_CLOCK3

TIMER_CLOCK4

TIMER_CLOCK5

XC0

XC1

XC2

TCCLKS

CLKI

Synchronous

Edge Detection

BURST

Peripheral Clock

Selected

Clock

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24.6.4 Clock Control

The clock of each counter can be controlled in two different ways: it can be enabled/disabled and started/stopped.

See Figure 24-4.

The clock can be enabled or disabled by the user with the CLKEN and the CLKDIS commands in the TC

Channel Control Register (TC_CCR). In Capture mode it can be disabled by an RB load event if LDBDIS is

set to 1 in the TC_CMR. In W avefo rm mode, it can be disabled by an RC Comp are event if CPCDIS is set to

1 in TC_CMR. When disabled, the start or the stop actions have no effect: only a CLKEN command in the

TC_CCR can re-enable the clock. When the clock is enabled, the CLKSTA bit is set in the TC_SR.

The clock can also be started or stopped: a trigger (software, synchro, external or compare) always starts

the clock. The clock can be stopped by an RB load event in Capture mode (LDBSTOP = 1 in TC_CMR) or

an RC compare event in Waveform mode (CPCSTOP = 1 in TC_CMR). The start and the stop commands

are effective only if the clock is enabled.

Figure 24-4. Clock Control

24.6.5 Operating Modes

Each channel can operate independently in two different modes:

Capture mode provides measurement on signals.

Waveform mode provides wave generation.

The TC operating mode is programmed with the WAVE bit in the TC_CMR.

In Capture mode, TIOAx and TIOBx are configured as inputs.

In Waveform mode, TIOAx is always configured to be an output and TIOBx is an output if it is not selected to be

the external trigger.

24.6.6 Trigger

A trigger resets the coun ter and star ts the counter clock. Three types of triggers are common to both modes, and a

fourth external trigger is available to each mode.

Regardless of the trigger used, it will be taken into account at the following active edge of the selected clock. This

means that the counte r value ca n be read differ ently from zer o just after a trigger, especially when a low frequen cy

signal is selected as the clock.

CLKSTA CLKEN CLKDIS

Stop

Event Disable

Event

Counter

Clock

Selected

Clock Trigger

541

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The following triggers are common to both modes:

Software Trigger: Each channel has a software trigger, available by setting SWTRG in TC_CCR.

SYNC: Each channel has a synchronization signal SYNC. When asserted, this signal has th e same effect as

a software trigger. The SYNC signals of all channels are asserted simultaneo usly by writing TC_BCR (Block

Control) with SYNC set.

Compar e RC Trigger: RC is implemented in e ach cha nne l and can pr ovide a tr igg er when th e cou nter valu e

matches the RC value if CPCTRG is set in the TC_CMR.

The channel can also b e configured to ha ve an external trigger . In Capture mode, the external trigger signal can be

selected between TIOAx and TIOBx. In Waveform mode, an external event can be programmed on one of the

following signals: TIOBx, XC0, XC1 or XC2. This external event can then be programmed to perform a trigger by

setting bit ENETRG in the TC_CMR.

If an external trigger is used, the duration of the pulses must be longer than the peripheral clock period in order to

be detected.

24.6.7 Capture Mode

Capture mode is entered by clearing the WAVE bit in the TC_CMR.

Capture mode allows the TC channel to perform measu rements such as pulse timing, frequency, period, duty

cycle and phase on TIOAx and TIOBx signals which are considered as inpu ts.

Figure 24-6 shows the configuration of the TC channel when programmed in Capture mode.

24.6.8 Capture Registers A and B

Registers A and B (RA and RB) are used as capture registers. They can be lo aded with th e coun ter va lue wh en a

programmable event occurs on the signal TIOAx.

The LDRA field in the TC_CMR defines the TIOAx selected edge for the loading of register A, and the LDRB field

defines the TIOAx selected edge for the loading of Register B.

The subsampling ratio defined by the SBSMPLR field in TC_CMR is applied to these selected edges, so that the

loading of Register A and Register B occurs once every 1, 2, 4, 8 or 16 selected edges.

RA is loaded only if it has not been loaded since the last trigger or if RB has been loaded since the last loading of

RA.

RB is loaded only if RA has been loaded since the last trigger or the last loading of RB.

Loading RA or RB before the read of the last value loaded sets the Overrun Error Flag (LOVRS bit) in the TC_SR.

In this case, the old value is overwritten.

When DMA is used, th e RAB register addres s must be configured as source address of the tr ansfer. The RAB

has been triggered upon loading Register A or Register B.

24.6.9 Transfer with PDC in Capture Mode

The PDC can perform access from the TC to system memory in Capture mode only.

Figure 24-5 illustrates how TC_RA and TC_RB can be loaded in the system memory without CPU intervention.

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542

Figure 24-5. Example of Trans fer with PDC in Capture Mode

24.6.10 Trigger Conditions

In addition to the SYNC signal, the so ftware trigger and t he RC compare trigger, an exter nal trigger can be defined.

The ABETRG bit in the TC_CMR selects TIOAx or TIOBx input signal as an external trigger . The External Trigger

Edge Selection parameter (ETRGEDG field in TC_CMR) defines the edge (rising, falling, or both) detected to

generate an external trigger. If ETRGEDG = 0 (none), the external trigger is disabled.

TIOB

TIOA

Transfer to System Memory

Internal Peripheral Trigger

RA RB RA RB

T1,T2,T3,T4 = System Bus load dependent (t

min

= 8 Peripheral Clocks)

T1 T2 T3 T4

ETRGEDG = 1, LDRA = 1, LDRB = 2, ABETRG = 0

ETRGEDG = 3, LDRA = 3, LDRB = 0, ABETRG = 0

TIOB

TIOA

Transfer to System Memory RA RA

T1,T2,T3,T4 = System Bus load dependent (t

min

= 8 Peripheral Clocks)

T1 T2 T3 T4

RA RA

(when RA or RB loaded)

Internal Peripheral Trigger

(when RA loaded)

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Figure 24-6. Capture Mode

TIMER_CLOCK1

TIMER_CLOCK2

TIMER_CLOCK3

TIMER_CLOCK4

TIMER_CLOCK5

XC0

XC1

XC2

TCCLKS

CLKI

CLKSTA CLKEN CLKDIS

BURST

TIOB

Capture

Counter

ABETRG

SWTRG

ETRGEDG CPCTRG

TC1_IMR

Trig

LDRBS

LDRAS

ETRGS

TC1_SR

LOVRS

COVFS

SYNC

MTIOB

TIOA

MTIOA

LDRA

LDBSTOP

If RA is not loaded

or RB is loaded If RA is loaded

LDBDIS

CPCS

INT

Edge

Detector

Edge

Detector

LDRB

Edge

Detector

CLK OVF

RESET

Timer/Counter Channel

Peripheral Clock

Synchronous

Edge Detection

Edge Subsampler

SBSMPLR

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544

24.6.11 Waveform Mode

Waveform mode is entered by setting the TC_CMRx.WAVE bit.

In Waveform mode, the TC channel generates one or two PWM signals with the same frequency and

independently programmable duty cycles, or generates different types of one-shot or repetitive pulses.

In this mode, TIOAx is configured as an output and TIOBx is defined as an output if it is not used as an external

event (EEVT parameter in TC_CMR).

Figure 24-7 shows the configuration of the TC channel when programmed in Waveform operating mode.

24.6.12 Waveform Selection

Depending on the WAVSEL parameter in TC_CMR, the behavior of TC_CV varies.

With any selection, TC_RA, TC_RB and TC_RC can all be used as compare registers.

RA Compare is used to control the TIO Ax output, RB Compare is used to control the TIOBx output (if corre ctly

configured) and RC Compare is used to control TIOAx and/or TIOBx outputs.

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Figure 24-7. Waveform Mode

TCCLKS

CLKI

CLKSTA CLKEN CLKDIS

CPCDIS

BURST

TIOB

Compare RA = Compare RB = Compare RC =

CPCSTOP

Counter

EEVT

EEVTEDG

SYNC

SWTRG

ENETRG

WAVSEL

TC1_IMR

Trig

ACPC

ACPA

AEEVT

ASWTRG

BCPC

BCPB

BEEVT

BSWTRG

TIOA

MTIOA

TIOB

MTIOB

CPAS

COVFS

ETRGS

TC1_SR

CPCS

CPBS

CLK OVF

RESET

Output Controller Output Controller

INT

Edge

Detector

Timer/Counter Channel

TIMER_CLOCK1

TIMER_CLOCK2

TIMER_CLOCK3

TIMER_CLOCK4

TIMER_CLOCK5

XC0

XC1

XC2

WAVSEL

Peripheral Clock

Synchronous

Edge Detection

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

546

24.6.12.1 WAVSEL = 00

When WAVSEL = 00, the value of TC_CV is incremented from 0 to 216-1. Once 216-1 has been reached, the valu e

of TC_CV is reset. Incrementation of TC_CV starts again and the cycle continues. See Figure 24-8.

An external event trigger or a software trigger can reset the value of TC_CV. It is important to note that the trigger

may occur at any time. See Figure 24-9.

RC Compare cannot be programmed to generate a trigger in this configuration. At the same time, RC Compare

can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the counter clock (CPCDIS = 1 in

TC_CMR).

Figure 24-8. WAVSEL = 00 without Trigger

Figure 24-9. WAVSEL = 00 with Trigger

Time

Counter Value

TIOB

TIOA

Counter cleared by compare match with 0xFFFF

0xFFFF

Waveform Examples

Time

Counter Value

TIOB

TIOA

Counter cleared by compare match with 0xFFFF

0xFFFF

Waveform Examples

Counter cleared by trigger

547

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.6.12.2 WAVSEL = 10

When WAVSEL = 10, the value of TC_CV is incremented from 0 to the value of RC, then automatically reset on a

RC Compare. Once the value of TC_CV has been reset, it is then incremented and so on. See Figure 24-10.

It is important to note that TC_CV can be reset at any time by an external event or a software trigger if both are

programmed correctly. See Figure 24-11.

In addition, RC Compare can stop the counter clock (CPCSTOP = 1 in TC_CMR) and/or disable the counter clock

(CPCDIS = 1 in TC_CMR).

Figure 24-10. WAVSEL = 10 without Trigger

Figure 24-11. WAVSEL = 10 with Trigger

Time

Counter Value

TIOB

TIOA

Counter cleared by compare match with RC

Waveform Examples

2n-1

(n = counter size)

Time

Counter Value

TIOB

TIOA

Counter cleared by compare match with RC

Waveform Examples

Counter cleared by trigger

2n-1

(n = counter size)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

548

24.6.12.3 WAVSEL = 01

When WAVSEL = 01, the value of TC_CV is incremented from 0 to 216-1 . Once 216-1 is reached, the value of

TC_CV is decremented to 0, then re-incremented to 216-1 and so on. See Figure 24-12.

A trigger such as an externa l event or a software trigger can mod ify TC_CV at any time. If a trigger occurs while

TC_CV is incrementing, TC_CV then decrements. If a trigger is received while TC_CV is decrementing, TC_CV

then increments. See Figure 24-13.

RC Compare cannot be programmed to generate a trigger in this configuration.

At the same time, RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock

(CPCDIS = 1).

Figure 24-12. WAVSEL = 01 without Trigger

Figure 24-13. WAVSEL = 01 with Trigger

Time

Counter Value

TIOB

TIOA

Counter decremented by compare match with 0xFFFF

0xFFFF

Waveform Examples

Time

Counter Value

TIOB

TIOA

Counter decremented by compare match with 0xFFFF

0xFFFF

Waveform Examples

Counter decremented

by trigger

Counter incremented

by trigger

549

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.6.12.4 WAVSEL = 11

When WAVSEL = 11, the value of TC_CV is incremented from 0 to RC. Once RC is reached, the value of TC_CV

is decremented to 0, then re-incremented to RC and so on. See Figure 24-14.

A trigger such as an externa l event or a software trigger can mod ify TC_CV at any time. If a trigger occurs while

TC_CV is incrementing, TC_CV then decrements. If a trigger is received while TC_CV is decrementing, TC_CV

then increments. See Figure 24-15.

RC Compare can stop the counter clock (CPCSTOP = 1) and/or disable the counter clock (CPCDIS = 1).

Figure 24-14. WAVSEL = 11 without Trigger

Figure 24-15. WAVSEL = 11 with Trigger

Time

Counter Value

TIOB

TIOA

Counter decremented by compare match with RC

Waveform Examples

2n-1

(n = counter size)

Time

Counter Value

TIOB

TIOA

Counter decremented by compare match with RC

Waveform Examples

Counter decremented

by trigger

Counter incremented

by trigger

2n-1

(n = counter size)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

550

24.6.13 External Event/Trigger Conditions

An external event can be progr ammed to be detected on one of the clock sources (XC0, XC1, XC2) or TIOBx. The

external event selected can then be used as a trigger.

The EEVT parameter in TC_CMR selects the external trigger. The EEVTEDG parameter defines the trigger edge

for each of the possible external triggers (rising, falling or both). If EEVTEDG is cleared (none), no external event

is defined.

If TIOBx is defined as an external event signal (EEVT = 0), TIOBx is no longer used as an output and the compare

generate a waveform on TIOAx.

When an external event is defined, it can be used as a trigger by setting bit ENETRG in the TC_CMR.

As in Capture mode, the SYNC signal and the software trigger are also available as triggers. RC Compare can

also be used as a trigger depending on the parameter WAVSEL.

24.6.14 Output Controller

The output controller defines the output level changes on TIOAx and TIOBx following an event. TIOBx Control is

used only if TIO B x is defined as output (not as an external event).

The following events control TIOAx and TIOBx:

Software Trigger

External Event

RC Compare

RA Compare controls TIOAx, and RB Compare controls TIOBx. Each of these events can be programmed to set,

clear or toggle the output as defined in the corresponding parameter in TC_CMR.

24.6.15 2-bit Gray Up/Down Counter for Stepper Motor

Each channel can be independ ently conf igured to gener at e a 2-bit Gray count waveform on corresponding TIOAx,

TIOBx outputs by means of the GCEN bit in TC_SMMRx.

Up or Down count can be defined by writing bit DOWN in TC_SMMRx.

It is mandatory to configure the channel in Waveform mode in the TC_CMR.

The period of the counters can be programmed in TC_RCx.

Figure 24-16. 2-bit Gray Up/Down Counter

TIOAx

TIOBx

DOWNx

TC_RCx

WAVEx = GCENx =1

551

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.6.16 Register Write Protection

To prevent any single software error from corrupting TC behavior, certain registers in the address space can be

write-protected by setting the WPEN bit in the TC Write Protection Mode Register (TC_WPMR).

The Timer Counter clock of the first channel must be enabled to access TC_WPMR.

The following registers can be write-protected:

TC Block Mode Register

TC Channel Mode Register: Capture Mode

TC Channel Mode Register: Waveform Mode

TC Stepper Motor Mode Register

TC Register A

TC Register B

TC Register C

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

552

24.7 Timer Counter (TC) User Interface

Notes: 1. Channel index ranges from 0 to 2.

2. Read-only if TC_CMRx.WAVE = 0

Table 24-6. Register Mapping

Offset(1) Register Name Access Reset

0x00 + channel * 0x40 + 0x00 Channel Control Register TC_CCR Write-only –

0x00 + channel * 0x40 + 0x04 Channel Mode Register TC_CMR Read/Write 0

0x00 + channel * 0x40 + 0x08 Stepper Motor Mode Register TC_SMMR Read/Write 0

0x00 + channel * 0x40 + 0x0C Register AB TC_RAB Read-only 0

0x00 + channel * 0x40 + 0x10 Counter Value TC_CV Read-only 0

0x00 + channel * 0x40 + 0x14 Register A TC_RA Read/Write(2) 0

0x00 + channel * 0x40 + 0x18 Register B TC_RB Read/Write(2) 0

0x00 + channel * 0x40 + 0x1C Register C TC_RC Read/Write 0

0x00 + channel * 0x40 + 0x20 Status Registe r TC_SR Read-only 0

0x00 + channel * 0x40 + 0x24 Interrupt Enable Register TC_IER Write-only –

0x00 + channel * 0x40 + 0x28 Interrupt Disable Register TC_IDR Write-only –

0x00 + channel * 0x40 + 0x2C Interru pt Mask Register TC_IMR Read-only 0

0xC0 Block Control Register TC_BCR Write-only –

0xC4 Block Mo de Register TC_BMR Read /Write 0

0xC8–0xD4 Reserved – – –

0xD8 Reserved – – –

0xE4 Write Protection Mode Register TC_WPMR Read/Write 0

0xE8–0xFC Reserved – – –

0x100–0x1A4 Reserved for PDC Registers – – –

553

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.1 TC Channel Control Register

Name: TC_CCRx [x=0..2]

Address: 0x40010000 (0)[0], 0x40010040 (0)[1], 0x40010080 (0)[2], 0x40014000 (1)[0], 0x40014040 (1)[1],

0x40014080 (1)[2]

Access: Write-only

• CLKEN: Counter Clock Enable Command

0: No effect.

1: Enables the clock if CLKDIS is not 1.

• CLKDIS: Counter Clock Disable Command

0: No effect.

1: Disables the clock.

• SWTRG: Software Trigger Command

0: No effect.

1: A software trigger is performed: the counter is reset and the clock is started.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––SWTRGCLKDISCLKEN

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

554

24.7.2 TC Channel Mode Register: Capture Mode

Name: TC_CMRx [x=0..2] (CAPTURE_MODE)

Address: 0x40010004 (0)[0], 0x40010044 (0)[1], 0x40010084 (0)[2], 0x40014004 (1)[0], 0x40014044 (1)[1],

0x40014084 (1)[2]

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.

• TCCLKS: Clock Selection

• CLKI: Clock Invert

0: Counter is incremented on rising edge of the clock.

1: Counter is incremented on falling edge of the clock.

• BURST: Burst Signal Selection

• LDBSTOP: Counter Clock Stopped with RB Loading

0: Counter clock is not stopped when RB loading occurs.

1: Counter clock is stopped when RB loading occurs.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– SBSMPLR LDRB LDRA

15 14 13 12 11 10 9 8

WAVE CPCTRG – – – ABETRG ETRGEDG

76543210

LDBDIS LDBSTOP BURST CLKI TCCLKS

Value Name Description

0 TIMER_CLOCK1 Clock selected: internal MCK/2 clock signal (from PMC)

1 TIMER_CLOCK2 Clock selected: internal MCK/8 clock signal (from PMC)

2 TIMER_CLOCK3 Clock selected: internal MCK/32 clock signal (from PMC)

3 TIMER_CLOCK4 Clock selected: internal MCK/128 clock signal (from PMC)

4 TIMER_CLOCK5 Clock selected: internal PCK3 clock signal (from PMC)

5 XC0 Clock selected: XC0

6 XC1 Clock selected: XC1

7 XC2 Clock selected: XC2

Value Name Description

0 NONE The clock is not gated by an external signal.

1 XC0 XC0 is ANDed with the selected clock.

2 XC1 XC1 is ANDed with the selected clock.

3 XC2 XC2 is ANDed with the selected clock.

555

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• LDBDIS: Counter Clock Disable with RB Loading

0: Counter clock is not disabled when RB loading occurs.

1: Counter clock is disabled when RB loading occurs.

• ETRGEDG: External Trigger Edge Selection

• ABETRG: TIOAx or TIOBx External Trigger Selection

0: TIOBx is used as an external trigger.

1: TIOAx is used as an external trigger.

• CPCTRG: RC Compare Trigger Enable

0: RC Compare has no effect on the counter and its clock.

1: RC Compare resets the counter and starts the counter clock.

• WAVE: Waveform Mode

0: Capture mode is enabled.

1: Capture mode is disabled (Waveform mode is enabled).

• LDRA: RA Loading Edge Selection

• LDRB: RB Loading Edge Selection

Value Name Description

0 NONE The clock is no t gated by an external signal.

1 RISING Rising edge

2 FALLING Fallin g ed g e

3 EDGE Each edge

Value Name Description

0 NONE None

1 RISING R ising edge of TIOAx

2 FALLING Falling edge of TIOAx

3 EDGE Each edge of TIOAx

Value Name Description

0 NONE None

1 RISING R ising edge of TIOAx

2 FALLING Falling edge of TIOAx

3 EDGE Each edge of TIOAx

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

556

• SBSMPLR: Loading Edge Subsampling Ratio

Value Name Description

0 ONE Load a Capture Register each selected edge

1 HALF Load a Capture Register every 2 selected edges

2 FOURTH Load a Capture Register every 4 selected edges

3 EIGHTH Load a Capture Register every 8 selected edges

4 SIXTEENTH Load a Capture Register every 16 selected edges

557

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.3 TC Channel Mode Register: Waveform Mode

Name: TC_CMRx [x=0..2] (WAVEFORM_MODE)

Address: 0x40010004 (0)[0], 0x40010044 (0)[1], 0x40010084 (0)[2], 0x40014004 (1)[0], 0x40014044 (1)[1],

0x40014084 (1)[2]

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.

• TCCLKS: Clock Selection

• CLKI: Clock Invert

0: Counter is incremented on rising edge of the clock.

1: Counter is incremented on falling edge of the clock.

• BURST: Burst Signal Selection

• CPCSTOP: Counter Clock Stopped with RC Compare

0: Counter clock is not stopped when counter reaches RC.

1: Counter clock is stopped when counter reaches RC.

31 30 29 28 27 26 25 24

BSWTRG BEEVT BCPC BCPB

23 22 21 20 19 18 17 16

ASWTRG AEEVT ACPC ACPA

15 14 13 12 11 10 9 8

WAVE WAVSEL ENETRG EEVT EEVTEDG

76543210

CPCDIS CPCSTOP BURST CLKI TCCLKS

Value Name Description

0 TIMER_CLOCK1 Clock selected: internal MCK/2 clock signal (from PMC)

1 TIMER_CLOCK2 Clock selected: internal MCK/8 clock signal (from PMC)

2 TIMER _CLOCK3 Clock selected: internal MCK/32 clock signal (from PMC)

3 TIMER_CLOCK4 Clock selected: internal MCK/128 clock signal (from PMC)

4 TIMER_CLOCK5 Clock selected: internal PCK3 clock signal (from PMC)

5 XC0 Clock selected: XC0

6 XC1 Clock selected: XC1

7 XC2 Clock selected: XC2

Value Name Description

0 NONE The clock is not gated by an external signal.

1 XC0 XC0 is ANDed with the selected clock.

2 XC1 XC1 is ANDed with the selected clock.

3 XC2 XC2 is ANDed with the selected clock.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

558

• CPCDIS: Counter Clock Disable with RC Compare

0: Counter clock is not disabled when counter reaches RC.

1: Counter clock is disabled when counter reaches RC.

• EEVTEDG: External Event Edge Selection

• EEVT: External Event Selection

Signal selected as external event.

Note: 1. If TIOB is chosen as the external event signal, it is configured as an input and no longer generates waveforms and

subsequently no IRQs.

• ENETRG: External Event Trigger Enable

0: The external event has no effect on the counter and its clock.

1: The external event resets the counter and starts the counter clock.

Note: Whatever the value programmed in ENETRG, the selected external event only controls the TIOAx output and TIOBx if not used as

input (trigger event input or other input used).

• WAVSEL: Waveform Selection

• WAVE: Waveform Mode

0: Waveform mode is disabled (Capture mode is enabled).

1: Waveform mode is enabled.

• ACPA: RA Compare Effect on TIOAx

Value Name Description

0 NONE None

1 RISING Rising edge

2 FALLING Falling edge

3 EDGE Each edge

Value Name Description TIOB Direction

0 TIOB TIOB(1) Input

1 XC0 XC0 Output

2 XC1 XC1 Output

3 XC2 XC2 Output

Value Name Description

0 UP UP mode without automatic trigger on RC Compare

1 UPDOWN UPDOWN mode without automatic trigger on RC Compare

2 UP_RC UP mode with automatic trigger on RC Compare

3 UPDOWN_RC UPDOWN mode with automatic trigger on RC Compare

Value Name Description

0 NONE None

1 SET Set

2 CLEAR Clear

3 TOGGLE Toggle

559

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• ACPC: RC Compare Effect on TIOAx

• AEEVT: External Event Effect on TIOAx

• ASWTRG: Software Trigger Effect on TIOAx

• BCPB: RB Compare Effect on TIOBx

• BCPC: RC Compare Effect on TIOBx

• BEEVT: External Event Effect on TIOBx

Value Name Description

0 NONE None

1 SET Set

2 CLEAR Clear

3 TOGGLE Toggle

Value Name Description

0 NONE None

1 SET Set

2 CLEAR Clear

3 TOGGLE Toggle

Value Name Description

0 NONE None

1 SET Set

2 CLEAR Clear

3 TOGGLE Toggle

Value Name Description

0 NONE None

1 SET Set

2 CLEAR Clear

3 TOGGLE Toggle

Value Name Description

0 NONE None

1 SET Set

2 CLEAR Clear

3 TOGGLE Toggle

Value Name Description

0 NONE None

1 SET Set

2 CLEAR Clear

3 TOGGLE Toggle

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

560

• BSWTRG: Software Trigger Effect on TIOBx

Value Name Description

0 NONE None

1 SET Set

2 CLEAR Clear

3 TOGGLE Toggle

561

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.4 TC Stepper Motor Mode Register

Name: TC_SMMRx [x=0..2]

Address: 0x40010008 (0)[0], 0x40010048 (0)[1], 0x40010088 (0)[2], 0x40014008 (1)[0], 0x40014048 (1)[1],

0x40014088 (1)[2]

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.

• GCEN: Gray Count Enable

0: TIOAx [x=0..2] and TIOBx [x=0..2] are driven by internal counter of channel x.

1: TIOAx [x=0..2] and TIOBx [x=0..2] are driven by a 2-bit Gray counter.

• DOWN: Down Count

0: Up counter.

1: Down counter.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––DOWNGCEN

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

562

24.7.5 TC Register AB

Name: TC_RABx [x=0..2]

Address: 0x4001000C (0)[0], 0x4001004C (0)[1], 0x4001008C (0)[2], 0x4001400C (1)[0], 0x4001404C (1)[1],

0x4001408C (1)[2]

Access: Read-only

• RAB: Register A or Register B

RAB contains the next unread capture Register A or Register B value in real time. It is usually read by the DMA after a

request due to a valid load edge on TIOAx.

When DMA is used, the RAB register address must be configured as source address of the transfer.

31 30 29 28 27 26 25 24

RAB

23 22 21 20 19 18 17 16

RAB

15 14 13 12 11 10 9 8

RAB

76543210

RAB

563

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.6 TC Counter Value Register

Name: TC_CVx [x=0..2]

Address: 0x40010010 (0)[0], 0x40010050 (0)[1], 0x40010090 (0)[2], 0x40014010 (1)[0], 0x40014050 (1)[1],

0x40014090 (1)[2]

Access: Read-only

• CV: Counter Value

CV contains the cou n ter valu e in re al tim e.

IMPORTANT: For 16-bit channels, CV field size is limited to register bits 15:0.

31 30 29 28 27 26 25 24

23 22 21 20 19 18 17 16

15 14 13 12 11 10 9 8

76543210

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

564

24.7.7 TC Register A

Name: TC_RAx [x=0..2]

Address: 0x40010014 (0)[0], 0x40010054 (0)[1], 0x40010094 (0)[2], 0x40014014 (1)[0], 0x40014054 (1)[1],

0x40014094 (1)[2]

Access: Read-only if TC_CMRx.WAVE = 0, Read/Write if TC_CMRx.WAVE = 1

This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.

• RA: Register A

RA contains the Register A value in real time.

IMPORTANT: For 16-bit channels, RA field size is limited to register bits 15:0.

31 30 29 28 27 26 25 24

23 22 21 20 19 18 17 16

15 14 13 12 11 10 9 8

76543210

565

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.8 TC Register B

Name: TC_RBx [x=0..2]

Address: 0x40010018 (0)[0], 0x40010058 (0)[1], 0x40010098 (0)[2], 0x40014018 (1)[0], 0x40014058 (1)[1],

0x40014098 (1)[2]

Access: Read-only if TC_CMRx.WAVE = 0, Read/Write if TC_CMRx.WAVE = 1

This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.

• RB: Register B

RB contains the Register B value in real time.

IMPORTANT: For 16-bit channels, RB field size is limited to register bits 15:0.

31 30 29 28 27 26 25 24

23 22 21 20 19 18 17 16

15 14 13 12 11 10 9 8

76543210

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

566

24.7.9 TC Register C

Name: TC_RCx [x=0..2]

Address: 0x4001001C (0)[0], 0x4001005C (0)[1], 0x4001009C (0)[2], 0x4001401C (1)[0], 0x4001405C (1)[1],

0x4001409C (1)[2]

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.

• RC: Register C

RC contains the Register C value in real time.

IMPORTANT: For 16-bit channels, RC field size is limited to register bits 15:0.

31 30 29 28 27 26 25 24

23 22 21 20 19 18 17 16

15 14 13 12 11 10 9 8

76543210

567

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.10 TC Status Register

Name: TC_SRx [x=0..2]

Address: 0x40010020 (0)[0], 0x40010060 (0)[1], 0x400100A0 (0)[2], 0x40014020 (1)[0], 0x40014060 (1)[1],

0x400140A0 (1)[2]

Access: Read-only

• COVFS: Counter Overflow Status (cleared on read)

0: No counter overflow has occurred since the last read of the Status Register.

1: A counter overflow has occurred since the last read of the Status Register.

• LOVRS: Load Overrun Status (cleared on read)

0: Load overrun has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1.

1: RA or RB have been loaded at least twice without any read of the corresponding regi ster since the last read of the Sta-

tus Register, if TC_CMRx.WAVE = 0.

• CPAS: RA Compare Status (cleared on read)

0: RA Compare has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 0.

1: RA Compare has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 1.

• CPBS: RB Compare Status (cleared on read)

0: RB Compare has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 0.

1: RB Compare has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 1.

• CPCS: RC Compare Status (cleared on read)

0: RC Compare has not occurred since the last read of the Status Register.

1: RC Compare has occurred since the last read of the Status Register.

• LDRAS: RA Loading Status (cleared on read)

0: RA Load has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1.

1: RA Load has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 0.

• LDRBS: RB Loading Status (cleared on read)

0: RB Load has not occurred since the last read of the Status Register or TC_CMRx.WAVE = 1.

1: RB Load has occurred since the last read of the Status Register, if TC_CMRx.WAVE = 0.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––––MTIOBMTIOACLKSTA

15 14 13 12 11 10 9 8

––––––RXBUFFENDRX

76543210

ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

568

• ETRGS: Extern a l Trigger Status (cleared on read )

0: External trigger has not occurred since the last read of the Status Register.

1: External trigger has occurred since the last read of the Status Register.

• ENDRX: End of Receiver Transfer (cleared by writing TC_RCR or TC_RNCR)

0: The Receive Coun te r Re gist er has not reached 0 since the last write in TC_RCR(1) or TC_RNCR(1).

1: The Receive Counter Register has reached 0 since the last write in TC_RCR or TC_RNCR.

• RXBUFF: Reception Buffer Full (cleared by writing TC_RCR or TC_RNCR)

0: TC_RCR or TC_RNCR have a value other than 0.

1: Both TC_RCR and TC_RNCR have a value of 0.

Note: 1. TC_RCR and TC_RNCR are PDC registers.

• CLKSTA: Clock Enabling Status

0: Clock is disabled.

1: Clock is enabled.

• MTIOA: TIOAx Mirror

0: TIOAx is low. If TC_CMRx.WAVE = 0, this means that TIOAx pin is low. If TC_CMRx.WAVE = 1, this means that TIOAx

is driven low.

1: TIOAx is high. If TC_CMRx.WAVE = 0, this means that TIOAx pin is high. If TC_CMRx.WAVE = 1, this means that

TIOAx is driven high.

• MTIOB: TIOBx Mirror

0: TIOBx is low. If TC_CMRx.WAVE = 0, this means that TIOBx pin is low. If TC_CMRx.WAVE = 1, this means that TIOBx

is driven low.

1: TIOBx is high. If TC_CMRx.WAVE = 0, this means that TIOBx pin is high. If TC_CMRx.WAVE = 1, this means that

TIOBx is driven high.

569

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.11 TC Interrupt Enable Register

Name: TC_IERx [x=0..2]

Address: 0x40010024 (0)[0], 0x40010064 (0)[1], 0x400100A4 (0)[2], 0x40014024 (1)[0], 0x40014064 (1)[1],

0x400140A4 (1)[2]

Access: Write-only

• COVFS: Counter Overflow

0: No effect.

1: Enables the Counter Overflow Interrupt.

• LOVRS: Load Overrun

0: No effect.

1: Enables the Load Overrun Interrupt.

• CPAS: RA Compare

0: No effect.

1: Enables the RA Compare Interrupt.

• CPBS: RB Compare

0: No effect.

1: Enables the RB Compare Interrupt.

• CPCS: RC Compare

0: No effect.

1: Enables the RC Compare Interrupt.

• LDRAS: RA Loading

0: No effect.

1: Enables the RA Load Interrupt.

• LDRBS: RB Loading

0: No effect.

1: Enables the RB Load Interrupt.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––RXBUFFENDRX

76543210

ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

570

• ETRGS: External Trigger

0: No effect.

1: Enables the External Trigger Interrupt.

• ENDRX: End of Receiver Transfer

0: No effect.

1: Enables the PDC Receive End of Transfer Interrupt.

• RXBUFF: Reception Buffer Full

0: No effect.

1: Enables the PDC Receive Buffer Full Interrupt.

571

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.12 TC Interrupt Disable Register

Name: TC_IDRx [x=0..2]

Address: 0x40010028 (0)[0], 0x40010068 (0)[1], 0x400100A8 (0)[2], 0x40014028 (1)[0], 0x40014068 (1)[1],

0x400140A8 (1)[2]

Access: Write-only

• COVFS: Counter Overflow

0: No effect.

1: Disables the Counter Overflow Interrupt.

• LOVRS: Load Overrun

0: No effect.

1: Disables the Load Overrun Interrupt (if TC_CMRx.WAVE = 0).

• CPAS: RA Compare

0: No effect.

1: Disables the RA Compare Interrupt (if TC_CMRx.WAVE = 1).

• CPBS: RB Compare

0: No effect.

1: Disables the RB Compare Interrupt (if TC_CMRx.WAVE = 1).

• CPCS: RC Compare

0: No effect.

1: Disables the RC Compare Interrupt.

• LDRAS: RA Loading

0: No effect.

1: Disables the RA Load Interrupt (if TC_CMRx.WAVE = 0).

• LDRBS: RB Loading

0: No effect.

1: Disables the RB Load Interrupt (if TC_CMRx.WAVE = 0).

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––RXBUFFENDRX

76543210

ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

572

• ETRGS: External Trigger

0: No effect.

1: Disables the External Trigger Interrupt.

• ENDRX: End of Receiver Transfer

0: No effect.

1: Disables the PDC Receive End of Transfer Interrupt.

• RXBUFF: Reception Buffer Full

0: No effect.

1: Disables the PDC Receive Buffer Full Interrupt.

573

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.13 TC Interrupt Mask Register

Name: TC_IMRx [x=0..2]

Address: 0x4001002C (0)[0], 0x4001006C (0)[1], 0x400100AC (0)[2], 0x4001402C (1)[0], 0x4001406C (1)[1],

0x400140AC (1)[2]

Access: Read-only

• COVFS: Counter Overflow

0: The Counter Overflow Interrupt is disabled.

1: The Counter Overflow Interrupt is enabled.

• LOVRS: Load Overrun

0: The Load Overrun Interrupt is disabled.

1: The Load Overrun Interrupt is enabled.

• CPAS: RA Compare

0: The RA Compare Interrupt is disabled.

1: The RA Compare Interrupt is enabled.

• CPBS: RB Compare

0: The RB Compare Interrupt is disabled.

1: The RB Compare Interrupt is enabled.

• CPCS: RC Compare

0: The RC Compare Interrupt is disabled.

1: The RC Compare Interrupt is enabled.

• LDRAS: RA Loading

0: The Load RA Interrupt is disabled.

1: The Load RA Interrupt is enabled.

• LDRBS: RB Loading

0: The Load RB Interrupt is disabled.

1: The Load RB Interrupt is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––RXBUFFENDRX

76543210

ETRGS LDRBS LDRAS CPCS CPBS CPAS LOVRS COVFS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

574

• ETRGS: External Trigger

0: The External Trigger Interrupt is disabled.

1: The External Trigger Interrupt is enabled.

• ENDRX: End of Receiver Transfer

0: The PDC Receive End of Transfer Interrupt is disabled.

1: The PDC Receive End of Transfer Interrupt is enabled.

• RXBUFF: Reception Buffer Full

0: The PDC Receive Buffer Full Interrupt is disabled.

1: The PDC Receive Buffer Full Interrupt is enabled.

575

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.14 TC Block Control Register

Name: TC_BCR

Address: 0x400100C0 (0), 0x400140C0 (1)

Access: Write-only

• SYNC: Synchro Command

0: No effect.

1: Asserts the SYNC signal which generates a software trigger simultaneously for each of the channels.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––SYNC

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

576

24.7.15 TC Block Mode Register

Name: TC_BMR

Address: 0x400100C4 (0), 0x400140C4 (1)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the TC Write Protection Mode Register.

• TC0XC0S: External Clock Signal 0 Selection

• TC1XC1S: External Clock Signal 1 Selection

• TC2XC2S: External Clock Signal 2 Selection

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – TC2XC2S TC1XC1S TC0XC0S

Value Name Description

0 TCLK0 Signal connected to XC0: TCLK0

1– Reserved

2 TIOA1 Signal connected to XC0: TIOA1

3 TIOA2 Signal connected to XC0: TIOA2

Value Name Description

0 TCLK1 Signal connected to XC1: TCLK1

1– Reserved

2 TIOA0 Signal connected to XC1: TIOA0

3 TIOA2 Signal connected to XC1: TIOA2

Value Name Description

0 TCLK2 Signal connected to XC2: TCLK2

1– Reserved

2 TIOA0 Signal connected to XC2: TIOA0

3 TIOA1 Signal connected to XC2: TIOA1

577

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

24.7.16 TC Write Protection Mode Register

Name: TC_WPMR

Address: 0x400100E4 (0), 0x400140E4 (1)

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x54494D (“TIM” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x54494D (“TIM” in ASCII).

The Timer Counter clock of the first channel must be enabled to access this register.

See Section 24.6.16 “Register Write Protection” for a list of registers that can be write-protected an d T ime r Co un te r cloc k

conditions.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x54494D PASSWD Writing any other value in this field aborts the write operation of the WPEN bit.

Always reads as 0.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

578

25. Supply Controller (SUPC)

25.1 Description

The Supply Controller (SUPC) controls the supply voltages of the system. The SUPC also generates the slow

clock by selecting either the low-power RC oscillator or the low-power crystal oscillator.

25.2 Embedded Characteristics

Manages the Core Power Supply VDDCORE by Controlling the Embedded Voltage Regulator

Supply Monitor Detection on VDDIO or a POR (Power-On Reset) on VDDCORE Can Trigger a Core Reset

Generates the Slow Clock SLCK, by Selecting Either the 32 kHz Low-power RC Oscillator or the 32 kHz

Low-power Crystal Oscillator

Supports Multiple Wakeup Sources for Exit from Backup Mode

16 Wakeup Inputs with Programmable Debouncing

Real-Time Clock Alarm

Real-Time Timer Alarm

Supply Monitor Detection on VDDIO, with Programmable Scan Per iod and Voltage Threshold

Low-power Tamper Detection on Two Inputs

Anti-tampering by Immediate Clear of the General-purpose Backup Registers

579

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

25.3 Block Diagram

Figure 25-1. Supply Controller Block Diagram

Software Controlled

Voltage Regulator

Matrix

SRAM

Watchdog

Timer

Cortex-M4

Flash

Peripherals

Peripheral

Bridge

Zero-Power

Power-on Reset

Supply

Monitor

RTC

Power

Management

Controller

Embedded

32 kHz RC

Oscillator

Xtal 32 kHz

Oscillator

Supply

Controller

Reset

Controller

Backup Power Supply (Supplied by VDDIO)

Core Power Supply

PLL

out

rtc_alarm

SLCK

proc_nreset

periph_nreset

Master Clock

MCK

SLCK

NRST

SLCK

FSTT0 - FSTT15 (1)

XIN32

XOUT32

osc32k_xtal_en

Slow Clock

SLCK

osc32k_rc_en

VDDCORE

VDDOUT

ADx

WKUP0 - WKUP15

RTT

rtt_alarm

SLCK

RTTDIS

VDDIO PIOx

PLLACK

Embedded

24/16/8 MHz

RC Oscillator

Main Clock

MAINCK

SLCK

XTALSEL

General Purpose

Backup Registers

vddcore_nreset

PIOA/B

Input/Output Buffers

ADC Analog

Circuitry

Note 1: FSTT0 - FSTT15 are possible Fast Startup sources, generated by WKUP0 - WKUP15 pins,

but are not physical pins.

VROFF

Power-on Reset

Core

BODDIS

PLL PLLBCK

SLCK

MAINCK

SRCB

VRVDD

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

580

25.4 Supply Controller Functional Description

25.4.1 Supply Controller Overview

The device can be div i de d int o two power supply areas:

VDDIO power supply: includes the Supply Controller, part of the Reset Controller, the slow clock switch, the

General-purpose Backup Registers, the Supply Monitor and the clock which includes the Real-time Timer

and the Real-time Clock

Core power supply: includes part of the Reset Controller, the POR core, the processor, the SRAM memory,

the Flash mem or y and th e pe rip h er als

The Supply Controller (SUPC) controls the supply voltage of the core power supply. The SUPC intervenes when

the VDDIO power supply rises (when the system is starting).

The SUPC also integrates the slow clock generator which is based on a 32 kHz crystal oscillator and an embedded

32 kHz RC oscillator. The slow clock defaults to the RC oscillator, but the software can enable the crystal oscillator

and select it as the slow clock source.

The SUPC and the VDDIO power supply have a reset circuitry based on a zero-power power-on reset cell. The

zero-power power-on reset allows the SUPC to start properly as soon as the VDDIO voltage becomes valid.

At startup of the system, once the backup voltage VDDIO is valid and the embedded 32 kHz RC oscillator is

stabilized, the SUPC starts up the core by sequentially enabling th e internal voltage regulator, waiting for the core

voltage VDDCORE to be valid, then releasing the reset signal of the core “vddcore_nreset” signal.

Once the system has started, the user can program a supply monitor and/or a brownout detector. If the supply

monitor detects a voltage on VDDIO that is too low, the SUPC can assert the reset signal of the core

“vddcore_nreset” signal until VDDIO is valid. Likewise, if the POR core detects a core voltage VDDCORE that is

too low, the SUPC can assert the reset signal “vddcore_nreset” until VDDCORE is valid.

When the Backup Low-Power mode is entered, the SUPC sequentially asserts the reset signal of the core power

supply “vddcore_nreset” and disables the voltage regulator, in order to supply only the VDDIO power supply. In

this mode, the current consumption is reduced to a few microamps for Backup part retention. Exit from this mode

is possible on multiple wakeup sources including an event on WKUP pins, or an RTC/RTT alarm. To exit this

mode, the SUPC operates in the same way as system startup.

25.4.2 Slow Clock Generator

The SUPC embeds a slow clock generator that is supplie d with the VDDIO power supp ly. As soon as the VDDIO is

supplied, both the crystal oscillator and the embedded RC oscillator are powered up, but only the embedded RC

oscillator is enabled. This allows the slow clock to be valid in a short time (about 100 µs).

The user can select the crystal oscillator to be the source of the slow clock, as it provides a more accurate

frequency. The command is made by writing the SUPC Control Register (SUPC_CR) with the XTALSEL bit at

1.This results in a sequence which first configures the PIO lines multiplexed with XIN32 and XOUT32 to be driven

by the oscillator, then enables the crystal os cillator, then counts a number of slow RC oscillator clock periods to

cover the startup time of the crystal oscillator (refer to the section “Electrical Characteristics” for details of 32 kHz

crystal oscillator startup time), then switches the slow clock on the output of the crystal oscillator and then disables

the RC oscillator to save power. The switching time may vary according to the slow RC oscillator clock frequency

range. The switch of the slow clock source is glitch free. The OSCSEL bit of the SUPC Status Register

(SUPC_SR) allows knowing when the switch sequence is done.

Coming back on the RC oscillator is only possible by shutting down the VDDIO power supply.

If the user does not need the crystal oscillator, the XIN32 and XOUT32 pins should be left unconnected.

The user can also set the crystal oscillator in Bypass mode instead of connecting a crystal. In this case, the user

has to provide the external clock signal on XIN32. The input characteristics of the XIN32 pin are given in the

581

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

product electrical characteristics section. In order to set the Bypass mode, the OSCBYPASS bit of the SUPC Mode

25.4.3 Core Voltage Regulator Control/Backup Low-Power Mode

The SUPC can be used to control the embedded voltage regulator.

The voltage regulator automatically adapts its quiescent current depending on the required load current. More

information can be found in the Electrical Characteristics.

The user can switch off the voltage regulator, and thus put the device in Backup mode, by writing a 1 to the

VROFF bit in SUPC_CR.

Backup mode can also be entered by executing the WFE (Wait for Event) Cor tex- M pr oces sor in stru ction with t he

SLEEPDEEP bit set to 1.

This asserts the vddcore_nreset signal after the write resynchronization time, which lasts two slow clock cycles

(worst case). Once the vddcore_n reset signal is assert ed, the processor and the perip herals are stop ped one slow

clock cycle before the core power supply shuts off.

25.4.4 Supply Monitor

The SUPC embeds a supply monitor which is located in the VDDIO power supply and which monitors VDDIO

power supply.

The supply monitor can be used to prevent the processor from falling into an unpredictable state if the main power

supply drops below a certain level.

The threshold of the supply monitor is programmable (refer to the “VDDIO Supply Monitor” characteristics in

section “Electrical Characteristics”). This threshold is programmed in the SMTH field of the SUPC Supply Monitor

Mode Register (SUPC_SMMR).

The supply monitor can also be enabled during one slow clock period on every one of either 32, 256 or 2048 slow

clock periods, depending on the choice of the user. This is configured by programming the SMSMPL fie ld in

SUPC_SMMR.

By enabling the supply monitor for such reduced times, the typical supply monitor power consumption is divided,

respectively, by factors of 2, 16 and 128, if the use r does not require continuous monitoring of the VDDIO power

supply.

A supply monitor detection can generate a reset of the core power supply or a wakeup of the core power supply.

Generating a core reset when a supply monitor detection occurs is enabled by writing the SMRSTEN bit to 1 in

SUPC_SMMR.

The SUPC provides two status bits in the SUPC_SR for the supply monitor:

The SMOS bit provides real-time information, which is updated a t e ach me asureme nt cycl e, o r at ea ch slow

clock cycle if the measurement is continuous.

The SMS bit provides saved information and shows a supply monitor detection has occurred since the last

read of SUPC_SR.

The SMS bit can generate an interrupt if the SMIEN bit is set to 1 in SUPC_SMMR.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

582

Figure 25-2. Supply Monitor Status Bit and Associated Interrupt

25.4.5 Power Supply Reset

25.4.5.1 Raising the Power Supply

As soon as the voltage VDDIO rises, the RC oscillator is powered up and the zero-power power-on reset cell

maintains its output low as long as VDDIO has not reached its target voltage. During this time, the SUPC is entirely

reset. When the VDDIO voltage becomes valid and zero-power power-on reset signal is released, a counter is

started for 5 slow clock cycles. This is the time it takes for the 32 kHz RC oscillator to stabilize.

After this time, the voltage regulator is enabled. The core power supply rises and the POR core provides the

bodcore_in signal as soon as the core voltage VDDCO RE is valid. This results in releasing the vddcore_nreset

signal to the Reset Controller after the bodcore_in signal has been confirmed a s valid for at least one slow clock

cycle.

Supply Monitor ON

3.3V

Threshold

SMS and SUPC interrupt

Read SUPC_SR

Periodic Sampling

Continuous Sampling (SMSMPL = 1)

583

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 25-3. Raising the VDDIO Power Supply

25.4.6 Core Reset

The SUPC m anages the vddc ore_nreset signal to the Reset Controller, as described in Section 25.4.5 ” Power

Supply Reset”. The vddcore_nre set signal is normally asserted before shutt ing down the core power supply and

released as soon as the core power supply is correctly regulated.

There are two additional sources which can be progr ammed to activate vddcore_nreset:

VDDIO supply monitor detection

POR core detection

25.4.6.1 Supply Monitor Reset

The supply monitor is capable of generating a reset of the system. This can be enabled by sett ing the SMRSTEN

bit in SUPC_SMMR.

If SMRSTEN is set and if a supply monitor detection occurs, the vddcor e_nrese t signal is immediately activated for

a minimum of one slow clock cycle.

25.4.6.2 POR Core Reset

The POR Core provid es the bodco re_in signal to the SUPC which indica tes that the vo ltage regu lation is operatin g

as programmed. If this signal is lost for longer than one slow clock period while the voltage regulator is enabled,

Zero-Power Power-On

Reset Cell output

22 - 42 kHz RC

Oscillator output

Fast RC

Oscillator output

Backup Power Supply

vr_on

bodcore_in

(POR Core output)

vddcore_nreset

NRST

(no ext. drive assumed)

proc_nreset

Note: After “proc_nreset” rising, the core starts fetching instructions from Flash at 8 MHz.

periph_nreset

7 x Slow Clock Cycles3 x Slow Clock

Cycles2 x Slow Clock

Cycles6.5 x Slow Clock

Cycles

TON V oltage

Regulator

Zero-Power POR

Core Power Supply

RSTC.ERSTL

(5 for startup slow RC + 2 for synchro.)

default = 2

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

584

the SUPC can assert vddcore_nreset. This feature is enabled by writing the bit BODRSTEN (POR Core Reset

Enable) to 1 in SUPC_MR.

If BODRSTEN is set and the voltage regulati on is lost (ou tp ut voltage of the re gulat or too low), the vdd core_nr eset

signal is asserted for a minimum of one slow clock cycle and then released if bodcore_in has been reactivated.

The BODRSTS bit is set in SUPC_SR so that the user can know the source of the last reset.

While the POR core output (bodcore_in) is cleared, the vddcore_nreset signal remains active.

25.4.7 Wakeup Sources

The wakeup events allow the device to exit Backup mode. When a wakeup event is detected, the SUPC performs

a sequence that automatically reenables the core power supply.

Figure 25-4. Wakeup Sou rces

25.4.7.1 Wakeup Inputs

The wakeup inputs, WKUPx, can be programmed to perform a wakeup of the core power supply. Each input can

be enabled by writing a 1 to the corresponding bit, WKUPENx, in the Wakeup Inputs register (SUPC_WUIR). The

wakeup level can be selecte d with the corr es po nd ing po lar ity bit , W KUPT x, als o locate d in SUPC_WU IR.

The resulting signals are wired-ORed to trigger a debounce counter, which is programmed with the WKUPDBC

field in SUPC_WUMR. The WKUPDBC field se lects a d ebo un cing p er iod of 3 , 32, 5 12 , 4,096 o r 32,76 8 slow clock

cycles. The du ration of th ese per iods corr espond s, resp ectively, to about 100 µs, about 1 ms, about 16 ms, about

128 ms and about 1 second (for a typical slow clock fr equency of 32 kHz). Progr amming WKUPDBC to 0x0 selects

WKUP15

WKUPEN15

WKUPT15

WKUPEN1

WKUPEN0

Debouncer

SLCK

WKUPDBC

WKUPS

RTCEN

rtc_alarm

SMEN

sm_out

Core

Supply

Restart

WKUPIS0

WKUPIS1

WKUPIS15

WKUPT0

WKUPT1

WKUP0

WKUP1

RTTEN

rtt_alarm

Debouncer

RTCOUT0

LPDBC

Debouncer

LPDBC

RTCOUT0

LPDBCS0

LPDBCS1

LPDBCEN1

WKUPT1

LPDBCEN0

WKUPT0

Falling/Rising

Edge Detect

Low-power

Tamper Detection

Logic

GPBR Clear

LPDBCCLR

LPDBCS1

LPDBCS0

Falling/Rising

Edge Detect

Falling/Rising

Edge Detect

Falling/Rising

Edge Detect

Falling/Rising

Edge Detect

585

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

an immediate wakeup, i.e., an enable d WKUP pin must be acti ve ac cord ing t o it s polar ity du ring a mini mum of one

slow clock period to wake up th e cor e powe r su pp ly.

If an enabled WKUP pin is asserted for a duration longer than the debouncing period, a wakeup of the core power

supply is started and the signals, WKUP0 to WKUPx as shown in Figure 25-4 "Wakeup Sources", a re latched in

SUPC_SR. This allows the user to identify the source of the wakeup. However, if a new wakeup condition occurs,

the primary information is lost. No new wakeup can be detected since the primary wakeup condition has

disappeared.

Before instructing the system to enter Backup mode, if the field WKUPDBC > 0, it must be checked that none of

the WKUPx pins that are enabled for a wakeup (exit from Backup mode) holds an active polarity. This is checked

by reading the pin status in the PIO Controller. If WKUPENx=1 and the pin WKUPx holds an active polarity, the

system must not be instructed to enter Backup mode.

Figure 25-5. Entering an d Exiting Backup Mode with a WKUP pin

25.4.7.2 Low-power Tamper Detection and Anti-Tampering

Low-power debouncer inputs (WKUP0, WKUP1) can be used for tam per detection.Separate debouncers are

embedded, one for WKUP0 input, one for WKUP1 input.

The WKUP0 and/or WKUP1 inputs perform a system wakeup upon tamper detection. This is enabled by setting

the LPDBCEN0/1 bit in the SUPC_WUMR.

WKUP0 and/or WKUP1 inputs can also be used when VDDCORE is powered to detect a tamper.

When the bit LPDBCENx is written to 1, WKUPx pins must no t be config ured to act a s a de bouncing sour ce fo r the

WKUPDBC counter (WKUPENx must be cleared in SUPC_WUIR).

Low-power tamper detection or debounce requires RTC output (RTCOUT0) to be configured to generate a duty

cycle programmable pulse (i.e., OUT0 = 0x7 in RTC_MR) in order to create the sampling points of both

debouncers. The sampling point is the falling edge of the RTCOUT0 waveform.

Figure 25-6 shows an example of an application where two tamper switches are used.

The debouncing period duration is configurable. The period is set for all de bouncers (i.e., the duration cannot be

adjusted for each debouncer). The number of successive identical samples to wake up the system can be

configured from 2 up to 8 in the LPDBC field of SUPC_WUMR. The period of time betwe en two samples can be

configured by programming the TPERIOD field in the RTC_MR. Power parameters can be adjusted by modifying

the period of time in the THIGH field in RTC_MR.

The wakeup polarity of the inputs can be independently configured by writing WKUPT0 and/ or WKUPT1 fields in

SUPC_WUMR.

WKUPx

WKUPTx=0

Active BACKUP Active BACKUP Active BACKUP

System

Edge detect +

debounce time

Edge detect +

debounce time

active runtime active runtime

VROFF=1

check

WKUPx

status

check

WKUPx

status

WKUPDBC > 0

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In order to determine which wakeup/tamper pin triggers the system wakeup, a status flag is associat ed for each

low-power debouncer. These flags are read in SUPC_SR.

A debounce event (tamper detection) can perform an immediate clear (0 delay) on the first half the general-

purpose backup registers (GPBR). The LPDBCCLR bit must be set in SUPC_WUMR.

Figure 25-6. Using WKUP Pins Without RTCOUTx Pins

MCU

WKUP0

WKUP1

VDDIO

Pull-up

Resistor

Pull-up

Resistor

GND

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25.4.8 Register Write Protection

To prevent any single software error from corrupting SUPC behavior, certain registers in the add ress space ca n be

write-protected by setting the WPEN bit in the System Controller Write Protection Mode Register (SYSC_WPMR).

The following registers can be write-protected:

RSTC Mode Register

RTT Mode Register

RTT Alarm Register

RTC Control Register

RTC Mode Register

RTC Time Alarm Register

RTC Calendar Alarm Register

General Purpose Backup Registers

Supply Controller Control Register

Supply Controller Supply Monitor Mode Register

Supply Controller Mode Register

25.4.9 Register Bits in Backup Domain (VDDIO)

The following configuration registers are physically located in the product backup domain:

RSTC Mode Register

RTT Mode Register

RTT Alarm Register

RTC Control Register

RTC Mode Register

RTC Time Alarm Register

RTC Calendar Alarm Register

General Purpose Backup Registers

Supply Controller Control Register

Supply Controller Supply Monitor Mode Register

Supply Controller Mode Register

Supply Controller Wakeup Mode Register

System Controller Wakeup Inputs Register

Supply Controller Status Register

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25.5 Supply Controller (SUPC) User Interface

The user interface of the Supply Controller is part of the System Controller User Interface.

25.5.1 System Controller (SYSC) User Interface

25.5.2 Supply Controller (SUPC) User Interface

Table 25-1. S ystem Controller Registers

Offset System Controller Peripheral Name

0x00–0x0C Reset Controller RSTC

0x10–0x2C Supply Controller SUPC

0x30–0x40 Real-Time Timer RTT

0x50–0x5C Watchdog Timer WDT

0x60–0x8C Real-Time Clock RTC

0x90–0xDC General-Purpose Backup Register GPBR

0xE0 Reserved –

0xE4 Write Protection Mode Register SYSC_WPMR

0xE8–0xF8 Reserved –

0x100–0x12C Reserved –

0x130 Real-Time Clock RTC

0x134–0x1FC Reserved –

Table 25-2. Register Mapping

Offset Register Name Access Reset

0x00 Supply Controller Control Register SUPC_CR Write-only –

0x04 Supply Controller Supply Monitor Mode Register SUPC_SMMR Read/Write 0x0000_0000

0x08 Supply Controller Mode Register SUPC_MR Read/Write 0x00E0_5400

0x0C Supply Controller Wakeup Mode Register SUPC_WUMR Read/Write 0x0000_0000

0x10 Supply Controller Wakeup Inputs Register SUPC_WUIR Read/Write 0x0000_0000

0x14 Supply Controller Status Register SUPC_SR Read-only 0x0000_0000

0x18 Reserved – – –

0x1C Supply Controller Power Mode Register SUPC_PWMR Read/Write 0x00FF_180A

0x20–0x2C Reserved – – –

589

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25.5.3 Supply Controller Control Register

Name: SUPC_CR

Address: 0x400E1410

Access: Write-only

This register can on ly be writte n if the W PEN bit is clea re d in the Syst em Con trolle r Writ e Pro te ctio n M od e Register

(SYSC_WPMR).

• VROFF: Voltage Regulator Off

0 (NO_EFFECT): No effect.

1 (STOP_VREG): If KEY is correct, asserts the system reset signal and stops the voltage regulator.

• XTALSEL: Crystal Oscillator Select

0 (NO_EFFECT): No effect.

1 (CRYSTAL_SEL): If KEY is correct, switches the slow clock on the crystal oscillator output.

• KEY: Password

31 30 29 28 27 26 25 24

KEY

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––XTALSELVROFF––

Value Name Description

0xA5 PASSWD Writing any other value in this field aborts the write operation.

Always reads as 0.

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25.5.4 Supply Controller Supply Monitor Mode Register

Name: SUPC_SMMR

Address: 0x400E1414

Access: Read/Write

This register can on ly be writte n if the W PEN bit is clea re d in the Syst em Con trolle r Writ e Pro te ctio n M od e Register

(SYSC_WPMR).

• SMTH: Supply Monitor Threshold

Selects the threshold voltage of the supply monitor. Refer to the section “Electrical Characteristics” for voltage values.

• SMSMPL: Supply Monitor Sampling Period

• SMRSTEN: Supply Monitor Reset Enable

0 (NOT_ENABLE): The core reset signal vddcore_nreset is not affected when a supply monitor detection occurs.

1 (ENABLE): The core reset signal vddcore_nreset is asserted when a supply monitor detection occurs.

• SMIEN: Supply Monitor Interrupt Enable

0 (NOT_ENABLE): The SUPC interrupt signal is not affected when a supply monitor detection occurs.

1 (ENABLE): The SUPC interrupt signal is asserted when a supply monitor detection occurs.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

– – SMIEN SMRSTEN – SMSMPL

76543210

–––– SMTH

Value Name Description

0 SMD Supply Monitor disabled

1 CSM Continuous Supp ly Monitor

2 32SLCK Supply Monitor enables one SLCK period every 32 SLCK periods

3 256SLCK Supply Monitor enables one SLCK period every 256 SLCK periods

4 2048SLCK Supply Monitor enables one SLCK period every 2,048 SLCK periods

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25.5.5 Supply Controller Mode Register

Name: SUPC_MR

Address: 0x400E1418

Access: Read/Write

This register can on ly be writte n if the W PEN bit is clea re d in the Syst em Con trolle r Writ e Pro te ctio n M od e Register

(SYSC_WPMR).

Note: Bits 23 and 14 must always be written to ‘1’.

• VDDSEL: VRVDD Field Selection

0 (FACTORY): If SUPC_PWMR.ECPWRS = 0, the voltage regulator output value is the factory-programmed value. If

SUPC_PWMR.ECPWRS = 1, the voltage regulator value is managed by the SUPC_PWMR.ECPWRx bits.

1 (USER_VRVDD): The voltage regulator output value is defined by the value programmed in the field VRVDD.

• VRVDD: Voltage Regulator Output Voltage Selection

Refer to the section “Electrical Characteristics” for details.

• BODRSTEN: POR Core Reset Enable

0 (NOT_ENABLE): The core reset signal vddcore_nreset is not affected when a brownout detection occurs.

1 (ENABLE): The core reset signal vddcore_nreset is asserted when a brownout detection occurs.

• BODDIS: POR Core Disable

0 (ENABLE): The core brownout detector is enabled.

1 (DISABLE): The core brownout detector is disabled.

• ONE: This bit must always be set to 1.

This bit must always be set to 1.

• OSCBYPASS: Oscillator Bypass

0 (NO_EFFECT): No effect. Clock selection depends on XTALSEL value.

1 (BYPASS): The 32 kHz crystal oscillator is bypassed if XTALSEL = 1. OSCBYPASS must be set prior to write

XTALSEL = 1.

31 30 29 28 27 26 25 24

KEY

23 22 21 20 19 18 17 16

ONEACTPSWITCHCDPSWITCHOSCBYPASS––––

15 14 13 12 11 10 9 8

– ONE BODDIS BODRSTEN VRVDD VDDSEL

76543210

––––––––

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• CDPSWITCH: Cache Data SRAM Power Switch

0 (OFF): The cache data SRAM is not powered.

1 (ON): The cache data SRAM is powered.

Refer to “Internal SRAM” in section “Memories”.

• CTPSWITCH: Cache Tag SRAM Power Switch

0 (OFF): The cache tag SRAM is not powered.

1 (ON): The cache tag SRAM is powered.

Refer to “Internal SRAM” in section “Memories”.

• ONEA: This bit must always be set to 1.

This bit must always be set to 1.

• KEY: Password Key

Value Name Description

0xA5 PASSWD Writing any other value in this field aborts the write operation.

Always reads as 0.

593

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25.5.6 Supply Controller Wakeup Mode Register

Name: SUPC_WUMR

Address: 0x400E141C

Access: Read/Write

• SMEN: Supply Monitor Wakeup Enable

0 (NOT_ENABLE): The supply monitor detection has no wakeup effect.

1 (ENABLE): The supply monitor detection forces the wakeup of the co re power supply.

• RTTEN: Real-time Timer Wakeup Enable

0 (NOT_ENABLE); The RTT alarm signal has no wakeup effect.

1 (ENABLE): The RTT alarm signal forces the wakeup of the core power supply.

• RTCEN: Real-time Clock Wakeup Enable

0 (NOT_ENABLE); The RTC alarm signal has no wakeup effect.

1 (ENABLE): The RTC alarm signal forces the wakeup of the core power supply.

• LPDBCEN0: Low-power Debouncer Enable WKUP0

0 (NOT_ENABLE): The WKUP0 input pin is not connected to the low-power debouncer.

1 (ENABLE): The WKUP0 input pin is connected to the low-power debouncer and forces a system wakeup.

• LPDBCEN1: Low-power Debouncer Enable WKUP1

0 (NOT_ENABLE): The WKUP1 input pin is not connected to the low-power debouncer.

1 (ENABLE): The WKUP1 input pin is connected to the low-power debouncer and forces a system wakeup.

• LPDBCCLR: Low-power Debouncer Clear

0 (NOT_ENABLE): A low-power debounce event does not create an immediate clear on the first half of GPBR registers.

1 (ENABLE): A low-power debounce event on WKUP0 or WKUP1 generates an immediate clear on the first half of GPBR

registers.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––– LPDBC

15 14 13 12 11 10 9 8

– WKUPDBC ––––

76543210

LPDBCCLR LPDBCEN1 LPDBCEN0 – RTCEN RTTEN SMEN –

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• WKUPDBC: Wakeup Inputs Debouncer Period

• LPDBC: Low-power Debouncer Period

Value Name Description

0 IMMED IATE Immediate, no debouncing, detected active at least on one Slow Clock edge.

1 3_SCLK WKUPx shall be in its active state for at least 3 SLCK periods

2 32_SCLK WKU Px shall be in its active state for at least 32 SLCK periods

3 512_SCLK WKUPx shall be in its active state for at least 512 SLCK periods

4 4096_SCLK WKUPx shall be in its active state for at least 4,096 SLCK periods

5 32768_SCLK WKUPx shall be in its active state for at least 32,768 SLCK periods

Value Name Description

0 DISABLE Disable the low-power debouncers.

1 2_RTCOUT0 WKUP0/1 in active state for at least 2 RTCOUTx periods

2 3_RTCOUT0 WKUP0/1 in active state for at least 3 RTCOUTx periods

3 4_RTCOUT0 WKUP0/1 in active state for at least 4 RTCOUTx periods

4 5_RTCOUT0 WKUP0/1 in active state for at least 5 RTCOUTx periods

5 6_RTCOUT0 WKUP0/1 in active state for at least 6 RTCOUTx periods

6 7_RTCOUT0 WKUP0/1 in active state for at least 7 RTCOUTx periods

7 8_RTCOUT0 WKUP0/1 in active state for at least 8 RTCOUTx periods

595

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25.5.7 System Controller Wakeup Inputs Register

Name: SUPC_WUIR

Address: 0x400E1420

Access: Read/Write

• WKUPEN0 - WKUPEN15: Wakeup Input Enable 0 to 15

0 (DISABLE): The corresponding wakeup input has no wakeup effect.

1 (ENABLE): The corresponding wakeup input forces the wakeup of the core power supply.

• WKUPT0 - WKUPT15: Wakeup Input Type 0 to 15

0 (LOW): A falling edge followed by a low level for a period defined by WKUPDBC on the corresponding wakeup input

forces the wakeup of the core power supply.

1 (HIGH): A rising edge followed by a high level for a period defined by WKUPDBC on the corresponding wakeup input

forces the wakeup of the core power supply.

31 30 29 28 27 26 25 24

WKUPT15 WKUPT14 WKUPT13 WKUPT12 WKUPT11 WKUPT10 WKUPT9 WKUPT8

23 22 21 20 19 18 17 16

WKUPT7 WKUPT6 WKUPT5 WKUPT4 WKUPT3 WKUPT2 WKUPT1 WKUPT0

15 14 13 12 11 10 9 8

WKUPEN15 WKUPEN14 WKUPEN13 WKUPEN12 WKUPEN11 WKUPEN10 WKUPEN9 WKUPEN8

76543210

WKUPEN7 WKUPEN6 WKUPEN5 WKUPEN4 WKUPEN3 WKUPEN2 WKUPEN1 WKUPEN0

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25.5.8 Supply Controller Status Register

Name: SUPC_SR

Address: 0x400E1424

Access: Read-only

Note: Because of the asynchronism between the slow clock (SLCK) and the system clock (MCK), the status register flag reset is taken

into account only two slow clock cycles after the read of the SUPC_SR.

• WKUPS: WKUP Wakeup Status (cleared on read)

0 (NO): No wakeup due to the assertion of the WKUP pins has occurred since the last read of SUPC_SR.

1 (PRESENT): At least one wakeup due to the assertion of the WKUP pins has occurred since the last read of SUPC_SR.

• BODRSTS: Brownout Detector Reset Status (cleared on read)

0 (NO): No core brownout rising edge event has been detected since the last read of SUPC_SR.

1 (PRESENT): At least one brownout output rising edge event has been detected since the last read of SUPC_SR.

When the voltage remains below the defined threshold, there is no rising edge event at the output of the brownout detec-

tion cell. The rising edge event occurs only when there is a voltage transition below the threshold.

• SMRSTS: Supply Monitor Reset Status (cleared on read)

0 (NO): No supply monitor detection has generated a core reset since the last read of SUPC_SR.

1 (PRESENT): At least one supply monitor detection has generated a core reset since the last read of SUPC_SR.

• SMS: Supply Monitor Status (cleared on read)

0 (NO): No supply mon it or det ec tio n since the last read of SUPC_SR .

1 (PRESENT): At least one supply monitor detection since the last read of SUPC_SR.

• SMOS: Supply Monitor Output Status

0 (HIGH): The supply monitor detected VDDIO higher than its threshold at its last measurement.

1 (LOW): The supply monitor detected VDDIO lower than its threshold at its last measurement.

• OSCSEL: 32-kHz Oscillator Selection Status

0 (RC): The slow clock SLCK is generated by the embedded 32 kHz RC oscillator.

1 (CRYST): The slow clock SLCK is generated by the 32 kHz crystal oscillator.

31 30 29 28 27 26 25 24

WKUPIS15 WKUPIS14 WKUPIS13 WKUPIS12 WKUPIS11 WKUPIS10 WKUPIS9 WKUPIS8

23 22 21 20 19 18 17 16

WKUPIS7 WKUPIS6 WKUPIS5 WKUPIS4 WKUPIS3 WKUPIS2 WKUPIS1 WKUPIS0

15 14 13 12 11 10 9 8

–LPDBCS1LPDBCS0–––––

76543210

OSCSEL SMOS SMS SMRSTS BODRSTS – WKUPS –

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• LPDBCS0: Low-power Debouncer Wakeup Status on WKUP0 (cleared on read)

0 (NO): No wakeup due to the assertion of the WKUP0 pin has occurred since the last read of SUPC_SR.

1 (PRESENT): At least one wakeup due to the assertion of the WKUP0 pin has occurred since the last read of SUPC_SR.

• LPDBCS1: Low-power Debouncer Wakeup Status on WKUP1 (cleared on read)

0 (NO): No wakeup due to the assertion of the WKUP1 pin has occurred since the last read of SUPC_SR.

1 (PRESENT): At least one wakeup due to the assertion of the WKUP1 pin has occurred since the last read of SUPC_SR.

• WKUPIS0-WKUPIS15: WKUP Input Status 0 to 15 (cleared on read)

0 (DISABLED): The corresponding wakeup input is disabled, or was inactive at the time the debouncer triggered a wakeup

event.

1 (ENABLED): The corresponding wakeup input was active at the time the debouncer triggered a wakeup event since the

last read of SUPC_SR.

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25.5.9 Supply Controller Power Mode Register

Name: SUPC_PWMR

Address: 0x400E142C

Access: Read/Write

• LPOWERS: Low Power Value Selection

0 (FACTORY): The trimming value applied to the regulator when the device is in Wait mode. This value is factory-defined.

1 (USER): The trimming value applied to the regulator is defined by the value programmed in the LPOWERx bits.

• LPOWER0 - LPOWER3: Low Power Value

The regulator trimming value that allows the device to run in Wait mode. Must be read by customer in the Flash unique

identifier page. Refer to “Calibration Bits” in section “Memories”.

• STUPTIME: Startup Time whe n Resuming from Wait Mode

0 (FAST): Fast startup.

1 (SLOW): Slow startup.

Refer to section “Electrical Characteristics”.

• ECPWRS: Enhanced Custom Power Value Selection

0 (FACTORY): The trimming value applied to the regulator when the device is in Active mode is factory-defined when

SUPC_MR.VDDSEL = 0. If SUPC_MR.VDDSEL = 1, the SUPC_MR.VRVDD manages the regulator output value.

1 (USER): If SUPC_MR.VDDSEL = 1, the trimming value applied to the regulator is defined by the value programmed in

ECPWRx bits.

• ECPWRx: Enhanced Custom Power Value

The regulator trimming value that allows the device to run in Active mode. Must be read by customer in the Flash unique

identifier page. Refer to “Unique Identifier in section “Memories”.

• SRAMxON: SRAM Power Control

0 (OFF): SRAMx is not powered.

1 (ON): SRAMx is powered.

Refer to “Internal SRAM” in section “Memories”.

31 30 29 28 27 26 25 24

KEY

23 22 21 20 19 18 17 16

DPRAMON SRAM6ON SRAM5ON SRAM4ON SRAM3ON SRAM2ON SRAM1ON SRAM0ON

15 14 13 12 11 10 9 8

– – – ECPWR3 ECPWR2 ECPWR1 ECPWR0 ECPWRS

76543210

STUPTIME – – LPOWER3 LPOWER2 LPOWER1 LPOWER0 LPOWERS

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• DPRAMON: Dual-port RAM Power Control

0 (OFF): USB dual-port RAM is not powered.

1 (ON): USB dual-port RAM is powered.

• KEY: Password Key

Value Name Description

0x5A PASSWD Writing any other value in this field aborts the write operation.

Always reads as 0.

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25.5.10 System Controller Write Protection Mode Register

Name: SYSC_WPMR

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x525443 (“RTC” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x525443 (“RTC” in ASCII).

See Section 25.4.8 ”Register Write Protection” for the list of registers that can be write-protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x525443 PASSWD Writing any other value in this field aborts the write operation of the WPEN bit.

Always reads as 0.

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26. Real-time Clock (RTC)

26.1 Description

The Real-time Clock (RTC) periphe ral is designed for very low power consumption. For optimal fun ctionality, the

RTC requires an accurate external 32.768 kHz clock, which can be provided by a crystal oscillator.

It combines a complete time-of-day clock with alarm and a Gregorian or Persian calendar, complemented by a

programmable periodic interrupt. The a larm and calendar registers ar e accessed by a 32-bit data bus.

The time and calendar values are cod ed in binary-coded de cimal (BCD) format. The time format can be 2 4-hour

mode or 12-hour mode with an AM/PM indicator. The number of periods of 1/1024 seconds within 1 second is

reported. This information allows a timestamping with an accuracy higher than 1 millisecond.

Updating time a nd calendar fields and configuring the alar m fields are performed by a parallel captur e on the 32-bit

data bus. An entry control is performed to avoid loading registers with incompatible BCD format data or with an

incompatible da te acco rd in g to th e cur ren t mo nt h/ yea r /ce nt ur y.

A clock divider calibration circuitry can be used to compensate for crystal oscillator frequency variations.

26.2 Embedded Characteristics

Full Asynchronous Design for Ultra Low Power Consumption

Gregorian and Persian Modes Supported

Milliseconds Image Report

Programmable Periodic Interrupt

Safety/security Features:

Valid Time and Date Programming Check

On-The-Fly Time and Date Validity Check

Counters Calibration Circuitry to Compensate for Crystal Oscillator Variations

Waveform Generation for Trigger Event

Register Write Protection

26.3 Block Diagram

Figure 26-1. Real-time Clock Block Diagram

User Interface

32768 Divider Time

Slow

Clock:

SLCK

System

Bus

Date

RTC Interrupt

Entry

Control

Interrupt

Control

Clock Calibration

RTCOUT0

(ADC AD[n:0] trigger)

RTCOUT1

(ADC AD[n] trigger)

Where n is the higher index

available (last channel)

Wave

Generator

Alarm

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26.4 Product Dependencies

26.4.1 Power Management

The Real-time Clock is continuously clocked at 3 2.768 kHz. The Power Management Contro ller has no effect on

RTC behavior.

26.4.2 Interrupt

RTC interrup t line is con ne cted on o ne of the in tern al sour ce s of the interrupt controller. RTC interrupt requires the

interrupt controller to be programmed first.

26.5 Functional Description

The RTC provid es a full binary-c oded decimal (BC D) clock that inclu des century (1 9/20), year (with le ap years),

month, date, day, hours, minutes and seconds reported in RTC Time Register (RTC_TIMR) and RTC Calendar

The MS field in the RTC Milliseconds Register (RTC_MSR) reports the number of periods of 1/1024 seconds

elapsed within 1 second. The MS field is cleared at the beginning of each 1-second period.

The MS field can be used for timestamping with an accuracy higher than 1 ms. It can also be post-processed by

software to provide the millisecond value. The data in milliseconds can be obtained by multiplying the value read in

the MS field by 1000/1024 (for an optimal accuracy, the result must be rounded and not truncated).

The valid year range is up to 2099 in Gregorian mode (or 1300 to 1499 in Persian mode).

The RTC can operate in 24-hour mode or in 12-hour mode with an AM/PM indicato r.

Corrections for leap years a re includ ed (a ll ye ar s divisi ble b y 4 being leap years except 1900). This is correct up to

the year 2099.

The RTC can generate events to trigger ADC measurements.

26.5.1 Reference Clock

The reference clock is the Slow Clock (SLCK). It c an be dr ive n int er nally or by an ex te rn al 32 .7 68 kHz crystal.

During low power modes of the processor, the oscillator runs and power consumption is critical. The crystal

selection has to take into account the current consumption for power saving and the frequency drift due to

temperat ur e ef fec t on the cir cuit for tim e ac cu ra cy.

26.5.2 Timing

The RTC is updated in real time at one-second intervals in Normal mod e for the counters of seconds, at one-

minute intervals for the counter of minutes and so on.

Due to the asynchronous op eration of the RTC with respect to the rest of the chip, to be certain that the value read

in the RTC registers (century, year, month, date, day, hours, minutes, seconds) are valid and stable, it is

necessary to read these reg isters twice. If the data is the same both times, then it is valid. Therefore , a minimum of

two and a maximum of three accesses are required.

26.5.3 Alarm

The RTC has five prog ra m ma b le fie lds: mo nth, date, hours, minutes and seconds.

Table 26-1. Peripheral IDs

Instance ID

RTC 2

603

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Each of these fields can be enabled or disabled to match the alarm condition:

If all the fields are enabled, an alarm flag is generated (the cor responding flag is asserted and an interrupt

generated if enabled) at a given month, date, hour/minute/second.

If only the “seconds” field is enabled, then an alarm is generated every minute.

Depending on the combination of fields enabled, a large num ber of possibilities are available to the user ranging

from minutes to 365/366 days.

Hour, minute and second matching alarm (SECEN, MINEN, HOUREN) can be enabled independently of SEC,

MIN, HOUR fields.

Note: To change one of the SEC, MIN, HOUR, DATE, MONTH fields, it is recommended to disable the field before changing

the value and then re-enable it after the change has been made. This requires up to three accesses to the

RTC_TIMALR or RTC_CALALR. The first access clears the enable correspondin g to the field to change (SECEN,

MINEN, HOUREN, DATEEN, MTHEN). If the field is already cleared, this access is not required. The second access

performs the change of the value (SEC, MIN, HOUR, DATE, MONTH). The third access is required to re-enable the

field by writing 1 in SECEN, MINEN, HOUREn, DATEEN, MTHEN fields.

26.5.4 Error Checking when Programming

Verification on user interface data is performed when accessing the century, year, month, date, day, hours,

minutes, seconds and alarms. A check is performed on illegal BCD entries such as illegal date of the month with

regard to the year and century configured.

If one of the time fields is not correct, the data is not loaded into the register/counter and a flag is set in the validity

any further side effects in the hardware. The same procedure is followed for the alarm.

The following checks are performe d :

1. Century (check if it is in range 19–20 or 13–14 in Persian mode)

2. Year (BCD entry check)

3. Date (check range 01–31)

4. Month (check if it is in BCD range 01–12, check validity regarding “date”)

5. Day (check range 1–7)

6. Hour (BCD checks: in 24-hour mode, check range 00–23 and check that AM/PM flag is not set if RTC is set

in 24-hour mode; in 12-hour mode check range 01–12)

7. Minute (check BCD and range 00–59)

8. Second (check BCD and range 00–59)

Note: If the 12-hour mode is selected by means of the RTC Mode Register (RTC_MR), a 12-hour value can be programmed

and the returned value on RTC_TIMR will be the corresponding 24-hour value. The entry control checks the valu e of

the AM/PM indicator (bit 22 of RTC_TIMR) to determine the range to be checked.

26.5.5 RTC Internal Free Running Counter Error Checking

To improve the reliability and security of the RTC, a permanent ch eck is performed on the internal free running

counters to report non-BCD or invalid date /time values.

An error is reported by TDERR bit in the status register (RTC_SR) if an incorrect value has been detected. The

flag can be cleared by setting the TDERRCLR bit in the Status Clear Command Register (RTC_SCCR).

Anyway the TDERR error flag will be set again if the source of the error has not been cleared before clearing the

TDERR flag. The clearing of the source of such error can be done by reprogramming a correct value on

RTC_CALR and/or RTC_TIMR.

The RTC internal free running counters may aut omatically clear the source of TD ERR due to their roll-over (i.e.,

every 10 seconds for SECONDS[3:0] field in RTC_TIMR). In this case the TDERR is held high until a clear

command is asserted by TDERRCLR bit in RTC_SCCR.

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604

26.5.6 Updating Time/Calendar

The update of the time/calendar must be synchronized on a second periodic event by either polling the

RTC_SR.SEC status bit or by enabling the SECEN interrupt in the RTC_IER register.

Once the second event occurs, the user must stop the RTC by setting the corresponding field in the Control

be set to update calendar fields (century, year, month, date, day).

The ACKUPD bit must then be read to 1 by either polling the RTC_SR or by enabling the ACKUPD interrupt in the

RTC_IER. Once ACKUPD is read to 1, it is mandatory to clear this flag by writing the corresponding bit in the

RTC_SCCR, afte r which the user can write to the Tim e Regis te r, th e Ca len da r Register, or both.

Once the update is finished, the user must write UPDTIM and/or UPDCAL to 0 in the RTC_CR.

The timing sequence of the time/calendar update is described in Figure 26-2.

When entering the Programm ing mode of the calendar fields, the time fields remain enabled. When entering the

Programming mode of the time fie lds, both th e time an d the calen dar fields are stopp ed. T his is due to th e loca tion

of the calendar logical circuity (downstream for low-power considerations). It is highly re commended to prepare all

the fields to be updated before entering Programming mode. In successive update operations, the user must wait

for at least one second after resetting the UPDTIM/UPDCAL bit in the RTC_CR before setting these bits again.

This is done by waiting for the SEC flag in the RTC_SR before setting the UPDTIM/UPDCAL bit. After resetting

UPDTIM/UPDCAL, the SEC flag must also be cleared.

Figure 26-2. Time/Calendar Update Timing Diagram

20 (counter stopped) 15 16

Clear

ACKUPD bit

Update request

from SW

Clear

UPDTIM bit

Update

RTC_TIMR.SEC to 15

Sofware

Time Line

12 43

RTC_SR.ACKUPD

SEC Event Flag

RTC_CR.UPDTIM

RTC_TIMR.SEC

1Hz RTC Clock

RTC BACK TO

NORMAL MODE

////

// //

605

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Figure 26-3. Gregorian and Persian Modes Update Sequence

Prepare Time or Calendar Fields

Set UPDTIM and/or UPDCAL

bit(s) in RTC_CR

Read RTC_SR

ACKUPD

= 1?

Clear ACKUPD bit in RTC_SCCR

Update Time and/or Calendar values in

RTC_TIMR/RTC_CALR

Clear UPDTIM and/or UPDCAL bit

in RTC_CR

Yes

Begin

End

Polling or

IRQ (if enabled)

Wait for second periodic event

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26.5.7 RTC Accurate Clock Calibration

The crystal oscillator that drives the RTC may not be as accurate as expected mainly due to temperature variation.

The RTC is equipped with circuitry able to correct slow clock crystal drift.

To compensate fo r possible temperature varia tions over time, this accurate clock ca libration circuitry can be

programmed on-the-fly and also programmed during application manufacturing, in o rder to correct the crystal

frequency ac curacy at r oom tempera ture (20– 25°C). The typical clock drift range at roo m temperatur e is ±20 ppm.

In the device oper ating temperature range, the 32.768 kHz crystal oscillator clock inaccuracy can be up to -

200 ppm.

The RTC clock calibration circuitry allows positive or negative correction in a range of 1.5 ppm to 1950 ppm.

The calibration circuitry is fully digital. Thus, the configured correction is independent of temperature, voltage ,

process, etc., and no additional measurement is required to check that the correction is effective.

If the correction value configured in the calibration circuitry results from an accurate crystal frequency measure,

the remaining ac cu ra cy is bounded by the value s liste d be low:

Below 1 ppm, for an initial crystal drift between 1.5 ppm up to 20 ppm, and from 30 ppm to 90 ppm

Below 2 ppm, for an initial crystal drift between 20 ppm up to 30 ppm, and from 90 ppm to 130 ppm

Below 5 ppm, for an initial crystal drift between 130 ppm up to 200 ppm

The calibration circuitry does not modify the 32.768 kHz crystal oscillator clock frequency but it acts by slightly

modifying the 1 Hz clock period from time to time. The correction event occurs every 1 + [(20 -

(19 x HIGHPPM)) x CORRECTION] seconds. When the period is modified, depending on the sign of the

correction, the 1 Hz clock period increases or reduces by around 4 ms. Depending on the CORRECTION,

NEGPPM and HIGHPPM values configured in RTC_MR, the period interval between two correction events differ s.

Figure 26-4. Calibration Circuitry

32.768 kHz

Oscillator

Other Logic

RTC

Time/Calendar

1Hz

CORRECTION, HIGHPPM

Integrator

Comparator

Divider by 32768

Add

32.768 kHz

NEGPPM

Suppress

607

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Figure 26-5. Calibration Circuitry Waveforms

The inaccuracy of a crystal oscillator at typical room temperature (±20 ppm at 20–25 °C) can be compensated if a

reference clock/signal is used to measure such inaccuracy. This kind of calibration operation can be set up during

the final product manufacturing by means of measurement equipment embedding such a reference clock. The

correction of value must be programmed into the (RTC_MR), and this value is kept as long as the circuitry is

powered (backup area). Removing the backup power supply ca ncels this calibration. This room temperature

calibration can be further processed by means of the networking capability of the target application.

Time

Monotonic 1 Hz

Counter value

32.768 kHz -50 ppm

32.768 kHz +50 ppm

Crystal frequency

remains unadjusted

Internal 1 Hz clock

is adjusted

Phase adjustment

(~4 ms)

User configurable period

(integer multiple of 1s or 20s)

Time

-50 ppm

-25 ppm

-50 ppm correction period

-25 ppm correction period

Nominal 32.768 kHz

Crystal clock

Internally divided clock (256 Hz)

Internally divided clock (128 Hz)

Clock pulse periodically suppressed

when correction period elapses

128 Hz clock edge delayed by 3.906 ms

when correction period elapses

Internally divided clock (256 Hz)

Internally divided clock (128 Hz)

Internally divided clock (64 Hz)

128 Hz clock edge delayed by 3.906 ms

when correction period elapses

Clock edge periodically added

when correction period elapses

1.000 second

1.003906 second

1.000 second

0.996094 second

NEGATIVE CORRECTION

POSITIVE CORRECTION

dashed lines = no correction

SAM G55 [DATASHEET]

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608

In any event, this adjustment does not take into account the temperature variation.

The frequency drift (u p to -200 ppm) due to temperature variation can be compensated using a reference tim e if

the application c an access such a refe rence. If a reference time cannot be used, a temperature sensor can be

placed close to the crystal oscillator in order to get the operating temperature of the crystal oscillator. Once

obtained, the temper ature may be converte d using a loo kup table (describ ing the accuracy/temper ature curve of

the crystal oscillator used) and RTC_MR configured accordingly. The calibration can be performed on-the-fly. This

adjustment method is not base d on a measurement of t he crystal fre quency/drift and the refore can be improved by

means of the networking capability of the target application.

If no crystal frequency a djustment has been done durin g manufacturing, it is still possible to do it. In the case

where a reference tim e of the day can be obtained through LAN/WAN network, it is possible to calculate the drift of

the application crystal oscillator by comparing the values read on RTC Time Register (RTC_TIMR) and

programming the HIGHPPM and CORRECTION fields on RTC_MR according to the difference measured

between the reference time and those of RTC_TIMR.

26.5.8 Waveform Generation

Waveforms can be genera ted by the RTC in order to take adva ntage of the RTC inherent p rescalers while the RTC

is the only powered circuitry (Low-power mode of operation, Backup mode) or in any active mode. Going into

Backup or Low-power operating modes does not affect the waveform generation outputs.

The RTC waveforms are internally routed to ADC trigger events and those events have a source driver selected

among five possibilities. Two different triggers can be generated at a time, the first one is configurable through field

OUT0 in RTC_MR while the second trigger is configurable through field OUT1 in RTC_MR. OUT0 field manages

the trigger for channel AD[n:0] (where n is the higher index available (last channel)), while OUT1 manages the

channel AD[n] only for specific modes. See the ADC section for selection of the measurement triggers and

associated mode of operations.

The first selection choice sticks the associated output at 0 (This is the reset value and it can be used at any time to

disable the waveform generation).

Selection choices 1 to 4 respectively select 1 Hz, 32 Hz, 64 Hz and 512 Hz.

Selection choice 6 provides a cop y of the a lar m flag, so th e associated ou tput is set high ( logical 1) wh en an alar m

occurs and immediately cleared when software clears the alarm interrupt source.

609

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Figure 26-6. Waveform Generation for ADC Trigger Event

To ADC trigger

event for

all channels

To ADC trigger

event for AD[n]

n = higher index

available

‘0’

1 Hz

32 Hz

64 Hz

512 Hz

toggle_alarm

flag_alarm

pulse

RTC_MR(OUT1)

‘0’

1 Hz

32 Hz

64 Hz

512 Hz

toggle_alarm

flag_alarm

pulse

RTC_MR(OUT0)

flag_alarm

alarm match

event 1

RTC_SCCR(ALRCLR)

alarm match

event 2

RTC_SCCR(ALRCLR)

toggle_alarm

pulse

Tperiod Tperiod

Thigh

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26.6 Real-time Clock (RTC) User Interface

Note: If an offset is not listed in the table it must be considered as reserved.

Table 26-2. Register Mapping

Offset Register Name Access Reset

0x00 C ontrol Register RTC_CR Read/Write 0x00000000

0x04 Mod e Register RTC_MR Read/Write 0x00000000

0x0C Calendar Register RTC_CALR Read/Write 0x01A11020

0x10 Time Alarm Register RTC_TIMALR Read/Write 0x00000000

0x14 Calendar Alarm Register RTC_CALALR Read/Write 0x01010000

0x18 St atus Register R TC_SR Read-only 0x00000000

0x1C Status Clear Command Register RTC_SCCR Write-only –

0x20 Interrupt Enable Register RTC_IER Write-only –

0x24 Interrupt Disable Register RTC_IDR Write-only –

0x28 Interrupt Mask Register RTC_IMR Read-only 0x000000 00

0x2C Valid Entry Register RTC_VER Read-only 0x00000000

0x30–0xC8 Reserved – – –

0xCC Reserved – – –

0xD0 Milliseconds Register RTC_MSR Read-only 0x00000000

0xD4–0xE0 Reserved – – –

0xE4 Write Protection Mode Register RTC_WPMR Read/Write 0x00000000

0xE8–0xF8 Reserved – – –

0xFC Reserved – – –

611

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26.6.1 RTC Control Register

Name: RTC_CR

Address: 0x400E1460

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the RTC Write Protection Mode Register.

• UPDTIM: Update Request Time Register

0: No effect or, if UPDTIM has been previously written to 1, stops the update procedure.

1: Stops the RTC time counting.

Time counting co nsis ts of seco nd , min u te an d hou r coun te rs. Tim e cou n te rs can be pro gr amm e d on ce this bit is set and

acknowledged by the bit ACKUPD of the RTC_SR.

• UPDCAL: Update Request Calendar Register

0: No effect or, if UPDCAL ha s be en previ ously written to 1, stops the update procedure.

1: Stops the RTC calendar counting.

Calendar counting consists of day, date, month, year and century counters. Calendar counters can be programmed once

this bit is set and acknowledged by the bit ACKUPD of the RTC_SR.

• TIMEVSEL: Time Event Selection

The event that generates the flag TIMEV in RTC_SR depends on the value of TIMEVSEL.

• CALEVSEL: Calendar Event Selection

The event that generates the flag CALEV in RTC_SR depends on the value of CALEVSEL

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––––– CALEVSEL

15 14 13 12 11 10 9 8

–––––– TIMEVSEL

76543210

––––––UPDCALUPDTIM

Value Name Description

0 MINUTE Minute change

1 HOUR H our change

2 MIDNIGHT Every day at midnight

3 NOON Every day at noo n

Value Name Description

0 WEEK Week change (every Monday at time 00:00:00)

1 MONTH Month change (every 01 of each month at time 00:00:00)

2 YEAR Year change (every January 1 at time 00:00:00)

3– Reserved

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26.6.2 RTC Mode Register

Name: RTC_MR

Address: 0x400E1464

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the RTC Write Protection Mode Register.

• HRMOD: 12-/24-hour Mode

0: 24-hour mode is selected.

1: 12-hour mode is selected.

• PERSIAN: PERSIAN Calendar

0: Gregorian calendar.

1: Persian calendar.

• NEGPPM: NEGative PPM Correction

0: Positive correction (the divider will be slightly higher than 32768).

1: Negative correction (the divider will be slightly lower than 32768).

Refer to CORRECTION and HIGHPPM field descriptions.

Note: NEGPPM must be cleared to correct a crystal slower than 32.768 kHz.

• CORRECTION: Slow Clock Correction

0: No correction

1–127: The slow clock will be corrected according to the formula given in HIGHPPM description.

• HIGHPPM: HIGH PPM Correction

0: Lower range ppm correction with accurate correction.

1: Higher range ppm correction with accurate correction.

If the absolute value of the cor rection to be applied is lower than 30 ppm, it is recommended to clear HIGHPPM. HIGHPPM

set to 1 is recommended for 30 ppm correction and above.

Formula:

If HIGHPPM = 0, then the clock frequency correction range is from 1.5 ppm up to 98 ppm. The RTC accuracy is less

than 1 ppm for a range correction from 1.5 ppm up to 30 ppm.

The correction field must be programmed according to the required correction in ppm; the formula is as follows:

31 30 29 28 27 26 25 24

– – TPERIOD – THIGH

23 22 21 20 19 18 17 16

–OUT1–OUT0

15 14 13 12 11 10 9 8

HIGHPPM CORRECTION

76543210

– – – NEGPPM – – PERSIAN HRMOD

CORRECTION 3906

20 ppm×

-----------------------1–=

613

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The value obtained must be rounded to the nearest integer prior to being programmed into CORRECTION field.

If HIGHPPM = 1, then the clock frequency correction ra nge is from 30.5 ppm up to 1 950 ppm. The RTC accuracy is

less than 1 ppm for a range correction from 30.5 ppm up to 90 ppm.

The correction field must be programmed according to the required correction in ppm; the formula is as follows:

The value obtained must be rounded to the nearest integer prior to be programmed into CORRECTION field.

If NEGPPM is set to 1, the ppm correction is negative (used to correct crystals that are faster than the nominal 32.768

kHz).

• OUT0: All ADC Channel Trigger Event Source Selection

• OUT1: ADC Last Channel Trigger Event Source Selection

Value Name Description

0 NO_WAVE No waveform, stuck at ‘0’

1 FREQ1HZ 1 Hz square wave

2 FREQ32HZ 32 Hz square wave

3 FREQ64HZ 64 Hz square wave

4 FREQ512HZ 512 Hz square wave

5 ALARM_TOGGLE Output toggles when alarm flag rises

6 ALARM_FLAG Output is a copy of the alarm flag

7 PROG_PULSE Duty cycle programmable pulse

Value Name Description

0 NO_WAVE No waveform, stuck at ‘0’

1 FREQ1HZ 1 Hz square wave

2 FREQ32HZ 32 Hz square wave

3 FREQ64HZ 64 Hz square wave

4 FREQ512HZ 512 Hz square wave

5 ALARM_TOGGLE Output toggles when alarm flag rises

6 ALARM_FLAG Output is a copy of the alarm flag

7 PROG_PULSE Duty cycle programmable pulse

CORRECTION 3906

ppm

------------1–=

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614

• THIGH: High Duration of the Output Pulse

• TPERIOD: Period of the Output Pulse

Value Name Description

0 H_31MS 31.2 ms

1 H_16MS 15.6 ms

2 H_4MS 3.91 ms

3 H_976US 976 µs

4 H_488US 488 µs

5 H_122US 122 µs

6 H_30US 30.5 µs

7 H_15US 15.2 µs

Value Name Description

0 P_1S 1 second

1 P_500MS 500 ms

2 P_250MS 250 ms

3 P_125MS 125 ms

615

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26.6.3 RTC Time Register

Name: RTC_TIMR

Address: 0x400E1468

Access: Read/Write

• SEC: Current Second

The range that can be set is 0–59 (BCD).

The lowest four bits encode the units. The higher bits encode the tens.

• MIN: Current Minute

The range that can be set is 0–59 (BCD).

The lowest four bits encode the units. The higher bits encode the tens.

• HOUR: Current Hour

The range that can be set is 1–12 (BCD) in 12-hour mode or 0–23 (BCD) in 24-hour mode.

• AMPM: Ante Meridiem Post Meridiem Indicator

This bit is the AM/PM indicator in 12-hour mode.

0: AM.

1: PM.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–AMPM HOUR

15 14 13 12 11 10 9 8

–MIN

76543210

– SEC

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616

26.6.4 RTC Calendar Register

Name: RTC_CALR

Address: 0x400E146C

Access: Read/Write

• CENT: Current Century

The range that can be set is 19–20 (Gregorian) or 13–14 (Persian) (BCD).

The lowest four bits encode the units. The higher bits encode the tens.

• YEAR: Current Year

The range that can be set is 00–99 (BCD).

The lowest four bits encode the units. The higher bits encode the tens.

• MONTH: Cu rre nt Mo n th

The range that can be set is 01–12 (BCD).

The lowest four bits encode the units. The higher bits encode the tens.

• DAY: Current Day in Current Week

The range that can be set is 1–7 (BCD).

The coding of the number (which number represents which day) is user-defined as it has no effect on the date counter.

• DATE: Current Day in Current Month

The range that can be set is 01–31 (BCD).

The lowest four bits encode the units. The higher bits encode the tens.

31 30 29 28 27 26 25 24

–– DATE

23 22 21 20 19 18 17 16

DAY MONTH

15 14 13 12 11 10 9 8

YEAR

76543210

–CENT

617

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26.6.5 RTC Time Alarm Register

Name: RTC_TIMALR

Address: 0x400E1470

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the RTC Write Protection Mode Register.

Note: To change one of the SEC, MIN, HOUR fields, it is recommended to disable the field before changing the value and then re-

enable it after the change has been made. This requires up to three accesses to the RTC_TIMALR. The first access clears the

enable corresponding to the field to change (SECEN, MINEN, HOUREN). If the field is already cleared, this access is not

required. The second access performs the change of the value (SEC, MIN, HOUR). The third access is required to re-enable the

field by writing 1 in SECEN, MINEN, HOUREN fields.

• SEC: Second Alarm

This field is the alarm field corresponding to the BCD-coded second counter.

• SECEN: Second Alarm Enable

0: The second-matching alarm is disabled.

1: The second-matching alarm is enabled.

• MIN: Minute Alarm

This field is the alarm field corresponding to the BCD-coded minute counter.

• MINEN: Minute Alarm Enabl e

0: The minute-matching alarm is disabled.

1: The minute-matching alarm is enabled.

• HOUR: Hour Alarm

This field is the alarm field corresponding to the BCD-coded hour counter.

• AMPM: AM/PM Indicator

This field is the alarm field corresponding to the BCD-coded hour counter.

• HOUREN: Hour Alarm Enable

0: The hour-matching alarm is disabled.

1: The hour-matching alarm is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

HOUREN AMPM HOUR

15 14 13 12 11 10 9 8

MINEN MIN

76543210

SECEN SEC

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618

26.6.6 RTC Calendar Alarm Register

Name: RTC_CALALR

Address: 0x400E1474

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the RTC Write Protection Mode Register.

Note: To change one of the DATE, MONTH fields, it is recommended to disable the field before changing the value an d then re-enable

it after the change has been made. This requires up to three accesses to the RTC_CALALR. The first access clears the enable

corresponding to the field to change (DATEEN, MTHEN). If the field is already cleared, this access is not required. The second

access performs the change of the value (DATE, MONTH). The third access is required to re-enable the field by writing 1 in

DATEEN, MTHEN fields.

• MONTH: Month Alarm

This field is the alarm field corresponding to the BCD-coded month counter.

• MTHEN: Month Alarm Enable

0: The month-matching alarm is disabled.

1: The month-matching alarm is enabled.

•DATE: Date Alarm

This field is the alarm field corresponding to the BCD-coded date counter.

• DATEEN: Date Alarm Enable

0: The date-matching alarm is disabled.

1: The date-matching alarm is enabled.

31 30 29 28 27 26 25 24

DATEEN – DATE

23 22 21 20 19 18 17 16

MTHEN – – MONTH

15 14 13 12 11 10 9 8

––––––––

76543210

––––––––

619

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26.6.7 RTC Status Register

Name: RTC_SR

Address: 0x400E1478

Access: Read-only

• ACKUPD: Acknowledge for Update

• ALARM: Alarm Flag

• SEC: Second Event

• TIMEV: Time Event

Note: The time event is selected in the TIMEVSEL field in the Control Register (RTC_CR) and can be any one of the following events:

minute change, hour change, noon, midnight (day change).

• CALEV: Calendar Event

Note: The calendar event is selected in the CALEVSEL field in the Control Register (RTC_CR) and can be any one of the following

events: week change, month change and year change.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – TDERR CALEV TIMEV SEC ALARM ACKUPD

Value Name Description

0 FREERUN Time and calendar registers cannot be updated.

1 UPDATE Time and calendar registers can be updated.

Value Name Description

0 NO_ALARMEVENT No alarm matching condition occurred.

1 ALARMEVENT An alarm matching condition has occurred.

Value Name Description

0 NO_SECEVENT No second event has occurred since the last clear.

1 SECEVENT At least one second event has occurred since the last clear.

Value Name Description

0 NO_TIMEVENT No time event has occurred since the last clear.

1 TIMEVENT At least one time event has occurred since the last clear.

Value Name Description

0 NO_CALEVENT No calendar event has occurred since th e last clear.

1 CALEVENT At least one calendar event has occurred since the last clear.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

620

• TDERR: Time and/or Date Free Running Error

Value Name Description

0 CORRECT The internal free running counters are carrying valid values since the last read of the Status

1 ERR_TIMEDATE The internal free running counters have been corrupted (invalid date or time, non-BCD

values) since the last read and/or they are still invalid.

621

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

26.6.8 RTC Status Clear Command Register

Name: RTC_SCCR

Address: 0x400E147C

Access: Write-only

• ACKCLR: Acknowledge Clear

0: No effect.

1: Clears corresponding status flag in the Status Register (RTC_SR).

• ALRCLR: Alarm Clear

0: No effect.

1: Clears corresponding status flag in the Status Register (RTC_SR).

• SECCLR: Second Clear

0: No effect.

1: Clears corresponding status flag in the Status Register (RTC_SR).

• TIMCLR: Time Clear

0: No effect.

1: Clears corresponding status flag in the Status Register (RTC_SR).

• CALCLR: Calendar Clear

0: No effect.

1: Clears corresponding status flag in the Status Register (RTC_SR).

• TDERRCLR: Time and/or Date Free Running Error Clear

0: No effect.

1: Clears corresponding status flag in the Status Register (RTC_SR).

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – TDERRCLR CALCLR TIMCLR SECCLR ALRCLR ACKCLR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

622

26.6.9 RTC Interrupt Enable Register

Name: RTC_IER

Address: 0x400E1480

Access: Write-only

• ACKEN: Acknowledge Update Interrupt Enable

0: No effect.

1: The acknowledge for update interrupt is enabled.

• ALREN: Alarm Interrupt Enable

0: No effect.

1: The alarm interrupt is enabled.

• SECEN: Second Event Interrupt Enable

0: No effect.

1: The second periodic interrupt is enabled.

• TIMEN: Time Event Interrupt Enable

0: No effect.

1: The selected time event interrupt is enabled.

• CALEN: Calendar Event Interrupt Enable

0: No effect.

1: The selected calendar event interrupt is enabled.

• TDERREN: Time and/or Date Error Interrupt Enable

0: No effect.

1: The time and date error interrupt is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – TDERREN CALEN TIMEN SECEN ALREN ACKEN

623

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

26.6.10 RTC Interrupt Disable Register

Name: RTC_IDR

Address: 0x400E1484

Access: Write-only

• ACKDIS: Acknowledge Update Interrupt Disable

0: No effect.

1: The acknowledge for update interrupt is disabled.

• ALRDIS: Alarm Interrupt Disable

0: No effect.

1: The alarm interrupt is disabled.

• SECDIS: Second Event Interrupt Disable

0: No effect.

1: The second periodic interrupt is disabled.

• TIMDIS: Time Event Interrupt Disable

0: No effect.

1: The selected time event interrupt is disabled.

• CALDIS: Calendar Event Interrupt Disable

0: No effect.

1: The selected calendar event interrupt is disabled.

• TDERRDIS: Time and/or Date Error Interrupt Disable

0: No effect.

1: The time and date error interrupt is disabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – TDERRDIS CALDIS TIMDIS SECDIS ALRDIS ACKDIS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

624

26.6.11 RTC Interrupt Mask Register

Name: RTC_IMR

Address: 0x400E1488

Access: Read-only

• ACK: Acknowledge Update Interrupt Mask

0: The acknowledge for update interrupt is disabled.

1: The acknowledge for update interrupt is enabled.

• ALR: Alarm Interrupt Mask

0: The alarm interrupt is disabled.

1: The alarm interrupt is enabled.

• SEC: Second Event Interrupt Mask

0: The second periodic interrupt is disabled.

1: The second periodic interrupt is enabled.

• TIM: Time Event Interrupt Mask

0: The selected time event interrupt is disabled.

1: The selected time event interrupt is enabled.

• CAL: Calendar Event Interrupt Mask

0: The selected calendar event interrupt is disabled.

1: The selected calendar event interrupt is enabled.

• TDERR: Time and/or Date Error Mask

0: The time and/or date error event is disabled.

1: The time and/or date error event is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – TDERR CAL TIM SEC ALR ACK

625

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

26.6.12 RTC Valid Entry Register

Name: RTC_VER

Address: 0x400E148C

Access: Read-only

• NVTIM: Non-valid Time

0: No invalid data has been detected in RTC_TIMR (Time Regi ster).

1: RTC_TIMR has contained invalid data since it was last programmed.

• NVCAL: Non-valid Calendar

0: No invalid data has been detected in RTC_CALR (Calendar Register).

1: RTC_CALR has contained invalid data since it was last programmed.

• NVTIMALR: Non-valid Time Alarm

0: No invalid data has been detected in RTC_TIMALR (Time Alarm Register).

1: RTC_TIMALR has contained invalid data since it was last programmed.

• NVCALALR: Non-valid Calendar Alarm

0: No invalid data has been detected in RTC_CALALR (Calendar Alarm Register).

1: RTC_CALALR has contained invalid data since it was last programmed.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––NVCALALRNVTIMALRNVCALNVTIM

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

626

26.6.13 RTC Milliseconds Register

Name: RTC_MSR

Address: 0x400E1530

Access: Read-only

• MS: Number of 1/1024 seconds elapsed within 1 second

This field reports a multiple of 1/1024 seconds. The field is synchronized with the fields reported in RTC_TIMR. Thus the

MS field is cleared after each elapsed second. This field is incremented monotonically over a period of 1 second and can

be used for timestamping with an accuracy better than 1 millisecond.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––––– MS

76543210

627

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

26.6.14 R TC Write Protection Mode Register

Name: RTC_WPMR

Address: 0x400E1544

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x525443 (“RTC” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x525443 (“RTC” in ASCII).

The following registers can be write-protected:

•RTC Mode Register

•RTC Time Alarm Register

•RTC Calendar Alarm Register

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x525443 PASSWD Writing any other value in this field aborts the write operation of the WPEN bit.

Always reads as 0.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

628

27. Real-time Timer (RTT)

27.1 Description

The Real-time Timer (RTT) is built around a 32-bit counter used to count roll-ove r events of the progra mmable 16 -

bit prescaler driven from th e 32-kHz slow clock source. It g enerate s a periodi c interr upt and/or trigger s an alarm on

a programmed value.

The RTT can also be configured to be driven by the 1Hz RTC signal, thus taking advantage of a calibrated 1Hz

clock.

The slow clock source can be fully disabled to reduce power consumption when only an elapse d seconds count is

required.

27.2 Embedded Characteristics

32-bit Free-running Counter on prescaled slow clock or RTC calibrated 1Hz clock

16-bit Configurable Prescaler

Interrupt on Alarm or Counter Increment

Programmable Event

27.3 Block Diagram

Figure 27-1. Real-time Timer

SLCK

RTPRES

RTTINC

ALMS

16-bit

Prescaler

32-bit

Counter

ALMV

CRTV

RTT_MR

RTT_VR

RTT_AR

RTT_SR

RTTINCIEN

RTT_MR

ALMIEN

rtt_int

RTT_MR

set

RTT_SR

read

RTT_SR

reset

RTT_MR

reload

rtt_alarm

RTTRST

RTT_MR

RTTRST

RTT_MR

RTTDIS

RTT_MR

RTC1HZ

RTC 1Hz

read

RTT_SR

RTTINC2

reset

RTT_SR set

RTT_MODR SELINC2 ‘0’

CRTV

modulo N

CRTV

modulo M

RTT_MODR SELTRGEV rtt_event

and

‘0’

and

RTT_MR

INC2AEN

(event to exit system from

low power mode)

15us 15us

RTPRES and

SELTRGEV

and

RTT_MR

EVAEN

629

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

27.4 Functional Description

The programmable 16-b it prescaler value can be configured thro ugh the RTPRES field in the “Real-time Time r

Mode Register” (RTT_MR).

Configuring the RTPRES field value to 0x8000 (default value) corresponds to feeding the real-time counter with a

1Hz signal (if the slow clock is 32.768 kHz). The 32-bit counter can count up to 232 seconds, corresponding to

more than 136 years, then roll over to 0. Bit RTTINC in the “Real-time Timer Status Register” (RTT_SR) is set

each time there is a prescaler roll-over (see Figure 27-2)

The real-time 32-bit counter can also be supplied by t he 1Hz RTC clock. This mode is interesting when the RTC

1Hz is calibrated (CORRECTION field ≠ 0 in RTC_MR) in order to guaranty the synchronism between RTC and

RTT counters.

Setting the RTC1HZ bit in the RTT_MR drives the 32-bit RTT counter from the 1Hz RTC clock. In this mode, the

RTPRES field has no effect on the 32-bit counter.

The prescaler roll-over generates an increment of the real-time timer counter if RTC1HZ = 0. Otherwise, if

RTC1HZ = 1, the real-time timer counter is incremented every second. The RTTINC bit is set independently from

the 32-bit counter increment.

The real-time timer can also be used as a free-running timer with a lower time-base. The best accuracy is achieved

by writing RTPRES to 3 in RTT_MR.

Programming RTPRES to 1 or 2 is forbidden.

If the RTT is configured to trigger an interrupt, the inte rrupt occu rs two slow clock cycles after reading the RTT_SR.

To prevent several executions of the interrupt handler, the interrupt must be disabled in the interrupt handler and

re-enabled when the RTT_SR is cleared.

The CRTV field can be read at any time in the “Real-time Timer Value Register” (RTT_VR). As this value can be

updated asynchronously with the Master Clock, the CRTV field must be read twice at the same value to read a

correct value.

The current value of the counter is compared with the value written in the “Real-time Timer Alarm Register”

(RTT_AR). If the counter value matches the alarm, the ALMS bit in the RTT_SR is set. The RTT_AR is set to its

maximum value (0xFFFF_FFFF) after a reset.

The ALMS flag is always a source of the RTT alarm signal that may be used to exit the system from low power

modes (see Figure 27-1).

The alarm interrupt must be disabled (ALMIEN must be cleared in RTT_MR) when writing a new ALMV value in

the RTT_AR.

The RTTINC bit can be used to start a periodic interrupt, the period being one second when the RTPRES field

value = 0x8000 and the slow clock = 32.768 kHz.

The RTTINCIEN bit must be cleared prior to writing a new RTPRES value in the RTT_MR.

Reading the RTT_SR automatically clears the RTTINC and ALMS bits.

Writing the RTTRST bit in the RTT_MR immediately reloads and restarts the clock divider with the new

programmed value. This also resets the 32-bit counter.

When not used, the Real-time Timer can be disabled in order to suppress dynamic power consumption in this

module. This can be achieved by setting the RTTDIS bit in the RTT_MR.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

630

Figure 27-2. RTT Counting

The RTTINC2 f lag is set when the n umber of presca ler roll-overs programmed through the SELINC2 field in the

“Real-time Timer Modulo Selection Register” (RTT_MODR) has been reached since the last read of the RTT_SR.

For example, if the SLCK frequency is 32 .768 kHz and RTPRES=32, the RTTINC flag rises 1024 times per second

(less than 1ms pe rio d ). If the field SE LIN C2 = 5, the RTTINC2 flag rises once per second.

Consequently, if RTTINC is defined as the unique source of interrupt (RTTINCEN=1 and ALMIEN=0 in RTT_MR),

the value read in RTT_SR by the interrupt handler determines if the current interrupt event corresponds to a 1-

second event (RTT_SR[2:1]=6) or a 1-millisecond event (RTT_SR[2:1]=2). See Figure 27-3.

It is possible to define the RTTINC2 flag as a source of the RTT alarm signal by setting the INC2AEN bit to 1 in

RTT_MR (see Figure 27-1).

An event can also be generated and its period of occurrence can be programmed through the SELTRGEV field in

RTT_MODR. This event can be enabled as a source of alarm if the bit EVAEN=1.

Prescaler

ALMVALMV-10 ALMV+1

RTPRES - 1

CRTV

read RTT_SR

ALMS (RTT_SR)

APB Interface

SLCK

RTTINC (RTT_SR)

ALMV+2 ALMV+3

...

APB cycle

631

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 27-3. RTTINC2 behavior

RTTINC

(1s/1024=

~1ms tick)

RTTINC2

(1s ag)

RTT

interrupt line

Read RTT_SR

CRTV L+1 L+2 N M+1 M+2MM+3

1 second1 second

~1 ms ~1 ms

SLCK=32.768KHz, RTPRES=32, SELINC2=5, SELTRGEV=4

~1 ms

RTT event

16 ms 16 ms16 ms 16 ms

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

632

27.5 Real-time Timer (RTT) User Interface

Table 27-1. Register Mapping

Offset R egister Name Access Reset

0x00 Mode Register RTT_MR Read/Write 0x0000_8000

0x04 Alarm Register RTT_AR Read/Write 0xFFFF_FFFF

0x08 Value Register RTT_VR Read-only 0x0000_0000

0x0C Status Register RTT_SR Read-only 0x0000_0000

0x10 Modulo Selection Register RTT_MODR Read/Write 0x0000_0000

633

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

27.5.1 Real-time Timer Mode Register

Name: RTT_MR

Address: 0x400E1430

Access: Read/Write

• RTPRES: Real-ti m e Timer Prescaler Value

Defines the number of SLCK periods required to increment the Real-time timer. RTPRES is defined as follows:

RTPRES = 0: The prescaler period is equal to 216 * SLCK periods.

RTPRES = 1 or 2: forbidden.

RTPRES ≠ 0,1 or 2: The prescaler period is equal to RTPRES * SLCK periods.

Note: The RTTINCIEN bit must be cleared prior to writing a new RTPRES value.

• ALMIEN: Alarm Interrupt Enable

0: The bit ALMS in RTT_SR has no effect on interrupt.

1: The bit ALMS in RTT_SR asserts interrupt.

• RTTINCIEN: Real-time Timer Increment Interrupt Enable

0: The bit RTTINC in RTT_SR has no effect on interrupt.

1: The bit RTTINC in RTT_SR asserts interrupt.

• RTTRST: Real-time Timer Restart

0: No effect.

1: Reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter.

• RTTDIS: Real-time Timer Disable

0: The real-time timer is enabled.

1: The real-time timer is disabled (no dynamic power cons um p tion) .

• INC2AEN: RTTINC2 Alarm Enable

0: The RTTINC2 flag is not a source of the RTT alarm signal.

1: The RTTINC2 flag is a source of the RTT alarm signal.

31 30 29 28 27 26 25 24

–––––––RTC1HZ

23 22 21 20 19 18 17 16

– EVAEN INC2AEN RTTDIS – RTTRST RTTINCIEN ALMIEN

15 14 13 12 11 10 9 8

RTPRES

76543210

RTPRES

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

634

• EVAEN: Trigger Event Alarm Enable

0: The rtt_event signal is not a source of the RTT alarm signal.

1: The rtt_event signal is a source of the RTT alarm signal.

• RTC1HZ: Real-Time Clock 1Hz Clock Selection

0: The RTT 32-bit counter is driven by the 16-bit prescaler roll-over events.

1: The RTT 32-bit counter is driven by the 1Hz RTC clock.

635

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

27.5.2 Real-time Timer Alarm Register

Name: RTT_AR

Address: 0x400E1434

Access: Read/Write

• ALMV: Alarm Value

When the CRTV valu e in RTT_ VR eq u als th e ALM V field , th e ALMS flag is set in RTT_SR. As soon as the ALMS flag

rises, the CRTV value equals ALMV+1 (refer to Figure 27-2).

Note: The alarm interrupt must be disabled (ALMIEN must be cleared in RTT_MR) when writing a new ALMV value.

31 30 29 28 27 26 25 24

ALMV

23 22 21 20 19 18 17 16

ALMV

15 14 13 12 11 10 9 8

ALMV

76543210

ALMV

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

636

27.5.3 Real-time Timer Value Register

Name: RTT_VR

Address: 0x400E1438

Access: Read-only

• CRTV: Current Real-time Value

Returns the curre n t valu e of the Real- tim e Time r.

Note: As CRTV can be updated asynchronously, it must be read twice at the same value.

31 30 29 28 27 26 25 24

CRTV

23 22 21 20 19 18 17 16

CRTV

15 14 13 12 11 10 9 8

CRTV

76543210

CRTV

637

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

27.5.4 Real-time Timer Status Register

Name: RTT_SR

Address: 0x400E143C

Access: Read-only

• ALMS: Real-time Alarm Status (cleared on read)

0: The Real-time Alarm has not occurred since the last read of RTT_SR.

1: The Real-time Alarm occurred since the last read of RTT_SR.

• RTTINC: Prescaler Roll-over Status (cleared on read)

0: No prescaler roll-over occurred since the last read of the RTT_SR.

1: Prescaler roll-over occurred since the last read of the RTT_SR.

• RTTINC2: Predefined Number of Prescaler Roll-over Status (cleared on read)

0: SELINC2=0 or the number of prescaler roll-overs programmed through the SELINC2 field in RTT_MODR has not been

reached since the last read of the RTT_SR.

1: The number of prescaler roll-over s pr ogr ammed th ro ug h the SELINC2 field has be en reached since the last re ad of the

RTT_SR.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––RTTINC2RTTINCALMS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

638

27.5.5 Real-time Timer Modulo Selection Reg ister

Name: RTT_MODR

Address: 0x400E1440

Access: Read/Write

• SELINC2: Selection of the 32-bit Counter Modulo to generate RTTINC2 flag

• SELTRGEV: Selection of the 32 -bit Counter Modulo to generate the trigg er event

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––– SELTRGEV

76543210

––––– SELINC2

Value Name Description

0 NO_RTTINC2 The RTTINC2 flag never rises

1 MOD64 The RTTINC2 flag is set when CRTV modulo 64 equals 0

2 MOD128 The RTTINC2 flag is set when CRTV modulo 128 equals 0

3 MOD256 The RTTINC2 flag is set when CRTV modulo 256 equals 0

4 MOD512 The RTTINC2 flag is set when CRTV modulo 512 equals 0

5 MOD1024 The RTTINC2 flag is set when CRTV modulo 1024 equals 0.

Example: If RTPRES=32 then RTTINC2 flag rises once per second if the slow clock

is 32.768 kHz.

6 MOD2048 The RTTINC2 flag is set when CRTV modulo 2048 equals 0

7 MOD4096 The RTTINC2 flag is set when CRTV modulo 4096 equals 0

Value Name Description

0 NO_EVENT No event generated

1 MOD2 Event occurs when CRTV modulo 2 equals 0

2 MOD4 Event occurs when CRTV modulo 4 equals 0

3 MOD8 Event occurs when CRTV modulo 8 equals 0

4 MOD16 Event occurs when CRTV modulo 16 equals 0

5 MOD32 Event occurs when CRTV modulo 32 equals 0

6 MOD64 Event occurs when CRTV modulo 64 equals 0

7 MOD128 Event occurs when CRTV modulo 128 equals 0

639

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

28. General Purpose Backup Registers (GPBR)

28.1 Description

The System Contr olle r em b ed s 25 6 bits of Ge ne ra l Purpo se Ba cku p re gisters organized as Eigh t 32-b it re gisters.

The Supply Controller module must be programmed accordingly. In the register SUPC_WUMR in the Supply

Controller module, LPDBCCLR, LPDBCEN0 and/or LPDBCEN1 bit must be configured to 1 and LPDBC must be

other than 0.

If a Tamper event has been detected, it is not possible to write to the General Purpose Backup registers while the

LPDBCS0 or LPDBCS1 flags are not cleared in the Supply Controller Status Register (SUPC_SR).

28.2 Embedded Characteristics

256 bits of General Purpose Backup Registers

Immediate Clear on Tamper Event

It is possible to generate an immediate clear of the content of General Purpose Backup registers 0 to

GPBR_NUMBER_DIV2-1 (first half) if a Low-power Debounce event is detected on one of the wakeup pins,

WKUP0 or WKUP1. The content of the other General Purpose Backup registers (second half) remains unchanged.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

640

28.3 General Purpose Backup Registers (GPBR) User In terface

Table 28-1. Register Mapping

Offset Register Name Access Reset

0x0 General Purpose Backup Register 0 SYS_GPBR0 Read/Write 0x00000000

... ... ... ... ...

0xAC General Purpose Backup Register 7 SYS_GPBR7 Read/Write 0x00000000

641

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

28.3.1 General Purpose Backup Register x

Name: SYS_GPBRx

Address: 0x400E1490

Access: Read/Write

These registers are reset at first power-up and on each loss of VDDIO.

• GPBR_VALUE: Value of GPBR x

If a Tamper event has been detected, it is not possible to write GPBR_VALUE as long as the LPDBCS0 or LPDBCS1 flag

has not been cleared in the Supply Controller Status Register (SUPC_SR).

31 30 29 28 27 26 25 24

GPBR_VALUE

23 22 21 20 19 18 17 16

GPBR_VALUE

15 14 13 12 11 10 9 8

GPBR_VALUE

76543210

GPBR_VALUE

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

642

29. Flexible Serial Communication Controller (FLEXCOM)

29.1 Description

The Flexible Serial Communication Controller (FLEXCOM) offers several serial communication protocols that are

managed by the three submodules USART, SPI and TWI.

A single submodule at a time can be enabled by the FLEXCOM Mode Register (FLEXCOM_MR). The I/O lines,

interrupt lines, and event lines of the three submodules are multiplexed by the FLEXCO M. All details related to

these submodules are provided in independent sections.

29.2 Embedded Characteristics

Selection of USART, SPI or TWI submodules

Multiplexing of interrupt lines into a single interrupt line

Multiplexing of the trigger events to PDC

29.3 Block Diagram

Figure 29-1. FLEXCOM Block Diagram

Peripheral

DMA Controller

(PDC)

Channel

Interrupt

Controller

USART

FLEXCOM Interrupt

FLEXCOM

PIO

Controller

SPI

PMC

Peripheral clock

APB

Bus clock

Peripheral Bridge

FLEXCOM

User

Interface

PMC.PCKx

TWI

RX trigger event

TX trigger event

mux mux

mux

FLEXCOM_MR =MR

Pads

txd,rxd,

sck,

rts,cts

mosi,

miso,

spck,

npcs0/1

twd,

twck

excom

I/Os

clock3

clock2

clock1

to USART, SPI, and TWI

MR=1

MR=2

MR=3

643

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

29.4 I/O Lines Description

Note: 1. FLEXCOM3 only

29.5 Product Dependencies

29.5.1 I/O Lines

The pins used for interfacing the FLEXCOM are multiplexed with the PIO lines. The programmer must first

program the PIO controller to assign the desired FLEXCOM pins to their peripheral function. If I/O lines of the

FLEXCOM are not used by the application, they can be used for other purposes by the PIO Controller.

29.5.2 Power Management

The peripheral clock is not continuously provided to the FLEXCOM. The programmer must first enable the

FLEXCOM Clock in the Power Management Controller (PMC) before using the FLEXCOM. However, if the

application does not require FLEXCOM operations, the FLEXCOM clock can be stopped and restarted later.

In SleepWalking mode (asynchronous partial wakeup), the PMC must be configured to enable SleepWalking for

the FLEXCOM in the Sleepwalking Enable Register (PMC_SLPWK_ER). The peripheral clock can be

automatically provided to the FLEXCOM, depending on the instructions (requests) provided by the FLEXCOM to

the PMC.

29.5.3 Interrupt Sources

The FLEXCOM interrupt line is connected on one of the internal sources of the interrupt controller. Using the

FLEXCOM interrupt requires the interrupt controller to be programmed first.

Table 29-1. I/O Line Description

Name

Description

TypeUSART/UART SPI TWI

TXD_IO1 TXD MOSI TWD I/O

RXD_IO2 RXD MISO TWCK I/O

SCK_IO3 SCK SPCK SMBALERT(1) I/O

CTS_IO4 CTS NPCS0/NSS – I/O

RTS_IO5 RTS NPCS1 – O

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29.6 FLEXCOM Functional Description

The selection of USART, SPI or TWI is defined in FLEXCOM_MR.

When a submodule is selected, the others are disabled and cannot be configured.

A unique interrupt line and the PDC channels are shared among the three submodules.

Table 29-2. FLEXCOM Configuration

Function

FLEX0 FLEX1 FLEX2 FLEX3 FLEX4 FLEX5 FLEX6 FLEX7

Main Function Subfunction

TWI 

TWI

High-speed SMBUS – – – ––––

High-speed Alternate Function 

High-speed Sleepwalking 

UART 

USART 

USART

Sleepwalking 

ISO7816 – – – – – 

IrDA –––––

LIN Mode – – – – –––

SPI Mode – – –––––

SPI 2 Chip Selects 

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29.7 Flexible Serial Communication Controller (FLEXCOM) User Interface

Table 29-3. Register Mapping

Offset Register Name Access Reset

0x0000 FLEXCOM Mode Register FLEXCOM_MR Read/Write 0x0

0x0004–0x000C Reserved – – –

0x0010 FLEXCOM Receive Hold ing Register FLEXCOM_RHR Read-only 0x0

0x0014–0x001C Reserved – – –

0x0020 FLEXCOM Transmit Holding Register FLEXCOM_THR Read/Write 0x0

0x0024–0x01FC Reserved – – –

0x0200–0x02FC Reserved for USART – – –

0x0300–0x0328 Reserved for USART PDC Registers – – –

0x032C–0x03FC Reserved – – –

0x0400–0x04FC Reserved for Fast SPI – – –

0x0500–0x0528 Reserved for Fast SPI PDC Registers – – –

0x052C–0x05FC Reserved – – –

0x0600–0x06FC Reserved for TWI – – –

0x0700–0x0728 Reserved for TWI PDC Registers – – –

0x072C–0x07FC Reserved – – –

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29.7.1 FLEXCOM Mode Register

Name: FLEXCOM_MR

Address: 0x4000C000 (0), 0x40020000 (1), 0x40024000 (2), 0x40018000 (3), 0x4001C000 (4), 0x40008000 (5),

0x40040000 (6), 0x40034000 (7)

Access: Read/Write

• OPMODE: FLEXCOM Operating Mode

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––– OPMODE

Value Name Description

0 NO_COM No communication

1 USART All related USART related protocols are selecte d (RS232, IrDA, ISO7816, LIN)

All SPI/TWI related registers are not accessible and have no impact on IOs.

2 SPI SPI operating mode is selecte d.

All USART/TWI related registers are not accessible and have no impact on IOs.

3TWI

All related TWI protocols are selected (TWI, SMBUS). All USART/SPI related registers are

not accessible and have no impact on IOs.

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29.7.2 FLEXCOM Transmit Holding Regist er

Name: FLEXCOM_THR

Address: 0x4000C020 (0), 0x40020020 (1), 0x40024020 (2), 0x40018020 (3), 0x4001C020 (4), 0x40008020 (5),

0x40040020 (6), 0x40034020 (7)

Access: Read/Write

•TXDATA: Transmit Data

This register is an image of:

• USART Transmit Holding Register (US_THR) if FLEXCOM_MR.OPMODE = 1

• SPI Transmit Data Register (SPI_TDR) if FLEXCOM_MR.OPMODE = 2

• TWI Transmit Holding Register (TWI_THR) if FLEXCOM_MR.OPMODE = 3

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

TXDATA

76543210

TXDATA

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29.7.3 FLEXCOM Receive Holding Register

Name: FLEXCOM_RHR

Address: 0x4000C010 (0), 0x40020010 (1), 0x40024010 (2), 0x40018010 (3), 0x4001C010 (4), 0x40008010 (5),

0x40040010 (6), 0x40034010 (7)

Access: Read-only

• RXDATA: Receive Data

This register is an image of:

• USART Receive Holding Register (US_RHR) if FLEXCOM_MR.OPMODE = 1

• SPI Receive Data Register (SPI_RDR) if FLEXCOM_MR.OPMODE = 2

• TWI Transmit Holding Register (TWI_RHR) if FLEXCOM_MR.OPMODE = 3

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

RXDATA

76543210

RXDATA

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30. Universal Synchronous Asynchronous Receiver Transceiver (USART)

30.1 Description

The Universal Synchronous Asynchronous Receiver Transceiver (USART) provides one full duplex universal

synchronous asynchronous serial link. Data frame format is widely programmable (data length, parity, number of

stop bits) to support a maximum of standards. The receiver implements parity error, framing error and overrun

error detection. The receiver timeout enables handling variable-length frames and the transmitter timeguard

facilitates communications with slow remote devices. Multidrop communications are also supported through

address bit handling in reception and transmission.

The USART features three test modes: Remote Loopback, Local Loopback and Automatic Echo.

The USART supports specific operating modes providing interfaces on LIN, and SPI buses, with ISO7816 T = 0 or

T = 1 smart card slots, and infrared transceivers. The hardware handshaking feature enables an out-of-band flow

control by automatic management of pins RTS and CTS.

The USART supports the connection to the Peripheral DMA Controller which enables data transfers to the

transmitter and from the receiver. The PDC provides chained buffer management without any intervention of the

processor.

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30.2 Embedded Characteristics

Programmable Baud Rate Generator

Baud Rate can be Independent of the Processor/Peripheral Clock

Asynchronous Partial wakeup on Receive Line Activity (SleepWalking)

Comparison Function on Received Character

5- to 9-bit Full-duplex Synchronous or Asynchronous Serial Comm unications

1, 1.5 or 2 Stop Bits in Asynchronou s Mode or 1 or 2 Stop Bits in Synchronous Mode

Parity Generation and Error Detection

Framing Error Detection, Overrun Error Detection

Digital Filter on Receive Line

MSB- or LSB-first

Optional Break Generation and Detection

By 8 or by 16 Over-sampling Receiver Frequency

Optional Hardware Handshaking RTS-CTS

Receiver Timeout and Tr an sm itt er Timeguard

Optional Multidrop Mode with Address Generation and Detection

ISO7816, T = 0 or T = 1 Protocols for Interfacing with Smart Cards

NACK Handling, Error Counter with Repetition and Iteration Limit

IrDA Modulation and Demodulation

Communication at up to 115.2 Kbps

SPI Mode

Master or Slave

Serial Clock Programmable Phase and Polarity

SPI Serial Clock (SCK) Frequency up to fperipheral clock/6

LIN Mode

Compliant with LIN 1.3 and LIN 2.0 Specifications

Master or Slave

Processing of Frames with Up to 256 Data Bytes

Response Data Length can be Configurable or Defined Automatically by the Identifier

Self-synchronization in Slave Node Configuration

Automatic Processing and Verification of the “Synch Break” and the “Synch Field”

“Synch Break” Detection Even When Partially Superimposed with a Data Byte

Automatic Identifier Parity Calculation/Sending and Verification

Parity Sending and Verification Can be Disabled

Automatic Checksum Calculation/sending and Verification

Checksum Sending and Verification Can be Disabled

Support Both “Classic” and “Enhanced” Checksum Types

Full LIN Error Checking and Reporting

Frame Slot Mode: Master Allocates Slots to the Scheduled Frames Automatically

Generation of the Wakeup Signal

Test Modes

Remote Loopback, Local Loopback, Automatic Echo

Supports Connection of two Peripheral DMA Controller Channels (PDC)

Offers Buffer Transfer without Processor Intervention

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30.3 Block Diagram

Figure 30-1. USART Block Diagram

Table 30-1. SPI Operating Mode

Pin USART Basic SPI Slave Basic SPI Master

RXD RXD MOSI MISO

TXD TXD MISO MOSI

RTS RTS – CS

CTS CTS CS –

(Peripheral) DMA

Controller

Channel Channel

Interrupt

Controller

Receiver

FLEXCOM

Interrupt

RXD

TXD

SCK

USART

PIO

Controller

CTS

RTS

Transmitter

Baud Rate

Generator

User Interface

PMC MCK

PCKx

DIV MCK/DIV

APB

FLEXCOM

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30.4 I/O Lines Description

30.5 Product Dependencies

30.5.1 I/O Lines

The pins used for interfacing the USART are mu ltiplexed with the SPI an d T WI lines within th e FLEXCOM module.

The programmer must first program the PIO controller to assign the desired FLEXCOM pins to their peripheral

function. If I/O lines of the FLEXCOM are not used by th e app lication, they can be used for other purposes by the

PIO Controller.

Table 30-2. I/O Line Description

Name Descript ion Type Active Le v el

SCK Serial Clock I /O —

TXD Transmit Serial Data

or Master Out Slave In (MOSI) in SPI Master mode

or Master In Slave Out (MISO) in SPI Slave mode I/O —

RXD Receive Serial Data

or Master In Slave Out (MISO) in SPI Master mode

or Master Out Slave In (MOSI) in SPI Slave mode I/O —

CTS Clear to Send

or Slave Select (NSS) in SPI Slave mode Input Low

RTS Request to Send

or Slave Select (NSS) in SPI Master mode Output Low

Table 30-3. I/O Lines

Instance Signal I/O Line Peripheral

USART0 RXD0/SPI0_MISO/TWCK0 PA9 A

USART0 SCK0/SPI0_SPCK PB0 A

USART0 SPI0_NPCS0/CTS0 PA25 A

USART0 SPI0_NPCS1/RTS0 PA26 A

USART0 TXD0/SPI0_MOSI/TWD0 PA10 A

USART1 RXD1/SPI1_MISO/TWCK1 PB2 A

USART1 SCK1/SPI1_SPCK PA27 A

USART1 SPI1_NPCS0/CTS1 PA28 A

USART1 SPI1_NPCS1/RTS1 PA29 A

USART1 TXD1/SPI1_MOSI/TWD1 PB3 A

USART2 RXD2/SPI2_MISO/TWCK2 PA5 A

USART2 SCK2/SPI2_SPCK PA15 B

USART2 SCK2/SPI2_SPCK PA24 B

USART2 SPI2_NPCS0/CTS2 PA16 A

USART2 SPI2_NPCS1/RTS2 PA15 A

USART2 TXD2/SPI2_MOSI/TWD2 PA6 A

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USART3 RXD3/SPI3_MISO/TWCK3 PA4 A

USART3 SCK3/SPI3_SPCK PB13 A

USART3 SPI3_NPCS0/CTS3 PB14 A

USART3 SPI3_NPCS1/RTS3 PB15 A

USART3 TXD3/SPI3_MOSI/TWD3 PA3 A

USART4 RXD4/SPI4_MISO/TWCK4 PB9 A

USART4 RXD4/SPI4_MISO/TWCK4 PB11 A

USART4 SCK4/SPI4_SPCK PB1 A

USART4 SPI4_NPCS0/CTS4 PB8 B

USART4 SPI4_NPCS1/RTS4 PB9 B

USART4 TXD4/SPI4_MOSI/TWD4 PB8 A

USART4 TXD4/SPI4_MOSI/TWD4 PB10 A

USART5 RXD5/SPI5_MISO/TWCK5 PA12 A

USART5 SCK5/SPI5_SPCK PA14 A

USART5 SPI5_NPCS0/CTS5 PA11 A

USART5 SPI5_NPCS1/RTS5 PA5 B

USART5 SPI5_NPCS1/RTS5 PB2 B

USART5 TXD5/SPI5_MOSI/TWD5 PA13 A

USART6 RXD6/SPI6_MISO/TWCK6 PB1 B

USART6 RXD6/SPI6_MISO/TWCK6 PB11 B

USART6 SCK6/SPI6_SPCK PB13 B

USART6 SPI6_NPCS0/CTS6 PB14 B

USART6 SPI6_NPCS1/RTS6 PB15 B

USART6 TXD6/SPI6_MOSI/TWD6 PB0 B

USART6 TXD6/SPI6_MOSI/TWD6 PB10 B

USART7 RXD7/SPI7_MISO/TWCK7 PA27 B

USART7 SCK7/SPI7_SPCK PA29 B

USART7 SPI7_NPCS0/CTS7 PA30 B

USART7 SPI7_NPCS1/RTS7 PA31 B

USART7 TXD7/SPI7_MOSI/TWD7 PA28 B

Table 30-3. I/O Lines (Contin ued)

Instance Signal I/O Line Peripheral

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30.5.2 Power Management

The peripheral clock is not continuo usly provid ed to th e USART. Th e pr ogramm er must fir s t en able the FLEXCOM

Clock in the Power Management Controller (PMC) and set the OPMODE field to value ‘1’ in the FLEXCOM Mode

If the OPMODE field differs from ‘1’, the USART clock is stopped.

In SleepWalking mode (asynchronous partial wakeup), the PMC must be configured to enable SleepWalking for

the FLEXCOM in the Sleepwalking Enable Register (PMC_SLPWK_ER). The peripheral clock can be

automatically provided to the FLEXCOM, depending on the instructions (requests) provided by the FLEXCOM to

the PMC.

30.5.3 Interrupt Sources

The USART interrupt line is the FLEXC OM interrupt line if the field OPMODE = 1 in FLEX_MR. The FLEXCOM

interrupt line is connected on one of the internal sources of the Interrupt Controller. Using the FLEXCOM interrupt

requires the Interrupt Controller to be programmed first.

Table 30-4. Peripheral IDs

Instance ID

USART0 8

USART1 9

USART2 14

USART3 19

USART4 20

USART5 21

USART6 22

USART7 7

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30.6 USART Functional Description

30.6.1 Baud Rate Generator

The baud rate generator provides the bit period clock named the baud rate clock to both the receiver and the

transmitter.

The baud rate generator clock source is selected by setting the USCLKS field in the USART M ode register

(US_MR) to us e on e of the follow ing :

The peripher al cloc k

A division of the peripheral clock, where the divider is product-dependent, but generally set to 8

A fully programmable processor/peripheral independent clock source provided by PMC (PCK)

The external clock, available on the SCK pin

The baud rate generator is based upon a 16-bit divider, which is programmed with the CD field of the Baud Rate

Generator register (US_BRGR). If a zero is written to CD, the baud rate generator does not generate any clock. If

a one is written to CD, the divider is bypassed and becomes inactive.

If the external SCK clock is selected, the duration of the low and high levels of the signal provided on the SCK pin

must be longer than a peripheral clock period. The frequency of the signal provided on SCK must be at least three

times lower than the frequency provide d on the peripheral clock in USART modes (field USART_MODE equals

0x0 to 0xB), or six times lower in SPI modes (field USART_MODE equals 0xE or 0xF).

If PMC PCK is selected, the baud rate is independent of the processor/peripheral clock and thus

processor/peripheral clock frequency can be changed without affecting the USART transfer. The PMC PCKx

frequency must a lways be three times lower than peripher al clock frequency. If PMC PCK is selected (USCLKS=2)

and the SCK pin is driven (CLKO=1), the CD field must be greater than 1.

Figure 30-2. Baud Rate Generator

30.6.1.1 Baud Rate in Asynchronous Mode

If the USART is programmed to operate in Asynchronous mode, the selected clock is first divided by CD, which is

field programmed in the US_BRGR. The resulting clock is provided to the receiver as a sampling clock and then

divided by 16 or 8, depending on how the OVER bit

in the US_MR is programmed.

If OVER is set, the receiver sampling is 8 times higher than the baud rate clock. If OVER is cleared, the sampling

is performed at 16 times the baud rate clock.

Peripheral clock/DIV 16-bit Counter

Baud Rate

Clock

Sampling

Divider

Sampling

Clock

PMC.PCKx

Peripheral clock

USCLKS

OVER SYNC

SYNC

USCLKS = 3

FIDI

SCK

SCK Selected Clock

Selected

Clock

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The baud rate is calcu la te d as pe r th e fo llowin g form u la:

This gives a maximum baud rate of peripheral clock divided by 8, assum ing that peripheral clock is the highest

possible clock and that the OVER bit is set.

Baud Rate Calculation Example

Table 30-5 shows calculations of CD to obtain a baud rate at 38,400 bit/s for different source clock frequencies.

This table also shows the actual resulting baud rate and the error.

The baud rate is calcu la te d with the following formula:

The baud rate error is calcula ted with the following formula. It is not recommended to work with an error higher

than 5%.

Baudrate SelectedClock

82 Over–()CD()

--------------------------------------------

Table 30-5. Baud Rate Example (OVER = 0)

Source Clock

(MHz) Expected Baud Rate

(Bit/s) Calculation Result CD Actual Baud Rate

(Bit/s) Error

3,686,400 38,400 6.00 6 38,400.00 0.00%

4,915,200 38,400 8.00 8 38,400.00 0.00%

5,000,000 38,400 8.14 8 39,062.50 1.70%

7,372,800 38,400 12.00 12 38,400.00 0.00%

8,000,000 38,400 13.02 13 38,461.54 0.16%

12,000,000 38,400 19.53 20 37,500.00 2.40%

12,288,000 38,400 20.00 20 38,400.00 0.00%

14,318,180 38,400 23.30 23 38,908.10 1.31%

14,745,600 38,400 24.00 24 38,400.00 0.00%

18,432,000 38,400 30.00 30 38,400.00 0.00%

24,000,000 38,400 39.06 39 38,461.54 0.16%

24,576,000 38,400 40.00 40 38,400.00 0.00%

25,000,000 38,400 40.69 40 38,109.76 0.76%

32,000,000 38,400 52.08 52 38,461.54 0.16%

32,768,000 38,400 53.33 53 38,641.51 0.63%

33,000,000 38,400 53.71 54 38,194.44 0.54%

40,000,000 38,400 65.10 65 38,461.54 0.16%

50,000,000 38,400 81.38 81 38,580.25 0.47%

BaudRate MCK CD 16×⁄=

Error 1ExpectedBaudRate

ActualBaudRate

---------------------------------------------------





–=

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30.6.1.2 Fractional Baud Rate in Asynchronous Mode

The baud rate generator is subject to the following limitation: the output frequency changes by only integer

multiples of the reference fre quency. An a pproa ch to th is problem is to integra te a fra ctional N clo ck gen er ator that

has a high resolution. The generator architecture is modified to obtain baud rate changes by a fraction of the

reference source clock. This fractional part is programmed with the FP field in the US_BRGR. If FP is not 0, the

fractional part is activated. The resolution is one eighth of the clock divider. The fractional baud rate is calculated

using the following formula:

The modified arc hit ec tu re is pres en te d in the followin g Figure 30-3.

Figure 30-3. Fractional Baud Rate Generator

Warning: When the value of field FP is greater th an 0, th e SCK (oversampling clock) gener-ates nonconstant duty

cycles. The SCK high duration is increased by “selected clock” period from time to time. The duty cycle depends

on the value of the CD field.

30.6.1.3 Baud Rate in Synchronous Mode or SPI Mode

If the USART is programmed to o per ate in Synchronous mode, th e sele cted clo ck is simply divided by the field CD

in the US_BRGR.

In Synchronous mode, if the external clock is selected (USCLKS = 3) and CLKO=0 (Slave mode), the clock is

provided directly by the signal on the USART SCK pin. No division is active. The value written in US_BRGR has no

effect. The external clock frequency must be at least 3 times lower than the system clock. In Synchronous mode

master (USCLKS = 0 or 1, CLKO set to ‘1’), the receive part limits the SCK maximum frequency to fperipheral clock/3 in

USART mode, or fperipheral clock/6 in SPI mode.

When either the external clock SCK or the internal clock divided (peripheral clock/DIV or PMC PCK) is selected,

the value programmed in CD must be even if the user has to ensure a 50:50 mark/space ratio on the SCK pin. If

the peripheral clock is selected, the baud rate generator ensures a 50:50 duty cycle on the SCK pin, even if the

value programmed in CD is odd.

Baudrate SelectedClock

82 Over–()CD FP

-------









----------------------------------------------------------------

MCK/DIV

16-bit Counter

Baud Rate

Clock

Sampling

Divider

Sampling

Clock

PMC.PCKx

MCK

USCLKS

OVER SYNC

SYNC

USCLKS = 3

FIDI

Glitch-free

Logic

Modulus

Control

FP SCK

(CLKO = 1)

SCK

(CLKO = 0)

Selected Clock

Selected

Clock

BaudRate SelectedClock

--------------------------------------

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30.6.1.4 Baud Rate in ISO 7816 Mode

The ISO7816 specification defines the bit rate with the following formula:

where:

B is the bit rate

Di is the bit-rate adjustment factor

Fi is the clock frequency division factor

f is the ISO7816 clock frequency (Hz)

Di is a binary value encoded on a 4-bit field, named DI, as represente d in Table 30-6.

Fi is a binary value encoded on a 4-bit field, named FI, as represen ted in Table 30-7.

Table 30-8 shows the resulting Fi/Di Ratio, which is the ratio between the ISO7816 clock and the baud rate clock.

If the USART is configured in ISO7816 mode, th e clock selected by th e USCLKS field in the US_ MR is first divide d

by the value programmed in US_BRGR.CD. The resulting clock can be provided to the SCK pin to feed the smart

card clock inputs. This means that US_MR.CLKO bit can be written to ‘1’.

This clock is then divided by the value programmed in the FI_DI_RATIO field in the FI_DI_Ratio register

(US_FIDI). This is performed by the Sampling Divider, which performs a division by up to 2047 in ISO7816 mode.

The noninteger values of the Fi/Di Ratio are not supported and the user m ust prog ram the FI _DI _RA TIO field t o a

value as close as possible to the expected value.

The FI_DI _RATIO field r esets to the value 0x174 (372 in decimal) and is the most common divider between the

ISO7816 clock and the bit rate (Fi = 372, Di = 1).

Figure 30-4 shows the relation between the Elementary Time Unit, corresponding to a bit time, and the ISO 7816

clock.

BDi

------f×=

Table 30-6. Binary and Decimal Values for Di

DI field 0001 0010 0011 0100 0101 0110 10 00 1001

Di (decimal) 1 2 4 8 16 32 12 20

Table 30-7. Binary and Decimal Values for Fi

FI field 0000 0001 0010 0011 0100 0101 0110 1001 1010 1011 1100 1101

Fi (decimal) 372 372 558 744 1116 1488 1860 512 7 68 1024 1536 2048

Table 30-8. Possible Values for the Fi/Di Ratio

Fi/Di 372 558 744 1116 1488 1806 512 768 1024 1536 2048

1 372 558 744 1116 1488 1860 512 768 1024 1536 2048

2 186 279 372 558 744 930 256 384 512 768 1024

4 93 139.5 186 279 372 465 128 192 256 384 512

8 46.5 69.75 93 139.5 186 232.5 64 96 128 192 256

16 23.25 34.87 46.5 69.75 93 116.2 32 48 64 96 128

32 11.62 17.43 23.25 34.87 46.5 58.13 16 24 32 48 64

12 31 46.5 62 93 124 155 42.66 64 85.33 128 170.6

20 18.6 27.9 37.2 55.8 74.4 93 25.6 38.4 51.2 76.8 102.4

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Figure 30-4. Elementary Time Unit (ETU)

30.6.2 Receiver and Transmitter Control

After reset, the receiver is disabled. The user must enabl e the receiver by setting the RXEN bit in the Control

After reset, the transmitter is disab led. The user must enable it by setting the TXEN bit in the US_CR. However ,

the transmitter registers can be programmed before being enabled.

The receiver and the transmitter can be enabled together or independently.

At any time, the software can perform a reset on the receiver or the transmitter of the USART by setting the

corresponding bit, RSTRX and RSTTX respectively, in the US_CR. The software resets clear the status flag and

reset internal state machines but the user interface configuration registers hold the value configured prior to

software reset. Regardless of what the receiver or the transmitter is performing, the communication is immediately

stopped.

The user can also independently disable the receiver or the transm itter by setting RXDIS and TXDIS respectively

in the US_CR. I f the receive r is disabled during a ch aracter r eception, the USART waits until the en d of recept ion

of the current character, then the reception is stopped. If the transmitter is disabled while it is operating, the

USART waits the e nd of transmission of both t he current character and ch aracter being stored in th e USART

Transmit Holding register (US_THR). If a timeguard is programmed, it is handled normally.

30.6.3 Synchronous and Asynchronous Modes

30.6.3.1 Transmitter Operations

The transmitter performs the same in both Synchronous and Asynchronous operating modes (SYNC = 0 or SYNC

= 1). One start bit, up to 9 data bits, one optional parity bit and up to two stop bits are successively shifted out on

the TXD pin at each falling edge of the programmed serial clock.

The number of data bits is selected by the CHRL field and the MODE 9 bit in US_MR. Nine bits are selected by

setting the MODE 9 bit regardless of the CHRL field. T he parity bit is set depending on the PAR field in US_MR.

The even, odd, space, marked or none parity bit can be configured. The MSBF field in the US_MR configures

which data bit is sent first. If written to ‘1’, the most significant bit is sent first. If written to 0, the less significant bit is

sent first. The number of stop bits is selected by the NBSTOP field in the US_MR. The 1.5 stop bit is supported in

Asynchronous mode only.

1 ETU

ISO7816 Clock

on SCK

ISO7816 I/O Line

on TXD

FI_DI_RATIO

ISO7816 Clock Cycles

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Figure 30-5. Character Transmit

The characters are sent by writing in the US_THR. The transmitter reports two status bits in the Channel Status

indicates that all the characters written in US_THR ha ve been pro cessed. Wh en the curre nt character processi ng

is completed, the last character written in US_TH R is transferred into the Shift register of the transmitter and

US_THR becomes empty, thus TXRDY rises.

Both TXRDY and TXEMPTY bits are low when the transmitter is disabled. Writing a character in US_THR while

TXRDY is low has no effect and the written character is lost.

Figure 30-6. Transmitter Status

30.6.3.2 Asynchronous Receiver

If the USART is programmed in Asynchronous op erating mode (SYNC = 0), the receiver oversamples the RXD

input line. The oversampling is e ither 16 or 8 times the b aud rate clock, d epending o n the OVER b it in the US_MR.

The receiver samples the RXD line. If the line is sampled during one half of a bit time to 0, a start bit is detected

and data, parity and stop bits are successively sampled on the bit rate clock.

If the oversampling is 16, ( OVER = 0), a start is detected at the eighth sample to 0. Data bits, parity bit and stop bit

are assumed to have a duration corresponding to 16 oversamplin g clock cycles. If th e over samp ling is 8 (O VER =

1), a start bit is detected at the fourth sample to 0. Data bits, parity bit and stop bit are assumed to have a duration

corresponding to 8 oversampling clock cycles.

The number of data bits, first bit sent and Parity mode are selected by the same fields and bits as the transmitter,

i.e., respectively CHRL, M ODE9, MSBF and PAR. For the synchronization m echanism only, the number of stop

bits has no effect on the receiver as it considers only one stop bit, regardless of the field NBSTOP, so that

resynchronization between the receiver and the transmitter can occur. Moreover, as soon as the stop bit is

sampled, the receiver starts looking for a new start bi t so that resynchronization can also be accomplished when

the transmitter is operating with one stop bit.

Figure 30-7 and Figure 30-8 illustrate start detection and character reception when USART operates in

Asynchronous mode.

D0 D1 D2 D3 D4 D5 D6 D7

TXD

Start

Bit Parity

Bit Stop

Bit

Example: 8-bit, Parity Enabled, One Stop

Baud Rate

Clock

D0 D1 D2 D3 D4 D5 D6 D7

TXD

Start

Bit Parity

Bit Stop

Bit

Baud Rate

Clock

Start

Bit

Write

US_THR

D0 D1 D2 D3 D4 D5 D6 D7 Parity

Bit Stop

Bit

TXRDY

TXEMPTY

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Figure 30-7. Asynchronous Start Detection

Figure 30-8. Asynchronous Character Reception

30.6.3.3 Synchronous Receiver

In Synchronous mod e (SYNC = 1), the receiver samples the RXD signal on each rising edge of the baud rate

clock. If a low level is detected, it is considered as a start. All data bits, the parity bit and the stop bits are sampled

and the receiver waits for the next start bit. Synchronous mode operations provide a high-speed transfer capability.

Configuration fields and bits are the same as in Asynchronous mode.

Figure 30-9 illustrates a character reception in Synchronous mode.

Figure 30-9 . Synchronous Mode Character Rec e ption

Sampling

Clock (x16)

RXD

Start

Detection

Sampling

Baud Rate

Clock

RXD

Start

Rejection

Sampling

12345678

123456701234

123456789 10111213141516D0

Sampling

D0 D1 D2 D3 D4 D5 D6 D7

RXD

Parity

Bit Stop

Bit

Example: 8-bit, Parity Enabled

Baud Rate

Clock

Start

Detection 16

samples 16

samples

D0 D1 D2 D3 D4 D5 D6 D7

RXD

Start

Sampling

Parity Bit Stop Bit

Example: 8-bit, Parity Enabled 1 Stop

Baud Rate

Clock

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30.6.3.4 Receiver Operations

When a character reception is completed, it is transferred to the Receive Holding register (US_RHR) and the

RXRDY bit in US_CSR rises. If a character is completed while the RXRDY is set, the OVRE (O verrun Er ror) bit is

set. The last character is transferred into US_RHR and ove rwrites the previous one. T he OVRE bit is cleared by

writing US_CR with the RSTSTA (Reset Status) bit to ‘1’.

Figure 30-10. Receiver Status

30.6.3.5 Parity

The USART supp orts five Parit y mode s that are se lected by writin g to t he PAR field in the U S_M R. T he PAR field

also enables the Multidrop mode, see Section 30.6.3.6 ”Multidrop Mode”. Even and odd parity bit generation and

error detection are supported.

If even parity is selected, the parity generator of the transmitter drives the parity bit to 0 if a number of 1s in the

character data bit is even, and to 1 if the number of 1s is odd. Accordingly, the receiver parity checker counts the

number of received 1s and reports a pa rity error if the sampled parity bit does not correspo nd. If odd parity is

selected, th e parity gen erator of the transmitt er drives the parity bit to 1 if a number of 1s in the character da ta bit

is even, and to 0 if the nu mber of 1 s is odd. Accordingl y, the r eceiver parity ch ecker counts the n umber of receive d

1s and reports a parity error if the sampled parity bit does not correspond. If the mark parity is used, the parity

generator of the transmitter drives the parity bit to 1 for all characters. The receiver parity checker reports an error

if the parity bit is sampled to 0. If the space parity is used, the parity generator of the transmitter drives the parity bit

to 0 for all characters. The receiver parity checker reports an error if the parity bit is sampled to 1. If parity is

disabled, the transmitter does not generate any parity bit and the receiver does not report any pa rity error.

Table 30-9 shows an example of the parity bit for the character 0x41 (character ASCII “A”) depending on the

configuration of the USART. Because there are two bits set to 1 in the character value, the parity bit is set to 1

when the parity is odd, or configured to 0 when the parity is even.

D0 D1 D2 D3 D4 D5 D6 D7

RXD

Start

Bit Parity

Bit Stop

Bit

Baud Rate

Clock

Write

US_CR

RXRDY

OVRE

D0 D1 D2 D3 D4 D5 D6 D7

Start

Bit Parity

Bit Stop

Bit

RSTSTA = 1

Read

US_RHR

Table 30-9. Parity Bit Example s

Character Hexadecimal Binary Parity Bit Parity Mod e

A 0x41 0100 0001 1 Odd

A 0x41 0100 0001 0 Even

A 0x41 0100 0001 1 Mark

A 0x41 0100 0001 0 Space

A 0x41 0100 0001 None None

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When the r eceiver detects a parity erro r, it sets the PA RE (Parity Error ) bit in the US_C SR. The PARE bit ca n be

cleared by writing the US_CR with the RSTSTA bit to ‘1’. Figure 30-11 illustrates the parity bit status setting and

clearing.

Figure 30-11. Parity Error

30.6.3.6 Multidrop Mode

If the value 0x6 or 0x07 is written to the PAR field in the US_MR, the USART runs in Multidrop mode. This mode

differentiates the data characters an d the address characters. Data is transmitted with the parity bit to 0 and

addresses are transmitted with the parity bit to 1.

If the USART is configured in Multid rop m ode, the receiver sets th e PARE parity error bit when the parity bi t is high

and the transmitter is able to send a character with the parity bi t high wh en a one is written to the SENTA bit in the

US_CR.

To handle parity error, the PARE bit is cleared when a one is writte n to the RSTSTA bit in the US_CR.

The transmitter sends an address byte (parity bit set) when SENDA is written to in the US_CR. In this case, the

next byte written to the US_THR is transmitted as an address. Any character written in the US_THR without having

written the command SENDA is transmitted normally with the parity to 0.

30.6.3.7 Transmitter Timeguard

The timeguard feature enables the USART interface with slow remote devices.

The timeguard function enables the transmitter to insert an idle state on the TXD line betwee n two characters. This

idle state actually acts as a long stop bit.

The duration of the idle state is programmed in the TG field of the Transmitter Timeg uard register (US_TTGR).

When this field is written to zero no timeguard is generated. Otherwise, the transmitter holds a high level on TXD

after each transmitted byte during the number of bit periods programmed in TG in addition to the number of stop

bits.

As illustrated in Figure 30-12, the behavior of TXRDY and TXEMPTY status bits is modified by the programming of

a timeguard. TXRDY rises only when the start bit of the next character is sent, and thus remains to 0 duri ng the

timeguard transmission if a character has been written in US_THR. TXEMPTY re mains low until the timeguard

transmission is completed as the timeguard is part of the current character being transmitted.

D0 D1 D2 D3 D4 D5 D6 D7

RXD

Start

Bit Bad

Parity

Bit

Stop

Bit

Baud Rate

Clock

Write

US_CR

PARE

RXRDY

RSTSTA = 1

Parity Error

Detect

Time Flags

Report

Time

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Figure 30-12. Timegua rd Operations

Table 30-10 indicates the maximum length of a timeguard period that the transmitter can handle in relation to the

function of the baud rate.

30.6.3.8 Receiver Timeout

The Receiver Timeout provides support in handling variable-length frames. This feature detects an idle condition

on the RXD line. When a timeout is detected, the bit TIMEOUT in the US_CSR rises and can generate an

interrupt, thus indicating to the driver an end of frame.

The timeout delay peri od (during which the receiver waits for a new ch aracter) is pr ogrammed in the T O field of the

Receiver Timeout register (US_RTOR). If the TO field is written to 0, the Receiver Timeout is disabled and no

timeout is detected. The TIMEOUT bit in the US_CSR remains at 0. Otherwise, the receiver loads a 16-bit counter

with the value programmed in TO. This counter is decremented at each bit period and reloaded each time a new

character is received. If the counter reaches 0, the TIMEOUT bit in US_CSR rises.

Then, the user can either:

Stop the counter clock until a new character is received. This is performed by writing a ‘1’ to the STTTO

(S t art Timeout) bit in the US_CR. In this case, the idle st ate on RXD before a new character is re ceived does

not provide a tim eout. This prevents having to handle an interrupt b efore a ch aracter i s received, and allo ws

waiting for the next idle state on RXD after a frame is received.

Obtain an interrupt while no character is received. This is performed by writing a ‘1’ to the RET TO (Reload

and Start Timeout) bit in the US_CR. If RETTO is performed, the counter starts counting down immediately

from the value T O. This en ables ge nerat ion of a periodic inte rrupt so that a user timeo ut can be ha ndled, for

example when no key is pressed on a keyboard.

D0 D1 D2 D3 D4 D5 D6 D7

TXD

Start

Bit Parity

Bit Stop

Bit

Baud Rate

Clock

Start

Bit

TG = 4

Write

US_THR

D0 D1 D2 D3 D4 D5 D6 D7 Parity

Bit Stop

Bit

TXRDY

TXEMPTY

TG = 4

Table 30-10. Maximum Timegua rd Length Depending on Baud Rate

Baud Rate (Bit/s) Bit Time (µs) Timeguard (ms)

1,200 833 212.50

9,600 104 26.56

14,400 69.4 17.71

19,200 52.1 13.28

28,800 34.7 8.85

38,400 26 6.63

56,000 17.9 4.55

57,600 17.4 4.43

115,200 8.7 2.21

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Figure 30-13 shows the block diagram of the Receiver Tim eout feature.

Figure 30-13. Rece iver Timeout Block Diagram

Table 30-11 gives the maximum timeout period for some standard baud rates.

30.6.3.9 Framing Error

The receiver is capable of detecting framing errors. A framing e rror happens when the stop bit of a received

character is detected at level 0. This can occur if the receiver and the transmitter are fully desynchronized.

A framing error is reported on the FRAME bit of US_CSR. The FRAME bit is asserted in the middle of the stop bit

as soon as the framing error is detected. It is cleared by writing US_CR with the RSTSTA bit to ‘1’.

Table 30-11. Maximum Timeout Period

Baud Rate (Bit/s) Bit T ime (µs) T imeo ut (ms)

600 1,667 109,225

1,200 833 54,613

2,400 417 27,306

4,800 208 13,653

9,600 104 6,827

14,400 69 4,551

19,200 52 3,413

28,800 35 2,276

38,400 26 1,704

56,000 18 1,170

57,600 17 1,138

200,000 5 328

16-bit Timeout

Counter

TIMEOUT

Baud Rate

Clock

Character

Received

RETTO

Load

Clock

16-bit

Value

STTTO

Clear

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Figure 30-14. Framing Error Status

30.6.3.10 Transmit Break

The user can request the transmitter to generate a break condition on the TXD line. A break condition drives the

TXD line low during at least one complete character. It appears the same as a 0x00 character sent with the parity

and the stop bits to 0. However, the transmitter holds the TXD line at least during one character until the user

requests the break condition to be removed.

A break is transmitted by writing US_CR with the STTBRK bit to ‘ 1’. This can be performed at any ti me, either while

the transmitter is empty (no character in either the Shift register or in US_THR) or when a character is being

transmitted. If a break is r equested while a character is being sh ifted out, the cha racter is first completed befo re the

TXD line is held low.

Once STTBRK command is requested further STTBRK commands are ignored until the end of the break is

completed.

The break condition is removed by writing US_CR with the STPBRK bit to ‘1’. If the STPBRK is requested before

the end of the minimum bre ak duration (one character, including start , data, parity and stop bits), the transmitter

ensures that the break condition completes.

The transmitter co nsiders the break as though it is a character, i.e., the STTBRK and STPBRK commands are

taken into account only if the TXRDY bit in US_CSR is to ‘1’ and the start of the break condition clears the TXRDY

and TXEMPTY bits as if a character is processed.

Writing US_CR with both STTBRK and STPBRK bits to ’1’ can lead to an unpredictable result. All STPBRK

commands request ed wi thout a pr eviou s STTB RK comman d ar e ignored. A byte written into the Transmit Holding

After the break condition, the transmitter returns the TXD line to 1 for a minimum of 12 bit times. Thus, the

transmitter ensures that the remote receiver detects correctly the end of break and the start of the next character.

If the timeguard is programmed with a value higher than 12, the TXD line is held high for the timeguard period.

After holding the TXD line for this period, the transmitter resumes normal operations.

Figure 30-15 illustrates the effect of both the Start Break (STTBRK) and Stop Break (STPBRK) commands on the

TXD line.

D0 D1 D2 D3 D4 D5 D6 D7

RXD

Start

Bit Parity

Bit Stop

Bit

Baud Rate

Clock

Write

US_CR

FRAME

RXRDY

RSTSTA = 1

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Figure 30-15. Break Transmission

30.6.3.11 Receive Break

The receiv er dete cts a brea k con ditio n whe n all d ata, par ity a nd s top bi ts are lo w. Th is corresponds to detecting a

framing error with data to 0x00, but FRAME remains low.

When the low stop bit is detected, the receiver asserts the RXBRK bit in US_CSR. This bit may be cleared by

writing US_CR with the bit RSTSTA to ’1’.

An end of receive b reak is detected by a high level for at least 2 /16 of a bit peri od in Asynchronous op erating mode

or one sample at high level in Synchronous operating mode. The end of break detection also asserts the RXBRK

bit.

30.6.3.12 Hardware Handshaking

The USART features a hardware handshaking out-of-band flow control. The RTS and CTS pins are used to

connect with the remote device, as shown in Figure 30-16.

Figure 30-16. Connection with a Remote Device for Hardware Handshaking

Setting the USART to operate with hardware handshaking is performed by writing the USART_MODE field in

US_MR to the value 0x2.

The USART behavior when hardware handshaking is enabled is the same as the behavior in standard

Synchronous or Asynchronous mode, except that the receiver drives the RTS pin as described below and the level

on the CTS pin modifies the behavior of the transmitter as described below. Using this mode requires using the

PDC channel for reception. The transmitter can handle hardware handshaking in any case.

D0 D1 D2 D3 D4 D5 D6 D7

TXD

Start

Bit Parity

Bit Stop

Bit

Baud Rate

Clock

Write

US_CR

TXRDY

TXEMPTY

STPBRK = 1

STTBRK = 1

Break Transmission End of Break

USART

TXD

CTS

Remote

Device

RXD

TXDRXD

RTS

CTS

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Figure 30-17. RTS Lin e Softwa re Control when US_MR.USART_MODE = 2

Figure 30-18 shows how the receiver operates if hardware handshaking is enabled. The RTS pin is driven high if

the receiver is disabled and if the status RXBUFF (Receive Buffer Full) coming from the PDC channel is high.

Normally, the remote device does not start transmitting while its CTS pin (driven by RTS) is high. As soon as the

receiver is enabled, the RTS falls, indicating to the remote device that it can start transmitting. Defining a new

buffer to the PDC clears the status bit RXBUFF and, as a result, asserts the pin RTS low.

Figure 30-18. Rece iver Behavior when Operating with Hardware Handshaking

Figure 30-19 shows how the transmitter operates if hardware handshaking is enabled. The CTS pin disables the

transmitter. If a character is being processed, the transmitter is disabled only after the completion of the current

character and transmission of the next character happens as soon as the pin CTS falls.

Figure 30-19. Transmitter Behavior when Operating with Hardware Handshaking

30.6.4 ISO7816 Mode

The USART features an ISO7816-compat ib le operat ing mode. This mo de permits inte rfacing with smart cards and

Security Access Modules (SAM) communicating through an ISO7816 link. Both T = 0 and T = 1 protocols defined

by the ISO7816 specification are supported.

Setting the USART in ISO7816 mode is perfor med by writing US_MR.USART_MODE to the value 0 x 4 for pr otocol

T = 0 and to the value 0x6 for protocol T = 1.

30.6.4.1 ISO7816 Mode Overview

The ISO7816 is a half duplex commu nication on only one bidirectional line. The baud rate is determ ined by a

division of the clock provided to the remote device (see Section 30-2 ”Baud Rate Generator”).

The USART connects to a smart card a s shown in Figure 30-20. The TXD line becomes bidirection al and the baud

rate generator feeds the ISO7816 clock on the SCK pin. As the TXD pin becomes bidirectional, its output remains

driven by the output of the transmitter but only when the transmitter is active while its input is directed to the input

of the receiver. The USART is considered as the master of the communication as it generate s the clock.

RTS

Write

US_CR.RTSDIS

RXD

Write

US_CR.RTSEN

RTS

RXBUFF

Write

US_CR

RXEN = 1

RXD RXDIS = 1

CTS

TXD

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Figure 30-20. Connection of a Smart Card to the USART

When operatin g in ISO7816, either in T = 0 o r T = 1 modes, the charact er format is fixed. Th e configuration is 8

data bits, even parity and 1 or 2 stop bits, regardless of the values programmed in the CHRL, MODE9, PAR and

CHMODE fields. US_MR.MSBF can be used to transmit LSB or MSB first. US_MR.PAR can be used to transmit in

Normal or Inverse mode. See Section 30.7.3 ”USART Mode Register” and “PAR: Parity Type” .

The USART cannot operate concurrently in both Receiver and Transmitter modes as the communication is

unidirectional at a time. It has to be configured according to the required mode by enabling or disabling either the

receiver or the transmitter as desired. Enabling both the receiver and the transmitter at the same time in ISO7816

mode may lead to unpredictable results.

The ISO7816 specification defines an inverse transmission format. Data bits of the character must be transmitted

on the I/O line at their negative value.

30.6.4.2 Protocol T = 0

In T = 0 protocol, a character is made up of one start bit, eight data bits, one parity bit and one guard time, which

lasts two bit times. The transmitter shifts out the bits and does not drive the I/O line during the guard time.

If no parity error is detected, the I/O line remains to 1 during the guard time and the transmitter can continue with

the transmission of the next character, as shown in Figure 30-21.

If a parity error is detected by the receiver, it drives the I/O line to 0 during the guard time, as shown in Figure 30-

22. This error bit is also named NA CK, for Non Acknowledge. In this case, the character lasts 1 bit time more, as

the guard time length is the same and is added to the error bit time which lasts 1 bit time.

When the USART is the receiver and it detects an error, it does not load the erroneous character in the US_RHR.

It sets US_SR.PARE so that the software can handle the error.

Figure 30-21. T = 0 Protocol without Parity Error

Figure 30-22. T = 0 Protocol with Parity Error

Smart

Card

SCK CLK

TXD I/O

USART

D0 D1 D2 D3 D4 D5 D6 D7

RXD

Parity

Bit

Baud Rate

Clock

Start

Bit Guard

Time 1 Next

Start

Bit

Guard

Time 2

D0 D1 D2 D3 D4 D5 D6 D7

I/O

Parity

Bit

Baud Rate

Clock

Start

Bit Guard

Time 1 Start

Bit

Guard

Time 2 D0 D1

Error

Repetition

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Receive Error Counter

The USART receiver also records the total number of errors. This can be read in the Number of Error (US_NER)

NB_ERRORS field.

Receive NACK Inhibit

The USART can also be configured to inhibit an error. This can be achieved by writing a ‘1’ to the

USART_MR.INACK. In this case, no error signal is driven on the I/O line even if a parity bit is detected.

Moreover, if INACK = 1, the erroneous received character is stored in the US_RHR, as if no error occurred and the

RXRDY bit rises.

Transmit Character Repetition

When the USART is transmitting a character and gets a NACK, it can automatically repeat the character before

moving on to the next o ne. Repe tition is enabled by writing th e US_MR.MAX_ITERATION to a value higher than 0.

Each character can be transmitted up to eight times; the first transmission plus seven repetitions.

If MAX_ITERATION does not equal zero, the USART repeats the character as many times as the value loaded in

MAX_ITERATION.

When the USART repetition number reaches MAX_ITERATION, and the last repeated character is not

acknowledged, US_CSR.ITER is set. If the repetition of the character is acknowledged by the receiver, the

repetitions are stopped and the iteration counter is cleared.

US_CSR.ITER can be cleared by writing a ‘1’ to US_CR.RSTIT.

Disable Successive Receive NACK

The receiver can limit the number of successive NACKs sent back to the remote transmitter. This is programmed

by setting US_MR.DSNACK. The maximum number of NACKs transmitted is configured in

US_MR.MAX_ITERATION . As soon as MAX_ITERATION is reached, no error signal is driven on the I/O line and

US_CSR.ITER is set.

30.6.4.3 Protocol T = 1

When operating in ISO7816 protocol T = 1, the transmission is similar to an asynchronous format with only one

stop bit. The parity is generated when transmitting and checked when receiving. Parity error detection sets

US_CSR.PARE.

30.6.5 IrDA Mode

The USART features an IrDA mode supplying half-duplex point-to-point wireless communication. It embeds the

modulator and demodulator which allows a glueless connection to the infrared transceivers, as shown in Figure

30-23. The modulator and demodulator are compliant with the IrDA specification version 1.1 and support data

transfer speeds ranging from 2.4 kbit/s to 115.2 kbit/s.

The USART IrDA mod e is enabled by setting US_MR.USAR T_MODE to the value 0 x8. The IrDA Filter register

(US_IF) is used to configure the demodulator filter. The USART transmitter and receiver operate in a normal

Asynchronous mode and all parameters are accessible. Note that the modulator and the demodulator are

activated.

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Figure 30-23. Connection to IrDA Transceivers

The receiver and the transmitter must be enabled or disabled depending on the direction of the transmission to be

managed.

To receive IrDA signals, the following must be done:

Disable TX and enable RX.

Configure th e TXD pin as PIO and set it as an output to 0 (to avoid LED transmission). Disable the internal

pull-up (better for power consumption).

Receive data.

30.6.5.1 IrDA Modulation

For baud rates up to and including 115.2 kbit/s, the RZI modulation scheme is used. “0” is represented by a light

pulse of 3/16th of a bit time. Some examples of signal pulse duration are shown in Table 30-12.

Figure 30-24 shows an example of character transmission.

Figure 30-24. IrDA Modulation

IrDA

Transceivers

RXD RX

TXD TX

USART

Demodulator

Modulator

Receiver

Transmitter

Table 30-12. IrDA Pulse Duration

Baud Rate Pulse Duration (3/16)

2.4 kbit/s 78.13 µs

9.6 kbit/s 19.53 µs

19.2 kbit/s 9.77 µs

38.4 kbit/s 4.88 µs

57.6 kbit/s 3.26 µs

115.2 kbit/s 1.63 µs

Bit Period Bit Period

Start

Bit Data Bits Stop

Bit

000

111 1

Transmitter

Output

TXD

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30.6.5.2 IrDA Baud Rate

Table 30-13 gives some examples of CD values, baud rate error and pulse duration. Note that the requirement on

the maximum acceptable error of ±1.87% must be met.

Table 30-13. IrDA Baud Rate Error

Peripheral Clock Baud Rate (Bit/s) CD Baud Rate Error Pulse Time (µs)

3,686,400 115,200 2 0.00% 1.63

20,000,000 115,200 11 1.38% 1.63

32,768,000 115,200 18 1.25% 1.63

40,000,000 115,200 22 1.38% 1.63

3,686,400 57,600 4 0.00% 3.26

20,000,000 57,600 22 1.38% 3.26

32,768,000 57,600 36 1.25% 3.26

40,000,000 57,600 43 0.93% 3.26

3,686,400 38,400 6 0.00% 4.88

20,000,000 38,400 33 1.38% 4.88

32,768,000 38,400 53 0.63% 4.88

40,000,000 38,400 65 0.16% 4.88

3,686,400 19,200 12 0.00% 9.77

20,000,000 19,200 65 0.16% 9.77

32,768,000 19,200 107 0.31% 9.77

40,000,000 19,200 130 0.16% 9.77

3,686,400 9,600 24 0.00% 19.53

20,000,000 9,600 130 0.16% 19.53

32,768,000 9,600 213 0.16% 19.53

40,000,000 9,600 260 0.16% 19.53

3,686,400 2,400 96 0.00% 78.13

20,000,000 2,400 521 0.03% 78.13

32,768,000 2,400 853 0.04% 78.13

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30.6.5.3 IrDA Demodulator

The demodulator is based on the IrDA Receive filter comprised of an 8-bit down counter which is loaded with the

value programmed in US_IF. When a falling edge is detected on the RXD pin, the Filter Counter starts counting

down at the peripheral clock speed. If a rising edge is detected on the RXD pin, the counter stops and is reloaded

with US_IF. If no rising edge is detected when the counter reaches 0, the input of the receiver is driven low during

one bit time.

Figure 30-25 illustrates the operations of the IrDA demodulator.

Figure 30-25. IrDA Demodulator Operations

The program m ed valu e in the U S_I F re gister must always mee t th e follo win g criteria :

tperipheral clock* (IRDA_FILTER + 3) < 1.41 µs

As the IrDA mode uses the same logic as the ISO7816, note that US_FIDI.FI_DI_RATIO must be set to a value

higher than 0 in order to make sure that IrDA communications operate correctly.

30.6.6 USART Comparison Function on Received Character

The effect of a comparison match changes if the system is in Wait or Active mode.

In Wait mode, if asynchronous partial wakeup is enabled, a system wakeup is performed (see Section 30.6.7

”USART Asynchronous and Partial Wakeup (SleepWalking)”).

In Active mode, the CM P flag in US_CSR is raised. It is set when the received chara cter matches the conditions

programmed in the USART Compar ison Register (US_CMPR). The CMP flag is set as soon as US_RHR is loaded

with the new received character. The CMP flag is cleared by writing a one to the RSTSTA bit in US_CR.

US_CMPR (see Section 30.7.28 ”USART Comparison Register”) can be programmed to provide different

comparison methods, as described below:

If VAL1 equals VAL2, then the comparison is performed on a single value and the flag is set to ’1’ if the

received character equals VAL1.

If VAL1 is strictly lower than VAL2, then any value between VAL1 and VAL2 sets the CMP flag.

If VAL1 is strictly higher than VAL2, then the CMP flag is set to ’1’ if any received character equals VAL1 or

VAL2.

When the CMPMODE bit is cleared in US_CM PR register, all received data is loaded in US_RHR and the CMP

flag is providing th e sta tu s of th e com p ar iso n re su lt.

By setting the CMPMODE bit, the comparison result triggers the start of the US_RHR loading (see Figure 30-26).

The trigger condition exists as soon as the received character value matches the conditions defined by VAL1,

VAL2 and CMPPAR in US_CMPR. The comparison trigger event is restarted by writing a ’1’ to the REQCLR bit in

US_CR.

The value programmed in VAL1 and VAL2 fields must not exceed the maximum value of the received character

(see CHRL field in US_MR).

MCK

RXD

Receiver

Input

Pulse

Rejected

65432 61

65432 0

Pulse

Accepted

Counter

Value

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Figure 30-26. Receive Holding Register Management

30.6.7 USART Asynchronous and Partial Wakeup (SleepWalking)

This operating mode is a means of data preprocessing that qualifies an incoming event, thus allowing the USART

to decide whether or not to wake up the system. Asynchronous and partial wakeup is mainly used when the

system is in Wait mode (refer to the section “Power Management Controller (PMC)” for details). It can also be

enabled when the system is fully running.

Asynchronous and partial wakeup (SleepWalking) requires the USART module to be programmed in UART mode

(SYNC=0 in US_MR).

The maximum USART bit rate that can be achieved when asynchron ous and partial wakeup is enabled is 19200.

The US_RHR must be read before enabling the asynchronous and partial wakeup.

When asynchronous and partial wakeup is enabled for the USART (refer to the section “Power Management

Controller (PMC)”), the PMC decodes a clo ck request from the USART. The request is generate d as soon as ther e

is a falling edge on the RXD line as this may indicate the be ginning of a start bit. If the system is in Wait mode

(processor and peripheral clocks switched off), the PMC restarts the fast RC oscillator and provides the clock only

to the USART.

As soon as the clock is provided by the PMC, the USART processes the received frame and compares the

received character with VAL1 and VAL2 in US_CMPR (Section 30.7.28 ”USART Comparison Register”).

The USART instructs the PMC to disable the peripheral clock if the received character value does not meet the

conditions defined by the VAL1 and VAL2 fields in US_CMPR (see Figure 30-28).

If the received character value meets the conditions, the USART instructs the PMC to exit the system from Wait

mode (see Figure 30-27).

The VAL1 and VAL2 fields can be programmed to provide different comparison methods and thus matching

conditions.

If VA L 1 equa ls VAL2, the n the compariso n is perfo rm e d on a single value and the wakeup is triggered if the

received character equals VAL1.

If VAL1 is strictly lower than VAL2, then any value between VAL1 and VAL2 wakes up the system.

If VAL1 is strictly higher than VAL2, then the wakeup is triggered if any received character equals VAL1 or

VAL2.

If VAL1 = 0 and VAL2 = 511, the wakeup is triggered as soon as a character is received .

RXD

0x0F 0x06

CMPMODE = 1, VAL1 = VAL2 = 0x06

RXRDY rising enabled

0xF0 0x08 0x06

Peripheral

Clock

Write REQCLR

RHR

0x06 0xF0 0x06

RXRDY

0x080x0F

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The matching condition can be configure d to include the parity bit (US_CMPR.CMPPAR). Thus, if the received

data matches the comparison condition de fin ed by VAL 1 an d VAL2 but a p ari ty erro r is en co untered , the ma tching

condition is cancelle d an d the USAR T instructs the PMC to disable th e cloc k (se e Figure 30-28).

If the processor and peripherals are running, the USART can be configured in Asynchr onous and Partial Wakeup

mode by enabling the PMC_SLPWK_ER (refer to the section “Power Management Controller (PMC)”). When

some activity is detected on the receive line, the USART requests the clock from the PMC and the comparison is

performed. If there is a comparison match, the USART continues to requ est the clock. If there is no match, the

clock is switched off for the USART only, until a new activity is detected.

The CMPMODE config uration has no effect when Asynchronous and Partial Wakeup mode is en abled for the

USART (refer to register PMC_SLPWK_ER in the section “Power Management Controller (PMC)”).

When the system is in Active mode and the USART enters Asynchronous and Partial Wakeup mode, the RXRDY

flag must be programmed as the unique source of the USART interrupt.

When the system exits Wait mod e as the r esult of a matching condition, the RXRDY flag is used to determine if the

USART is the source for the exit from Wait mode.

Figure 30-27. Asynchronous Wakeup Use Case Examples

D0 D1 D7

RHR = 0x55,

VAL1 = 0x55

=> match

and Parity

D0 D1 D7

RHR = 0x55,

VAL1 = 0x54, VAL2 = 0x56

=> match

and Parity

D0 D1 D7

RHR = 0x75,

VAL1 = 0x75

=> match

Case with VAL1 = VAL2 = 0x55, CMPPAR = 1

RXD

Idle Start Parity = OK Stop

PCLK_req

PCLK

(Main RC)

SystemWakeUp_req

Case with VAL1 = 0x54, VAL2 = 0x56, CMPPAR = 1

RXD

Idle Start Parity = OK Stop

PCLK_req

PCLK

(Main RC)

SystemWakeUp_req

Case with VAL1 = 0x75, VAL2 = 0x76, CMPPAR = 0

RXD

Idle Start Parity = NOK Stop

PCLK_req

PCLK

(Main RC)

SystemWakeUp_req

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Figure 30-28. Asynchro no us Event Generating Only Partial Wakeup

30.6.8 SPI Mode

The USART embeds a mode providing a basic Serial Peripheral Interface (SPI).

The SPI bus used in this SPI mode is a synchronous serial data link that provides communication with external

devices in Master or Slave mode. It also e nables communication b etween processors if an extern al processor is

connected to the system.

The Serial Peripheral Interface is essentially a shift register that serially transmits data bits to other SPIs. During a

data transfer, one SPI system acts as the “master” which controls the data flow, while the other devices act as

“slaves'' which have data shifted into and out by the master. Different CPUs can take turns being masters and one

master may simultaneously shif t data into multiple slaves. (Multiple master protocol is the opposite of single

master protocol, where one CPU is always the master while all of the others are always slaves.) However, only

one slave may drive its output to write data back to the master at any given time.

A slave device is selected when its NSS signal is asserted by the master. The USART in SPI Master mode can

address only one SPI slave because it can generate only one NSS signal.

The SPI system consists of two data lines and two control lines:

Master Out Slave In (MOSI): This data line supplies the output data from the master shifted into the input of

the slave.

Master In Slave Out (MISO): This data line supplies the output data from a slave to the input of the master.

Serial Clock (SCK): This control line is driven by the master and regulates the flow of the data bits. The

master may transmit data at a variety of bit rates. The SCK line cycles once for each bit that is transmitted.

Slave Select (NSS): This control line allows the master to select or deselect the slave.

D0 D1 D7

RHR = 0xF5,

VAL1/2 = 0xF5

=> match

RHR = 0x85,

VAL1 = 0x00

=> no match

Case with VAL1 = VAL2 = 0x00, CMPPAR = Don’t care

RXD

PCLK_req

PCLK

(Main RC)

SystemWakeUp_req

Idle Start Parity Stop

Case with VAL1 = 0xF5, VAL2 = 0xF5, CMPPAR = 1

RXD

PCLK_req

PCLK

(Main RC)

SystemWakeUp_req

Idle Start Stop

Parity = NOK

DATA match

and Parity NOK

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30.6.8.1 Modes of Operation

The USART can operate in SPI Master mode or in SPI Slave mode.

Operation in SPI Master mode is programmed by writing 0xE to the USART_MODE field in US_MR. In this case,

the SPI lines must be connected as described below:

The MOSI line is driven by the output pin TXD.

The MISO line drives the input pin RXD.

The SCK line is driven by the output pin SCK.

The NSS line is driven by the output pin RTS.

Operation in SPI Slave mode is programm ed by writing 0xF to the USART_MODE field in US_MR. In this case, the

SPI lines must be connected as described below:

The MOSI line drives the input pin RXD.

The MISO line is driven by the output pin TXD.

The SCK line drives the input pin SCK.

The NSS line drives the input pin CTS.

In order to avoid u npredicted behavior, any ch ange of the SPI mode mu st be followed by a software reset of the

transmitter and of the receiver (except the initial configuration after a hardware reset). See Section 30.6.8.4

”Receiver and Transmitter Control”.

30.6.8.2 Bit Rate

In SPI mode, the bit rate generator operates in the same way as in USART Synchronous mode (see Section

30.6.1.3 ”Baud Rate in Synch ronous Mode or SPI Mode”). However, some restrictions apply:

In SPI Master mode:

The external clock SCK must not be selected (USCLKS ≠ 0x3), and bit CLKO must be set to ‘1’ in the

US_MR, in order to generate correctly the serial clock on the SCK pin.

To obtain correct behavior of the receiver and the transmitter, the value programmed in CD must be greater

than or equal to 6.

If the divided peripheral clock is selected, the value pro grammed in CD must be even to ensure a 50:50

mark/space ratio on the SCK pin; this value can be odd if the periph eral clock is selected.

In SPI Slave mode:

The external clock (SCK) selection is forced regardless of the value of the USCLKS field in the US_MR.

Likewise, the value written in US_BRGR has no effect, because the clock is provided directly by the signal

on the USART SCK pin.

To obtain correct beha vior of th e receiver and the transmitter, the external clock (SCK) frequency must be at

least 6 times lower than the system clock.

30.6.8.3 Data Transfer

Up to nine data bits are successively shifted out on the TXD pin at each rising or falling edge (depending of CPOL

and CPHA) of the programmed serial clock. There is no Start bit, no Parity bit and no Stop bit.

The number of data bits is selected by the CHRL field and the MODE 9 bit in the US_MR. The nine bits are

selected by setting the MODE 9 bit regard less of the CHRL fi eld. The MSB data bit is always sent first in SPI mode

(Master or Slave).

Four combinations of polarity and phase are availab le for data transfers. The clock po larity is prog rammed with the

CPOL bit in the US_MR. The clock phase is programmed with the CPHA bit. These two parameters determine the

edges of the clock signal upon which data is driven and sampled. Each of the two parameters has two possible

states, resulting in four possible combinations that are incompatible with one another. Thus, a master/slave pair

must use the same parameter pair values to communicate. If multiple slaves are used and fixed in different

configurations, the master must reconfigure itself each time it needs to communicate with a different slave.

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Figure 30-29. SPI Trans f er Format (CPHA = 1, 8 bits per transfer)

Table 30-14. SPI Bus Protocol Mode

SPI Bus Protocol Mode CPOL CPHA

001

100

211

310

SCK

(CPOL = 0)

SCK

(CPOL = 1)

MOSI

SPI Master ->TXD

SPI Slave -> RXD

NSS

SPI Master -> RTS

SPI Slave -> CTS

SCK cycle (for reference)

MSB

LSB

1 2345 786

MISO

SPI Master ->RXD

SPI Slave -> TXD

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Figure 30-30. SPI Trans f er Format (CPHA = 0, 8 bits per transfer)

30.6.8.4 Receiver and Transmitter Control

See Section 30.6.2 ”Receiver and Transmitter Control”.

30.6.8.5 Character Transmission

The characters are sent by writing in US_THR. An additional condition for transmitting a character can be added

when the USART is configured in SPI Master mode. In the “USART Mode Register (SPI_MODE)” (USART_MR),

the value configured on WRDBT can pre vent an y cha racter transmission (even if US_THR has been written) while

the receiver side is not ready (character not read). When WRDBT equals ‘0’, the character is transmitted whatever

the receiver status. If WRDBT is set to ‘1’, the transmitter waits for the US_RHR to be read before transmitting the

character (RXRDY flag cleared), thus preventing any overflow (character loss) on the receiver side.

The chip select line is deasserted for a period equivalent to three bits between the transmission of two data.

The transmitter reports two status bits in US_CSR: TXRDY (Transmitter Ready), which indicates that US_THR is

empty and TX EMPTY, which indicate s that all the char acters wr itten in US_THR h ave been pr ocessed . When the

current character processing is completed, the last character written in US_THR is transferred into the Shift

Both TXRDY and TXEMPTY bits are low when the transmitter is disabled. Writing a character in US_THR while

TXRDY is low has no effect and the written character is lost.

If the USART is in SPI Slave mode and if a character must be sent while the US_THR is empty, the UNRE

(Underrun Error) bit is set. The TXD transmission line stays at high level during all this time. The UNRE bit is

cleared by writing a one to the RSTSTA (Reset Status) bit in US_CR.

In SPI Master mode, the slave select line (NSS) is asserted at low level 1 tbit (Time bit) before the transmission of

the MSB bit and released at high level 1 tbit after the transmission of the LSB bit. So, the slave select line (NSS) is

always released betwee n each charac ter transm ission and a mi nimum de lay of 3 t bit always inserted. However, in

order to address slave devices su pporting the CSAAT mode (C hip Select Active After Transfer), the slave select

line (NSS) can be forced at low level by writing a one to the RTSEN bit in the US_CR. The slave se lect lin e ( NSS)

can be released at high level only by writing a one to the RTSDIS bit in the US_CR (for example, when all data

have been transferred to the slave device).

SCK

(CPOL = 0)

SCK

(CPOL = 1)

1 2345 7

MOSI

SPI Master -> TXD

SPI Slave -> RXD

MISO

SPI Master -> RXD

SPI Slave -> TXD

NSS

SPI Master -> RTS

SPI Slave -> CTS

SCK cycle (for reference) 8

MSB

LSB

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In SPI Slave mode, the transmitter does not require a falling edge of the slave select line (NSS) to initiate a

character transmission but only a low level. However, this low level must be present on the slave select line (NSS)

at least 1 tbit before the first serial clock cycle corresponding to the MSB bit.

30.6.8.6 Character Reception

When a character reception is completed, it is transferred to the US_RHR and the RXRDY bit in the Status register

(US_CSR) ris es. If a character is co mpleted while RXRDY is set, the OVRE (Overrun Error) bit is set. The last

character is tr ansferred in to US_RHR an d overwrites the previous one. T he OVRE bit is clear ed by writing a one to

the RSTSTA (Reset Status) bit in the US_CR.

To ensure correct behavior of the receiver in SPI Slave mode, the master device sending the frame must ensure a

minimum delay of 1 tbit between each character transmission. The re ceiver does not require a falling edge of the

slave select line (NSS) to initiate a character reception but only a low level. However, this low level must be

present on the slave select line (NSS) at least 1 tbit before the first serial clock cycle corresponding to the MSB bit.

30.6.8.7 Receiver Timeout

Because the receiver bit rate clock is active only during data transfers in SPI mode, a receiver timeout is

impossible in this mode, whatever the timeout value is (field TO) in the US_RTOR.

30.6.9 LIN Mode

The LIN mode provides master node and slave node connectivity on a LIN bus.

The LIN (Local Inte rconnect Network) is a serial communication protocol which efficiently supports the con trol of

mechatronic nodes in distributed automotive applications.

The main properties of the LIN bus are:

Single master/multiple slaves concept

Low-cost silicon implementation based on common UART/SCI interface hardware, an equivalent in

software, or as a pure state machine.

Self synchronization without quartz or ceramic resonator in the slave nodes

Deterministic signal transmission

Low cost single-wire implementation

Speed up to 20 kbit/s

LIN provides cost efficient bus communication where the bandwidth and versatility of CAN are not required.

The LIN mode enables processing LIN frames with a minimum of action from the microprocessor.

30.6.9.1 Modes of Operation

The USART can act either as a LIN master node or as a LIN slave node.

The node configuration is selected by configuring US_MR.USART_MODE:

LIN master node (USART_MODE = 0xA)

LIN slave node (USART_MODE = 0xB)

In order to avoid unpredicted behavior, any change of the LIN node configuration must be followed by a software

reset of the transmitter and of the receiver (except the initial node configuration after a hardware reset). See

Section 30.6.9.3 ”Receiver and Transmitter Control”.

30.6.9.2 Baud Rate Configuration

See Section 30.6.1.1 ”Baud Rate in Asynchronous Mode”.

LIN master node: The baud rate is configured in US_BRGR.

LIN slave node: The in itial baud rate is configured in US_BRGR. This configuration is automatically copied in

the LIN Baud Rate register (US_LI NBRR) when writing US_BRGR. After the synchronization procedure, the

baud rate is updated in US_LINBRR.

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30.6.9.3 Receiver and Transmitter Control

See Section 30.6.2 ”Receiver and Transmitter Control”.

30.6.9.4 Character Transmission

See Section 30.6.3.1 ”Transmitter Operations”.

30.6.9.5 Character Reception

See Section 30.6.3.4 ”Receiver Operations”.

30.6.9.6 Header Transmission (master Node Configuration)

All the LIN Frames start with a header which is sent by the Master node and consists of a Synch Break Field,

Synch Field and Identifier Field.

So in Master node configuration, the frame handling starts with the sending of the header.

The header is transmitted as soon as the identifier is written in the USART LIN Iden tifier register (US_LINIR). At

this moment the flag TXRDY falls.

The Break Field , th e Sy nc h Fie ld an d the Identifier Field are sent automatically one after the ot he r.

The Break Field consists of 13 dominant bits and 1 recessive bit, the Synch Field is the character 0x55 and the

Identifier corresponds to the character written in US_LINIR. The Identifier parity bits can be automatically

computed and sent (see Section 30.6.9.9 ”Identifier Parity”).

The flag TXRDY rises when the identifier character is transferred into the Shift register of the transmitter.

As soon as the Synch Break Field is transmitted, US_CSER.LINBK is set to ’1’. Likewise, as soon as the Identifier

Field is sent, the flag bit US_CSR.LINID is set to ’1’. These flags are reset by writing a o ne to US_CR.RSTSTA.

Figure 30-31. Header Transmission

30.6.9.7 Header Reception (Slave Node Configuration)

All the LIN frames start with a h eader which is sen t by th e master node and con sists of a Synch Break Field, Synch

Field and Iden tifie r Field .

In slave node c onfig ur a tion , th e fra m e ha nd lin g sta rt s with th e re ce ptio n of the hea d er.

The USART uses a break detection threshold of 11 nomina l bit times at the actual baud rate. At any time, if 11

consecutive recessive bits are detected on the bus, the USART detects a Break Field. As long as a Break Field

has not been detected, the USART stays idle and the received data are not taken in account.

TXD

Baud Rate

Clock

Start

Bit

Write

US_LINIR

10101010

TXRDY

Stop

Bit Start

Bit ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7Break Field

13 dominant bits (at 0)

Stop

Bit

Break

Delimiter

1 recessive bit

(at 1)

Synch Byte = 0x55

US_LINIR ID

LINID

in US_CSR

LINBK

in US_CSR

Write RSTSTA=1

in US_CR

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When a Break Field has be en detecte d, th e flag LINBK in US_CSR is set to ’1’ and the USART expects the Synch

Field character to be 0x55. This field is used to update the actual baud rate in order to stay synchronized (see

Section 30.6.9.8 ”Slave Node Synchronization”). If the received Synch character is not 0x55, an Inconsistent

Synch Field error is generated (see Section 30.6.9.14 ”LIN Errors”).

After receiving the Synch Field, the USART expects to receive the Identifier Field.

When the Identifier Field has been received, the flag bit US_CSR.LINID is set to ’1’. At this moment,

US_LINIR.IDCHR is updated with the received character. The Identifier parity bits can be automatically computed

and checked (see Section 30.6.9.9 ”Identifier Parity”).

If the Header is not entirely received within the time given by the maximum length of the header tHeader_Maximum, the

error flag US_CSR.LINHTE is set to ’1’.

The flag bits LINID, LINBK and LINHTE are reset by writing a one to US_CR.RSTSTA.

Figure 30-32. Header Reception

30.6.9.8 Slave Node Synchronization

The synchronization is done only in slave node configuration. The procedure is based on time measurement

between falling edges of the Synch Field. The falling edges are available in distances of 2, 4, 6 and 8 bit times.

Figure 30-33. Synch Field

The time measurement is made by a 19-bit counter clocked by the sampling clock (see Section 30.6.1 ”Baud Rate

Generator”).

When the start bit of the Synch Fie ld is detected, the counter is reset. Then during the next 8 tbit of the Synch Field,

the counter is incremented. At the end of these 8 tbit, the counter is stopped. At this moment, the 16 most

significant bits of the counter (valu e divided by 8) give the ne w clock divider (LINCD) and the 3 least significant bits

of this value (the remainder) give the new fractional part (LINFP).

RXD

Baud Rate

Clock

Write RSTSTA=1

in US_CR

LINID

US_LINIR

LINBK

Start

Bit 10101010

Stop

Bit Start

Bit ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7Break Field

13 dominant bits (at 0)

Stop

Bit

Break

Delimiter

1 recessive bit

(at 1)

Synch Byte = 0x55

Start

bit Stop

bit

Synch Field

8 tbit

2 tbit

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Once the Synch Field has been entirely received, the clock divider (LINCD) an d the fractional part (LINFP) are

updated in the LIN Baud Rate register (US_LINBRR) with the computed valu es if the Synchronization is not

disabled by the SYNCDIS bit in the LIN Mode register (US_LINMR).

After reception of the Synch Field:

If it appears that the computed baud rate deviation compared to the initial baud rate is superior to the

maximum tolerance FTol_Unsynch (±15%), then the clock divider (LINCD) and the fractional part (LINFP)

are not updated, and the error flag US_CSR.LINSTE is set to ’1’.

If it appears that the sampled Synch character is not equal to 0x55, then the clock divider (LINCD) and the

fractional part (LINFP) are not updated, and the error flag US_CSR.LINISFE is set to ’1’.

Flags LINSTE and LINISFE are reset by writing US_CR.RSTSTA to ’1’.

Figure 30-34. Slave Node Synchronization

The accuracy of the synchronization depends on several pa rameters:

The nominal clock frequency (fNom) (the theoretical slave nod e clock frequency)

The baud rat e

The oversampling (Over=0 => 16X or Over=1 => 8X)

The following formula is used to compute the deviation of the slave bit rate relative to the master bit rate after

synchroniza tio n (f SLAVE is the real slave node clock frequency).

fTOL_UNSYNCH is the deviation o f the real slave node clock from the nominal clock frequency. The LIN Standard

imposes that it must not exceed ±15%. The LIN Standard imposes also that for communication between two

RXD

Baud Rate

Clock

LINIDRX

Synchro Counter 000_0011_0001_0110_1101

US_BRGR

Clock Divider (CD)

US_BRGR

Fractional Part (FP)

Initial CD

Initial FP

Reset

US_LINBRR

Clock Divider (CD) 0000_0110_0010_1101

US_LINBRR

Fractional Part (FP) 101

Initial CD

Initial FP

Start

Bit 10101010

Stop

Bit Start

Bit ID0 ID1 ID2 ID3 ID4 ID5 ID6 ID7Break Field

13 dominant bits (at 0)

Stop

Bit

Break

Delimiter

1 recessive bit

(at 1)

Synch Byte = 0x55

Baud rate deviation 100 α[ 82Over–()β+]Baud rate××× 8f

SLAVE

------------------------------------------------------------------------------------------





Baud rate deviation 100 α[ 82Over–()β+]Baud rate×××

8fTOL_UNSYNCH

100

-------------------------------------





fNom

××

------------------------------------------------------------------------------------------







0.5–α+0.5 -1 β+1<<≤≤

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684

nodes, their bit rate must not differ by more than ±2%. This means that the baud rate deviation must not exceed

±1%.

It follows from that, a minimum value for the nominal clock frequency:

Examples:

Baud rate = 20 kbit/s, OVER=0 (Oversampling 16X) => fNom(min) = 2.64 MHz

Baud rate = 20 kbit/s, OVER=1 (Oversampling 8X) => fNom(min) = 1.47 MHz

Baud rate = 1 kbit/s, OVER=0 (Oversampling 16X) => fNom(min) = 132 kHz

Baud rate = 1 kbit/s, OVER=1 (Oversampling 8X) => fNom(min) = 74 kHz

30.6.9.9 Identifier Parity

A protected identifier consists of two subfields; the identifier an d the identifier parity. Bits 0 to 5 are assigne d to th e

identifier and bits 6 an d 7 are as sig ne d to the par ity.

The USART interface ca n generate/check these parity bits, b ut this feature can also be disabled. The user can

choose between two modes using US_LINMR.PARDIS:

PARDIS = 0:

During header transmission, the parity bits are computed and sent with the 6 least significant bits of

US_LINIR.IDCHR. The bits 6 and 7 of this register are discarded.

During header reception, the parity bits of the identifier are checked. If the parity bits are wrong, an

Identifier Parity error occurs (see Section 30.6.3.5 ”Parity”). Only the 6 least significant bits of the

IDCHR field are updated with the received Identifier. Bits 6 and 7 are stuck to 0.

PARDIS = 1:

During header transmission, all the bits of US_LINIR.IDCHR are sent on the bus.

During header reception, all the bits of IDCHR are updated with the received Identifier.

30.6.9.10 Node Action

Depending on the identifier, the node is affected – or not – by the LIN response. Consequently, after sending or

receiving the identifier, the USART must be configured. There are three possible configurations:

PUBLISH: the node sends the response.

SUBSCRIBE: the node receives the response.

IGNORE: the node is not concerned by the re sponse, it does not send and does not receive the response.

This configuration is made by the field, Node Action (NACT), in US_LINMR (see Section 30.7.25 ”USART LIN

Mode Register”).

Example: a LIN cluster that contains a master and two slaves:

Data transfer from the master to slave1 and to slave2:

NACT(master)=PUBLISH

NACT(slave1)=SUBSCRIBE

NACT(slave2)=SUBSCRIBE

Data transfer from the master to slave1 only:

NACT(master)=PUBLISH

NACT(slave1)=SUBSCRIBE

fNom min() 100 0.5 8 2 Over–()×× 1+[]Baudrate×

815–

100

---------1+





×1%×

-------------------------------------------------------------------------------------------







Hz=

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NACT(slave2)=IGNORE

Data transfer from slave1 to the master:

NACT(master)=SUBSCRIBE

NACT(slave1)=PUBLISH

NACT(slave2)=IGNORE

Data transfer from slave1 to slave2:

NACT(master)=IGNORE

NACT(slave1)=PUBLISH

NACT(slave2)=SUBSCRIBE

Data transfer from slave2 to the master and to slave1:

NACT(master)=SUBSCRIBE

NACT(slave1)=SUBSCRIBE

NACT(slave2)=PUBLISH

30.6.9.11 Response Data Length

The LIN response data length is the number of data fields (bytes) of the response excluding the checksum.

The response data length can either be configured by the user or be defined automatically by bits 4 and 5 of the

Identifier (compatibility to LIN Specification 1.1). The user can choose between these two modes using

US_LINMR.DLM:

DLM = 0: The respon se data length is configured by the user via US_LINMR.DLC. The respon se dat a length

is equal to (DLC + 1) byte s. DLC can be programmed from 0 to 255, so the response can cont ain from 1 dat a

byte up to 256 data bytes.

DLM = 1: The response data length is defined by the Identifier (US_LINIR.IDCHR) according to the table

below. US_LINMR.DLC is discarded. The response can contain 2 or 4 or 8 data bytes.

Figure 30-35. Response Data Length

Table 30-15. Response Data Length if DLM = 1

IDCHR[5] IDCHR[4] Response Data Length [Bytes]

00 2

01 2

10 4

11 8

User configuration: 1 - 256 data fields (DLC+1)

Identifier configuration: 2/4/8 data fields

Sync

Break Sync

Field Identifier

Field Checksum

Field

Data

Field Data

Field

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30.6.9.12 Checksum

The last field of a frame is the checksum. The checksum contains the inverted 8- bit sum with carry, over all data

bytes or all data bytes and the protected identifier. Checksum calculation over the data bytes only is called classic

checksum and it is used for comm uni cation with LIN 1.3 slaves. Checksum calculation over the data bytes a nd th e

protected identifier byte is called enhanced checksum and it is used for communication with LIN 2.0 slaves.

The USART can be configured to:

Send/check an enhanced checksum automatically (CHKDIS = 0 & CHKTYP = 0)

Send/check a classic checksum automatically (CHKDIS = 0 & CHKTYP = 1)

Not send/check a checksum (CHKDIS = 1)

This configuration is made by the Checksum Type (CHKTYP) and Checksum Disable (CHKDIS) fields of

US_LINMR.

If the checksum feature is disabled, the user can send it manually all the same, by considering the checksum as a

normal data byte and by adding 1 to the response data length (see Section 30.6.9.11 ”Response Data Length”).

30.6.9.13 Frame Slot Mode

This mode is useful for master nodes only. It enforces the following ru le: each frame slot must be longer than or

equal to tFrame_Maximum.

If the Frame Slot mode is enabled (FSDIS = 0) and a frame tran sfer has been completed, the TXRDY flag is set

again only after tFrame_Maximum delay, from the start of frame. So the master node cannot send a new header if the

frame slot duration of the previous frame is lower than tFrame_Maximum.

If the Frame Slot mode is disabled (FSDIS = 1) and a frame transfer has been completed, the TXRDY flag is set

again immediately.

The tFrame_Maximum is calculated as follows:

If the checksum is sent (CHKDIS = 0):

tHeader_Nominal = 34 × tbit

tResponse_Nominal = 10 × (NData + 1) × tbit

tFrame_Maximum = 1.4 × (tHeader_Nominal + tResponse_Nominal + 1)(1)

tFrame_Maximum = 1.4 × (34 + 10 × (DLC + 1 + 1) + 1) × tbit

tFrame_Maximum = (77 + 14 × DLC) × tbit

If the checksum is not sent (CHKDIS = 1):

tHeader_Nominal = 34 × tbit

tResponse_Nominal = 10 × NData × tbit

tFrame_Maximum = 1.4 × (tHeader_Nominal + tResponse_Nominal + 1)(1)

tFrame_Maximum = 1.4 × (34 + 10 × (DLC + 1) + 1) × tbit

tFrame_Maximum = (63 + 14 × DLC) × tbit

Note: 1. The term “+1” leads to an integer result for tFrame_Maximum (LIN Specification 1.3).

687

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Figure 30-36. Frame Slot Mode

30.6.9.14 LIN Errors

Bit Error

This error is generated in master of slave node configuration, when the USART is transmitting and if the

transmitted value on the Tx line is different from the value sampled on the Rx line. If a bit error is detected, the

transmission is aborted at the next byte border.

This error is reported by flag US_CSR.LINBE.

Inconsistent Synch Field Error

This error is generated in slave node configuration if the Synch Fi eld character received is other than 0x55.

This error is reported by flag US_CSR.LINISFE.

Identifier Parity Error

This error is generated in slave node configuration, if the parity of the identifier is wrong. This error can be

generated only if the parity feature is enabled (PARDIS = 0).

This error is reported by flag US_CSR.LINIPE.

Checksum Error

This error is generated in master of slave node configuration, if the received checksum is wrong. This flag can be

set to ‘1’ only if the checksum feature is enabled (CHKDIS = 0).

This error is reported by flag US_CSR.LINCE.

Slave Not Responding Error

This error is generated in master of slave node configuration, when the USART expects a response from another

node (NACT = SUBSCRIBE) but no valid message appears on the bus within the time given by the maximum

length of the message frame, t Frame_Maximum (see Section 30.6.9.13 ” Fr ame Slot M ode ” ) . This erro r is disabled if the

USART does not expect any message (NACT = PUBLISH or NACT = IGNORE).

This error is reported by flag US_CSR.LINSNRE.

Synch Tolerance Error

This error is generated in slave node configuration if, after the clock synchronization procedure, it appears that the

computed baud rate deviation compared to the initial baud rate is superior to the maximum tolerance

FTol_Unsynch (±15%).

This error is reported by flag US_CSR.LINSTE.

Break Synch Protected

Identifier Data N Checksum

Header

Inter-

frame

space

Response

space

Frame

Frame slot = tFrame_Maximum

Response

TXRDY

Write

US_THR

Write

US_LINID

Data 1 Data 2 Data 3

Data3

Data N-1

Data N

Frame Slot Mode

Disabled Frame Slot Mode

Enabled

LINTC

Data 1

SAM G55 [DATASHEET]

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688

Header Timeout Error

This error is generated in slave node configuration, if the Header is not entirely received within the time given by

the maximum length of the Header, tHeader_Maximum.

This error is reported by flag US_CSR.LINHTE.

30.6.9.15 LIN Frame Handling

Master Node Configuration

Write TXEN and RXEN in US_CR to enable both the transmitter and the receiver.

Write USART_MODE in US_MR to select the LIN mode and the master node configuration.

Write CD and FP in US_BRGR to configure the baud rate.

Write NACT, PARDIS, CHKDIS, CHKTYPE, DLCM, FSDIS and DLC in US_LINMR to configure the frame

transfer.

Check that TXRDY in US_CSR is set to ‘1’.

Write IDCHR in US_LINIR to send the header.

What comes next depends on the NACT configuration:

Case 1: NACT = PUBLISH, the USART sends the response.

Wait until TXRDY in US_CSR rises.

Write TCHR in US_THR to send a byte.

If all the data have not been written, redo the two previous steps.

Wait until LINTC in US_CSR rises.

Check the LIN err or s.

Case 2: NACT = SUBSCRIBE, the USART receives the response.

Wa it until RXRDY in US_CSR rises.

Read RCHR in US_RHR.

If all the data have not been read, redo the two previous steps.

Wait until LINTC in US_CSR rises.

Check the LIN err or s.

Case 3: NACT = IGNORE, the USART is not concerned by the response.

Wait until LINTC in US_CSR rises.

Check the LIN err or s.

689

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 30-37. Master Node Configuration, NACT = PUBLISH

Figure 30-38. Master Node Configuration, NACT = SUBSCRIBE

Figure 30-39. Master No de Configuration, NACT = IGNORE

Frame

Break Synch Protected

Identifier Data 1 Data N Checksum

TXRDY

Write

US_THR

Write

US_LINIR

Data 1 Data 2 Data 3

Data N-1

Data N

RXRDY

Header

Inter-

frame

space

Response

space

Frame slot = TFrame_Maximum

Response

Data3

LINTC

FSDIS=1 FSDIS=0

Break Synch Protected

Identifier Data 1 Data N Checksum

TXRDY

Read

US_RHR

Write

US_LINIR

Data 1

Data N-1

RXRDY

Data NData N-2

Header

Inter-

frame

space

Response

space

Frame

Frame slot = TFrame_Maximum

Response

Data3

LINTC

FSDIS=0FSDIS=1

TXRDY

Write

US_LINIR

RXRDY

LINTC

Break Synch Protected

Identifier Data 1 Data N Checksum

Data N-1

Header

Inter-

frame

space

Response

space

Frame

Frame slot = TFrame_Maximum

Response

Data3

FSDIS=1 FSDIS=0

SAM G55 [DATASHEET]

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Slave Node Configuration

Write TXEN and RXEN in US_CR to enable both the transmitter and the receiver.

Write USART_MODE in US_MR to select the LIN mode and the slave node configuration.

Write CD and FP in US_BRGR to configure the baud rate.

Wait until LINID in US_CSR rises.

Check LINISFE and LINPE errors.

Read IDCHR in US_RHR.

Write NACT, PARDIS, CHKDIS, CHKTYPE, DLCM and DLC in US_LINMR to configure the frame transfer.

IMPORTANT: If the NACT configuration for this frame is PUBLISH, the US_LINMR must be written with NACT =

PUBLISH even if this field is alread y correctly configur ed, in or de r to set the TXREADY flag a nd the co rr espo nding

write transfer request.

What comes next depends on the NACT configuration:

Case 1: NACT = PUBLISH, the LIN controller sends the response.

Wait until TXRDY in US_CSR rises.

Write TCHR in US_THR to send a byte.

If all the data have not been written, redo the two previous steps.

Wait until LINTC in US_CSR rises.

Check the LIN err or s.

Case 2: NACT = SUBSCRIBE, the USART receives the response.

Wa it until RXRDY in US_CSR rises.

Read RCHR in US_RHR.

If all the data have not been read, redo the two previous steps.

Wait until LINTC in US_CSR rises.

Check the LIN err or s.

Case 3: NACT = IGNORE, the USART is not concerned by the response.

Wait until LINTC in US_CSR rises.

Check the LIN err or s.

Figure 30-40. Slave Node Configuration, NACT = PUBLISH

Break Synch Protected

Identifier Data 1 Data N Checksum

TXRDY

Write

US_THR

Read

US_LINID

Data 1 Data 3

Data N-1

Data N

RXRDY

LINIDRX

Data 2

LINTC

691

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 30-41. Slave Node Configuration, NACT = SUBSCRIBE

Figure 30-42. Slave Node Configuration, NACT = IGNORE

30.6.9.16 LIN Frame Handling with PDC

The USART can be used in association with the PDC in order to tr ansfer data dire ctly into/from the on- and off-ch ip

memories with out an y pr ocessor interven tio n.

The PDC uses the trigger flags, TXRDY and RXRDY, to write or read into the USART. The PDC always writes in

US_THR and it always reads in US_RHR. The size of the data written or read by the PDC in the USART is a lways

a byte.

Master Node Configuration

The user can choose between two PDC modes by the PDCM bit in US_LINMR:

PDCM = 1: the LIN configuration is stored in the WRITE buffer and it is written by the PDC in the US_THR

(instead of the US_LINMR). Because the PDC transfer size is limited to a byte, the transfer is split into two

accesses. During the first access the bits, NACT, PARDIS, CHKDIS, CHKTYP, DLM and FSDIS are written.

During the second access, the 8-bit DLC field is written.

PDCM = 0: the LIN config ur at ion is not store d in the WRIT E bu ffer and it must be writ ten by the use r in

US_LINMR.

The WRITE buffer also contains the Identifier and the DATA, if the USART sends the response (NACT =

PUBLISH).

The READ buffer contains the DATA if the USART receives the response (NACT = SUBSCRIBE).

TXRDY

Read

US_RHR

Read

US_LINID

RXRDY

LINIDRX

LINTC

Break Synch Protected

Identifier Data 1 Data N Checksum

Data 1

Data N-1

Data N-1 Data NData N-2

TXRDY

Read

US_RHR

Read

US_LINID

RXRDY

LINIDRX

LINTC

Break Synch Protected

Identifier Data 1 Data N ChecksumData N-1

SAM G55 [DATASHEET]

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Figure 30-43. Master Node with PDC (PDCM = 1)

Figure 30-44. Master Node with PDC (PDCM = 0)

Slave Node Configuration

In this configuration, the PDC trans fers only the DATA. The Identifier must be read by the user in the US_LINIR.

The LIN mode must be written by the user in US_LINMR.

The WRITE buffer contains the DATA if the USART sends the response (NACT = PUBLISH).

The READ buffer contains the DATA if the USART receives the response (NACT = SUBSCRIBE).

NACT

PARDIS

CHKDIS

CHKTYP

DLM

FSDIS

DLC

IDENTIFIER

DATA 0

DATA N

WRITE BUFFER

(Peripheral) DMA

Controller (Peripheral) DMA

Controller

USART3

LIN CONTROLLER

APB bus

NACT

PARDIS

CHKDIS

CHKTYP

DLM

FSDIS

DLC

IDENTIFIER

DATA 0

DATA N

WRITE BUFFER

RXRDY

TXRDY

USART3

LIN CONTROLLER

APB bus

READ BUFFER

NODE ACTION = PUBLISH NODE ACTION = SUBSCRIBE

RXRDY

TXRDY

APB bus

USART3

LIN CONTROLLER DATA 0

DATA N

WRITE BUFFER

USART3

LIN CONTROLLER

READ BUFFER

NODE ACTION = PUBLISH NODE ACTION = SUBSCRIBE

APB bus

IDENTIFIER

DATA 0

DATA N

WRITE BUFFER

IDENTIFIER

(Peripheral) DMA

Controller (Peripheral) DMA

Controller

693

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 30-45. Slave Node with PDC

30.6.9.17 Wakeup Request

Any node in a sleeping LIN cluster may request a wakeup.

In the LIN 2.0 specification, the wakeu p request is issued by forcing the bus to the dominant state from 250 µs to 5

ms. For this, it is necessary to send the character 0xF0 in order to impose 5 successive dominant bits. Whatever

the baud rate is, this character complies with the specified timings.

Baud rate min = 1 kbit/s -> tbit = 1 m s -> 5 t bit = 5 ms

Baud rate max = 20 kbit/s -> tbit = 50 µs -> 5 tbit = 250 µs

In the LIN 1.3 specification, the wakeup request should be generated with character 0x80 in order to impose eight

successive dominant bits.

Using the WKUPTYP bit in US_LINMR, the user can choose to send either a LIN 2.0 wakeup request

(WKUPTYP = 0) or a LIN 1.3 wakeup request (WKUPTYP = 1).

A wakeup request is transmitted by writing US_CR with the LINWKUP bit to ’1’. Once the transfer is completed, the

LINTC flag is asserted in the Status register (US_SR). It is cleared by writing the US_CR with the RSTSTA bit to

’1’.

30.6.9.18 Bus Idle Timeout

If the LIN bus is inactive for a certain duration, the slave nodes automatically enter Sleep mode. In the LIN 2.0

specification, this timeout is set to 4 seconds. In the LIN 1.3 specification, it is set to 25,000 tbit.

In slave node configuration, the receiver timeout dete cts an idle condition on the RXD line. Whe n a timeout is

detected, the US_CSR.TIMEOUT rises and can generate an interrupt, thus indicating to the driver to enter Sleep

mode.

The timeout delay period (during which the receiver waits for a new character) is programmed in US_RTOR.TO. If

a ‘0’ is written to TO, the Receiver Timeout is disabled and no timeout is detected. US_CSR.TIMEOUT remains at

‘0’. Otherwise, the receiver loads a 17 -bit counter with the value programmed in TO. This counter is decremented

at each bit period and reloaded each time a new character is received. If the counter reaches 0,

US_CSR.TIMEOUT rises.

If US_CR.STTTO is written to ‘1’, the counter clock is stopped until a first character is received.

If US_CR.RETTO is written to ‘1’, the counter starts counting down immediately from the value TO.

DATA 0

DATA N

RXRDY

USART3

LIN CONTROLLER

APB bus

READ BUFFER

NACT = SUBSCRIBE

DATA 0

DATA N

TXRDY

USART3

LIN CONTROLLER

APB bus

WRITE BUFFER

(Peripheral) DMA

Controller (Peripheral) DMA

Controller

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30.6.10 Test Modes

The USART can be programmed to operate in three different test modes. The internal loopback capability enables

on-board diagnostics. In Loopback mode, the USART interface pins are disconnected or not, and reconfigured for

loopback internally or externally.

30.6.10.1 Normal Mode

Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD pin.

Figure 30-46. Normal Mode Configuration

30.6.10.2 Automatic Echo Mode

Automatic Echo mode is used for bit-by-bit retransmission. When a bit is received on the RXD pin, it is sent to the

TXD pin, as shown in Figure 30-47. Progra mming the transmitter has no effect on the TXD pin. The RXD pin is still

connected to the receiver input, thus the receiver remains active.

Figure 30-47. Automatic Echo Mode Configuration

30.6.10.3 Local Loopback Mode

Local Loopback mode con nects the output of the tr ansmitter directly to the input of the receiver, as shown in Figure

30-48. The TXD and RXD pins are not used. The RXD pin has no effect on the receiver and the TXD pin is

continuously driven high, as in idle state.

Table 30-16. Receiver Timeout Prog ramming

LIN Specification Baud Rate Timeout period TO

2.0

1,000 bit/s

4,000

2,400 bit/s 9,600

9,600 bit/s 38,400

19,200 bit/s 76,800

20,000 bit/s 80,000

1.3 – 25,000 tbit 25,000

Receiver

Transmitter

RXD

TXD

Receiver

Transmitter

RXD

TXD

695

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 30-48. Local Loopback Mode Configuration

30.6.10.4 Remote Loopback Mode

Remote Loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 30-49. The transmitter

and the receiver are disabled and have no effect. This mode is used for bit-by-bit retransmission.

Figure 30-49. Remote Loopback Mode Configuration

30.6.11 USART Register Write Protection

To prevent any single software error from corrupting USART behavior, certain registers in the address space can

be write-protected by setting the WPEN bit in the “USART Write Protection Mode Register” (US_WPMR).

If a write access to a write-protected register is detected, the WPVS flag in the “USART Write Protection Status

attempted.

The WPVS bit is automatically cleared after reading the US_WPSR.

The following registers can be write-protected:

“USART Mode Register”

“USART Baud Rate Generator Register”

“USART Receiver Timeout Register”

“USART Transmitter Timeguard Register”

“USART FI DI RATIO Register”

“USART IrDA FILTER Register”

“USART Comparison Register”

Receiver

Transmitter

RXD

TXD

Receiver

Transmitter

RXD

TXD

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

696

30.7 Universal Synchronous Asynchronous Receiver Transmitter (USART) User Interface

Notes: 1. Write is possible only in LIN master node configuration.

Table 30-17. Register Mapping

Offset Register Name Access Reset

0x000 USART Control Register US_CR Write-only –

0x004 USART Mode Register US_MR Read/Write –

0x008 USART Interrupt Enable Register US_IER W rite-only –

0x00C USART Interrupt Disable Register US_IDR Write-only –

0x010 USART Interrupt Mask Register US_IMR Read-only 0x0

0x014 USART Channel Status Register US_CSR Read-only –

0x018 USART Receive Holding Register US_RHR Read-only 0x0

0x01C USART Transmit Holding Register US_THR Write-only –

0x020 USART Baud Rate Generator Register US_BRGR Read/Write 0x0

0x024 USART Receiver Timeout Register US_RTOR Read/Write 0x0

0x028 USART Transmitter Timeguard Register US_TTGR Read/Write 0x0

0x02C–0x03C Reserved – – –

0x040 USART FI DI Ratio Register US_FIDI Read/Write 0x174

0x044 USART Number of Errors Register US_NER Read-only –

0x048 Reserved – – –

0x04C USART IrDA Filter Register US_IF Read/Write 0x0

0x050 Reserved – – –

0x054 USART LIN Mode Register US_LINMR Read/Write 0x0

0x058 USART LIN Identifier Register US_LINIR Read/Write(1) 0x0

0x05C USART LIN Baud Rate Register US_L INBRR Read-only 0x0

0x060–0x088 Reserved – – –

0x090 USART Comparison Register US_C MPR Read/Write 0x0

0x094–0x0E0 Reserved – – –

0x0E4 USART W rite Protection Mode Register US_WPMR Read/Write 0x0

0x0E8 USART W rite Protection Status Register US_WPSR Read-only 0x0

0x0EC–0x0F8 Reserved – – –

697

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.1 USART Control Register

Name: US_CR

Address: 0x4000C200 (0), 0x40020200 (1), 0x40024200 (2), 0x40018200 (3), 0x4001C200 (4), 0x40008200 (5),

0x40040200 (6), 0x40034200 (7)

Access: Write-only

For SPI control, see ”USART Control Register (SPI_MODE)”.

• RSTRX: Reset Receiver

0: No effect.

1: Resets the receiver.

• RSTTX: Reset Transmitter

0: No effect.

1: Resets the transmitter.

• RXEN: Receiver Enable

0: No effect.

1: Enables the receiver, if RXDIS is 0.

• RXDIS: Receiver Disable

0: No effect.

1: Disables the receiver.

• TXEN: Transmitter Enable

0: No effect.

1: Enables the transmitter if TXDIS is 0.

• TXDIS: Transmitter Disable

0: No effect.

1: Disables the transmitter.

31 30 29 28 27 26 25 24

–––REQCLR––––

23 22 21 20 19 18 17 16

– – LINWKUP LINABT RTSDIS RTSEN – –

15 14 13 12 11 10 9 8

RETTO RSTNACK RSTIT SENDA STTTO STPBRK STTBRK RSTSTA

76543210

TXDIS TXEN RXDIS RXEN RSTTX RSTRX – –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

698

• RSTSTA: Reset Status Bits

0: No effect.

1: Clears the status bits PARE, FRAME, OVRE, LINBE, LINISFE, LINIPE, LINCE, LINSNRE, LINSTE, LINHTE, LINID,

LINTC, LINBK, CMP and RXBRK in US_CSR.

• STTBRK: Start Break

0: No effect.

1: Starts transmission of a break after the characters present in the US_THR and the Transmit Shift Register have been

transmitted. No effect if a break is already being transmitted.

• STPBRK: Stop Break

0: No effect.

1: Stops transmission of the break after a min imum of one character length and transmits a high level d uring 12-bit pe riods.

No effect if no break is being transmitted.

• STTTO: Clear TIMEOUT Flag and Start Timeout After Next Character Received

0: No effect.

1: Starts waiting for a character before enabling the timeout counter. Immediately disables a timeout period in progress.

Clears the status bit TIMEOUT in US_CSR.

• SENDA: Send Address

0: No effect.

1: In Multidrop mode only, the next character written to the US_THR is sent with the address bit set.

• RSTIT: Reset Iterat io n s

0: No effect.

1: Clears the bit ITER in US_CSR. No effect if the ISO7816 is not enabled.

• RSTNACK: Reset Non Acknowledge

0: No effect

1: Clears NACK in US_CSR.

• RETTO: Start Timeout Immediately

0: No effect.

1: Immediately restarts timeout period.

• RTSEN: Request to Send Enable

0: No effect.

1: Drives the RTS pin to 1 if US_MR.USART_MODE field = 2, else drives the RTS pin to 0 if US_MR.USART_MODE

field = 0.

• RTSDIS: Request to Send Disable

0: No effect.

1: Drives the RTS pin to 0 if US_MR.USAR T_ MODE field = 2 (if PDC Re ce ive buffe r is not fu ll), else dr ives th e RTS pin to

1 if US_MR.USART_MODE field = 0.

699

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• LINABT: Abort LIN Transmission

0: No effect.

1: Abort the current LIN transmission.

• LINWKUP: Send LIN Wakeup Signal

0: No effect:

1: Sends a wakeup signal on the LIN bus.

• REQCLR: Request to Clear the Comparison Trigger

SleepWalking enabled:

0: No effect.

1: Clears the potential clock request currently issued by the USART, thus the potential system wakeup is cancelled.

SleepWalking disabled:

0: No effect.

1: Restarts the comparison trigger to enable US_RHR loading.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

700

30.7.2 USART Control Register (SPI_MODE)

Name: US_CR (SPI_MODE)

Address: 0x4000C200 (0), 0x40020200 (1), 0x40024200 (2), 0x40018200 (3), 0x4001C200 (4), 0x40008200 (5),

0x40040200 (6), 0x40034200 (7)

Access: Write-only

This configuration is relevant only if USART_MODE=0xE or 0xF in ”USART Mode Register”.

• RSTRX: Reset Receiver

0: No effect.

1: Resets the receiver.

• RSTTX: Reset Transmitter

0: No effect.

1: Resets the transmitter.

• RXEN: Receiver Enable

0: No effect.

1: Enables the receiver, if RXDIS is 0.

• RXDIS: Receiver Disable

0: No effect.

1: Disables the receiver.

• TXEN: Transmitter Enable

0: No effect.

1: Enables the transmitter if TXDIS is 0.

• TXDIS: Transmitter Disable

0: No effect.

1: Disables the transmitter.

• RSTSTA: Reset Status Bits

0: No effect.

1: Resets the status bits OVRE, UNRE in US_CSR.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––RCSFCS––

15 14 13 12 11 10 9 8

–––––––RSTSTA

76543210

TXDIS TXEN RXDIS RXEN RSTTX RSTRX – –

701

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• FCS: Force SPI Chip Select

Applicable if USART operates in SPI Master mode (USART_MODE = 0xE):

0: No effect.

1: Forces the Slave Select Line NSS (RTS pin) to 0, even if USART is not transmitting, in order to address SPI slave

devices supporting the CSAAT mode (Chip Select Active After Transfer).

• RCS: Release SPI Chip Select

Applicable if USART operates in SPI Master mode (USART_MODE = 0xE):

0: No effect.

1: Releases the Slave Select Line NSS (RTS pin).

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

702

30.7.3 USART Mode Register

Name: US_MR

Address: 0x4000C204 (0), 0x40020204 (1), 0x40024204 (2), 0x40018204 (3), 0x4001C204 (4), 0x40008204 (5),

0x40040204 (6), 0x40034204 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

For SPI configuration, see ”USART Mode Register (SPI_MODE)”.

• USART_MODE: USART Mode of Operation

The PDC transfers are supported in all USART modes of operation.

• USCLKS: Clock Selection

31 30 29 28 27 26 25 24

– – – FILTER – MAX_ITERATION

23 22 21 20 19 18 17 16

INVDATA – DSNACK INACK OVER CLKO MODE9 MSBF

15 14 13 12 11 10 9 8

CHMODE NBSTOP PAR SYNC

76543210

CHRL USCLKS USART_MODE

Value Name Description

0x0 NORMAL Normal mode

0x2 HW_HANDSHAKING Hardware Handshaki ng

0x4 IS07816_T_0 IS07816 Protocol: T = 0

0x6 IS07816_T_1 IS07816 Protocol: T = 1

0x8 IRDA IrDA mode

0xA LIN_MASTER LIN Master mode

0xB LIN_SLAVE LIN Slave mode

0xE SPI_MASTER SPI Master mode (CLKO must be written to 1 and USCLKS = 0, 1 or 2)

0xF SPI_SLAVE SPI Slave mode

Value Name Description

0 MCK Peripheral clock is selected

1 DIV Peripheral clock Divided (DIV=8) is selected

2PMC_PCK

PMC programmable clock (PCK) is selected.

If the SCK pin is driven (CLKO=1), the CD field must be greater than 1.

3 SCK External pin (SCK) is selected

703

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• CHRL: Character Length

• SYNC: Synchronous Mode Select

0: USART operates in Asynchronous mode (UART).

1: USART operates in Synchronous mode.

•PAR: Parity Type

• NBSTOP: Number of Stop Bits

• CHMODE: Channel Mode

•MSBF: Bit Order

0: Least significant bit is sent/received first.

1: Most significant bit is sent/received first.

• MODE9: 9-bit Character Length

0: CHRL defines character length.

1: 9-bit character length.

Value Name Description

0 5_BIT Character length is 5 bits

1 6_BIT Character length is 6 bits

2 7_BIT Character length is 7 bits

3 8_BIT Character length is 8 bits

Value Name Description

0 EVEN Even parity

1 ODD Odd parity

2 SPACE Parity forced to 0 (Space)

3 MARK Parity forced to 1 (Mark)

4NONo parity

6 MULTIDROP Multid r op mode

Value Name Description

0 1_BIT 1 stop bit

1 1_5_BIT 1.5 stop bits (SYNC = 0) or reserved (SYNC = 1)

2 2_BIT 2 stop bits

Value Name Description

0 NORMAL Normal mode

1 AUTOMATIC Automatic Echo. Receiver input is connected to the TXD pin.

2 LOCAL_LOOPBACK L ocal Loopback. Transmitter output is connected to the Receiver Input.

3 REMOTE_LOOPBACK Remote Loopback. RXD pin is internally connected to the TXD pin.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

704

• CLKO: Clock Output Select

0: The USART does not drive the SCK pin (Synchronou s Slave mode or Asynchronous mode with external b aud rate clock

source).

1: The USART drives the SCK pin if USCLKS does not select the extern al clock SCK (USART Synchron ous Master Mode).

• OVER: Oversampling Mode

0: 16x Oversampling.

1: 8x Oversampling.

• INACK: Inhibit Non Acknowledge

0: The NACK is generated.

1: The NACK is not generated.

• DSNACK: Disable Successive NACK

0: NACK is sent on the ISO line as soon as a parity error occurs in the received character (unless INACK is set).

1: Successive parity errors are counted up to the value specified in the MAX_ITERATION field. These parity errors gener-

ate a NACK on the ISO line. As soon as th is value is reache d, no additional NACK is sent on the ISO line. The flag ITER is

asserted.

Note: T he MAX_ITERATION field must be set to 0 if DSNACK is cleared.

• INVDATA: Inverted Data

0: The data field transmitted on TXD line is the same as the one written in US_THR or the content read in US_RHR is the

same as RXD line. Normal mode of operation.

1: The data field transmitted on TXD line is inve rted (voltage polarity only) compared to the value written on US_THR or the

content read in US_RHR is inverted compared to what is received on RXD line (or ISO7816 IO line). Inverted mode of

operation, use fu l for cont actless card application. To be used with MSBF configuratio n bit .

• MAX_ITERATION: Maximum Number of Automatic Iteration

0–7: Defines the maximum number of iterations in mode ISO7816, protocol T = 0.

• FILTER: Receive Line Filter

0: The USART does not filter the receive line.

1: The USART filters the receive line using a three-sample filter (1/16-bit clock) (2 over 3 majority).

705

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.4 USART Mode Register (SPI_MODE)

Name: US_MR (SPI_MODE)

Address: 0x4000C204 (0), 0x40020204 (1), 0x40024204 (2), 0x40018204 (3), 0x4001C204 (4), 0x40008204 (5),

0x40040204 (6), 0x40034204 (7)

Access: Read/Write

This configuration is relevant only if USART_MODE = 0xE or 0xF in ”USART Mode Register”.

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

• USART_MODE: USART Mode of Operation

• USCLKS: Clock Selection

• CHRL: Character Length

• CPHA: SPI Clock Phase

– Applicable if USART operates in SPI mode (USART_MODE = 0xE or 0xF):

0: Data is changed on the leading edge of SPCK and captured on the following edg e of SPCK.

1: Data is captured on the leading edge of SPCK and changed on the following edge of SPCK.

CPHA determines which e dge of SPCK causes data to change a nd which edge causes da ta to be captured. CPHA is used

with CPOL to produce the required clock/data relationship between master and slave devices.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – – WRDBT – CLKO – CPOL

15 14 13 12 11 10 9 8

–––––––CPHA

76543210

CHRL USCLKS USART_MODE

Value Name Description

0xE SPI_MASTER SPI Master mode

0xF SPI_SLAVE SPI Slave mode

0 MCK Peripheral clock is selected

1 DIV Peripheral clock Divided (DIV=8) is selected

2 PMC_PCK A PMC programmable clock (PCK) is selected

3 SCK External pin (SCK) is selected

Value Name Description

3 8_BIT Character length is 8 bits

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

706

• CHMODE: Channel Mode

• CPOL: SPI Clock Polarity

Applicable if USART operates in SPI mode (Slave or Master, USART_MODE = 0xE or 0xF):

0: The inactive state value of SPCK is logic level zero.

1: The inactive state value of SPCK is logic level one.

CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with CPHA to prod uce the requir ed

clock/data relationship between master and slave devices.

• CLKO: Clock Output Select

0: Mandatory for SPI slave mode, the USART receives the SCK clock.

1: Mandatory for SPI master mode, the USART drives the SCK pin if USCLKS does not select the external clock SCK.

• WRDBT: Wait Read Data Before Transfer

0: The character transmission starts as soon as a character is written into US_THR register (assuming TXRDY was set).

1: The character transmission starts when a character is written and only if RXRDY flag is cleared (US_RHR has been

read).

Value Name Description

0 NORMAL Normal mode

1 AUTOMATIC Automatic Echo mode. Receiver input is connected to the TXD pin.

2 LOCAL_LOOPBACK L ocal Loopback mode. Transmitter output is connected to the Receiver Input.

3 REMOTE_LOOPBACK Remote Loopback mode. RXD pin is internally connected to the TXD pin.

707

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.5 USART Interrupt Enable Register

Name: US_IER

Address: 0x4000C208 (0), 0x40020208 (1), 0x40024208 (2), 0x40018208 (3), 0x4001C208 (4), 0x40008208 (5),

0x40040208 (6), 0x40034208 (7)

Access: Write-only

For SPI specific configuration, see ”USART Interrupt Enable Register (SPI_MODE)”.

For LIN specific configuration, see ”USART Interrupt Enable Register (LIN_MODE)”.

The following configuration values are valid for all listed bit names of this register:

0: No effect

1: Enables the corresponding interrupt.

• RXRDY: RXRDY Interrupt Enable

• TXRDY: TXRDY Interrupt Enable

• RXBRK: Receiver Break Interrupt Enable

• ENDRX: End of Receive Buffer Interrupt Enable (available in all USART modes of operation)

• ENDTX: End of Transmit Buffer Interrupt Enable (available in all USART modes of operation)

• OVRE: Overrun Error Interrupt Enable

• FRAME: Framing Error Interrupt Enable

• PARE: Parity Error Interrupt Enable

• TIMEOUT: Timeout Interrupt Enable

• TXEMPTY: TXEMPTY Interrupt Enable

• ITER: Max number of Repetitions Reached Interrupt Enable

• TXBUFE: Transmit Buffer Empty Interrupt Enable (available in all USART modes of operation)

• RXBUFF: Receive Buffer Full Interrupt Enable (available in all USART modes of operation)

• NACK: Non Acknowledge Interrupt Enable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–CMP– –CTSIC– – –

15 14 13 12 11 10 9 8

– – NACK RXBUFF TXBUFE ITER TXEMPTY TIMEOUT

76543210

PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

708

• CTSIC: Clear to Send Input Change Interrupt Enable

• CMP: Comparison Interrupt Enable

709

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.6 USART Interrupt Enable Register (SPI_MODE)

Name: US_IER (SPI_MODE)

Address: 0x4000C208 (0), 0x40020208 (1), 0x40024208 (2), 0x40018208 (3), 0x4001C208 (4), 0x40008208 (5),

0x40040208 (6), 0x40034208 (7)

Access: Write-only

This configuration is relevant only if USART_MODE = 0xE or 0xF in ”USART Mode Register”.

The following configuration values are valid for all listed bit names of this register:

0: No effect

1: Enables the corresponding interrupt.

• RXRDY: RXRDY Interrupt Enable

• TXRDY: TXRDY Interrupt Enable

• OVRE: Overrun Error Interrupt Enable

• TXEMPTY: TXEMPTY Interrupt Enable

• UNRE: SPI Underrun Error Interrupt Enable

• NSSE: NSS Line Event (CTS pin) Interrupt Enable

• CMP: Comparison Interrupt Enable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–CMP––NSSE–––

15 14 13 12 11 10 9 8

– – – RXBUFF TXBUFE UNRE TXEMPTY –

76543210

– – OVRE ENDTX ENDRX – TXRDY RXRDY

• ENDRX: End of Receive Buffer Interrupt Enable

• ENDTX: End of Transmit Buffer Interrupt Enable

• TXBUFE: Transmit Buffer Empty Interrupt Enable

• RXBUFF: Receive Buffer Full Interrupt Enable

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

710

30.7.7 USART Interrupt Enable Register (LIN_MODE)

Name: US_IER (LIN_MODE)

Address: 0x4000C208 (0), 0x40020208 (1), 0x40024208 (2), 0x40018208 (3), 0x4001C208 (4), 0x40008208 (5),

0x40040208 (6), 0x40034208 (7)

Access: Write-only

This configuration is relevant only if USART_MODE = 0xA or 0xB in ”USART Mode Register”.

The following configuration values are valid for all listed bit names of this register:

0: No effect

1: Enables the corresponding interrupt.

• RXRDY: RXRDY Interrupt Enable

• TXRDY: TXRDY Interrupt Enable

• OVRE: Overrun Error Interrupt Enable

• FRAME: Framing Error Interrupt Enable

• PARE: Parity Error Interrupt Enable

• TIMEOUT: Timeout Interrupt Enable

• TXEMPTY: TXEMPTY Interrupt Enable

• LINBK: LIN Break Sent or LIN Break Received Interrupt Enable

• LINID: LIN Identifier Sent or LIN Identifier Received Interrupt Enable

• LINTC: LIN Transfer Completed Interrupt Enable

• LINBE: LIN Bus Error Interrupt Enable

31 30 29 28 27 26 25 24

LINHTE LINSTE LINSNRE LINCE LINIPE LINISFE LINBE –

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

LINTC LINID LINBK RXBUFF TXBUFE – TXEMPTY TIMEOUT

76543210

PARE FRAME OVRE ENDTX ENDRX – TXRDY RXRDY

• ENDRX: End of Receive Buffer Interrupt Enable

• ENDTX: End of Transmit Buffer Interrupt Enable

• TXBUFE: Transmit Buffer Empty Interrupt Enable

• RXBUFF: Receive Buffer Full Interrupt Enable

711

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• LINISFE: LIN Inconsistent Synch Field Error Interrupt Enable

• LINIPE: LIN Identifier Parity Interrupt Enable

• LINCE: LIN Checksum Error Interrupt Enable

• LINSNRE: LIN Slave Not Responding Error Interrupt Enable

• LINSTE: LIN Synch Tolerance Error Interrupt Enable

• LINHTE: LIN Header Timeout Error Interrupt Enable

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

712

30.7.8 USART Interrupt Disable Register

Name: US_IDR

Address: 0x4000C20C (0), 0x4002020C (1), 0x4002420C (2), 0x4 001820C (3), 0x4001C20C (4), 0x4000820C (5),

0x4004020C (6), 0x4003420C (7)

Access: Write-only

For SPI specific configuration, see ”USART Interrupt Disable Register (SPI_MODE)”.

For LIN specific configuration, see ”USART Interrupt Disable Register (LIN_MODE)”.

The following configuration values are valid for all listed bit names of this register:

0: No effect

1: Disables the corresponding interrupt.

• RXRDY: RXRDY Interrupt Disable

• TXRDY: TXRDY Interrupt Disable

• RXBRK: Receiver Break Interrupt Disable

• ENDRX: End of Receive Buffer Interrupt Enable (available in all USART modes of operation)

• ENDTX: End of Transmit Buffer Interrupt Disable (available in all USART modes of operation)

• OVRE: Overrun Error Interrupt Enable

• FRAME: Framing Error Interrupt Disable

• PARE: Parity Error Interrupt Disable

• TIMEOUT: Timeout Interrupt Disable

• TXEMPTY: TXEMPTY Interrupt Disable

• ITER: Max Number of Repetitions Reached Interrupt Disable

• TXBUFE: Transmit Buffer Empty Interrupt Enable (available in all USART modes of operation)

• RXBUFF: Receive Buffer Full Interrupt Enable (available in all USART modes of operation)

• NACK: Non Acknowledge Interrupt Disable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–CMP– –CTSIC– – –

15 14 13 12 11 10 9 8

– – NACK RXBUFF TXBUFE ITER TXEMPTY TIMEOUT

76543210

PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY

713

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• CTSIC: Clear to Send Input Change Interrupt Disable

• CMP: Comparison Interrupt Disable

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

714

30.7.9 USART Interrupt Disable Register (SPI_MODE)

Name: US_IDR (SPI_MODE)

Address: 0x4000C20C (0), 0x4002020C (1), 0x4002420C (2), 0x4 001820C (3), 0x4001C20C (4), 0x4000820C (5),

0x4004020C (6), 0x4003420C (7)

Access: Write-only

This configuration is relevant only if USART_MODE = 0xE or 0xF in ”USART Mode Register”.

The following configuration values are valid for all listed bit names of this register:

0: No effect

1: Disables the corresponding interrupt.

• RXRDY: RXRDY Interrupt Disable

• TXRDY: TXRDY Interrupt Disable

• OVRE: Overrun Error Interrupt Disable

• TXEMPTY: TXEMPTY Interrupt Disable

• UNRE: SPI Underrun Error Interrupt Disable

• NSSE: NSS Line Event (CTS pin) Interrupt Disable

• CMP: Comparison Interrupt Disable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–CMP––NSSE–––

15 14 13 12 11 10 9 8

– – – RXBUFF TXBUFE UNRE TXEMPTY –

76543210

– – OVRE ENDTX ENDRX – TXRDY RXRDY

• ENDRX: End of Receive Buffer Interrupt Disable

• ENDTX: End of Transmit Buffer Interrupt Disable

• TXBUFE: Transmit Buffer Empty Interrupt Disable

• RXBUFF: Receive Buffer Full Interrupt Disable

715

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.10 USART Interrupt Disable Register (LIN_MODE)

Name: US_IDR (LIN_MODE)

Address: 0x4000C20C (0), 0x4002020C (1), 0x4002420C (2), 0x4 001820C (3), 0x4001C20C (4), 0x4000820C (5),

0x4004020C (6), 0x4003420C (7)

Access: Write-only

This configuration is relevant only if USART_MODE = 0xA or 0xB in ”USART Mode Register”.

The following configuration values are valid for all listed bit names of this register:

0: No effect

1: Disables the corresponding interrupt.

• RXRDY: RXRDY Interrupt Disable

• TXRDY: TXRDY Interrupt Disable

• OVRE: Overrun Error Interrupt Disable

• FRAME: Framing Error Interrupt Disable

• PARE: Parity Error Interrupt Disable

• TIMEOUT: Timeout Interrupt Disable

• TXEMPTY: TXEMPTY Interrupt Disable

• LINBK: LIN Break Sent or LIN Break Received Interrupt Disable

• LINID: LIN Identifier Sent or LIN Identifier Received Interrupt Disable

• LINTC: LIN Transfer Completed Interrupt Disable

• LINBE: LIN Bus Error Interrupt Disable

31 30 29 28 27 26 25 24

LINHTE LINSTE LINSNRE LINCE LINIPE LINISFE LINBE –

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

LINTC LINID LINBK RXBUFF TXBUFE – TXEMPTY TIMEOUT

76543210

PARE FRAME OVRE ENDTX ENDRX – TXRDY RXRDY

• ENDRX: End of Receive Buffer Interrupt Disable

• ENDTX: End of Transmit Buffer Interrupt Disable

• TXBUFE: Transmit Buffer Empty Interrupt Disable

• RXBUFF: Receive Buffer Full Interrupt Disable

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

716

• LINISFE: LIN Inconsistent Synch Field Error Interrupt Disable

• LINIPE: LIN Identifier Parity Interrupt Disable

• LINCE: LIN Checksum Error Interrupt Disable

• LINSNRE: LIN Slave Not Responding Error Interrupt Disable

• LINSTE: LIN Synch Tolerance Error Interrupt Disable

• LINHTE: LIN Header Timeout Error Interrupt Disable

717

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.11 USART Interrupt Mask Register

Name: US_IMR

Address: 0x4000C210 (0), 0x40020210 (1), 0x40024210 (2), 0x40018210 (3), 0x4001C210 (4), 0x40008210 (5),

0x40040210 (6), 0x40034210 (7)

Access: Read-only

For SPI specific configuration, see ”USART Interrupt Mask Register (SPI_MODE)”.

For LIN specific configuration, see ”USART Interrupt Mask Register (LIN_MODE)”.

The following configuration values are valid for all listed bit names of this register:

0: The corresponding interrupt is not enabled.

1: The corresponding interrupt is enabled.

• RXRDY: RXRDY Interrupt Mask

• TXRDY: TXRDY Interrupt Mask

• RXBRK: Receiver Break Interrupt Mask

• ENDRX: End of Receive Buffer Interrupt Mask (available in all USART modes of opera tion)

• ENDTX: End of Transmit Buffer Interrupt Mask (available in all USART modes of operation)

• OVRE: Overrun Error Interrupt Mask

• FRAME: Framing Error Interrupt Mask

• PARE: Parity Error Interrupt Mask

• TIMEOUT: Timeout Interrupt Mask

• TXEMPTY: TXEMPTY Interrupt Mask

• ITER: Max Number of Repetitions Reached Interrupt Mask

• TXBUFE: Transmit Buffer Empty Interrupt Mask (available in all USART modes of operation)

• RXBUFF: Receive Buffer Full Interrupt Mask (available in all USART modes of operation)

• NACK: Non Acknowledge Interrupt Mask

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–CMP– –CTSIC– – –

15 14 13 12 11 10 9 8

– – NACK RXBUFF TXBUFE ITER TXEMPTY TIMEOUT

76543210

PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

718

• CTSIC: Clear to Send Input Change Interrupt Mask

• CMP: Comparison Interrupt Mask

719

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.12 USART Interrupt Mask Register (SPI_MODE)

Name: US_IMR (SPI_MODE)

Address: 0x4000C210 (0), 0x40020210 (1), 0x40024210 (2), 0x40018210 (3), 0x4001C210 (4), 0x40008210 (5),

0x40040210 (6), 0x40034210 (7)

Access: Read-only

This configuration is relevant only if USART_MODE = 0xE or 0xF in ”USART Mode Register”.

The following configuration values are valid for all listed bit names of this register:

0: The corresponding interrupt is not enabled.

1: The corresponding interrupt is enabled.

• RXRDY: RXRDY Interrupt Mask

• TXRDY: TXRDY Interrupt Mask

• OVRE: Overrun Error Interrupt Mask

• TXEMPTY: TXEMPTY Interrupt Mask

• UNRE: SPI Underrun Error Interrupt Mask

• NSSE: NSS Line Event (CTS pin) Interrupt Mask

• CMP: Comparison Interrupt Mask

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–CMP––NSSE–––

15 14 13 12 11 10 9 8

– – – RXBUFF TXBUFE UNRE TXEMPTY –

76543210

– – OVRE ENDTX ENDRX – TXRDY RXRDY

• ENDRX: End of Receive Buffer Interrupt Mask

• ENDTX: End of Transmit Buffer Interrupt Mask

• TXBUFE: Transmit Buffer Empty Interrupt Mask

• RXBUFF: Receive Buffer Full Interrupt Mask

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

720

30.7.13 USART Interrupt Mask Register (LIN_MODE)

Name: US_IMR (LIN_MODE)

Address: 0x4000C210 (0), 0x40020210 (1), 0x40024210 (2), 0x40018210 (3), 0x4001C210 (4), 0x40008210 (5),

0x40040210 (6), 0x40034210 (7)

Access: Read-only

This configuration is relevant only if USART_MODE = 0xA or 0xB in ”USART Mode Register”.

The following configuration values are valid for all listed bit names of this register:

0: The corresponding interrupt is not enabled.

1: The corresponding interrupt is enabled.

• RXRDY: RXRDY Interrupt Mask

• TXRDY: TXRDY Interrupt Mask

• OVRE: Overrun Error Interrupt Mask

• FRAME: Framing Error Interrupt Mask

• PARE: Parity Error Interrupt Mask

• TIMEOUT: Timeout Interrupt Mask

• TXEMPTY: TXEMPTY Interrupt Mask

• LINBK: LIN Break Sent or LIN Break Received Interrupt Mask

• LINID: LIN Identifier Sent or LIN Identifier Received Interrupt Mask

• LINTC: LIN Transfer Completed Interrupt Mask

• LINBE: LIN Bus Error Interrupt Mask

31 30 29 28 27 26 25 24

LINHTE LINSTE LINSNRE LINCE LINIPE LINISFE LINBE –

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

LINTC LINID LINBK RXBUFF TXBUFE – TXEMPTY TIMEOUT

76543210

PARE FRAME OVRE ENDTX ENDRX – TXRDY RXRDY

• ENDRX: End of Receive Buffer Interrupt Mask

• ENDTX: End of Transmit Buffer Interrupt Mask

• TXBUFE: Transmit Buffer Empty Interrupt Mask

• RXBUFF: Receive Buffer Full Interrupt Mask

721

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• LINISFE: LIN Inconsistent Synch Field Error Interrupt Mask

• LINIPE: LIN Identifier Parity Interrupt Mask

• LINCE: LIN Checksum Error Interrupt Mask

• LINSNRE: LIN Slave Not Responding Error Interrupt Mask

• LINSTE: LIN Synch Tolerance Error Interrupt Mask

• LINHTE: LIN Header Timeout Error Interrupt Mask

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

722

30.7.14 U SART Cha n ne l Status Register

Name: US_CSR

Address: 0x4000C214 (0), 0x40020214 (1), 0x40024214 (2), 0x40018214 (3), 0x4001C214 (4), 0x40008214 (5),

0x40040214 (6), 0x40034214 (7)

Access: Read-only

For SPI specific configuration, see ”USART Channel Status Register (SPI_MODE)”.

For LIN specific configuration, see ”USART Channel Status Register (LIN_MODE)”.

• RXRDY: Receiver Ready (cleared by reading US_RHR)

0: No complete character has been rece ived since the last read of US_RHR or the receiver is disabled. If characters were

being received when the receiver was disabled, RXRDY changes to 1 when the receiver is enabled.

1: At least one complete character has been received and US_RHR has not yet been read.

• TXRDY: Transmitter Ready (cleared by writing US_THR)

0: A character is in the US_THR waiting to be transferred to the Transmit Shift Register, or an STTBRK command has

been requested, or the transmitter is disabled. As soon as the transmitter is enabled, TXRDY becomes 1.

1: There is no character in the US_THR.

• RXBRK: Break Received/End of Break (cleared by writing a one to the bit US_CR.RSTSTA)

0: No break received or end of break detected since the last RSTSTA.

1: Break received or end of break detected since the last RSTSTA.

• ENDRX: End of RX Buffer (cleared by writing US_RCR or US_RNCR)

0: The Receive Counter Register has not reached 0 since the last write in US_RCR or US_RNCR(1).

1: The Receive Counter Register has reached 0 since the last write in US_RCR or US_RNCR(1).

• ENDTX: End of TX Buffer (cleared by writing US_TCR or US_TNCR)

0: The Transmit Counter Register has not reached 0 since the last write in US_TCR or US_TNCR(1).

1: The Transmit Counter Register has reached 0 since the last write in US_TCR or US_TNCR(1).

• OVRE: Overrun Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No overrun error has occurre d sin ce the las t R STSTA.

1: At least one overrun error has occurred since the last RSTSTA.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

CTS CMP – – CTSIC – – –

15 14 13 12 11 10 9 8

– – NACK RXBUFF TXBUFE ITER TXEMPTY TIMEOUT

76543210

PARE FRAME OVRE ENDTX ENDRX RXBRK TXRDY RXRDY

723

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• FRAME: Framing Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No stop bit has been detected low since the last RSTSTA.

1: At least one stop bit has been detected low since the last RSTSTA.

• PARE: Parity Error (cleared by writing a one to the US_CR.RSTSTA)

0: No parity error has been detected since the last RSTSTA.

1: At least one parity error has been detected since the last RSTSTA.

• TIMEOUT: Receiver Timeout (cleared by writing a one to the bit US_CR.STTTO)

0: There has not been a timeout since the last Start Timeout command (STTTO in US_CR) or the Timeout Register is 0.

1: There has been a timeout since the last Start Timeout command (STTTO in US_CR).

• TXEMPTY: Transmitter Empty (cleared by writing US_THR)

0: There are characters in either US_THR or the Transmit Shift Register, or the transmitter is disabled.

1: There are no characters in US_THR, nor in the Transmit Shift Register.

• ITER: Max Number of Repetitions Reached (cleared by writing a one to the bit US_CR.RSTIT)

0: Maximum number of repetitions has not been reached since the last RSTIT.

1: Maximum number of repetitions has been reached since the last RSTIT.

• TXBUFE: TX Buffer Empty (cleared by writing US_TCR or US_TNCR)

0: US_TCR or US_TNCR have a value other than 0(1).

1: Both US_TCR and US_TNCR have a value of 0(1).

• RXBUFF: RX Buffer Full (cleared by writing US_RCR or US_RNCR)

0: US_RCR or US_RNCR have a value other than 0(1).

1: Both US_RCR and US_RNCR have a value of 0(1).

Note: 1. US_RCR, US_RNCR, US_TCR and US_TNCR are PDC registers.

• NACK: Non Acknowledge Interrupt (cleared by writing a one to the bit US_CR.RSTNACK)

0: Non acknowledge has not been detected since the last RSTNACK.

1: At least one non acknowledge has been detected since the last RSTNACK.

• CTSIC: Clear to Send Input Change Flag (cleared on read)

0: No input change has been detected on the CTS pin since the last read of US_CSR.

1: At least one input change has been detected on the CTS pin since the last read of US_CSR.

• CMP: Comparison Status (cleared by writing a one to the bit US_CR.RSTSTA command)

0: No received character matched the comparison criteria programmed in VAL1, VAL2 fields and CMPPAR bit in si nce the

last RSTSTA.

1: A received character matched the comparison criteria since the last RSTSTA.

• CTS: Image of CTS Input

0: CTS input is driven low.

1: CTS input is driven high.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

724

30.7.15 USART Cha nne l Status Register (SPI_MODE)

Name: US_CSR (SPI_MODE)

Address: 0x4000C214 (0), 0x40020214 (1), 0x40024214 (2), 0x40018214 (3), 0x4001C214 (4), 0x40008214 (5),

0x40040214 (6), 0x40034214 (7)

Access: Read-only

This configuration is relevant only if USART_MODE = 0xE or 0xF in ”USART Mode Register”.

• RXRDY: Receiver Ready (cleared by reading US_RHR)

0: No complete character has been rece ived since the last read of US_RHR or the receiver is disabled. If characters were

being received when the receiver was disabled, RXRDY changes to 1 when the receiver is enabled.

1: At least one complete character has been received and US_RHR has not yet been read.

• TXRDY: Transmitter Ready (cleared by writing US_THR)

0: A character is in the US_THR waiting to be transferred to the Transmit Shift Register or the transmitter is disabled. As

soon as the tran sm itte r is enab led , T XRDY be co me s 1.

1: There is no character in the US_THR.

• OVRE: Overrun Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No overrun error has occurre d sin ce the las t R STSTA.

1: At least one overrun error has occurred since the last RSTSTA.

• TXEMPTY: Transmitter Empty (cleared by writing US_THR)

0: There are characters in either US_THR or the Transmit Shift Register, or the transmitter is disabled.

1: There are no characters in US_THR, nor in the Transmit Shift Register.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

NSSCMP––NSSE–––

15 14 13 12 11 10 9 8

– – – RXBUFF TXBUFE UNRE TXEMPTY –

76543210

– – OVRE ENDTX ENDRX – TXRDY RXRDY

• ENDRX: End of RX Buffer (cleared by writing US_RCR or US_RNCR)

0: The Receive Counter Register has not reached 0 since the last write in US_RCR or US_RNCR(1).

1: The Receive Counter Register has reached 0 since the last write in US_RCR or US_RNCR(1).

• ENDTX: End of TX Buffer (cleared by writing US_TCR or US_TNCR)

0: The Transmit Counter Register has not reached 0 since the last write in US_TCR or US_TNCR(1).

1: The Transmit Counter Register has reached 0 since the last write in US_TCR or US_TNCR(1).

725

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• UNRE: Underrun Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No SPI underrun error has occurred since the last RSTSTA.

1: At least one SPI underrun error has occurred since the last RSTSTA.

• NSSE: NSS line event (CTS pin) (cleared on read)

0: No NSS line event has been detected on the CTS pin since the last read of US_CSR.

1: A rising or falling edge has been detected on the NSS line since the last read of US_CSR.

• CMP: Comparison Match (cleared by writing a one to the bit US_CR.RSTSTA)

0: No received character matched the comparison criteria programmed in VAL1,VAL2 fields and CMPPAR bit in

US_CMPR since the last RSTSTA.

1: A received character matched the comparison criteria since the last RSTSTA.

• NSS: Image of NSS line event (CTS pin)

This bit, associated with the NSSE bit, determines if the NSS line event is a rising or a falling edge.

0: NSS line is driven low.

1: NSS line is driven high.

• TXBUFE: TX Buffer Empty (cleared by writing US_TCR or US_TNCR)

0: US_TCR or US_TNCR have a value other than 0(1).

1: Both US_TCR and US_TNCR have a value of 0(1).

• RXBUFF: RX Buffer Full (cleared by writing US_RCR or US_RNCR)

0: US_RCR or US_RNCR have a value other than 0(1).

1: Both US_RCR and US_RNCR have a value of 0(1).

Note: 1. US_RCR, US_RNCR, US_TCR and US_TNCR are PDC registers.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

726

30.7.16 USART Channel Status Register (LIN_MODE)

Name: US_CSR (LIN_MODE)

Address: 0x4000C214 (0), 0x40020214 (1), 0x40024214 (2), 0x40018214 (3), 0x4001C214 (4), 0x40008214 (5),

0x40040214 (6), 0x40034214 (7)

Access: Read-only

This configuration is relevant only if USART_MODE = 0xA or 0xB in ”USART Mode Register”.

• RXRDY: Receiver Ready (cleared by reading US_RHR)

0: No complete character has been rece ived since the last read of US_RHR or the receiver is disabled. If characters were

being received when the receiver was disabled, RXRDY changes to 1 when the receiver is enabled.

1: At least one complete character has been received and US_RHR has not yet been read.

• TXRDY: Transmitter Ready (cleared by writing US_THR)

0: A character is in the US_THR waiting to be transferred to the Transmit Shift Register or the transmitter is disabled. As

soon as the tran sm itte r is enab led , T XRDY be co me s 1.

1: There is no character in the US_THR.

• OVRE: Overrun Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No overrun error has occurre d sin ce the las t R STSTA.

1: At least one overrun error has occurred since the last RSTSTA.

• FRAME: Framing Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No stop bit has been detected low since the last RSTSTA.

1: At least one stop bit has been detected low since the last RSTSTA.

31 30 29 28 27 26 25 24

LINHTE LINSTE LINSNRE LINCE LINIPE LINISFE LINBE –

23 22 21 20 19 18 17 16

LINBLS–––––––

15 14 13 12 11 10 9 8

LINTC LINID LINBK RXBUFF TXBUFE – TXEMPTY TIMEOUT

76543210

PARE FRAME OVRE ENDTX ENDRX – TXRDY RXRDY

• ENDRX: End of RX Buffer (cleared by writing US_RCR or US_RNCR)

0: The Receive Counter Register has not reached 0 since the last write in US_RCR or US_RNCR(1).

1: The Receive Counter Register has reached 0 since the last write in US_RCR or US_RNCR(1).

• ENDTX: End of TX Buffer (cleared by writing US_TCR or US_TNCR)

0: The Transmit Counter Register has not reached 0 since the last write in US_TCR or US_TNCR(1).

1: The Transmit Counter Register has reached 0 since the last write in US_TCR or US_TNCR(1).

727

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• PARE: Parity Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No parity error has been detected since the last RSTSTA.

1: At least one parity error has been detected since the last RSTSTA.

• TIMEOUT: Receiver Timeout (cleared by writing a one to the bit US_CR.RSTSTA)

0: There has not been a timeout since the last start timeout command (STTTO in US_CR) or the Timeout Register is 0.

1: There has been a timeout since the last start timeout command.

• TXEMPTY: Transmitter Empty (cleared by writing US_THR)

0: There are characters in either US_THR or the Transmit Shift Register, or the transmitter is disabled.

1: There are no characters in US_THR, nor in the Transmit Shift Register.

• LINBK: LIN Break Sent or LIN Break Received (cleared by writing a one to the bit US_CR.RSTSTA)

Applicable if USART operates in LIN Master mode (USART_MODE = 0xA):

0: No LIN break has been sent since the last RSTSTA.

1: At least one LIN break has been sent since the last RSTSTA

If USART operates in LIN Slave mode (USART_MODE = 0xB):

0: No LIN break has been received since the last RSTSTA.

1:At least one LIN break has been received since the last RSTSTA.

• LINID: LIN Identifier Sent or LIN Identifier Received (cleared by writing a one to the bit US_CR.RSTSTA)

If USART operates in LIN Master mode (USART_MODE = 0xA):

0: No LIN identifier has been sent since the last RSTSTA.

1:At least one LIN identifier has been sent since the last RSTSTA.

If USART operates in LIN Slave mode (USART_MODE = 0xB):

0: No LIN identifier has been received since the last RSTSTA.

1:At least one LIN identifier has been received since the last RSTSTA

• LINTC: LIN Transfer Completed (cleared by writing a one to the bit US_CR.RSTSTA)

0: The USART is idle or a LIN transfer is ongoing.

1: A LIN transfer has been completed since the last RSTSTA.

• LINBLS: LIN Bus Line Status

0: LIN bus line is set to 0.

1: LIN bus line is set to 1.

• TXBUFE: TX Buffer Empty (cleared by writing US_TCR or US_TNCR)

0: US_TCR or US_TNCR have a value other than 0(1).

1: Both US_TCR and US_TNCR have a value of 0(1).

• RXBUFF: RX Buffer Full (cleared by writing US_RCR or US_RNCR)

0: US_RCR or US_RNCR have a value other than 0(1).

1: Both US_RCR and US_RNCR have a value of 0(1).

Note: 1. US_RCR, US_RNCR, US_TCR and US_TNCR are PDC registers.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

728

• LINBE: LIN Bit Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No bit error has been detected since the last RSTSTA.

1: A bit error has been detected since the last RSTSTA.

• LINISFE: LIN Inconsistent Synch Field Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No LIN inconsistent synch field error has been detected since the last RSTSTA.

1: The USART is configured as a slave node and a LIN Inconsistent synch field error has been dete cted since the last

RSTSTA.

• LINIPE: LIN Identifier Parity Error (cleared by writing a one to the bit US_ CR.RSTSTA)

0: No LIN identifier parity error has been detected since the last RSTSTA.

1: A LIN identifier parity error has been detected since the last RSTSTA.

• LINCE: LIN Checksum Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No LIN checksum error has been detected since the last RSTSTA.

1: A LIN checksum error has been detected since the last RSTSTA.

• LINSNRE: LIN Slave Not Responding Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No LIN slave not responding error has been detected since the last RSTSTA.

1: A LIN slave not responding error has been detected since the last RSTSTA.

• LINSTE: LIN Synch Tolerance Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No LIN synch tolerance error has been detected since the last RSTSTA.

1: A LIN synch tolerance error has been detected since the last RSTSTA.

• LINHTE: LIN Header Timeout Error (cleared by writing a one to the bit US_CR.RSTSTA)

0: No LIN header timeout error has been detected since the last RSTSTA.

1: A LIN header timeout error has been detected since the last RSTSTA.

729

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.17 USART Receive Holding Regis ter

Name: US_RHR

Address: 0x4000C218 (0), 0x40020218 (1), 0x40024218 (2), 0x40018218 (3), 0x4001C218 (4), 0x40008218 (5),

0x40040218 (6), 0x40034218 (7)

Access: Read-only

• RXCHR: Received Character

Last character received if RXRDY is set.

• RXSYNH: Received Sync

0: Last character received is a data.

1: Last character received is a command.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

RXSYNH ––––––RXCHR

76543210

RXCHR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

730

30.7.18 USART Transmit Holding Register

Name: US_THR

Address: 0x4000C21C (0), 0x4002021C (1), 0x4002421C (2), 0x4 001821C (3), 0x4001C21C (4), 0x4000821C (5),

0x4004021C (6), 0x4003421C (7)

Access: Write-only

• TXCHR: Charact e r to be Transmitted

Next character to be transmitted after the current character if TXRDY is not set.

• TXSYNH: Sync Field to be Transmitted

0: The next character sent is encoded as a data. Start frame delimiter is DATA SYNC.

1: The next character sent is encoded as a command. Start frame delimiter is COMMAND SYNC.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

TXSYNH ––––––TXCHR

76543210

TXCHR

731

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.19 USART Baud Rate Generator Register

Name: US_BRGR

Address: 0x4000C220 (0), 0x40020220 (1), 0x40024220 (2), 0x40018220 (3), 0x4001C220 (4), 0x40008220 (5),

0x40040220 (6), 0x40034220 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

• CD: Clock Divider

• FP: Fractional Part

0: Fractional divider is disabled.

1–7: Baud rate resolution, defined by FP × 1/8.

Warning: When the value of field FP is greater than 0, the SCK (oversampling clock) generates nonconstant duty cycles.

The SCK high duration is increased by “selected clock” period from time to time. The duty cycle depends on the value of

the CD field.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––– FP

15 14 13 12 11 10 9 8

76543210

USART_MODE ≠ ISO7816

USART_MODE = ISO7816

SYNC = 0 SYNC = 1

USART_MODE = SPI

(Master or Slave)OVER = 0 OVER = 1

0 Baud Rate Clock Disabled

1 to 65535 CD = Selected Clock /

(16 × Baud Rate) CD = Selected Clock /

(8 × Baud Rate) CD = Selected Clock /

Baud Rate CD = Selected Clock /

(FI_DI_RATIO × Baud Rate)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

732

30.7.20 USART Receiver Timeout Register

Name: US_RTOR

Address: 0x4000C224 (0), 0x40020224 (1), 0x40024224 (2), 0x40018224 (3), 0x4001C224 (4), 0x40008224 (5),

0x40040224 (6), 0x40034224 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

• TO: Timeout Value

0: The receiver timeout is disabled.

1–131071: The receiver timeout is enabled and the timeout delay is TO × bit period.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––––––TO

15 14 13 12 11 10 9 8

76543210

733

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.21 U SART Transmitter Timeguard Register

Name: US_TTGR

Address: 0x4000C228 (0), 0x40020228 (1), 0x40024228 (2), 0x40018228 (3), 0x4001C228 (4), 0x40008228 (5),

0x40040228 (6), 0x40034228 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

• TG: Timeguard Value

0: The transmitter timeguard is disabled.

1–255: The transmitter timeguard is enabled and TG is timeguard delay / bit period.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

734

30.7.22 USART FI DI RATIO Register

Name: US_FIDI

Address: 0x4000C240 (0), 0x40020240 (1), 0x40024240 (2), 0x40018240 (3), 0x4001C240 (4), 0x40008240 (5),

0x40040240 (6), 0x40034240 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

• FI_DI_RATIO: FI Over DI Ratio Value

0: If ISO7816 mode is selected, the baud rate generator generates no signal.

3 – 2047: If ISO7816 mode is selected, the baud rate is the clock provided on SCK divided by FI_DI_RATIO.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

FI_DI_RATIO

76543210

FI_DI_RATIO

735

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.23 USART Number of Errors Register

Name: US_NER

Address: 0x4000C244 (0), 0x40020244 (1), 0x40024244 (2), 0x40018244 (3), 0x4001C244 (4), 0x40008244 (5),

0x40040244 (6), 0x40034244 (7)

Access: Read-only

This register is relevant only if USART_MODE = 0x4 or 0x6 in ”USART Mode Register”.

• NB_ERRORS: Number of Errors

Total number of errors that occurred during an ISO7816 transfer. This register automatically clears when read.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

NB_ERRORS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

736

30.7.24 USART IrDA FILTER Register

Name: US_IF

Address: 0x4000C24C (0), 0x4002024C (1), 0x4002424C (2), 0x4 001824C (3), 0x4001C24C (4), 0x4000824C (5),

0x4004024C (6), 0x4003424C (7)

Access: Read/Write

This register is relevant only if USART_MODE = 0x8 in ”USART Mode Register”.

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

• IRDA_FILTER: IrDA Filter

The IRDA_FIL TE R valu e m ust be defined to meet the following criteria:

tperipheral clock x (IRDA_FILTER + 3) < 1.41 µs

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

IRDA_FILTER

737

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.25 USART LIN Mode Register

Name: US_LINMR

Address: 0x4000C254 (0), 0x40020254 (1), 0x40024254 (2), 0x40018254 (3), 0x4001C254 (4), 0x40008254 (5),

0x40040254 (6), 0x40034254 (7)

Access: Read/Write

This register is relevant only if USART_MODE = 0xA or 0xB in ”USART Mode Register”.

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

• NACT: LIN Node Action

Values which are not listed in the table must be considered as “reserved”.

• PARDIS: Parity Disable

0: In master node configuration, the identifier parity is computed and sent automatically. In master node and slave node

configuration, the parity is checked automatically.

1: Whatever the node configuration is, the Identifier parity is not computed/sent and it is not checked.

• CHKDIS: Checksum Disable

0: In master node configuration, the checksum is computed and sent automatically. In slave node configuration, the check-

sum is checked automatically.

1: Whatever the node configuration is, the checksum is not computed/sent and it is not checked.

• CHKTYP: Checksum Type

0: LIN 2.0 “enhanced” checksum

1: LIN 1.3 “classic” checksum

• DLM: Data Length Mode

0: The response data length is defined by the field DLC of this register.

1: The response data length is defined by the bits 5 and 6 of the identifier (IDCHR in US_LINIR).

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––SYNCDIS PDCM

15 14 13 12 11 10 9 8

DLC

76543210

WKUPTYP FSDIS DLM CHKTYP CHKDIS PARDIS NACT

Value Name Description

00 PUBLISH The USART transmits the response.

01 SUBSCRIBE The USART receives the response.

10 IGNORE The USART does not transmit and does not rece ive the response.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

738

• FSDIS: Frame Slot Mode Disable

0: The Frame Slot mode is enabled.

1: The Frame Slot mode is disabled.

• WKUPTYP: Wakeup Signal Type

0: Setting the bit LINWKUP in the control register sends a LIN 2.0 wakeup signal.

1: Setting the bit LINWKUP in the control register sends a LIN 1.3 wakeup signal.

• DLC: Data Length Control

0–255: Defines the response data length if DLM = 0,in that case the response data length is equal to DLC+1 bytes.

• PDCM: PDC Mode

0: The LIN mode register US_LINMR is not written by the PDC.

1: The LIN mode register US_LINMR (excepting that flag) is written by the PDC.

• SYNCDIS: Synchronization Disable

0: The synchronization procedure is performed in LIN slave node configuration.

1: The synchronization procedure is not performed in LIN slave node configur ation.

739

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.26 USART LIN Identifier Register

Name: US_LINIR

Address: 0x4000C258 (0), 0x40020258 (1), 0x40024258 (2), 0x40018258 (3), 0x4001C258 (4), 0x40008258 (5),

0x40040258 (6), 0x40034258 (7)

Access: Read/Write or Read-only

This register is relevant only if USART_MODE = 0xA or 0xB in ”USART Mode Register”.

• IDCHR: Identifier Character

If USART_MODE = 0xA (master node configuration):

IDCHR is Read/Write and its value is the identifier character to be transmitted.

If USART_MODE = 0xB (slave node configuration):

IDCHR is Read-only and its value is the last identifier character that has been received.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

IDCHR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

740

30.7.27 USART LIN Baud Rate Register

Name: US_LINBRR

Address: 0x4000C25C (0), 0x4002025C (1), 0x4002425C (2), 0x4 001825C (3), 0x4001C25C (4), 0x4000825C (5),

0x4004025C (6), 0x4003425C (7)

Access: Read-only

This register is relevant only if USART_MODE = 0xA or 0xB in ”USART Mode Register”.

Returns the baud rat e va lue after the synchronizati on process completion.

• LINCD: Clock Divider after Synchronizat ion

• LINFP: Fractional Part after Synchronization

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––– LINFP

15 14 13 12 11 10 9 8

LINCD

76543210

LINCD

741

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.28 USART Comparison Register

Name: US_CMPR

Address: 0x4000C290 (0), 0x40020290 (1), 0x40024290 (2), 0x40018290 (3), 0x4001C290 (4), 0x40008290 (5),

0x40040290 (6), 0x40034290 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in ”USART Write Protection Mode Register”.

• VAL1: First Comparison Value for Received Character

0 to 511.

• CMPMODE: Comparison Mode

• CMPPAR: Comp are Parity

0: The parity is not checked and a bad parity cannot prevent the system from waking up.

1: The system wakeup is performed if both a matching condition on data exists an d the parity is correct.

• VAL2: Second Comparison Value for Received Character

0 to 511.

31 30 29 28 27 26 25 24

–––––––VAL2

23 22 21 20 19 18 17 16

VAL2

15 14 13 12 11 10 9 8

– CMPPAR – CMPMODE – – – VAL1

76543210

VAL1

Value Name Description

0 FLAG_ONLY Any character is received and comparison function drives CMP flag.

1 START_CONDITION Comparison condition must be met to start reception of all incoming characters until

REQCLR is set.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

742

30.7.29 USART Write Protection Mode Register

Name: US_WPMR

Address: 0x4000C2E4 (0), 0x400202E4 (1), 0x400242E4 (2 ), 0x400182E4 (3), 0x4001C2E4 (4), 0x400082E4 (5),

0x400402E4 (6), 0x400342E4 (7)

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x555341 (“USA” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x555341 (“USA” in ASCII).

See Section 30.6.11 ”USART Register Write Protection” for the list of registers that can be write-protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

———————WPEN

Value Name Description

0x555341 PASSWD Writing any other value in this field aborts the write operation of the WPEN bit. Always reads as

743

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

30.7.30 USART Write Protection Status Register

Name: US_WPSR

Address: 0x4000C2E8 (0), 0x400202E8 (1), 0x400242E8 (2 ), 0x400182E8 (3), 0x4001C2E8 (4), 0x400082E8 (5),

0x400402E8 (6), 0x400342E8 (7)

Access: Read-only

• WPVS: Write Protection Violation Status

0: No write protec tion v iola tio n ha s oc curred since the last read of the US_WPSR.

1: A write protection violation has occur red since the last rea d of the US_WPSR. If th is violation is an unauthorize d attempt

to write a protected register, the associated violation is reported into field WPVSRC.

• WPVSRC: Write Protection Vi olation Source

When WPVS = 1, WPVSRC indicates the register address offset at which a write access has been attempted.

31 30 29 28 27 26 25 24

————————

23 22 21 20 19 18 17 16

WPVSRC

15 14 13 12 11 10 9 8

WPVSRC

76543210

———————WPVS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

744

31. Serial Peripheral Interface (SPI)

31.1 Description

The Serial Per ipheral Interface (SPI) circuit is a synchronous serial data link that provides communication with

external devices in Master or Slave mode. It also enables communication between processors if an external

processor is connected to the system.

The Serial Peripheral Interface is essentially a Shift register that serially transmits data bits to other SPIs. During a

data transfer, one SPI system acts as the “master”' which controls the data flow, while the other devices act as

“slaves'' which have data shifted into and out by the master. Different CPUs can take turn being masters (multiple

master protocol, contrary to single master protocol where one CPU is always the master while all of the others are

always slaves). One master can simultaneously shift data into multiple slaves. However, only one slave can drive

its output to write data back to the master at any given time.

A slave device is selected when the master asserts its NSS signal. If multiple slave devices exist , the master

generates a separate slave select signal for each slave (NPCS).

The SPI system consists of two data lines and two control lines:

Master Out Slave In (MOSI): This data line su pp lies the output data from the master shifted into the input(s)

of the slave(s).

Master In Slave Out (MISO): This data line supplies the output data from a slave to the input of the master.

There may be no more than one slave transmitting data during any pa rticular transfer.

Serial Clock (SPCK): This control line is driven by the master and regulates the flow of the data bits. The

master can transmit data at a variety of bit rates; there is one SPCK pulse for each bit that is transmitted.

Slave Select (NSS): This control line allows slaves to be turned on and off by hardware.

31.2 Embedded Characteristics

Master or Slave Serial Peripheral Bus Interface

8-bit to 16-bit programmable data length per chip select

Programmable phase and polarity per chip select

Programmable transfer delay between consecutive transfers and delay before SPI clock per chip

select

Programmable delay between chip selects

Asynchronous Partial Wakeup (SleepWalking) Capability

Master mode can drive SPCK up to Peripheral Clock

Master mode bit rate can be independent of the processor/peripheral clock

Slave mode operates on SPCK, asynchronously with core and bus clock

Two chip selects with external decoder support allow communication with up to 3 peripherals

Selectable Mode Fault Detection

Communication with Serial External Devices Supported

Serial memories, such as DataFlash and 3-wire EEPROMs

Serial peripherals, such as ADCs, DACs, LCD controllers, CAN controllers and sensors

External copr oc ess or s

Connection to PDC Channel Capabilities, Optimizing Data Transfers

One channel for the receiver

One channel for the transmitter

745

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.3 Block Diagram

Figure 31-1. SPI Block Diagram

31.4 Application Block Diagram

Figure 31-2. Application Bloc k Dia gram: Single Master/Multiple Slave Implementation

PDC

SPI

Peripheral bridge

PMC

Peripheral

clock

Bus clock

AHB Matrix

Trig.

events

FLEXCOM

user interface

PIO

flags

MOSI

MISO

SPCK

NPCSx

PCKx

PADs

Interrupt

Controller

FLEXCOM

Interrupt

SPI Master

SPCK

MISO

MOSI

NPCS0

NPCS1

SPCK

MISO

MOSI

NSS

Slave 0

SPCK

MISO

MOSI

NSS

Slave 1

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

746

31.5 I/O Lines Description

31.6 Product Dependencies

31.6.1 I/O Lines

The pins used for inte rfacing the SPI are mu lti plexed with the USART an d TWI lines within th e FLEXCOM mod ule.

The programmer must first program the PIO controller to assign the desired FLEXCOM pins to their peripheral

function. If the I/O lines of the FLEXCOM are not used by the applicat ion, the y can b e used for ot her pu rposes by

the PIO controller.

Table 31-1. Signal Descr iption

Pin Name Pin Descriptio n

Type

Master Slave

MISO Master In Slave Out Input Output

MOSI Master Out Sl ave In Output Input

SPCK Serial Clock Output Input

NPCS1 Peripheral Chip Select Output Unused

NPCS0/NSS P eripheral Chip Select/Slave Select Output Input

Table 31-2. I/O Lines

Instance Signal I/O Line Peripheral

SPI0 RXD0/SPI0_MISO/TWCK0 PA9 A

SPI0 SCK0/SPI0_SPCK PB0 A

SPI0 SPI0_NPCS0/CTS0 PA25 A

SPI0 SPI0_NPCS1/RTS0 PA26 A

SPI0 TXD0/SPI0_MOSI/TWD0 PA10 A

SPI1 RXD1/SPI1_MISO/TWCK1 PB2 A

SPI1 SCK1/SPI1_SPCK PA27 A

SPI1 SPI1_NPCS0/CTS1 PA28 A

SPI1 SPI1_NPCS1/RTS1 PA29 A

SPI1 TXD1/SPI1_MOSI/TWD1 PB3 A

SPI2 RXD2/SPI2_MISO/TWCK2 PA5 A

SPI2 SCK2/SPI2_SPCK PA15 B

SPI2 SCK2/SPI2_SPCK PA24 B

SPI2 SPI2_NPCS0/CTS2 PA16 A

SPI2 SPI2_NPCS1/RTS2 PA15 A

SPI2 TXD2/SPI2_MOSI/TWD2 PA6 A

SPI3 RXD3/SPI3_MISO/TWCK3 PA4 A

SPI3 SCK3/SPI3_SPCK PB13 A

SPI3 SPI3_NPCS0/CTS3 PB14 A

SPI3 SPI3_NPCS1/RTS3 PB15 A

747

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.6.2 Power Management

The peripheral clo ck is not continuously provided to the SPI. T he programmer must first enable the FL EXCOM

clock in the Power Management Controller (PMC) and set the OPMODE field to 2 in FLEXCOM Mode Register

(FLEX_MR) before using the SPI.

If the OPMODE field differs from 2, the SPI clock is stopped.

In SleepWalking mode (asynchronous partial wakeup), the PMC must be configured to enable SleepWalking for

the FLEXCOM in the Sleepwalking Enable Register (PMC_SLPWK_ER). The peripheral clock can be

automatically provided to the FLEXCOM, depending on the instructions (requests) provided by the FLEXCOM to

the PMC.

SPI3 TXD3/SPI3_MOSI/TWD3 PA3 A

SPI4 RXD4/SPI4_MISO/TWCK4 PB9 A

SPI4 RXD4/SPI4_MISO/TWCK4 PB11 A

SPI4 SCK4/SPI4_SPCK PB1 A

SPI4 SPI4_NPCS0/CTS4 PB8 B

SPI4 SPI4_NPCS1/RTS4 PB9 B

SPI4 TXD4/SPI4_MOSI/TWD4 PB8 A

SPI4 TXD4/SPI4_MOSI/TWD4 PB10 A

SPI5 RXD5/SPI5_MISO/TWCK5 PA12 A

SPI5 SCK5/SPI5_SPCK PA14 A

SPI5 SPI5_NPCS0/CTS5 PA11 A

SPI5 SPI5_NPCS1/RTS5 PA5 B

SPI5 SPI5_NPCS1/RTS5 PB2 B

SPI5 TXD5/SPI5_MOSI/TWD5 PA13 A

SPI6 RXD6/SPI6_MISO/TWCK6 PB1 B

SPI6 RXD6/SPI6_MISO/TWCK6 PB11 B

SPI6 SCK6/SPI6_SPCK PB13 B

SPI6 SPI6_NPCS0/CTS6 PB14 B

SPI6 SPI6_NPCS1/RTS6 PB15 B

SPI6 TXD6/SPI6_MOSI/TWD6 PB0 B

SPI6 TXD6/SPI6_MOSI/TWD6 PB10 B

SPI7 RXD7/SPI7_MISO/TWCK7 PA27 B

SPI7 SCK7/SPI7_SPCK PA29 B

SPI7 SPI7_NPCS0/CTS7 PA30 B

SPI7 SPI7_NPCS1/RTS7 PA31 B

SPI7 TXD7/SPI7_MOSI/TWD7 PA28 B

Table 31-2. I/O Lines (Contin ued)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

748

31.6.3 Interrupt

The SPI interrupt line is the FLEXCOM interrupt line if the field OPMODE = 2 in FLEX_MR. The FLEXCOM

interrupt line is connected to one of the internal sources of the Interrupt Controller. Using the FLEXCOM interrupt

requires the Interrupt Controller to be programmed first.

Table 31-3. Peripheral IDs

Instance ID

SPI0 8

SPI1 9

SPI2 14

SPI3 19

SPI4 20

SPI5 21

SPI6 22

SPI7 7

749

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31.7 SPI Functional Description

31.7.1 Modes of Operation

The SPI operates in Master mode or in Slave mode.

The SPI operates in Master mode by setting the MSTR bit in the SPI Mode Register (SPI_MR):

The NPCS0 to NPCS1 pins are all configured as outputs

The SPCK pin is driven

The MISO line is wired on the receiver input

The MOSI line is driven as an output by the transmitter.

The SPI operates in Slave mode if the MSTR bit in SPI_MR is cleared:

The MISO line is driven by the tr an sm itte r outp u t

The MOSI line is wired on the receiver input

The SPCK pin is driven by the transmitter to synchronize the receiver.

The NPCS0 pin becomes an input, and is used as a slave select signal (NSS)

The NPCS1 pin is not driven and can be used for oth er purposes.

The data transfers are identically programmable for both modes of operations. The bit rate generator is activated

only in Master mode.

31.7.2 Data Transfer

Four combinations of polarity and phase are availab le for data transfers. The clock po larity is prog rammed with the

CPOL bit in the SPI Chip Select register (SPI_CSR). The clock phase is programmed with the NCPHA bit. These

two parameters determine the edges of the clock signal on which data is driven and sampled. Each of the two

parameters has two possible states, resu lting in four possible combinations that a re incompatible with one a nother.

Consequently, a master/slave pair must use the same parameter pair values to communicate. If multiple slaves

are connected and req uire different configurations, the master m ust reconfigure itself each time it needs to

communicate with a different slave.

Table 31-4 shows the four modes and corres po nd in g paramete r se ttin gs .

Figure 31-3 and Figure 31-4 show examples of data transfers.

Table 31-4. SPI Bus Protocol Mode

SPI Mode CPOL NCPHA Shift SPCK Edge Capture SPCK Edge SPCK Inactive Level

0 0 1 Falling Rising Low

1 0 0 Rising Falling Low

2 1 1 Rising Falling High

3 1 0 Falling Rising High

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

750

Figure 31-3. SPI Transfer Format (NCPHA = 1, 8 bits per transfer)

Figure 31-4. SPI Transfer Format (NCPHA = 0, 8 bits per transfer)

31.7.3 Master Mode Operations

When configured in Master mode, the SPI operates on the clock generated by the internal programmable bit rate

generator. It fully controls the data transfers to and from the slave(s) connected to th e SPI bus. The SPI drives the

chip select line to the slave and the serial clock signal (SPCK).

SPCK

(CPOL = 0)

SPCK

(CPOL = 1)

MOSI

(from master)

MISO

(from slave)

NSS

(to slave)

SPCK cycle (for reference)

MSB

LSB

* Not defined.

12345 786

SPCK

(CPOL = 0)

SPCK

(CPOL = 1)

1 2345 7

MOSI

(from master)

MISO

(from slave)

NSS

(to slave)

SPCK cycle (for reference) 8

MSB

LSB

* Not defined.

751

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

The SPI features two holding registers, the Transmit Data register (SPI_TDR) and the Receive Data register

(SPI_RDR), and a single shift register. The holding registers maintain the data flow at a constant rate.

After enabling the SPI, a data transfer starts when the processor writes to SPI_TDR. The written data is

immediately transferre d in the Shift register and the transfer on the SPI bus sta rts. While the data in the Shift

loaded in the SPI_RDR without transmitting data. If there is no data to transmit, a dummy data can be used

(SPI_TDR filled with ones). When the WDRBT bit is set, a new data cannot be transmitted if the SPI_RDR has not

been read. If Receiving mode is n ot required, for example when communicating with a slave recei ver only (such as

an LCD), the receive status flags in the SPI Status register (SPI_SR) can be discarded.

Before writing the TDR, the PCS field in SPI_MR must be set in order to select a slave.

If new data is written in SPI_TDR during the tra nsfer, it is kept in SPI_TDR until the current transfer is completed.

Then, the received data is transferred from the Shift register to the SPI_RDR, the data in the SPI_TDR is loaded in

the Shift register and a new transfer starts.

As soon as the SPI_TDR is written, the Tr ansmit Data Register Empty (TDRE) flag in the SPI_SR is cleared. When

the data written in the SPI_TDR is loaded into the Shift register, the TDRE flag in the SPI_SR is set. The TDRE bit

is used to trigger the Transmit PDCchannel (see Figure 31-5).

The end of transfer is in dicated by th e TXEMPTY flag in SPI _SR. If a transfer delay (DLYBCT) is greater than 0 for

the last transfer, TXEMPTY is set after the completion of this delay. The peripheral clock can be switched off at this

time.

Note: When the SPI is enabled, the TDRE and TXEMPTY flags are set.

Figure 31-5. TDRE and TXEMPTY flag behavior

The transfer of received data from the Sh ift register to the SPI_RDR is indicated by the Receive Data Register Full

bit (RDRF) in the SPI_SR. When the received data is read, the RDRF bit is cleared.

If SPI_RDR has not been read before new data is received, the Overrun Error bit (OVRES) in SPI_SR is set. As

long as this flag is set, data is loaded in SPI_RDR. The user has to read the status register to clear the OVRES bit.

Figure 31-6 shows a block diagram of the SPI when operating in Master mode. Fig ure 31-7 ”Master Mode Flow

Diagram” shows a flow chart describing how transfers are handled.

TDRE

TXEMPTY

Transfer

Write SPI_CR.SPIEN =1 Write SPI_THR

Transfer Transfer

Write SPI_THR Write SPI_THR

automatic set

THR loaded

in shifter

automatic set

THR loaded

in shifter

automatic set

THR loaded

in shifter

DLYBCT DLYBCT

DLYBCT

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31.7.3.1 Master Mode Block Diagram

Figure 31-6. Master Mode Block Diagram

Shift Register

SPCK

MOSI

LSBMSB

MISO

SPI_RDR RD

SPI

Clock

TDRE

SPI_TDR TD

RDRF

OVRES

SPI_CSRx

CPOL

NCPHA

BITS

Peripheral clock Baud Rate Generator

SPI_CSRx

SCBR

NPCSx

NPCS0

SPI_MR PCS

SPI_TDR PCS

MODF

Current

Peripheral

SPI_RDR PCS

SPI_CSRx

CSAAT

PCSDEC

MODFDIS

MSTR

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31.7.3.2 Master Mode Flow Diagram

Figure 31-7. Master Mode Flow Diagram

SPI Enable

TDRE/TXEMPTY are set

CSAAT ?

(HW check)

PS ?

(HW check)

NPCS <= SPI_TDR(PCS) NPCS <= SPI_MR(PCS)

Delay DLYBS

Shifter <= SPI_TDR(TD)

TDRE is set

Data Transfer

(SPI bus driven)

SPI_RDR(RD) <= Shifter

RDRF is set

TDRE ?

(HW check)

NPCS deasserted

Delay DLYBCS

Fixed

peripheral

Variable

peripheral

Delay DLYBCT

0 (i.e. a new write to SPI_TDR occured while data transfer or delay DLYBCT)

1CSAAT ?

(HW check)

PS ?

(HW check) 0

SPI_TDR(PCS)

= NPCS ?

(HW check)

yes SPI_MR(PCS)

= NPCS ?

(HW check)

NPCS deasserted

Delay DLYBCS

NPCS <= SPI_TDR(PCS)

NPCS deasserted

Delay DLYBCS

NPCS <= SPI_MR(PCS),

SPI_TDR(PCS)

Fixed

peripheral

Variable

peripheral

- NPCS defines the current Chip Select

- CSAAT, DLYBS, DLYBCT refer to the fields of the

Chip Select Register corresponding to the Current Chip Select

- ‘x <= y’ must be interpreted as ‘x is loaded with y’ where x,y

represent either register fields or SPI pins

- HW = hardware, SW = software

TDRE/TXEMPTY are cleared

Write SPI_TDR ? no

yes

TXEMPTY is set

TDRE ?

(SW check)

Read SPI_RDR(RD)

if read is required

From this step,

SPI_TDR can be

rewritten for the

next transfer

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Figure 31-8 shows the behavior of Transmit Data Register Empty (TDRE), Receive Data Register (RDRF) and

Transmission Register Empty (TXEMPTY) statu s flags within the SPI_SR during an 8-bit data transfe r in Fixed

mode without the PDC involved.

Figure 31-8. Status Register Flags Behavior

Figure 31-9 shows the behavior of Transmission Register Empty (TXEMPTY), End of RX buffer (ENDRX), End of

TX buffer (ENDTX), RX Buffer Full (RXBUFF) and TX Buffer Empty (TXBUFE) status flags within SPI_SR during

an 8-bit data transfer in F ixed mode with the Peripheral Data Controlle r involved. The PDC is programmed to

transfer and receive three data. The next pointer and counter are not used. The RDRF and TDRE are not shown

because these flags are managed by the PDC when using the PDC.

SPCK

MOSI

(from master)

MISO

(from slave)

NPCS0

MSB

LSB

1 2345 786

RDRF

TDRE

TXEMPTY

Write in

SPI_TDR

RDR read

shift register empty

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Figure 31-9. PDC Status Register Flags Behavior

31.7.3.3 Clock Generation

The SPI bit rate clock is generated by dividing a source clock, which can be the peripheral clock or a

programmable clock from the PMC (PCKx). The divider can be any value between 1 and 255.

If the SCBR field is programmed to 1and the clock source is PMC PCKx, the operating bit rate is peripheral clock

(see the elec trical characteri stics section for the SPCK maximum frequency). Triggering a transfer while SCBR is

at 0 can lead to unpredictable results.

At reset, SCBR is 0 and the user has to program it to a valid value before performing the first transfer.

The divisor can be defined independently for each chip select, as it has to be programmed in the SCBR field in

SPI_CSR. This allows the SPI to automatically adapt the bit rate for each interfaced peripheral without

reprogramming.

If PCKx is selected as a source clock (BRSRCCLK = 1 in SPI_MR), the bit rate is independent of the

processor/bus clock. Thus the processor clock can be changed while the SPI is enabled. The processor clock

frequency change s must be performed only b y programming the PRES field in PMC _MCKR (see PMC section).

Other methods to modify the processor/bus clock frequency (PLL multiplier, etc.) are forbidden when SPI is

enabled.

The peripheral clock frequency must be at least tree times higher than PCKx.

31.7.3.4 Transfer Delays

Figure 31-10 shows a chip select transfer change and con secutive transfe rs on the same chip select. Three delays

can be programmed to modify the transfer waveforms:

The delay between the chip se lect s. It is programm able only once fo r all ch ip select s b y writing the DLYBCS

field in SPI_MR. The SPI slave device deactivation delay is managed through DLYBCS. If there is only one

SPI slave device connected to th e master, the DLYBCS field does not need to be configured. If several slave

devices are connected to a master, DLYBCS must be configured depending on the highest deactivation

delay. Refer to the SPI slave device electrical characteristics.

654321

SPCK

MOSI

(from master)

NPCS0

MSB

LSB

654321

12 3

ENDTX

TXEMPTY

MSB

LSB

654321

MISO

(from slave)

654321

ENDRX

TXBUFE

RXBUFF

TDRE

(not required

if PDC is used) PDC loads first byte

PDC loads 2nd byte

(double buffer effect) PDC loads last byte

MSB

MSBMSB MSB

LSBLSB

LSB

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The delay before SPCK, independently programmable for each chip select by writing the DLYBS field. The

SPI slave device activation delay is managed through DLYBS. Refer to the SPI slave device electrical

characteristics to define DLYBS.

The delay between consecutive transfers, independently progra mmable for each chip select by writing the

DLYBCT field. The time required by the SPI slave device to process received data is managed through

DLYBCT. This time depends on the SPI slave system activity.

These delays allow the SPI to be adapted to the interfaced peripherals and their speed and bus release time.

Figure 31-10. Programmable Delays

31.7.3.5 Peripheral Selection

The serial peripherals are selected through the assertion of the NPCS0 to NPCS1 signals. By default, all NPCS

signals are high before and after each transfer.

Fixed Peripheral Select Mode: SPI exchanges dat a with only one peripheral.

Fixed peripheral select mode is enabled by clearing the PS bit in SPI_MR. In this case, the current

peripheral is defined by the PCS field in SPI_MR and the PCS field in SPI_TDR has no effect.

Variable Peripheral Select Mode: Dat a can be e xchanged with more than on e periph eral without ha ving to

reprogram the NPCS field in SPI_MR.

Variable peripheral select Mode is enabled by setting the PS bit to one in SPI_MR. The PCS field in

SPI_TDR is used to select the current peripheral. This means that the peripheral sel ection can be defined for

each new data. The value to write in SPI_TDR has the following format:

[xxxxxxx(7-bit) + LASTXFER(1-bit)(1)+ xxxx(4-bit) + PCS (4-bit) + DATA (8 to 16-bit)] with PCS equals the

chip select to assert, as defined in Sectio n 31.8.4 ”SPI Transmit Data Register” and LASTXFER bit at 0 or 1

depending on the CSAAT bit.

Note: 1. Optional

CSAAT, LASTXFER and CSNAAT bits are discussed in Section 31.7.3.9 ”Peripheral Deselection with PDC”.

If LASTXFER is used, the command must be issued after writing the last character. Instead of LASTXFER,

the user can use the SPIDIS command. After the end of the PDC transfer, it is necessary to wait for the

TXEMPTY flag and then write SPIDIS into the SPI Control Register (SPI_CR). This does not change the

configuration register values). The NPCS is disabled after the last character transfer. Then, another PDC

transfer can be started if the SPIEN has previously been written in SPI_CR.

31.7.3.6 SPI Peripheral DMA Controller (PDC)

In both Fixed and Variable peripheral select modes, the Peripheral DMA Controller (PDC) can be used to reduce

processor overhead.

DLYBCS DLYBS DLYBCT DLYBCT

Chip Select 1

Chip Select 2

SPCK

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The fixed peripheral selection allows buffer transfers with a single peripheral. Using the PDC is an optimal means,

as the size of the data transfer between the memory and the SPI is either 8 bits or 16 bits. However, if the

peripheral selection is modified, the SPI_MR must be reprogrammed.

The variable peripheral selection allows bu ffer transfers with multiple peripherals without reprogramming the

SPI_MR. Data written in SPI_TDR is 32 bits wide and defines the real data to be transmitted and the destination

peripheral. Usin g the PDC in this mode re quires 32-bit wide buf fers, with the data in th e LSBs and the PCS and

LASTXFER fields in the MSBs. However, the SPI still controls the number of bits (8 to16) to be transferred through

MISO and MOSI lines with the chip select configurati on registers (SPI_CSRx). This is not the optimal means in

terms of memory size for the buffers, but it provides a very effective means to exchange data with several

peripherals without any intervention of the processor.

Transfer Size

Depending on the data size to transmit, from 8 to 16 bits, the PDC manages automatically t he type of pointer size

it has to point to. The PDC performs the following transfer, de pending on the mode and numbe r of bits per data.

Fixed mode:

8-bit data:

1-Byte transfer,

PDC pointer address = address + 1 byte,

PDC counter = counter - 1

9-bit to 16-bit data:

2-Byte transfer. n-bit data transfer with don’t care data (MSB) filled with zeros,

PDC pointer address = address + 2 bytes,

PDC counter = counter - 1

Variable mode:

In Variable mode, PDC pointer addr ess = addr ess +4 byte s and PDC cou nter = counter - 1 fo r 8 to 16-

bit transfer size.

When using the PDC, the TDRE and RDRF flags are handled by the PDC. The user’s application

does not have to check th ese bit s. Only End of RX Buf fer (ENDRX), End of TX Buf fer (ENDTX), Buf fer

Full (RXBUFF), TX Buffer Empty (TXBUFE) are significant. For furth er details about the Peripheral

DMA Controller and user interface, refer to the PDC section of the product datasheet.

31.7.3.7 Peripheral Chip Select Decoding

The user can program the SPI to operate with up to 3 slave peripherals by decoding the two chip select lines,

NPCS0 to NPCS1 with an external decoder/demultiplexer (refer to Figure 31-11). This can be enabled by setting

the PCSDEC bit in SPI_MR.

When oper ating without de coding, the SPI makes sure th at in any case only one chip select line is activated, i.e.,

one NPCS line driven low at a time. If two bits ar e defined lo w in a PCS field, only the lowest numbered chip select

is driven low.

When operating with d ecoding, the SPI directly outputs the value defined by the PCS field on the NPCS lines of

either SPI_MR or SPI_TDR (depending on PS).

As the SPI sets a default value of 0x3 on the chip select li nes (i.e. all chip select lines at 1) when not processing

any transfer, only 3 peripherals can be decoded.

The SPI has only two Chip Select registers. As a result, when external decoding is activated, each NPCS chip

select defines the characteristics of u p to two periph erals. As an example, SPI_CRS0 defines the characteristics of

the externally decoded peripherals 0 to 1, corresponding to the PCS values 0x0 to 0x1. Consequently, the user

has to make sure to connect compatible peripherals on the decoded chip select lines

0 to 1 and 2

. Figure 31-11

shows this type of implementation.

If the CSAAT bit is used, with or without the PDC, the Mode Fault detection for NPCS0 line must be disabled. This

is not required for all ot he r chip select lines since mode fault detection is only on NPCS0.

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Figure 31-11. Chip Select Decoding Application Block Diagram: Sin gle Master/Multiple Slave Implementation

31.7.3.8 Peripheral Deselection without PDC

During a transfer of more than one data on a Chip Select without the PDC, SPI_TDR is loaded by the processor,

the TDRE flag rises as so on as the co ntent of SPI_TDR is transferr ed into the inte rnal Shift register. When this flag

is detected high, SPI_TDR can be reloaded. If this reload by the processor occurs before the end of the current

transfer and if the next transfer is performed on the same chip select as the current transfer, the Chip Select is not

de-asserted between the two transfe rs. But depending on the application software handling the SPI status register

flags (by interrupt or polling method) or servicing other interrupts or other tasks, the processor may not reload the

SPI_TDR in time to keep the chip select active (low). A null DLYBCT value (delay between consecutive transfers)

in SPI_CSR, will give even less time for the processor to reload the SPI_TDR. With some SPI slave peripherals, if

the chip select line must remain active (low) during a full set of transfe rs, communication errors can occur.

To facilitate interfacing with such devices, the Chip Select registers [CSR0...CSR1] can be programmed with the

Chip Select Active After Transfer (CSAAT) bit to 1. This allows the chip select lines to remain in their current state

(low = active) until a transfer to another chip sele ct is required. Even if the SPI_TDR is not reloaded, the ch ip select

remains active. To de-assert the chip select line at the end of the tran sfer, the Last transfer Bit (LASTXFER) in

SPI_CR must be set after writing the last data to transmit into SPI_TDR.

31.7.3.9 Peripheral Deselection with PDC

PDC provides faster reloads of SPI_TDR compared to software. However, depending on the system activity, it is

not guarantee d that the SPI_ TDR is written with the next da ta before the end of the cur rent transfer. Conseq uently,

a data can be lost by the de-assertion of the NPCS line for SPI slav e peripherals requiring the chip select line to

remain active between two transfers. The only way to guarantee a safe transfer in this case is the use of the

CSAAT and LASTXFER bits.

Figure 31-12 shows different peripheral deselection cases and the effect of the CSAAT bit.

When the CSAAT bit is set to 0, the NPCS does not rise in all cases between two transfers on the same peripheral.

During a tr ansfer on a C hip Select, the TD RE flag r ises as soon as the co ntent o f SPI_TD R is tran sferre d into the

internal shift register. When this flag is detected, the SPI_TDR can be reloaded. If this reload occurs before the

end of the current transfer and if the next transfer is performed on the same chip select as the current transfer, the

Chip Select is not de-asserted between the two transfers. This can lead to difficulties to interface with some serial

peripherals requiring the chip select to be de-asserted after each transfer. To facilitate interfacing with such

devices, the SPI_CSR can be programmed with the Chip Select Not Activ e A fter Transfer (CSNAAT) bit at 1. This

SPI Master

SPCK

MISO

MOSI

NPCS0

NPCS1

SPCK

External 1-of-n Decoder/Demultiplexer

MISO MOSI

NSS

Slave 0

SPCK MISO MOSI

NSS

Slave 1

SPCK MISO MOSI

NSS

Slave 3

Decoded chip select lines

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allows the chip select lines to be de-asserted systematically during a time “DLYBCS” (the value of the CSNAAT bit

is taken into account only if the CSAAT bit is set to 0 for the same chip select).

Figure 31-12 shows different peripheral deselection cases and the effect of the CSAAT and CSNAAT bits.

Figure 31-12. Peripheral Deselection

31.7.3.10 Mode Fault Detection

The SPI has the capability to operate in multi-master environment. Consequently, the NPCS0/NSS line must be

monitored. If one of the masters on the SPI bus is currently transm itting, the NPCS0/NSS line is low and the SPI

must not transmit a data. A mode fault is detected when the SPI is programmed in Master mode and a low level is

driven by an external master on the NPCS0/NSS signal. In multi-master environment, NPCS0, MOSI, MISO and

NPCS[0..n]

Write SPI_TDR

TDRE

NPCS[0..n]

Write SPI_TDR

TDRE

NPCS[0..n]

Write SPI_TDR

TDRE

DLYBCS

PCS = A

DLYBCS

DLYBCT

PCS = B

DLYBCS

PCS = A

DLYBCS

DLYBCT

PCS = B

DLYBCS

DLYBCT

PCS=A

ADLYBCS

DLYBCT

PCS = A

DLYBCT

CSAAT = 0 and CSNAAT = 0

DLYBCT

CSAAT = 1 and CSNAAT = 0 / 1

DLYBCS

PCS = A

DLYBCT

CSAAT = 0 and CSNAAT = 1

NPCS[0..n]

Write SPI_TDR

TDRE

PCS = A

DLYBCT

CSAAT = 0 and CSNAAT = 0

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SPCK pins must be configured in open drain (through the PIO controller). When a mode fault is detected, the

MODF bit in SPI_SR is set until SPI_SR is read and th e SPI is automatically disabled until it is re-enabled by

setting the SPIEN bit in SPI_CR.

By default, the mode fault detection is enabled. The user can disable it by setting the MODFDIS bit in SPI_MR.

31.7.4 SPI Slave Mode

When operating in Slave mode, the SPI processes data bits on the clock provided on the SPI clock pin (SPCK).

The SPI waits until NSS goes active before receiving the serial clock fr om an extern al master. Whe n NSS falls, the

clock is validated and the d ata is load ed in SPI_RDR dep en ding on the BITS field conf igur ed in SPI_CSR0. These

bits are processed following a phase and a polarity defined respectively by the NCPHA and CPOL bits in

SPI_CSR0. Note that BITS, CPOL and NCPHA of the other Chip Select registers have no effect when the SPI is

programmed in Slave mode.

The bits are shifted out on the MISO line and samp led on the MOSI line.

Note: For more information on the BITS field, see also the note below the SPI_CSRx bitmap in Section 31.8.9 ”SPI Chip

Select Register”.)

When all bits are processed, the received data is transferred in SPI_RDR and the RDRF bit rises. If SPI_RDR has

not been read before new data is received, the Overrun Error bit (OVRES) in SPI_SR is set. As long as this flag is

set, data is loaded in SPI_RDR. The user must read SPI_SR to clear the OVRES bit.

When a transfer starts, the data shifted out is the data present in the Shift register. If no data has been written in

SPI_TDR, the last data received is transferred. If no data has been received since the last reset, all bits are

transmitted low, as the Shift register resets to 0.

When a first data is written in SPI_TDR , it is transferred immediately in the Shift register and the TDRE flag rises.

If new data is written, it remains in SPI_TDR until a transfer occurs, i.e. NSS falls and ther e is a valid clock on the

SPCK pin. When the transfer occurs, the last data written in SPI_TDR is transferred in the Shift register and the

TDRE flag rises. This enables frequent updates of critical variables with single transfers.

Then, a new data is loaded in th e Shift register from SPI_TDR. If no char acter is ready to be transmit ted, i.e. no

character has been written in SPI_TDR since the last load from SPI_TDR to the Shift register, the SPI_TDR is

retransmitted. In this case the Underrun Error Status Flag (UNDES) is set in the SPI_SR.

Figure 31-13 shows a block diagram of the SPI when operating in Slave mode.

Figure 31-13. Slave Mode Functional Block Diagram

Shift Register

SPCK

SPIENS

LSB MSB

NSS

MOSI

SPI_RDR RD

SPI

Clock

TDRE

SPI_TDR TD

RDRF

OVRES

SPI_CSR0

CPOL

NCPHA

BITS

SPIEN

SPIDIS

MISO

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31.7.5 SPI Comparison on Received Character

The SPI comparison feature is only relevant in SPI Slave mode (MSTR = 0 in SPI_MR).

The effect of a comparison match changes if the system is in Wait or Active mode.

In Wait mode, if asynchronous partial wakeup is enabled, a system wakeup is performed (see Section 31.7.6 ”SPI

Asynchronous and Partial Wakeup (SleepWalking)”).

In Active mode, the CMP flag in SPI_SR is raised. It is set when the received character matches the conditions

programmed in th e SPI Comparison Register (SPI_CMPR ). The CMP flag is set as soon as SPI_RDR is load ed

with the new received character. The CMP flag is cleared by reading SPI_ S R.

SPI_CMPR (see Section 31.8.10 ”SPI Comparison Register”) can be programmed to provide di ffer en t compar iso n

methods, as described below:

If VAL1 equals VAL2, then the comparison is performed on a single value and the flag is set to 1 if the

received character equals VAL1.

If VAL1 is strictly lower than VAL2, then any value between VAL1 and VAL2 sets the CMP flag.

If VAL1 is strictly higher than VAL2, then the CMP flag is set to 1 if any received character equals VAL1 or

VAL2.

When the CMPMODE bit is cleared in SPI_CMPR, all received data is loaded in SPI_RDR and the CMP flag

provides the status of the comparison result.

By setting the CMPMODE bit, the comparison result triggers the start of the SPI_RDR loading (see Figure 31-14).

The trigger condition exists as soon as the received character value mat ches the conditio ns defined by VAL1 and

VAL2 in SPI_CMPR. The comparison trigger event is restarted by setting the REQCLR bit in SPI_CR if

SleepWalking mode is disabled.

The value programmed in VAL1 and VAL2 fields must not exceed the maximum value of the received character

(see BITS field in SPI_CSR0).

Figure 31-14. Rece ive Data Register Management

MOSI

0x0F 0x06

CMPMODE = 1, VAL1 = VAL2 = 0x06

RDRF rising enabled

0xF0 0x08 0x06

Peripheral

Clock

Write REQCLR

RDR 0x06 0xF0 0x06

NSS

RDRF

0x08

0x0F

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31.7.6 SPI Asynchronous and Partial Wakeup (SleepWalking)

This operating mode is a means of data pre-processing that qualifies an incoming event, thus allowing the SPI to

decide whet her or not to wake up the system. Asynchronous and partial wakeup is mainly used when the system

is in Wait mode (see the PMC section for further details). It can also be enabled when the system is fully running.

Asynchronous and partial wakeup can be used only when SPI is configured in Slave mode (MSTR is cleared in

SPI_MR).

The maximum SPI clock (SPCK) frequency that can be provided by the SPI master is bounded by the peripheral

clock frequency. The SPCK frequency must be lower than or equal to the peripheral clock. The NSS line must be

de-asserted by the SPI master between two characters. The NSS de-assertion duration time must be greater than

or equal to six peripheral clock periods. The time between the assertion of NSS line (falling edge) and the first

edge of the SPI clock must be higher than 5 µs.

The SPI_RDR must be read before enabling the asynchronous and partial wakeup.

When asynchronous and partial wakeup is enabled for the SPI (see the PMC section), the PMC decodes a clock

request from the SPI. The request is generated as soon as there is a falling edge on the NSS line as this may

indicate the beg inn ing o f a frame. If the system is in Wait mode ( pro cessor an d perip her al clocks switche d off), the

PMC restarts the fast RC oscillator and provides the clock only to the SPI.

The SPI processes the received frame and compares the received character with VAL1 and VAL2 in SPI_CMPR

(Section 31.8.10 ”SPI Com paris on Registe r”).

The SPI instructs the PMC to disable the peripheral clock if the received character value does not meet the

conditions defined by the VAL1 and VAL2 fields in SPI_CMPR (see Figure 31-16 ”Asynchronous Event

Generating Only Partial Wakeup”).

If the receiv ed character value mee ts these conditions, the SPI instructs the PMC to exit the system from Wait

mode (see Figure 31-15 ”Asynchronous Wakeup Use Case Example”).

The VAL1 and VAL2 fields can be programmed to provide different comparison methods and thus matching

conditions.

If VA L 1 equa ls VAL2, the n the compariso n is perfo rm e d on a single value and the wakeup is triggered if the

received character equals VAL1.

If VAL1 is strictly lower than VAL2, then any value between VAL1 and VAL2 wakes up the system.

If VAL1 is strictly higher than VAL2, the wakeup is triggered if any received character equals VAL1 or VAL2.

If VAL1 = 0 and VAL2 = 65535, the wakeup is triggered as soon as a character is received.

If the processo r an d p eri phera ls ar e runnin g, the SPI can b e co nfigured in a synchronou s and p ar tial wakeu p mode

by enabling the PMC_SLPWK_ER (see PMC sectio n). When activity is detected on the receive line, the SPI

requests the clock from the PMC and the comparison is performed. If there is a comparison match, the SPI

continues to request the clock. If there is no match, the clock is switched off for the SPI only, until a new activity is

detected.

The CMPMODE configuration has no effect when asynchronous and partial wakeup mode is enabled for the SPI

(see PMC_SLPWK_ER in PMC section).

When the system is in Active mode and the SPI enters asynchronous and partial wakeup mode, the RDRF flag

must be programmed as the unique source of the SPI interrupt.

When the syste m exits Wait mo de as the result of a matchin g condition, the RDRF flag is used to determ ine if the

SPI is the source for the exit from Wait mode.

763

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 31-15. Asynchronous Wakeup Use Case Example

Figure 31-16. Asynch ron ous Event Generating Only Partial Wakeup

31.7.7 SPI Register Write Protection

To prevent any single softwa re error from corrupting SPI behavior, certain registers in the address space can be

write-protected by setting the WPEN bit in the SPI Write Protection Mode Register (SPI_WPMR).

If a write access to a write-protected register is detected, the WPVS flag in the SPI Write Protection Status

attempted.

The WPVS bit is automatically cleared after reading SPI_WPSR.

The following registers can be write-protected:

SPI Mode Register

RHR = 0x55,

VAL1 = 0x55

=> match

Case with VAL1 = VAL2 = 0x55

NSS

Idle

PCLK_req

PCLK

(Main RC)

SystemWakeUp_req

Idle

5us

MOSI

RHR = 0x7F,

VAL1 = 0x55

No Match

Case with VAL1 = VAL2 = 0x55

NSS

Idle

PCLK_req

PCLK

(Main RC)

SystemWakeUp_req

Idle

5us

MOSI

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

764

SPI Chip Select Register

SPI Comparison Register

31.8 Serial Peripheral Interface (SPI) User Interface

Table 31-5. Register Mapping

Offset Register Name Access Reset

0x000 SPI Control Register SPI_CR Write-only –

0x004 SPI Mode Register SPI_MR Read/Write 0x0

0x008 SPI Receive Data Register SPI_RDR Read-only 0x0

0x00C SPI Transmit Data Register SPI_TDR Write-only –

0x010 SPI Status Register SPI_SR Read-only 0x000000F0

0x014 SPI Interrupt Enabl e Register SPI_IER Write-only –

0x018 SPI Interrupt Disable Register SPI_IDR Write-only –

0x01C SPI Interrupt Mask Register SPI_IMR Read-only 0x0

0x020–0x02C Reserved – – –

0x030 SPI Chip Select Register 0 SPI_CSR0 Read/Write 0x0

0x034 SPI Chip Select Register 1 SPI_CSR1 Read/Write 0x0

0x038–0x03C Reserved – – –

0x040–0x044 Reserved – – –

0x048 SPI Comparison Register SPI_CMPR Read/Write 0x0

0x04C–0x0E0 Reserved – – –

0x0E4 SPI Write Protection Mode Register SPI_WPMR Read/Write 0x0

0x0E8 SPI Write Protection Status Register SPI_WPSR Read-only 0x0

0x0EC–0x0F8 Reserved – – –

765

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.8.1 SPI Control Register

Name: SPI_CR

Address: 0x4000C400 (0), 0x40020400 (1), 0x40024400 (2), 0x40018400 (3), 0x4001C400 (4), 0x40008400 (5),

0x40040400 (6), 0x40034400 (7)

Access: Write-only

• SPIEN: SPI Enable

0: No effect.

1: Enables the SPI to transfer and receive data.

• SPIDIS: SPI Disable

0: No effect.

1: Disables the SPI.

If a transfer is in progress when SPIDIS is set, the SPI completes the transmission of the shift register and does not start

any new transfer, even if the SPI_THR is loaded.

All pins are set in Input mode after completion of the transmission in progress, if any.

• SWRST: SPI Software Reset

0: No effect.

1: Reset the SPI. A software-triggered hardware reset of the SPI interface is performed.

The SPI is in Slave mode after software reset.

PDC channels are not affected by software reset.

• REQCLR: Request to Clear the Comparison Trigger

SleepWalking enabled:

0: No effect.

1: Clears the potential clock request currently issued by the SPI, thus the potential system wakeup is cancelled.

SleepWalking disabled:

0: No effect.

1: Restarts the comparison trigger to enable SPI_RDR loading.

• LASTXFER: Last Transfer

0: No effect.

31 30 29 28 27 26 25 24

–––––––LASTXFER

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––REQCLR––––

76543210

SWRST–––––SPIDISSPIEN

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

766

1: The current NPCS will be de-asserted after the character written in TD has been transferred. When CSAAT is set, the

communication with the current serial peripheral can be closed by raising the corresponding NPCS line as soon as TD

transfer is completed.

Refer to Section 31.7.3.5 ”Peripheral Selection”for more details.

767

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.8.2 SPI Mode Register

Name: SPI_MR

Address: 0x4000C404 (0), 0x40020404 (1), 0x40024404 (2), 0x40018404 (3), 0x4001C404 (4), 0x40008404 (5),

0x40040404 (6), 0x40034404 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in ”SPI Write Protection Mode Register”.

• MSTR: Master/Slave Mode

0: SPI is in Slave mode.

1: SPI is in Master mode.

• PS: Peripheral Select

0: Fixed Peripheral Select.

1: Variable Peripheral Select.

• PCSDEC: Chip Select Decode

0: The chip selects are directly connected to a peripheral device.

1: The two NPCS chip select lines are connected to a 2- to 4-bit decoder.

When PCSDEC equals one, up to 3 Chip Select sign als can b e g ene rate d with the two NPCS lines using an exte rnal 2- to

4-bit decoder. The Chip Select registers define the char acteristics of the 3 chip selects, with the following rules:

SPI_CSR0 defines peripheral chip select signals 0 to 1.

SPI_CSR1 defines peripheral chip select signal 2.

• BRSRCCLK: Bit Rate Source Clock

0 (PERIPH_CLK): The peripheral clock is the source clock for the bit rate generation.

1 (PMC_PCK): PMC PCKx is the source clock for the bit rate generation, thus the bit rate can be independent of the

core/peripheral clock.

Note: If the bit BRSRCCLK = 1, the CSAAT bit must be cleared in SPI_ CSRx and the SCBR field must be programmed with a value

greater than 1.

• MODFDIS: Mode Fault Detection

0: Mode fault detection is enabled.

1: Mode fault detection is disabled.

• WDRBT: Wait Data Read Before Transfer

31 30 29 28 27 26 25 24

DLYBCS

23 22 21 20 19 18 17 16

–––––– PCS

15 14 13 12 11 10 9 8

–––CMPMODE––––

76543210

LLB – WDRBT MODFDIS BRSRCCLK PCSDEC PS MSTR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

768

0: No Effect. In Master mode, a transfer can be initiated regardless of the SPI_RDR state.

1: In Master mode, a transfer can start only if the SPI_RDR is empty, i.e., does not contain any unread data. This mode

prevents overrun error in reception.

• CMPMODE: Comparison Mode

• LLB: Local Loopback Enable

0: Local loopback path disabled.

1: Local loopback path enabled.

LLB controls the local loopback on the data shift register for testing in Master mode only (MISO is internally connected on

MOSI).

• PCS: Peripheral Chip Select

This field is only used if fixed peripheral select is active (PS = 0).

If PCSDEC = 0:

PCS = x0 NPCS[1:0] = 10

PCS = 01 NPCS[1:0] = 01

PCS = 11 forbidden (no peripheral is selected)

(x = don’t care)

If PCSDEC = 1:

NPCS[1:0] output signals = PCS

• DLYBCS: Delay Between Chip Selects

This field defines the delay between the inactivation and the activatio n of NPCS. The DLYBCS time guarantees no n- over-

lapping chip selects and solves bus contentions in case of peripherals having long data float times.

If DLYBCS is less than or equal to six, six peripheral clock periods are inserted by default.

Otherwise, the following equations determine the delay:

if SPI_MR.BRSRCCLK = 0:

if SPI_MR.BRSRCCLK = 1:

Value Name Description

0 FLAG_ONLY Any cha ra c ter is received and comparison function drives CMP flag.

1START_CONDITIO

NComparison condition must be met to start reception of all incoming characters until REQCLR is set.

Delay Between Chip Selects DLYBCS

fperipheral clock

---------------------------------

Delay Between Chip Selects DLYBCS

fPCKx

-----------------------

769

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.8.3 SPI Receive Data Register

Name: SPI_RDR

Address: 0x4000C408 (0), 0x40020408 (1), 0x40024408 (2), 0x40018408 (3), 0x4001C408 (4), 0x40008408 (5),

0x40040408 (6), 0x40034408 (7)

Access: Read-only

• RD: Receive Data

Data received by the SPI Interface is stored in this register in a right-justified format. Unused bits are read as zero.

• PCS: Peripheral Chip Select

In Master mode on ly, these bits indicate th e value on the NPCS pins at the end of a tra nsfer. Otherwise, these bits are read

as zero.

Note: When using Variable peripheral select mode (PS = 1 in SPI_MR), it is mandatory to set the WDRBT field to 1 if the PCS field must

be processed in SPI_RDR.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––– PCS

15 14 13 12 11 10 9 8

76543210

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

770

31.8.4 SPI Transmit Data Register

Name: SPI_TDR

Address: 0x4000C40C (0), 0x4002040C (1), 0x4002440C (2), 0x4 001840C (3), 0x4001C40C (4), 0x4000840C (5),

0x4004040C (6), 0x4003440C (7)

Access: Write-only

• TD: Transmit Data

Data to be transmitted by the SPI Interface is stored in this register. Information to be transmitted must be written to the

transmit data register in a right-justified format.

• PCS: Peripheral Chip Select

This field is only used if variable peripheral select is active (PS = 1).

If PCSDEC = 0:

PCS = x0 NPCS[1:0] = 10

PCS = 01 NPCS[1:0] = 01

PCS = 11 forbidden (no peripheral is selected)

(x = don’t care)

If PCSDEC = 1:

NPCS[1:0] output signals = PCS

• LASTXFER: Last Transfer

0: No effect.

1: The current NPCS is de-asserted after the transfer of the ch ar ac ter writt en in TD. When CSAAT is set, the communica-

tion with the current serial peripheral can be closed by raising the corresponding NPCS line as soon as TD transfer is

completed.

This field is only used if variable peripheral select is active (PS = 1).

31 30 29 28 27 26 25 24

–––––––LASTXFER

23 22 21 20 19 18 17 16

–––– PCS

15 14 13 12 11 10 9 8

76543210

771

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.8.5 SPI Status Register

Name: SPI_SR

Address: 0x4000C410 (0), 0x40020410 (1), 0x40024410 (2), 0x40018410 (3), 0x4001C410 (4), 0x40008410 (5),

0x40040410 (6), 0x40034410 (7)

Access: Read-only

• RDRF: Receive Data Register Full (cleared by reading SPI_RDR)

0: No data has been received since the last read of SPI_RDR.

1: Data has been received and the received data has been transferred from the shift register to SPI_RDR since the last

read of SPI_RDR.

• TDRE: Transmit Data Register Empty (cleared by writing SPI_TDR)

0: Data has been written to SPI_TDR and not yet transferred to the shift register.

1: The last data wr itten in the SPI_TD R has been transferred to the shift register.

TDRE equals zero when the SPI is disabled or at reset. The SPI enable command sets this bi t to 1.

• MODF: Mode Fault Error (cleared on read)

0: No mode fault has be en de te cte d sin ce th e las t rea d of SPI_SR .

1: A mode fault occurred since the last read of SPI_SR.

• OVRES: Overrun Error Status (cleared on read)

0: No overrun ha s be en de tec te d sin ce th e last rea d of SPI_SR .

1: An overrun has occurred since the last read of SPI_SR.

An overrun occurs when SPI_RDR is loaded at least twice from the shift register since the la st read of the SPI_RDR.

• ENDRX: End of RX buffer (cleared by writing SPI_RCR or SPI_RNCR)

0: The Receive Counter register has not reached 0 since the last write in SPI_RCR(1) or SPI_RNCR(1).

1: The Receive Coun te r re gis te r ha s reached 0 since the last write in SPI_RCR(1) or SPI_RNCR(1).

• ENDTX: End of TX buffer (cleared by writing SPI_TCR or SPI_TNCR)

0: The Transmit Counter register has not reached 0 since the last write in SPI_TCR(1) or SPI_TNCR(1).

1: The Transmit Counter register has reached 0 since the last write in SPI_TCR(1) or SPI_TNCR(1).

• RXBUFF: RX Buffer Full (cleared by writing SPI_RCR or SPI_RNCR)

0: SPI_RCR(1) or SPI_RNCR(1) has a value other than 0.

1: Both SPI_RCR(1) and SPI_RNCR(1) have a value of 0.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––––––SPIENS

15 14 13 12 11 10 9 8

––––CMPUNDES TXEMPTY NSSR

76543210

TXBUFE RXBUFF ENDTX ENDRX OVRES MODF TDRE RDRF

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

772

• TXBUFE: TX Buffer Empty (cleared by writing SPI_TCR or SPI_TNCR)

0: SPI_TCR(1) or SPI_TNCR(1) has a value other than 0.

1: Both SPI_TCR(1) and SPI_ T NCR (1) have a value of 0.

• NSSR: NSS Rising (cleared on read)

0: No rising edge detected on NSS pin since the last read of SPI_SR.

1: A rising edge occurred on NSS pin since the last read of SPI_SR.

• TXEMPTY: Transmission Registers Empty (cleared by writing SPI_TDR)

0: As soon as data is written in SPI_TDR.

1: SPI_TDR and internal shift r egister are empty. If a transfer delay has been defined, TXEMPTY is set after the e nd of this

delay.

• UNDES: Underrun Error Status (slave mode only) (cleared on read)

0: No underrun has been detected since the last read of SPI_SR.

1: A transfer started whereas no data has been loaded in SPI_TDR, occur red since th e last read of SPI_SR .

• SPIENS: SPI Enable Status

0: SPI is disabled.

1: SPI is enabled.

• CMP: Comparison Status (cleared on read)

0: No received character matched the comparison criteria programmed in the VAL1 and VAL2 fields in SPI_CMPR since

the last SPI_SR read.

1: A received character matched the comparison criteria since the last SPI_SR read.

Note: 1. SPI_RCR, SPI_RNCR, SPI_TCR, SPI_TNCR are PDC registers.

773

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.8.6 SPI Interrupt Enable Register

Name: SPI_IER

Address: 0x4000C414 (0), 0x40020414 (1), 0x40024414 (2), 0x40018414 (3), 0x4001C414 (4), 0x40008414 (5),

0x40040414 (6), 0x40034414 (7)

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Enables the corresponding interrupt.

• RDRF: Receive Data Register Full Interrupt Enable

• TDRE: SPI Transmit Data Register Empty Interrupt Enable

• MODF: Mode Fault Error Interrupt Enable

• OVRES: Overrun Error Interrupt Enable

• ENDRX: End of Receive Buffer Interrupt Enable

• ENDTX: End of Transmit Buffer Interrupt Enable

• RXBUFF: Receive Buffer Full Interrupt Enable

• TXBUFE: Transmit Buffer Empty Interrupt Enable

• NSSR: NSS Rising Interrupt Enable

• TXEMPTY: Transmission Registers Empty Enable

• UNDES: Underrun Error Interrupt Enable

• CMP: Comparison Interrupt Enable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––CMPUNDES TXEMPTY NSSR

76543210

TXBUFE RXBUFF ENDTX ENDRX OVRES MODF TDRE RDRF

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

774

31.8.7 SPI Interrupt Disable Register

Name: SPI_IDR

Address: 0x4000C418 (0), 0x40020418 (1), 0x40024418 (2), 0x40018418 (3), 0x4001C418 (4), 0x40008418 (5),

0x40040418 (6), 0x40034418 (7)

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Disables the corresponding interrupt.

• RDRF: Receive Data Register Full Interrupt Disable

• TDRE: SPI Transmit Data Register Empty Interrupt Disable

• MODF: Mode Fault Error Interrupt Disable

• OVRES: Overrun Error Interrupt Disable

• ENDRX: End of Receive Buffer Interrupt Disable

• ENDTX: End of Transmit Buffer Interrupt Disable

• RXBUFF: Receive Buffer Full Interrupt Disable

• TXBUFE: Transmit Buffer Empty Interrupt Disable

• NSSR: NSS Rising Interrupt Disable

• TXEMPTY: Transmission Registers Empty Disable

• UNDES: Underrun Error Interrupt Disable

• CMP: Comparison Interrupt Disable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––CMPUNDES TXEMPTY NSSR

76543210

TXBUFE RXBUFF ENDTX ENDRX OVRES MODF TDRE RDRF

775

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.8.8 SPI Interrupt Mask Register

Name: SPI_IMR

Address: 0x4000C41C (0), 0x4002041C (1), 0x4002441C (2), 0x4 001841C (3), 0x4001C41C (4), 0x4000841C (5),

0x4004041C (6), 0x4003441C (7)

Access: Read-only

The following configuration values are valid for all listed bit names of this register:

0: The corresponding interrupt is not enabled.

1: The corresponding interrupt is enabled.

• RDRF: Receive Data Register Full Interrupt Mask

• TDRE: SPI Transmit Data Register Empty Interrupt Mask

• MODF: Mode Fault Error Interrupt Mask

• OVRES: Overrun Error Interrupt Mask

• ENDRX: End of Receive Buffer Interrupt Mask

• ENDTX: End of Transmit Buffer Interrupt Mask

• RXBUFF: Receive Buffer Full Interrupt Mask

• TXBUFE: Transmit Buffer Empty Interrupt Mask

• NSSR: NSS Rising Interrupt Mask

• TXEMPTY: Transmission Registers Empty Mask

• UNDES: Underrun Error Interrupt Mask

• CMP: Comparison Interrupt Mask

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––CMPUNDES TXEMPTY NSSR

76543210

TXBUFE RXBUFF ENDTX ENDRX OVRES MODF TDRE RDRF

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

776

31.8.9 SPI Chip Select Register

Name: SPI_CSRx[x=0..1]

Address: 0x4000C430 (0), 0x40020430 (1), 0x40024430 (2), 0x40018430 (3), 0x4001C430 (4), 0x40008430 (5),

0x40040430 (6), 0x40034430 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ”SPI Write Protection Mode Register”.

Note: SPI_CSRx registers must be wr itten even if the us er w a n ts to use the default reset values. The BITS field is not updated with the

translated value unless the register is written.

• CPOL: Clock Polarity

0: The inactive state value of SPCK is logic level zero.

1: The inactive state value of SPCK is logic level one.

CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the

required cloc k/d a ta re lat ion sh ip between master and slave devices.

• NCPHA: Clock Phase

0: Data is changed on the leading edge of SPCK and captured on the following edg e of SPCK.

1: Data is captured on the leading edge of SPCK and changed on the following edge of SPCK.

NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is

used with CPOL to produce the required clock/data relationship between master and slave devices.

• CSNAAT: Chip Select Not Active After Transfer (Ignored if CSAAT = 1)

0: The Peripheral Chip Select does not rise between two transfers if the SPI_TDR is reloaded before the end of the first

transfer and if the two transfers occur on the same Chip Select.

1: The Peripheral Chip Select rises systematically after each transfer performed on the same slave. It remains inactive

after the end of transfer for a minimal duration of:

If SPI_MR.BRSRCCLK = 0:

• (if DLYBCS field is different from 0)

If SPI_MR.BRSRCCLK = 1:

•

If field DLYBCS is lower than 6, a minimum of six periods is introduced.

31 30 29 28 27 26 25 24

DLYBCT

23 22 21 20 19 18 17 16

DLYBS

15 14 13 12 11 10 9 8

SCBR

76543210

BITS CSAAT CSNAAT NCPHA CPOL

DLYBCS

fperipheral clock

---------------------------------

DLYBCS

fPCKx

-----------------------

777

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• CSAAT: Chip Select Active After Transfer

0: The Peripheral Chip Select Line rises as soon as the last transfer is achieved.

1: The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is

requested on a different chip select.

Note: If the bit BRSRCCLK = 1, the CSAAT bit must be cleared.

• BITS: Bits Per Transfer

(See the note below the SPI_CSRx bitmap.)

The BITS field determines the number of data bits transferred.

• SCBR: Serial Clock Bit Rate

In Master mode, the SPI Interface uses a modulus counter to derive the SPCK bit rate from the clock defined by the bit

BRSRCCLK. The bit rate is selected by writing a value from 1 to 255 in the SCBR field. The following equa tions determine

the SPCK bit rate:

if SPI_MR.BRSRCCLK = 0:

if SPI_MR.BRSRCCLK = 1:

Programming the SCBR field to 0 is forbidden. Triggering a transfer while SCBR is at 0 can lead to unpredictable results.

If BRSRCCLK = 1 in SPI_MR, SCBR must be programmed with a value greater than 1.

At reset, SCBR is 0 and the user has to program it at a valid value before performing the first transfer.

Note: If one of the SCBR fields in SPI_CSRx is set to 1, the other SCBR fields in SPI_CSRx must be set to 1 as well if they are used to

process transfers. If they are not used to transfer data, they can be set at any value.

• DLYBS: Delay Before SPCK

This field defines the delay from NPCS falling edge (activation) to the first valid SPCK transition.

When DLYBS field value equals zero, this delay is half the SPCK clock period.

Otherwise, the following equations determine the delay:

if SPI_MR.BRSRCCLK = 0:

Value Name Description

0 8_BIT 8 bits for transfer

1 9_BIT 9 bits for transfer

2 10_BIT 10 bits for transfer

3 11_BIT 11 bits for transfer

4 12_BIT 12 bits for transfer

5 13_BIT 13 bits for transfer

6 14_BIT 14 bits for transfer

7 15_BIT 15 bits for transfer

8 16_BIT 16 bits for transfer

SPCK Bit Rate fperipheral clock

SCBR

---------------------------------

SPCK Bit Rate fPCKx

SCBR

---------------

Delay Before SPCK DLYBS

fperipheral clock

---------------------------------

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

778

if SPI_MR.BRSRCCLK = 1:

• DLYBCT: Delay Between Consecutive Transfers

This field defines the delay between two consecutive transfers with the same peripheral without removing the chip select.

The delay is always inserted after each transfer and before removing the chip select if needed.

When DLYBCT equals zero, no delay between consecutive transfers is inserted and the clock keeps its duty cycle over the

character transfers.

Otherwise, the following equations determine the delay:

if SPI_MR.BRSRCCLK = 0:

if SPI_MR.BRSRCCLK = 1:

Delay Before SPCK DLYBS

fPCKx

-------------------

Delay Between Consecutive Transfers 32 DLYBCT×

fperipheral clock

------------------------------------

Delay Between Consecutive Transfers 32 DLYBCT×fPCKx

------------------------------------

779

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

31.8.10 SPI Comparison Registe r

Name: SPI_CMPR

Address: 0x4000C448 (0), 0x40020448 (1), 0x40024448 (2), 0x40018448 (3), 0x4001C448 (4), 0x40008448 (5),

0x40040448 (6), 0x40034448 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in ”SPI Write Protection Mode Register”.

• VAL1: First Comparison Value for Received Character

0–65535

• VAL2: Second Comparison Value for Received Character

0–65535

31 30 29 28 27 26 25 24

VAL2

23 22 21 20 19 18 17 16

VAL2

15 14 13 12 11 10 9 8

VAL1

76543210

VAL1

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

780

31.8.11 SPI Write Protection Mode Register

Name: SPI_WPMR

Address: 0x4000C4E4 (0), 0x400204E4 (1), 0x400244E4 (2 ), 0x400184E4 (3), 0x4001C4E4 (4), 0x400084E4 (5),

0x400404E4 (6), 0x400344E4 (7)

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x535049 (“SPI” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x535049 (“SPI” in ASCII)

See Section 31.7.7 ”SPI Register Write Protection” for the list of registers that can be write-protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x535049 PASSW

DWriting any other value in this field aborts the write operation of the WPEN bit.

Always reads as 0.

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31.8.12 SPI Write Protection Status Register

Name: SPI_WPSR

Address: 0x4000C4E8 (0), 0x400204E8 (1), 0x400244E8 (2 ), 0x400184E8 (3), 0x4001C4E8 (4), 0x400084E8 (5),

0x400404E8 (6), 0x400344E8 (7)

Access: Read-only

• WPVS: Write Protection Violation Status

0: No write protection violation has occurred since the last read of SPI_WPSR.

1: A write protection violation has occurre d sin ce the last r ead of SPI_WPSR. If this violation is an unautho rized attempt to

write a protected register, the associated violation is reported into field WPVSRC.

• WPVSRC: Write Protection Vi olation Source

When WPVS = 1, WPVSRC indicates the register address offset at which a write access has been attempted.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

WPVSRC

76543210

–––––––WPVS

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32. Two-wire Interface (TWI)

32.1 Description

The Two- wire I nt er fa ce (T WI ) in te rconnects com p on en ts o n a unique two-wire bus, made up of one clock line and

one data line with speeds of up to 400 kbits per second in Fast mode and up to 3.4 Mbits per second in High-

speed Slave mode only, based on a byte-oriented transfer format. It can be used with any Atmel Two-wire

Interface bus Serial EEPROM and I2C-compatible devices(1), such as a Real-Time Clock (RTC), Dot

Matrix/Gra phic LCD Controller a nd temperature sensor. The TWI is programmable as a master or a slave with

sequential or single-byte access. Multiple master capability is supported.

A configurable baud rate g enerator permits the output data rate to be adapted to a wide range of core clock

frequencies.

Note: 1. See Table 32-1 for details on compatibility with I²C Standard.

Note: 1. 10-bit support in Master mode only

32.2 Embedded Characteristics

TWI/SMBUS Characteristics

Bit Rate: Up to 400 kbit/s in Fast Mode and 3.4 Mbit/s in High-Speed Mode (Slave Only)

Bit Rate can be independent of the Processor/Peripheral Clock

SMBus support

Asynchronous Partial Wakeup (SleepWalking) Capability

Compatible with Atmel Two-wire Interface Serial Memory and I²C Compatible Devices(1)

Master and Multi-Master Operation (Standard and Fast Mode Only)

Slave Mode Operation (Standard, Fast and High-Speed Mode)

One, Two or Three Bytes for Slave Address

Sequential Read/Write Operations

General Call Supported in Slave Mode

Connection to Peripheral DMA Controller (PDC) Channels Optimizes Data Transfers

One Channel for the Receiver, One Channel for the Transmitter

Register Write Protection

Note: 1. See Table 32-1 for details on compatibility with I²C Standard.

Table 32-1. Atmel TWI Compatibility with I2C Standard

I2C Standard Atmel TWI

Standard Mode Speed (100 kHz) Supported

Fast Mode Speed (400 kHz) Supported

High-speed Mode (Slave only, 3.4 MHz) Supported

7- or 10-bit(1) Slave Addressing Supported

Repeated Start (Sr) Condition Supported

ACK and NACK Management Supported

Input Filtering Supported

Slope Control Not supported

Clock Stretching Supported

Multi Master Capability Supported

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32.3 Block Diagram

Figure 32-1. TWI Block Diagram

32.4 I/O Lines Description

PDC

TWI

Peripheral bridge

PMC

Peripheral

clock

Bus clock

AHB Matrix

Trigger

events

FLEXCOM

User Interface Flags

TWD

TWCK

PCKx

PIO PADs

Interrupt

Controller

FLEXCOM

Interrupt

Table 32-2. I/O Line s Description

Name Description Type

TWD Two-wire Serial Data (drives external serial data line – SDA) I/O

TWCK Two-wire Serial Clock (drives external seria l clock line – SCL) I/O

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32.5 Product Dependencies

32.5.1 I/O Lines

The pins used fo r interfacing the TWI are m ultiplexed with the USART and SPI lines within F LEXCOM module.

The programmer must first program the PIO controller to assign the desired FLEXCOM pins to their peripheral

function. If I/O lines of the FLEXCOM are not used by th e app lication, they can be used for other purposes by the

PIO Controller.

Both TWD and TWCK are bidirectional lines, connected to a positive supply voltag e via a cur ren t sou rce or pu ll-up

resistor. When the bus is free, both lines are high. The output stages of devices connected to the bus must have

an open-drain or open-collector to perform the wired-AND function.

TWD and T WCK pins may be m ultiplexed with PIO line s. To enable the TWI, the user must program the PIO

Controller to dedicate TWD and TWCK as peripheral lines.

The user must not program TWD and TWCK as open-drain. This is already done by the hardware.

Table 32-3. I/O Lines

Instance Signal I/O Line Peripheral

TWI0 RXD0/SPI0_MISO/TWCK0 PA9 A

TWI0 TXD0/SPI0_MOSI/TWD0 PA10 A

TWI1 RXD1/SPI1_MISO/TWCK1 PB2 A

TWI1 TXD1/SPI1_MOSI/TWD1 PB3 A

TWI2 RXD2/SPI2_MISO/TWCK2 PA5 A

TWI2 TXD2/SPI2_MOSI/TWD2 PA6 A

TWI3 RXD3/SPI3_MISO/TWCK3 PA4 A

TWI3 TXD3/SPI3_MOSI/TWD3 PA3 A

TWI4 RXD4/SPI4_MISO/TWCK4 PB9 A

TWI4 RXD4/SPI4_MISO/TWCK4 PB11 A

TWI4 TXD4/SPI4_MOSI/TWD4 PB8 A

TWI4 TXD4/SPI4_MOSI/TWD4 PB10 A

TWI5 RXD5/SPI5_MISO/TWCK5 PA12 A

TWI5 TXD5/SPI5_MOSI/TWD5 PA13 A

TWI6 RXD6/SPI6_MISO/TWCK6 PB1 B

TWI6 RXD6/SPI6_MISO/TWCK6 PB11 B

TWI6 TXD6/SPI6_MOSI/TWD6 PB0 B

TWI6 TXD6/SPI6_MOSI/TWD6 PB10 B

TWI7 RXD7/SPI7_MISO/TWCK7 PA27 B

TWI7 TXD7/SPI7_MOSI/TWD7 PA28 B

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32.5.2 Power Management

The TWI is not continuously clocked. The programmer must first enable the FLEXCOM Clock in the Power

Management Controller (PMC) and configure the field OPMODE = 3 in the FLEXCOM Mode Register (FLEX_MR)

before using the TWI. If the OPMODE field differs from 3, the TWI clock is stopped.

In SleepWalking mode (asynchronous partial wakeup), the PMC must be configured to enable SleepWalking for

the FLEXCOM in the Sleepwalking Enable Register (PMC_SLPWK_ER). Depending on the instructions (requests)

provided by the FLEXCOM to the PMC, the system clock may or may not be automatically provided to the

FLEXCOM.

32.5.3 Interrupt Sources

The TWI interrupt line is the FLEXCOM interrupt line if the field OPMODE = 3 in FLEX_MR. The FLEXCOM

interrupt line is connected on one of the internal sources of the Interrupt Controller. Using the FLEXCOM interrupt

requires the Interrupt Controller to be programmed first.

Table 32-4. Peripheral IDs

Instance ID

TWI0 8

TWI1 9

TWI2 14

TWI3 19

TWI4 20

TWI5 21

TWI6 22

TWI7 7

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32.6 TWI Functional Description

32.6.1 Transfer Format

The data put on th e T W D line mu st b e 8 bits long. Data is transf erred MSB firs t; each by te must be followed by an

acknowledgement. The number of bytes per transfer is unlimited (see Figure 32-3).

Each transfer begins with a START condition and terminates with a STOP condition (see Figure 32-2).

A high-to-low transition on the TWD line while TWCK is high defines the START condition.

A low-to-high transition on the TWD line while TWCK is high defines a STOP condition.

Figure 32-2. START and STOP Conditions

Figure 32-3. Transfer Format

32.6.2 Modes of Operation

The TWI has different modes of operation:

Master Transmitter mode (Standard and Fast modes only)

Master Receiver mode (Standard and Fast modes only)

Multi-master Transmitter mode (Standard and Fast modes only)

Multi-master Receiver mode (Standard and Fast modes only)

Slave Transmitter mode (Standard, Fast and High-speed mode)

Slave Receiver mode (Standard, Fast and High-speed modes)

These modes are described in the following sections.

TWD

TWCK

Start Stop

TWD

TWCK

Start Address R/W Ack Data Ack Data Ack Stop

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32.6.3 Master Mode

32.6.3.1 Definition

The master is the device that starts a transfer, generates a clock and stops it. This operating mode is not available

if high-speed mode is selected.

32.6.3.2 Programming Master Mode

The following fields must be programmed before entering Master mode:

1. TWI_MMR.DADR (+ TWI_MMR.IADRSZ + TWI_IADR.IADR if a 10-bit device is addressed): The device

address is used to access slave devices in Read or Write mode.

2. In TWI_CWGR, CKDIV + CHDIV + CLDIV: Clock waveform.

3. TWI_CR.SVDIS: Disables the Slave mode.

4. TWI_CR.MSEN: Enables the Master mode.

Note: If the TWI is already in Master mode, the device address (DADR) can be configured without disabling the Master

mode.

32.6.3.3 Transfer Speed/ Bit Rate

The TWI speed is defined in the TWI Clock Waveform Generator Register (TWI_CWGR).

The TWI bit rate can be based either on the peripheral clock if the BRSRCCLK bit value is 0 or on a programmable

clock source provided by the PMC (PCKx) if the BRSRCCLK bit value is 1.

If BRSRCCLK = 1, the bit rate is independent of the processor/peripheral clock and thus the processor/peripheral

clock frequency can be changed without affecting the TWI transfer rate.

The PMC PCKx frequency must be at least three times lower than the peripheral clock frequency.

32.6.3.4 Master Transmitter Mode

This operating mode is not available if High-speed mode is selected.

After the master initiates a START condition when writing into the TWI Transmit Holding Register (TWI_THR), it

sends a 7-bit slave address, config ured in the Master Mode register (DADR in TWI_MMR), to n otify the slave

device. The bit following the slave address indicates the transfer direction, 0 in this case (MREAD = 0 in

TWI_MMR).

The TWI transfers require the slave to acknowledge each received byte. During the acknowledge clock pulse

(ninth pulse), the master releases the data line (HIGH), enabling the slave to pull it down in order to generate the

acknowledge. If the slave does not acknowledg e the byte, then the Not Acknowledge flag (NACK) is set in the TWI

Status Register (T WI_SR) of the master an d a STOP co ndition is sent. The NACK flag must be cleare d by re ading

TWI_SR before th e next write into TWI_THR. As with the ot her status bits, an interrupt can be gener ated if enabled

in the TWI Interrupt Enable Register (TWI_IER). If the slave acknowledges the byte, the data written in TWI_THR

is then shifted in the internal shifter and transferred. When an acknowledge is detected, the TXRDY bit is set until

a new write in TWI_THR.

TXRDY is used as transmit ready for the PDC transmit channel.

While no new data is written in TWI_THR, the serial clock line is tied low. When new data is written in TWI_THR,

the SCL is released and the data is sent. To generate a STOP event, the STOP command must be performed by

writing in the STOP bit of the TWI Control Register (TWI_CR).

After a master write transfer, the Serial Clock line is stretched (tied low) while no new data is written in TWI_THR

or until a STOP command is performed.

See Figure 32-4, Figure 32-5, and Figure 32-6.

Note: In Master mode, the TXRDY flag can be cleared by first setting the bit TWI_CR .MSD IS and then setting th e bi t

TWI_CR.MSEN.

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Figure 32-4. Master Write with One Data Byte

Figure 32-5. Master Write with Multiple Data Bytes

Figure 32-6. Master Write with One Byte Internal Address and Multiple Data Bytes

TXCOMP

TXRDY

Write TWI_THR (DATA)

STOP Command sent (write in TWI_CR)

TWD ADATAAS DADR W P

A DATA n AS DADR W DATA n+1 A PDATA n+2 A

TXCOMP

TXRDY

Write TWI_THR (Data n)

Write TWI_THR (Data n+1) Write TWI_THR (Data n+2)

Last data sent

STOP command performed

(by writing in the TWI_CR)

TWD

TWCK

A DATA n AS DADR W DATA n+1 A PDATA n+2 A

TXCOMP

TXRDY

Write TWI_THR (Data n)

Write TWI_THR (Data n+1) Write TWI_THR (Data n+2)

Last data sent

STOP command performed

(by writing in the TWI_CR)

TWD IADR A

TWCK

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32.6.3.5 Master Receiver Mode

Master Receiver mode is not available if High-speed mode is selected.

The read sequence begins by setting the START b it. After th e start condition has been sent, the master sends a 7-

bit slave address to notify the sla ve device. The bit following the slave address indicates the transfer direction, 1 in

this case (MREAD = 1 in TWI_MMR). During the acknowledge clock pulse (9th pulse), th e master releases the

data line (HIGH), enabling the slave to pull it do wn in order to generate the acknowledge. The master polls the

data line during this clock pulse and sets the NACK bit in TWI_SR if the slave does not acknowledge the byte.

If an acknowledge is received, the master is then ready to receive data from the slave. After data has been

received, the master sends an acknowledge condition to notify the slave that the data has been received except

for the last da ta (see Figure 32 -7). When the RXRDY bit is set in TWI_SR, a character has been received in the

TWI Receive-Holding Register (TWI_RHR). The RXRDY bit is reset when reading TWI_RHR.

When a single data byte read is performed, with or witho ut internal address (IADR), the START and STOP bits

must be set at the same time. See Figure 32-7, ”Master Read with One Data Byte” . When a multiple data byte read

is performed, with or without in te rn al addre s s (IADR), th e STO P bi t mu st be se t a ft er th e ne xt - to -l a st da ta rec e ive d

(same condition applies for START bit to generate a repeated start). See Figure 32-8, ”Master Read with Multiple

Data Bytes”. For internal address usage, see Section 32.6.3.6 ”Internal Address”.

If TWI_RHR is full (RXRDY high) and the master is receiving data, the serial clock line will be tied low before

receiving the last bit of the data and until TWI_RHR is read. Once TWI_RHR is read, the master will stop stretching

the serial clock line and end the data reception, see Figure 32-9.

Warning: When receiving multiple bytes in Master Read mode, if the next-to-last access is not read (the RXRDY

flag remains high), the last access will not be completed until TWI_RHR is read. The last access stops on the next-

to-last bit (clock stre tching). Whe n TWI_RHR is read th ere is only half a bit perio d to send the STOP bit (or START

bit) command, else another read access might occur (spurious access).

A possible workaround is to raise the STOP bit (or START bit) command before reading TWI_RHR on the next-to-

last access (within IT handler).

Figure 32-7. Master Read with One Data Byte

Figure 32-8. Master Read with Multiple Data Bytes

AS DADR R DATA N P

TXCOMP

Write START &

STOP Bit

RXRDY

Read RHR

TWD

AS DADR R DATA n A ADATA (n+1) A DATA (n+m)DATA (n+m)-1 PTWD

TXCOMP

Write START Bit

RXRDY

Write STOP Bit

after next-to-last data read

Read RHR

DATA n Read RHR

DATA (n+1) Read RHR

DATA (n+m)-1 Read RHR

DATA (n+m)

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Figure 32-9. Master Read Clock Stretching with Multiple Data Bytes

RXRDY is used as receive ready trigger event for the PDC receive channel.

32.6.3.6 Internal Address

The TWI interface can perform transfers with 7-bit slave address devices and with 10-bit slave address devices.

7-bit Slave Addressing

When addressing 7-bit slave devices, the internal address bytes are used to perform random address (read or

write) accesses to rea ch one or more data bytes, e.g., wit hin a memory page location in a serial memory. When

performing read o perations with an interna l addr ess, the TWI perfor ms a write operation to set the intern al add ress

into the slave d evice, and th en switch to Ma ster Receiver mod e. Note that the second start condition (a fter sending

the IADR) is sometimes called “repeated start” (Sr) in I2C fully-compatible devices. See Figure 32-11, ”Master

Read with One, Two or Three Bytes Internal Address and One Data Byte”.

See Figure 32-10, ”Master Write with One, Two or Three Bytes Internal Address and One Data Byte” and Figure

32-12, ”Internal Address Usage” for the master write operation with internal address.

The three internal address bytes are configurable through the TWI Master Mode Register (TWI_MMR).

If the slave device supports only a 7-bit address, i.e. no internal address, IADRSZ must be set to 0.

The abbreviations listed below are used in Figure 32-10 and Figure 32-11:

ADATA nAS DADR W DATA n+1 A PDATA n+2 A

TXCOMP

RXRDY

Read RHR (Data n)

STOP command performed

(by writing in the TWI_CR)

TWD

TWCK

Read RHR (Data n+1) Read RHR (Data n+2)

Clock Streching

SStart

Sr Rep eated Start

PStop

WWrite

RRead

A Acknowledge

N Not Acknowledge

DADR Device Address

IADR Internal Address

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Figure 32-10. Master Write with One, Two or Three Bytes In ternal Address and One Data Byte

Figure 32-11. Master Read with One, Two or Three Bytes Intern al Addr ess and One Data Byte

10-bit Slave Addressing

For a slave address higher than seven bits, the user must configure the address size (IADRSZ) and set the other

slave address bits in the TWI Internal Address Register (TWI_IADR). The two remaining internal address bytes,

IADR[15:8] and IADR[23:16], can be used the same way as in 7-bit slave addressing.

Example: Address a 10-bit device (10-bit device address is b1 b2 b3 b4 b5 b6 b7 b8 b9 b10)

1. Program IADRSZ = 1

2. Program DADR with 1 1 1 1 0 b1 b2 (b1 is the MSB of the 10-bit address, b2, etc.)

3. Program TWI_IADR with b3 b4 b5 b6 b7 b8 b9 b10 (b10 is the LSB of the 10-bit address)

Figure 32-12 shows a byte write to an Atmel AT24LC512 EEPROM. This demonstrates the use of internal

addresses to access the device.

Figure 32-12. Internal Address Usage

32.6.3.7 Repeated Start

In addition to internal addr ess mode, repeated start ( Sr) can be gene rated manually by writing the START bit at the

end of a transfer instead of the STOP bit . In such case the parameters of the next transfer (direction, SADR, etc.)

will need to be set before writing the START bit at the end of the pre viou s tra n sfe r.

See Section 32.6.3.14 for detailed flowcharts.

Note that generating a repeated start after a single data read is not suppor te d.

S DADR W A IADR(23:16) A IADR(15:8) A IADR(7:0) A DATA A P

S DADR W A IADR(15:8) A IADR(7:0) A P

DATA A

A IADR(7:0) A P

DATA AS DADR W

TWD Three bytes internal address

Two bytes internal address

One byte internal address

TWD

S DADR WA IADR(23:16) A IADR(15:8) AIADR(7:0) A

S DADR W A IADR(15:8) A IADR(7:0) A

AIADR(7:0) A

S DADR W

DATA N P

Sr DADR R A

Sr DADR R A DATA N P

TWD

Three bytes internal address

Two bytes internal address

One byte internal address

Device

Address

FIRST

WORD ADDRESS SECOND

WORD ADDRESS DATA

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32.6.3.8 Bus Clear Command

The TWI interface can perform a Bus Clear Command:

1. Configure the Master mode (DADR, CKDIV, etc.).

2. Start the transfer by setting the CLEAR bit in TWI_CR.

Note: If alternative command is used (ACMEN bit set to 1) DATAL field must be set to 0.

32.6.3.9 Using the Peripheral DMA Controller (PDC) in Master Mode

The use of the PDC significantly reduces the CPU loa d.

To ensure correct implementation, respect the following programming sequences:

Data Transmit with the PDC in Master Mode

The PDC transfer size must be defined with the buff er size minus 1. The remaining character mu st be managed

without PDC to ensure that the exact number of bytes are transmitted regardless of system bus latency conditions

during the end of the buffer transfer period.

If Alternative Command mode is disabled (ACMEN bit set to 0):

1. Initialize the transmit PDC (memory pointers, transfer size - 1).

2. Configure the Master mode (DADR, CKDIV, MREAD = 0, etc.).

3. Start the transfer by setting the PDC TXTEN bit.

4. Wait for the PDC ENDTX flag either by using the polling method or ENDTX interrupt.

5. Disable the PDC by setting the PDC TXTDIS bit.

6. Wait for the TXRDY flag in TWI_SR.

7. Set the STOP command in TWI_CR.

8. Write the last character in TWI_THR.

9. (Only if peripheral clock must be disabled) Wait for the TXCOMP flag to be raised in TWI_SR.

If Alternative Command mode is enabled (ACMEN bit set to 1):

1. Initialize the transmit PDC (memory pointers, transfer size).

2. Configure the Master mode (DADR, CKDIV, etc.).

3. Start the transfer by setting the PDC TXTEN bit.

4. Wait for the PDC ENDTX flag either by using the polling method or ENDTX interrupt.

5. Disable the PDC by setting the PDC TXTDIS bit.

6. (Only if peripheral clock must be disabled) Wait for the TXCOMP flag to be raised in TWI_SR.

Data Receive with the PDC in Master Mode

The PDC transfer size must be defined with the buffer size minus 2. The two remaining characters must be

managed without PDC to ensure that the exact number of bytes are received regardless of system bus latency

conditions during the end of the buffer transfer period.

If Alternative Command mode is disabled (ACMEN bit set to 0):

1. Initialize the receive PDC (memory pointers, transfer size - 2).

2. Configure the Master mode (DADR, CKDIV, MREAD = 1, etc.).

3. Set the PDC RXTEN bit.

4. (Master Only) Write the START bit in TWI_CR to start the transfer.

5. Wait for the PDC ENDRX flag either by using polling method or ENDRX interrupt.

6. Disable the PDC by setting the PDC RXTDIS bit.

7. Wait for the RXRDY flag in TWI_SR.

8. Set the STOP command in TWI_CR to end the transfer.

9. Read the penultimate character in TWI_RHR.

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10. Wait for the RXRDY flag in TWI_SR.

11. Read the last character in TWI_RHR.

12. (Only if peripheral clock must be disabled) Wait for the TXCOMP flag to be raised in TWI_SR.

If Alternative Command mode is enabled (ACMEN bit set to 1):

1. Initialize the transmit PDC (memory pointers, transfer size).

2. Configure the Master mode (DADR, CKDIV, etc.).

3. Set the PDC RXTEN bit.

4. (Master Only) Write the START bit in TWI_CR to start the transfer.

5. Wait for the PDC ENDTX Flag either by using the polling method or ENDTX interrupt.

6. Disable the PDC by setting the PDC TXTDIS bit.

7. (Only if peripheral clock must be disabled) Wait for the TXCOMP flag to be raised in TWI_SR.

32.6.3.10 SMBus Mode

SMBus mode is enabled when the SMEN bit is written to one in TWI_CR. SMBus mode operation is similar to I²C

operation with the following exceptions:

Only 7-bit addressing can be used.

The SMBus standard describes a set of timeout va lues to ensure progress and throughput on the bus.

These timeout values must be programmed into the TWI SMBus Timing Register (TWI_SMBTR).

Transmissions can optionally include a CRC byte, called Packet Error Check (PEC).

A set of addresses has been reserved for pr otocol handling, such as aler t response address (ARA) and host

header (HH) address. Address matching on these addresses can be enabled by appropriately configuring

TWI_CR.

Packet Error Checking

Each SMBus transfer can optionally end with a CRC byte, called the PEC byte. Writing the PECEN bit in TWI_C R

to one enables automatic PEC handling in the current transfer. Transfers with and without PEC can freely be

intermixed in the same system, since some slaves may not support PEC. The PEC LFSR is always updated on

every bit transmitted or received, so that PEC handling on combined transfers will be correct.

In Master Transmitter mode, the master calculates a PEC value and transmits it to the slave after all data bytes

have been transmitted. Upon reception of this PEC byte, the slave will compare it to the PEC value it has

computed itself. If the values match, the data was received correctly, and the slave will return an ACK to the

master. If the PEC values differ, data was corrupted, and the slave will return a NACK value. Some slaves may not

be able to check the received PEC in time to return a NACK if an error occurred. In this case, the slave should

always return an ACK after the PEC b yte, and some other mechanism must be implem ented to verify that the

transmission was received correctly.

In Master Receiver mode, the slave calculates a PEC value and transmits it to the master after all data bytes have

been transmitted. Upon re ception of this PEC byte, the master will com pare it to the PEC value it has computed

itself. If the values match, the data was received correctly. If the PEC values d iffer, data was corr upted, and the

PECERR bit in TWI_SR is set. In Master Receiver mode, the PEC byte is always followed by a NACK transmitted

by the master, since it is the last byte in the transfer.

In combined transfers, the PECRQ bit should only be set in the last of the combined transfers. If Alternative

Command mode is enabled, only the NPEC bit should be set.

Consider the following transfer:

S, ADR+W, COMMAND_BYTE, ACK, SR, ADR+R, DATA_BYTE, ACK, PEC_BYTE, NACK, P

See Section 32.6.3.14 ”Read/Write Flowcharts” for detailed flowcharts.

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Timeouts

The TLOWS and TLOWM fields in TWI_SMBTR configure the SM Bus timeout values. If a timeout occurs, the

master will transmit a STOP condition and leave the bus. The TOUT bit is also set in TWI_SR.

32.6.3.11 SMBUS Quick Command (Master Mode Only)

The TWI interface can perform a quick command:

1. Configure the Master mode (DADR, CKDIV, etc.).

2. Write the MREAD bit in TWI_MMR at the value of the one-bit command to be sent.

3. Start the transfer by setting the QUICK bit in TWI_CR.

Note: If alternative command is used (ACMEN bit set to 1) DATAL field must be set to 0.

Figure 32-13. SMBUS Quick Command

32.6.3.12 Alternative Command

Another way to configure th e transfer is to enable the Alte rnative Comman d mode with the ACMEN bit of TWI_CR.

In this mode, the transfer is configured through the TWI Alternative Comma nd Register (TWI_ACR ). It is possible

to define a simple read or write transfer or a combined transfer with a re peated start.

In order to set a simple transfer, the DATAL field and the DIR bit of TWI_ACR must be filled accordin gly and the

NDATAL field must be cleared. To begin the transfer, either set the START bit in TWI_CR in case of a read

transfer, or write in TWI_THR in case of a write transfer.

For a combined transfer linked by a repeated start, the NDATAL field must be filled with the length of the second

transfer and the NDIR bit with the corresponding direction.

The PEC and NPEC bits are used to set a PEC bit. In the case of a single transfer with PEC, the PEC bit must be

set. In the case of a combined transfer, the NPEC bit must be set.

Note: If Alternative Command mode is used, the field TWI_MMR.IADRSZ must be set to 0.

See Section 32.6.3.14 for detailed flowcharts.

32.6.3.13 Handling Errors in Alternative Command

In case of NACK generated by a slave device or SMBus timeout error, th e TWI stops immediately the frame bu t

the PDC transfer may still be active. To prevent a new frame to be restarted with remaining PDC data (transmit),

the TWI prevents any start of frame until the LOCK flag is cleared in TWI_SR.

The LOCK bit in TWI_SR indicates the state of the TWI (locked or not locked).

When the TWI is locked, no transfer will begin until the LOCK is cleared using the LOCKCLR bit in TWI_CR and

error flags cleared reading TWI_SR.

In case of error, TWI_THR may have been loaded with a new data. The THRCLR bit in TWI_CR can be used to

flush TWI_THR. If the THRCLR bit is set, the TXRDY and TXCOMP flags are set.

TXCOMP

TXRDY

Write QUICK command in TWI_CR

TWD AS DADR R/W P

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32.6.3.14 Read/Write Flowcharts

The flowch arts shown in Figure 32-15, Figure 32-16, Figure 32-21, Figure 32-22 and Figure 32-23 give examples

for read and write operations. A polling or interrupt method can be used to check the status bits. The interrupt

method requires that TWI_IER be configured first.

Figure 32-14. TWI Write Operation with Single Data Byte without Internal Address

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS

Set the Master Mode register:

- Device slave address (DADR)

- Transfer direction bit

Write ==> bit MREAD = 0

Load T ransmit register

TWI_THR = Data to send

Read Status register

TXRDY = 1?

Read Status register

TXCOMP = 1?

Transfer finished

Yes

BEGIN

Write STOP Command

TWI_CR = STOP

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Figure 32-15. TWI Write Operation with Single Data Byte and Internal Address

BEGIN

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS

Set the Master Mode register:

- Device slave address (DADR)

- Internal address size (IADRSZ)

- Transfer direction bit

Write ==> bit MREAD = 0

Load transmit register

TWI_THR = Data to send

Read Status register

TXRDY = 1?

Read Status register

TXCOMP = 1?

Transfer finished

Set the internal address

TWI_IADR = address

Yes

Write STOP command

TWI_CR = STOP

797

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Figure 32-16. TWI Write Operation with Multiple Data Bytes with or without Internal Address

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS

Set the Master Mode register:

- Device slave address

- Internal address size (if IADR used)

- Transfer direction bit

Write ==> bit MREAD = 0

Internal address size = 0?

Load Transmit register

TWI_THR = Data to send

Read Status register

TXRDY = 1?

Data to send?

Read Status register

TXCOMP = 1?

END

BEGIN

Set the internal address

TWI_IADR = address

Yes

TWI_THR = data to send

Yes

Write STOP Command

TWI_CR = STOP

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

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Figure 32-17. SMBus Write Operation with Multiple Data Bytes with or without Internal Address and PEC Sending

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS + SMBEN + PECEN

Set the Master Mode register:

- Device slave address

- Internal address size

(if IADR used)

- Transfer direction bit

Write ==> bit MREAD = 0

Internal address size = 0?

Load Transmit register

TWI_THR = Data to send

Read Status register

TXRDY = 1?

Data to send?

Read Status register

TXCOMP = 1?

END

BEGIN

Set the internal address

TWI_IADR = address

Yes

TWI_THR = data to send

Yes

Write PECRQ Command

Write STOP Command

TWI_CR = STOP & PECRQ

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

799

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Figure 32-18. SMBus Write Operation with Multiple Data Bytes with PEC and Alternative Command Mode

Set the Control register:

TWIH_CR = MSEN + SVDIS + ACMEN + SMBEN + PECEN

Set the Master Mode register:

- Device slave address

Set the Alternative Command Register:

- DATAL, DIR, PEC

Load Transmit register

TWI_THR = Data to send

Read Status register

TXRDY = 1?

Data to send?

Read Status register

TXCOMP = 1?

END

BEGIN

TWI_THR = data to send

Yes

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

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Figure 32-19. TWI Write Operation with Multiple Data Bytes and Read Operation with Multiple Data Bytes (Sr)

Internal address size = 0?

Set the internal address

TWI_IADR = address

Yes

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS

Set the Master Mode register:

- Device slave address

- Internal address size (if IADR used)

- Transfer direction bit

Read ==> bit MREAD = 0

BEGIN

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Load Transmit register

TWI_THR = Data to send

Read Status register

TXRDY = 1?

Data to send ?

Yes

Start the transfer

TWI_CR = START

Read Status register

RXRDY = 1?

Last data to read

but one?

Yes

Read Receive Holding register (TWI_RHR)

Set the Master Mode register:

- Device slave address

- Internal address size (if IADR used)

- TWI_IADR = address (if Internal address size = 0)

- Transfer direction bit

Read ==> bit MREAD = 1

Read Status register

RXRDY = 1?

Yes

Read Receive Holding register (TWI_RHR)

Stop the transfer

TWI_CR = STOP

Read status register

TXCOMP = 1?

END

Yes

TWI_THR = data to send

Yes

Set the next transfer

parameters and

send the repeated start

command

801

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Figure 32-20. TWI Write Operation with Multiple Data Bytes + Read Operation and Alternative Command Mode + PEC

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS + ACMEN

Set the Master Mode register:

- Device slave address

Set the Alternative Command Register:

- DATAL, PEC, NDATAL, NPEC

- DIR = WRITE

- NDIR = READ

BEGIN

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Load Transmit register

TWI_THR = Data to send

Read Status register

TXRDY = 1?

Data to send ?

Yes

Read Status register

RXRDY = 1?

Last data to read ?

Yes

Read Receive Holding register (TWI_RHR)

Read status register

TXCOMP = 1?

END

Yes

TWI_THR = data to send

Yes

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Figure 32-21. TWI Read Op eration with Single Data Byte without Internal Address

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS

Set the Master Mode register:

- Device slave address

- Transfer direction bit

Read ==> bit MREAD = 1

Start the transfer

TWI_CR = START | STOP

Read status register

RXRDY = 1?

Read Status register

TXCOMP = 1?

END

BEGIN

Yes

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Read Receive Holding Register

803

SAM G55 [DATASHEET]

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Figure 32-22. TWI Read Op eration with Single Data Byte and Internal Add ress

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS

Set the Master Mode register:

- Device slave address

- Internal address size (IADRSZ)

- Transfer direction bit

Read ==> bit MREAD = 1

Read Status register

TXCOMP = 1?

END

BEGIN

Yes

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Yes

Set the internal address

TWI_IADR = address

Start the transfer

TWI_CR = START | STOP

Read Status register

RXRDY = 1?

Read Receive Holding register

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Figure 32-23. TWI Read Operation with Multiple Data Bytes with or without Internal Address

Internal address size = 0?

Start the transfer

TWI_CR = START

Stop the transfer

TWI_CR = STOP

Read Status register

RXRDY = 1?

Last data to read

but one?

Read status register

TXCOMP = 1?

END

Set the internal address

TWI_IADR = address

Yes

Read Receive Holding register (TWI_RHR)

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS

Set the Master Mode register:

- Device slave address

- Internal address size (if IADR used)

- Transfer direction bit

Read ==> bit MREAD = 1

BEGIN

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Read Status register

RXRDY = 1?

Yes

Read Receive Holding register (TWI_RHR)

805

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Figure 32-24. TWI Read Operat io n with Multiple Data Bytes with or without Interna l Ad dress with PEC

Internal address size = 0?

Start the transfer

TWI_CR = START

Check PEC and Stop the transfer

TWI_CR = STOP & PECRQ

Read Status register

RXRDY = 1?

Last data to read

but one ?

Read status register

TXCOMP = 1?

END

Set the internal address

TWI_IADR = address

Yes

Read Receive Holding register (TWI_RHR)

Set the Control register:

TWI_CR = MSEN + SVDIS + SMBEN + PECEN

Set the Master Mode register:

- Device slave address

- Internal address size (if IADR used)

- Transfer direction bit

Read ==> bit MREAD = 1

BEGIN

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Read Status register

RXRDY = 1?

Yes

Read Receive Holding register (TWI_RHR)

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806

Figure 32-25. TWI Read Operation with Multiple Data Bytes with Alternative Command Mode with PEC

Start the transfer

TWI_CR = START

Read Status register

RXRDY = 1?

Last data to read ?

Read status register

TXCOMP = 1?

END

Yes

Read Receive Holding register (TWI_RHR)

Set the Control register:

TWI_CR = MSEN + SVDIS + SMBEN + ACMEN + PECEN

Set the Master Mode register:

- Device slave address

Set the Alternative Command Register:

- DATAL, DIR, PEC

BEGIN

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Yes

Read Status register

RXRDY = 1?

Yes

Read the received PEC:

Read Receive Holding register (TWI_RHR)

807

SAM G55 [DATASHEET]

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Figure 32-26. TWI Read Op eration with Multiple Data Bytes + Write Operation with Multiple Data Bytes (Sr)

Internal address size = 0?

Start the transfer

TWI_CR = START

Start the transfer (Sr)

TWI_CR = START

Read Status register

RXRDY = 1?

Last data to read

but one?

Read status register

TXCOMP = 1?

END

Set the internal address

TWI_IADR = address

Yes

Read Receive Holding register (TWI_RHR)

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS

Set the Master Mode register:

- Device slave address

- Internal address size (if IADR used)

- Transfer direction bit

Read ==> bit MREAD = 1

BEGIN

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Read Status register

RXRDY = 1?

Yes

Read Receive Holding register (TWI_RHR)

Set the Master Mode register:

- Device slave address

- Internal address size (if IADR used)

-TWI_IADR = address (if Internal address size = 0)

- Transfer direction bit

Read ==> bit MREAD = 0

Read Status register

TXRDY = 1?

Data to send ?

TWI_THR = data to send

Stop the transfer

TWI_CR = STOP

Yes

Set the next transfer

parameters and

send the repeated start

command

Read the last byte

of the first read transfer

SAM G55 [DATASHEET]

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808

Figure 32-27. TWI Read Op eration with Multiple Data Bytes + Write with Alternative Command Mode with PEC

Start the transfer

TWI_CR = START

Read Status register

RXRDY = 1?

Last data to read ?

Read status register

TXCOMP = 1?

END

Yes

Read Receive Holding register (TWI_RHR)

Set the Control register:

- Master enable

TWI_CR = MSEN + SVDIS + ACMEN

Set the Master Mode register:

- Device slave address

Set the Alternative Command Register:

- DATAL, PEC, NDATAL, NPEC

- DIR = READ

- NDIR = WRITE

BEGIN

Set TWI clock

(CLDIV, CHDIV, CKDIV) in TWI_CWGR

(Needed only once)

Yes

Read Status register

TXRDY = 1?

Data to send ?

TWI_THR = data to send

Yes

809

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32.6.4 Multi-Master Mode

32.6.4.1 Definition

In Multi-master mo de, more than one m aster may handle the bus at the sam e time without data corruption by u sing

arbitration.

Arbitration starts as soon as two or more masters place information on the bus at the same time, and stops

(arbitration is lost) for the master that intends to send a logical one while the other master sends a logical zero.

As soon as arbitration is lost by a master, it stops sending data and listens to the bus in order to detect a STOP.

When the STOP is detected, the master that has lost arbitration may put its data on the bus by respecting

arbitration.

Arbitration is illustrated in Figure 32-29.

32.6.4.2 Different Multi-Master Modes

Two Multi-master modes may be distinguished:

TWI as Master Only—TWI is considered as a master only and will never be addressed.

TWI as Master or Slave—TWI may be either a master or a slave and may be addressed.

Note: Arbitration in supported in both Multi-master modes.

TWI as Master Only

In this mode, the TWI is considered as a master only (MSEN is always at one) and must be driven like a master

with the ARBLST (ARBitration Lost) flag in addition.

If arbitration is lost (ARBLST = 1), the user must reinitiate the data transfer.

If the user starts a transfer (ex.: DADR + START + W + Write in THR) and if the bus is busy, the TWI automatically

waits for a STOP condition on the bus to initiate the transfer (see Figure 32-28).

Note: The state of the bus (busy or free) is not indicated in the user interface.

TWI as Master or Slave

The automatic reversal from master to slave is not supported in case of a lost arbitration.

Then, in the case where TWI may be either a master or a slave, the user must manage the pseudo Mu lti-master

mode described in the steps below:

1. Program the TWI in Slave mode (SADR + MSDIS + SVEN) and perform a slave access (if TWI is

addressed).

2. If the TWI has to be set in Master mode, wait until TXCOMP flag is at 1.

3. Program the Master mode (DADR + SVDIS + MSEN) and start the transfer (ex: START + Write in THR).

4. As soon as the Master mode is enabled, the TWI scans the bus in order to detect if it is busy or free. When

the bus is considered as free, the TWI initiates the transfer.

5. As soon as the transfer is initiated and until a STOP condition is sent, the arbitration becomes relevant and

the user must monitor the ARBLST flag.

6. If the arbitration is lost (ARBLST is set to 1), the user must program the TWI in Slave mode in case the

master that won the arbitration wants to access the TWI.

7. If the TWI has to be set in Slave mode, wait until TXCOMP flag is at 1 and then program the Slave mode.

Note: In case the arbitration is lost and the TWI is addressed, the TWI will not acknowledge even if it is programmed in Slave

mode as soon as ARBLST is set to 1. Then the master must repeat SADR.

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Figure 32-28. User Sends Data While the Bus is Busy

Figure 32-29. Arbitration Cases

TWCK

TWD DATA sent by a master

STOP sent by the master START sent by the TWI

DATA sent by the TWI

Bus is busy

Bus is free

A transfer is programmed

(DADR + W + START + Write THR) Transfer is initiated

TWI DATA transfer Transfer is kept

Bus is considered as free

TWCK

Bus is busy Bus is free

A transfer is programmed

(DADR + W + START + Write THR) Transfer is initiated

TWI DATA transfer Transfer is kept

Bus is considered as free

Data from a Master

Data from TWI S0

ARBLST

S 0 0

TWD S0

Arbitration is lost

TWI stops sending data

Data from the master Data from the TWI

Arbitration is lost

The master stops sending data

Transfer is stopped Transfer is programmed again

(DADR + W + START + Write THR)

TWCK

TWD

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The flowchart shown in Figure 32-30 gives an example of read and write operations in Multi-master mode.

Figure 32-30. Multi-Master Flowchart

Program the SLAVE mode:

SADR + MSDIS + SVEN

SVACC = 1 ?

TXCOMP = 1 ?

GACC = 1 ?

Decoding of the

programming sequence

Prog seq

OK ?

Change SADR

SVREAD = 1 ?

Read Status Register

RXRDY= 1 ?

Read TWI_RHR

TXRDY= 1 ?

EOSACC = 1 ?

Write in TWI_THR

Need to perform

a master access ?

Program the Master mode

DADR + SVDIS + MSEN + CLK + R / W

Read Status Register

ARBLST = 1 ?

MREAD = 1 ?

TXRDY= 0 ?

Write in TWI_THR

Data to send ?

RXRDY= 0 ?

Read TWI_RHR Data to read?

Read Status Register

TXCOMP = 0 ?

GENERAL CALL TREATMENT

Yes

Stop Transfer

TWI_CR = STOP

No No

START

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32.6.5 Slave Modes

32.6.5.1 Definition

Slave mode is defined as a mode where the device receives the clock and the address from another device calle d

the master.

In this mode, the device never initiates and never completes the transmission (START, REPEATED_START and

STOP conditions are always provided by the master).

32.6.5.2 Programming Slave Mode

The following fields must be programmed before entering Slave mode:

1. TWI_SMR.SADR: The slave device address is used in order to be accessed by master devices in Read or

Write mode.

2. (Optional) TWI_SMR.MASK can be set to mask some SADR address bits and thus allow multiple address

matching.

3. TWI_CR.MSDIS: Disables the Master mode.

4. TWI_CR.SVEN: Enables the Slave mode.

As the device receives the clock, values written in TWI_CWGR are not taken into account.

32.6.5.3 Receiving Data

After a START or repeated START condition is detected, and if the address sent by the master matches the slave

address programmed in the SADR (Slave Address) field, the SVACC (Slave Access) flag is set and SVREAD

(Slave Read) indicates the direction of the transfer.

SVACC remains high until a STOP condition or a repeated START is dete cted. When such a condition is detected,

EOSACC (End Of Slave Access) flag is set.

Read Sequence

In the case of a read sequence (SVREAD is high), the TWI transfers data written in TWI_THR until a STOP

condition or a REPEATED_START + an address different from SADR is detected. Note that at the end of the read

sequence TXCOMP (Transmission Complete) flag is set and SVACC reset.

As soon as data is written in TWI_THR, the T XRDY (Transmit Holding Register Ready) flag is reset, and it is set

when the internal shifter is empty and the sent data acknowledged or not. If the data is not acknowledged, the

NACK flag is set.

Note that a STOP or a repeated START always follows a NACK.

See Figure 32-31.

Note: In Slave mode, the TXRDY flag can be cleared by first setting the bit TWI_CR.SVDIS and then setting the bit

TWI_CR.SVEN.

Write Sequence

In the case of a write sequen ce (SVREAD is low), the RXRDY (Receive Holding Register Read y) flag is set as

soon as a character has been received in TWI_RHR. RXRDY is reset when reading TWI_RHR.

TWI continues receiving data until a STOP condition or a REPEATED_START + an address different from SADR

is detected. Note that at the end of the write sequence TXCOMP flag is set and SVACC reset.

See Figure 32-32.

Clock Stretching Sequence

If TWI_THR or TWI_RHR is not written/read in time, the TWI performs a clock stretching.

Clock stretching information is given by the SCLWS (Clock Wait State) bit.

See Figure 32-34 and Figure 32-35.

813

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Note: Clock stretching can be disabled by configuring the SCLWSDIS bit in the TWI Slave Mode Register (TWI_SMR). In

that case, UNRE and OVRE flags will indicate underrun (when TWI_THR is not filled on time) or overrun (when

TWI_RHR is not read on time).

General Call

In the case where a GENERAL CALL is performed, GACC (General Call Access) flag is set.

After GACC is set, it is up to the user to interpret the meaning of the GENERAL CALL and to decode the new

address programming sequence.

See Figure 32-33.

32.6.5.4 Data Transfer

Read Operation

The Read mode is defined as a data requirement from the master.

After a START or a REPEATED START condition is detected, the decoding of the address starts. If the slave

address (SADR) is decoded, SVACC is set and SVREAD indicates the direction of the transfer.

Until a STOP or REPEATED START condition is detected, TWI continues sending data loaded in TWI_THR.

If a STOP condition or a REPEATED START + an address different from SADR is detected, SVACC is reset.

Figure 32-31 describes the read ope ration.

Figure 32-31. Read Access Ordered by a Master

Notes: 1. When SVACC is low, the state of SVREAD becomes irrelevant.

2. TXRDY is reset when data has been transmitted from TWI_THR to the internal shifter and set when this data has been

acknowledged or non acknowledged.

Write THR Read RHR

SVREAD has to be taken into account only while SVACC is active

TWD

TXRDY

NACK

SVACC

SVREAD

EOSACC

SADRS ADR R NA R A DATA A A DATA NA S/SrDATA NA P/S/Sr

SADR matches,

TWI answers with an ACK

SADR does not match,

TWI answers with a NACK ACK/NACK from the Master

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Write Operation

The Write mode is defined as a data transmission from the master.

After a START or a REPEATED START, the decoding of the address starts. If the slave address is decoded,

SVACC is set and SVREAD indicates the direction of the transfer (SVREAD is low in this case).

Until a STOP or REPEATED START condition is detected, TWI stores the received data in TWI_RHR.

If a STOP condition or a REPEATED START + an address different from SADR is detected, SVACC is reset.

Figure 32-32 describes the write operation.

Figure 32-32. Write Access Ordered by a Master

Notes: 1. When SVACC is low, the state of SVREAD becomes irrelevant.

2. RXRDY is set when data has been transmitted from the internal shifter to TWI_RHR and reset when this data is read.

General Call

The general call is per fo rm ed in or de r to chan g e th e ad dres s of the s lav e.

If a GENERAL CALL is detected, GACC is set.

After the detection of general call, it is up to the user to decode the commands which follow.

In case of a WRITE command, the user has to decode the programming sequence and program a new SADR if

the programming sequence matches.

Figure 32-33 describes the genera l call access.

Figure 32-33. Master Performs a General Call

Note: This method allows to create a user-sp ecific programming sequence by choosing th e number of programming bytes. The

programming sequence has to be provided to the master.

RXRDY

Read RHR

SVREAD has to be taken into account only while SVACC is active

TWD

SVACC

SVREAD

EOSACC

SADR does not match,

TWI answers with a NACK

SADRS ADR W NA W A DATA A A DATA NA S/SrDATA NA P/S/Sr

SADR matches,

TWI answers with an ACK

0000000 + W

GENERAL CALL P

GENERAL CALL Reset or write DADD A New SADR

DATA1 A DATA2 A

New SADR

Programming sequence

TXD

GACC

SVACC

RESET command = 00000110X

WRITE command = 00000100X

Reset after read

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Clock Stretching

In both Read and Write modes, it may happen that the TWI_THR/TWI_RHR buffer is not filled/emptied before the

emission/reception of a new character. In this case, to avoid sending/receiving undesired data, a clock stretching

mechanism is implemented.

Note: Clock stretching can be disabled by setting the SCLWSDIS bit in TWI_SMR. In that case UNRE and OVRE flags will

indicate underrun (when TWI_ THR is not filled on time) or overrun (when TWI_RHR is not read on time).

Clock Stretching in Read Mode

The clock is tied low if the internal shifter is empty and if a STOP or REPEATED START condition was not

detected. It is tied low until the internal shifter is loaded.

Figure 32-34 describes the clock stretching in Read mode.

Figure 32-34. Clock Stretching in Read Mode

Notes: 1. TXRDY is reset when data has been written in TWI_THR to the internal shifter and set when this data has been

acknowledged or non acknowledged.

2. At the end of the read sequence, TXCOMP is set after a STOP or after a REPEATED_START + an address different from

SADR.

3. SCLWS is automatically set when the clock stretching mechanism is started.

DATA1

The clock is stretched after the ACK, the state of TWD is undefined during clock stretching

SCLWS

SVACC

SVREAD

TXRDY

TWCK

TWI_THR

TXCOMP

The data is memorized in TWI_THR until a new value is written

TWI_THR is transmitted to the internal shifter Ack or Nack from the master

DATA0DATA0 DATA2

Clock is tied low by the TWI

as long as THR is empty

SSADR

SRDATA0AADATA1 ADATA2 NA S

XXXXXXX

Write THR

As soon as a START is detected

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816

Clock Stretching in Write Mode

The clock is tied low if the internal shifter and TWI_R HR are full. If a STOP or REPEATED_START condition was

not detected, it is tied low until TWI_RHR is read.

Figure 32-35 describes the clock stretching in Write mode.

Figure 32-35. Clock Stretching in Write Mode

Notes: 1. At the end of the read sequence, TXCOMP is set after a STOP or after a REPEATED_START + an address different from

SADR.

2. SCLWS is automatically set when the clock stretching mechanism is started and automatically reset when the mechanism is

finished.

Reversal after a Repeated Start

Reversal of Read to Write

The master initiates the communication by a read command and finish es it by a write com m a nd .

Figure 32-36 describes the repeated start and the reversal from Read mode to Write mode.

Figure 32-36. Repeated Start and Reversal from Read Mode to Write Mode

Note: 1. TXCOMP is only set at the end of the transmission because after the repeated start, SADR is detected again.

Rd DATA0 Rd DATA1 Rd DATA2

SVACC

SVREAD

RXRDY

SCLWS

TXCOMP

DATA1 DATA2

SCL is stretched after the acknowledge of DATA1

As soon as a START is detected

TWCK

TWD

TWI_RHR

Clock is tied low by the TWI as long as RHR is full

DATA0 is not read in the RHR

ADRS SADR W ADATA0AADATA2DATA1 S

S SADR R ADATA0A DATA1 SADRSr

NA W A DATA2 A DATA3 A P

Cleared after read

DATA0 DATA1

DATA2 DATA3

SVACC

SVREAD

TWD

TWI_THR

TWI_RHR

EOSACC

TXRDY

RXRDY

TXCOMP

As soon as a START is detected

817

SAM G55 [DATASHEET]

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Reversal of Write to Read

The master initiates the communication by a write command and finishes it by a read command. Figure 32-37

describes the repeated start and the reversal from Write mode to Read mode.

Figure 32-37. Repeated Start and Rever sal from Write Mode to Read Mode

Notes: 1. In this case, if TWI_THR has not been written at the end of the read command, the clock is automatically stretched before

the ACK.

2. TXCOMP is only set at the end of the transmission because after the repeated start, SADR is detected again.

Using the Peripheral DMA Controller (PDC) in Slave Mode

The use of the PDC significantly reduces the CPU loa d.

Data Transmit with the PDC in Slave Mode

The following procedure shows an example to transmit data with PDC.

1. Initialize the transmit PDC (memory pointers, transfer size).

2. Start the transfer by setting the PDC TXTEN bit.

3. Wait for the PDC ENDTX Flag either by using the polling method or ENDTX interrupt.

4. Disable the PDC by setting the PDC TXTDIS bit.

5. (Only if peripheral clock must be disabled) Wait for the TXCOMP flag to be raised in TWI_SR.

Data Receive with the PDC in Slave Mode

The following procedure show s an example to tran smit data with PDC where the number of characters to receive

is known.

1. Initialize the receive PDC (memory pointers, transfer size).

2. Set the PDC RXTEN bit.

3. Wait for the PDC ENDRX flag either by using polling method or ENDRX interrupt.

4. Disable the PDC by setting the PDC RXTDIS bit.

5. (Only if peripheral clock must be disabled) Wait for the TXCOMP flag to be raised in TWI_SR.

SMBus Mode

SMBus mode is enabled when SMEN bit is written to one in TWI_CR. SMBus mode operation is similar to I²C

operation with the following exceptions:

Only 7-bit addressing can be used.

The SMBus standard describes a set of timeout va lues to ensure progress and throughput on the bus.

These timeout values must be programmed into TWI_SMBTR.

S SADR W ADATA0A DATA1 SADRSr

R A DATA2 A DATA3 NA P

Cleared after read

DATA0

DATA2 DATA3

DATA1

TXCOMP

TXRDY

RXRDY

As soon as a START is detected

Read TWI_RHR

SVACC

SVREAD

TWD

TWI_RHR

TWI_THR

EOSACC

SAM G55 [DATASHEET]

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818

 A set of addresses have bee n rese rved for protocol ha nd lin g, such as aler t re sp on se addre ss (ARA) and

host header (HH) address. Address matching on these addresses can be enabled by appropriately

configuring TWI_CR.

Packet Error Checking

Each SMBus transfer can optionally end with a CRC byte, called the PEC byte. Writing the PECEN bit in TWI_C R

to one will send/check the PEC field of the TWI frame in the current transfer. The PEC generator is always updated

on every bit transmitted or received, so that PEC handling on following linked transfers will be correct.

In Slave Receiver mode, the master calculates a PEC value and transmits it to the slave after all data bytes have

been transmitted. Upon reception of this PEC byte, the slave will compare it to the PEC value it has computed

itself. If the values match, the data was received correctly, and the s lave will return an ACK to the master. If the

PEC values differ, data was corrupted, and the slave will return a NACK value. The PECERR bit in TWI_SR is set

automatically if a PEC error occurred.

In Slave Transmitter mode, the slave calculates a PEC value and transmits it to the master after all data bytes

have been transmitted. Upon reception of this PEC byte, the master will compare it to the PEC value it has

computed itself. If the values match, the data was received correctly. If the PEC values differ, data was corrupted,

and the master must take appropriate action.

See Section 32.6.5.8 ”Slave Read/Write Flowcharts” for detailed flowcharts.

Timeouts

TWI_SMBTR configures the SMBus timeout values. If a timeout occurs, the slave will leave the bus. The TOUT bit

is also set in TWI_SR.

32.6.5.5 High-Speed Slave Mode

High-speed mode is enab led when the HSEN bit is written to one in TWI_CR . Furthermore, the analog pad filter

must be enabled, the PADFEN bit must be written to one in TWI_FILTR and the FILT bit must be cleared . TWI

High-speed mode operation is similar to TWI operation with the following exceptions:

1. A master code is received first at normal speed before entering High-speed mode period.

2. When TWI High-speed mode is active, clock stretching is only allowed af ter acknowledge (ACK), not-

acknowledge (NACK), START (S) or repeated START (Sr) (as consequence OVF may happen).

TWI High-speed mode allows transfers of up to 3.4 Mbit/s.

The TWI slave in High-speed mode requires that the peripheral clock runs at a minimum of 14 M Hz if slave cloc k

stretching is enabled (SCLWSDIS bit at ‘0’). If slave clock stretching is disabled (SCLWSDIS bit at ‘1’), the

peripheral clock must run at a minimum of 11 MHz (theoretical value given considering the absence of latency in

the system).

Note: When slave clock stretching is disabled, TWI_RHR must always be read before receiving the next data (MASTER

write frame). It is strongly recommended to use either the polling method on the RXRDY flag in TWI_SR, or the PDC.

If the receive is managed by an interrupt, the TWI interrupt priority must be set to the right level and its latency

minimized to avoid receive overrun.

Note: When slave clock stretching is disabled, the TWI_THR must be filled with the first data to send before the beginning of

the frame (MASTER read frame). It is strongly recommended to use either the polling method on the TXRDY flag in

TWI_SR, or the PDC. If the transmit is managed by an interrupt, the TWI interrupt priority must be set to the right level

and its latency minimized to avoid transmit underrun.

Read/Write Operation

A TWI high-speed frame always begins with the following sequence:

1. START condition (S)

2. Master Code (0000 1XXX)

3. Not-acknowledge (NACK)

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When the TWI is progra mmed in Slave mode and TWI High-speed mode is activated, master code matching is

activated and internal timings are set to match the TWI High-speed mode r equirements.

Figure 32-38. High-Speed Mode Read/Write

Usage

TWI High-speed mode usage is the same as the standard TWI (see Section 32.6.3.14).

32.6.5.6 Alternative Command

In Slave mode, Alterna tive Command mode is used when SM Bus mode is enabled to send or check the PEC byte.

Alternative Command mode is enabled by setting the ACMEN bit of the TWI Control Register and the transfer is

configured in TWI_ACR.

For a combined transfer with PEC, only the NPEC bit in TWI_ACR must be set as the PEC byte is sent once at th e

end of the frame.

See Section 32.6.5.8 ”Slave Read/Write Flowcharts” for detailed flowcharts.

32.6.5.7 TWI Asynchronous and Partial Wakeup (SleepWalking)

The TWI module include s an asynchronous start condition detector, it is capab le of waking the device up from a

Sleep mode upon an address match (and optionally an additional data match), including Sleep modes where the

TWI peripheral clock is stopped.

TWI_RHR must be read prior to enable the asynchronous and partial wakeup.

After detecting the START condition on the bus, the TWI will stretch TWCK until the TWI peripheral clock h as

started. The time required for starting the TWI peripheral depends on which Sleep mode the device is in. After the

TWI peripheral clock has started, the TWI releases its TWCK stretching and receives one byte of data (slave

address) on the bus. At this time, only a limite d par t of the device, including the TWI module, receives a clock, thus

saving power. If th e address ph ase ca uses a TWIS add ress match (and op tiona lly if th e first data b yte causes d ata

match as well), the entire device is wakened and normal TWI address matching actions are performed. Normal

TWI transfer then follows. If the TWI module is not addressed (or if the optional data match fails), the TWI

peripheral clock is automatically stopped and the device returns to its original Sleep mode.

The TWI module has the capability to match on more than one address. The SADR1EN, SADR2EN and

SADR3EN bits in TWI_SMR allow to enable address matching on additional addresses which can be configured

through SADR1, SADR2 and SADR3 fields in the TWI_SWMR. The SleepWalking matching process can be

extended to the first received data byte if DATAMEN bit in TWI_SMR is set, in that case a complete matching

includes address matching and first received data matching. The DATAM field in TWI_SWMR allows to configure

the data to match on the first received byte.

When the system is in Active mode and the TWI enters Asynchronous Partial Wakeup mode, the flag SVACC

must be programmed as the unique source of the TWI interrupt and the data match comparison must be disabled.

NA SADR R/WS MASTER CODE DATA A/NA P

Sr A

NA SADR R/WS MASTER CODE DATA A/NA Sr

Sr A SADR P

F/S Mode

F/S Mode HS Mode

HS Mode

F/S Mode

SAM G55 [DATASHEET]

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820

When the system exits Wait mode as the result of a matching condition, the SVACC flag is used to determine if the

TWI is the source of the exit from Wait mode.

Figure 32-39. Address Match Only (Data Matching Disabled)

Figure 32-40. No Ad dress Match (Data Matching Disabled)

SADR R/W DATA A/NA P

S A

Address Matching Area

A/NA

DATA

Clock

Stretching

PClk

Startup

PClk_request

PClk

SystemWakeUp_req

SADR R/W P

SNA

Address Matching Area

Clock

Stretching

PClk

Startup

PClk_request

PClk

SystemWakeUp_req

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Figure 32-41. Address Match and Data Match (Data Matching Enabled)

Figure 32-42. Address Match and No Data Match (Data Match ing Enabled)

SADR W DATA A/NA P

S A

Address Matching + Data Matching Area

DATA

Clock

Stretching

PClk

Startup

PClk_request

PClk

SystemWakeUp_req

SADR W DATA NA P

Address Matching + Data Matching Area

DATA

Clock

Stretching

PClk

Startup

PClk_request

PClk

SystemWakeUp_req

SAM G55 [DATASHEET]

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822

32.6.5.8 Slave Read/Write Flowcharts

The flow chart shown in Figure 32-43 gives an example of re ad and write op erations in Slave mode. A polling or

interrupt me thod can be used to chec k the status bits. The interrupt method requires that TWI_IER be configured

first.

Figure 32-43. Read/Write Flowchart in Slave Mode

Set the SLAVE mode:

SADR + MSDIS + SVEN

SVACC = 1 ?

TXCOMP = 1 ?

GACC = 1 ?

Decoding of the

programming sequence

Prog seq

OK ?

Change SADR

SVREAD = 1 ?

Read Status Register

RXRDY= 1 ?

Read TWI_RHR

TXRDY= 1 ?

EOSACC = 1 ?

Write in TWI_THR

END

GENERAL CALL TREATMENT

No No

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Figure 32-44. Read/Write Flowchart in Slave Mode with SMBus PEC

Set the SLAVE mode:

SADR + MSDIS + SVEN + SMBEN + PECEN

SVACC = 1 ?

TXCOMP = 1 ?

GACC = 1 ?

Decoding of the

programming sequence

Prog seq

OK ?

Change SADR

SVREAD = 1 ?

Read Status Register

RXRDY= 1 ?

Read TWI_RHR

TXRDY= 1 ?

EOSACC = 1 ?

Write in TWI_THR

END

GENERAL CALL TREATMENT

Last data to read ?

Write in PECRQ

Last data sent ?

Write in PECRQ

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

824

Figure 32-45. Read/Write Flowchart in Slave Mode with SMBus PEC and Alternative Command Mode

32.6.6 TWI Comparison Function on Received Character

The comparison function differs if the asynchronous partial wakeup (Sleepwalking) is enabled or not.

If asynchronous partial wakeup is disabled (see PMC section), the TWI has the capability to extend the address

matching on up to three slave addresses. The SADR1EN, SADR2EN and SADR3EN bits in TWI_SMR enable

address matching on additional addresses which can be configured through SADR1, SADR2 and SADR3 fields in

the TWI_SWMR. The DATAMEN bit had no effect.

The SVACC bit is set when there is a comparison match with the received slave address.

Set the SLAVE mode:

SADR + MSDIS + SVEN + SMBEN + PECEN + ACMEN

SVACC = 1 ?

TXCOMP = 1 ?

GACC = 1 ?

Decoding of the

programming sequence

Prog seq

OK ?

Change SADR

SVREAD = 1 ?

Read Status Register

RXRDY= 1 ?

Read TWI_RHR

TXRDY= 1 ?

EOSACC = 1 ?

Write in TWI_THR

END

GENERAL CALL TREATMENT

825

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32.6.7 TWI Register Write Protection

To prevent any single software error from corrupting TWI behavior, certain registers in the address space can be

write-protected by setting the WPEN bit in the TWI Write Protection Mode Register (TWI_WPMR).

If a write access to a write-protected register is detected, the WPVS bit in the TWI Write Protection Status Register

(TWI_WPSR) is set and the field WPVSRC indicates the register in which the write access has been attempted.

The WPVS bit is automatically cleared after reading TWI_WPSR.

The following registers can be write-protected:

TWI Slave Mode Register (TWI_SMR)

TWI Clock Waveform Generator Register (TWI_CWGR)

TWI SMBus Timing Register (TWI_SMBTR)

TWI SleepWalking Matching Register (TWI_SWMR)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

826

32.7 Two-wire Interface (TWI) User Interface

Table 32-5. Register Mapping

Offset Register Name Access Reset

0x000 TWI Control Register TWI_CR Write-only –

0x004 TWI Master Mode Register TWI_MMR Read/Write 0x00000000

0x008 TWI Slave Mode Register TWI_SMR Read/Write 0x00000000

0x00C TWI Internal Address Register TWI_IADR Read/Write 0x00000000

0x010 TWI Clock Waveform Generator Register TWI_CWGR Read/Write 0x00000000

0x014–0x01C Reserved – – –

0x020 TWI Status Register TWI_SR Rea d-only 0x0300F009

0x024 TWI Interrupt Enable Register TWI_IER Write-only –

0x028 TWI Interrupt Disable Register TWI_IDR Write-only –

0x02C TW I Interrupt Ma sk Register TWI_IMR Rea d-only 0x00000000

0x030 TWI Receive Holding Register TWI_RHR Read-only 0x00000000

0x034 TWI Transmit Holding Register TWI_THR Write-only –

0x038 TWI SMBus Timing Register TWI_SMBTR Read/Write 0x00000000

0x03C Reserved – – –

0x040 TWI Alternative Command Register TWI_ACR Read/Write 0x00000000

0x044 TWI Filter Register TWI_FILTR Read/Write 0x00000000

0x048 Reserved – – –

0x04C TWI SleepWalking Matching Register TWI_SWMR Read/Write 0x00000000

0x050–0x0CC Reserved – – –

0x0D0–0x0E0 Reserved – – –

0x0E4 TWI Write Protection Mode Register TWI_WPMR Read/Write 0x00000000

0x0E8 TWI Write Protection Status Register TWI_WPSR Read-only 0x00000000

0x0EC–0x0FC Reserved – – –

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32.7.1 TWI Control Register

Name: TWI_CR

Address: 0x4000C600 (0), 0x40020600 (1), 0x40024600 (2), 0x40018600 (3), 0x4001C600 (4), 0x40008600 (5),

0x40040600 (6), 0x40034600 (7)

Access: Write-only

• START: Send a START Condition

0: No effect.

1: A frame beginning with a START bit is transmitted according to the features def ine d in th e TWI Master Mode Regi st er

(TWI_MMR).

This action is necessary when the TWI peripheral needs to read data from a slave. When configured in Master mode with

a write operation, a frame is sent as soon as the user writes a character in TWI_THR.

• STOP: Send a STOP Condition

0: No effect.

1: STOP Condition is sent just after completing the current byte transmission in Master Read mode.

– In single data byte master read, the START and STOP must both be set.

– In multiple data bytes master read, the STOP must be set after the last data received but one.

– In Master Read mode, if a NACK bit is received, the ST OP is automatically performed.

– In master data write operation, a STOP condition will be sent after the transmission of the current data is

finished.

• MSEN: TWI Master Mode Enabled

0: No effect.

1: Enables the Master mode (MSDIS must be written to 0).

Note: Switching from slave to Master mode is only permitted when TXCOMP = 1.

• MSDIS: TWI Master Mode Disabled

0: No effect.

1: The Master mode is disabled, all pending data is transmitted. The shifter and holding characters (i f it contains data) are

transmitted in case of write operation. In read operation, the character being transferred must be completely received

before disabling.

31 30 29 28 27 26 25 24

–––––LOCKCLR–THRCLR

23 22 21 20 19 18 17 16

––––––ACMDISACMEN

15 14 13 12 11 10 9 8

CLEAR PECRQ PECDIS PECEN SMBDIS SMBEN HSDIS HSEN

76543210

SWRST QUICK SVDIS SVEN MSDIS MSEN STOP START

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

828

• SVEN: TWI Slave Mode Enabled

0: No effect.

1: Enables the Slave mode (SVDIS must be written to 0).

Note: Switching from Master to Slave mode is only permitted when TXCOMP = 1.

• SVDIS: TWI Slave Mode Disabled

0: No effect.

1: The Slave mode is disabled. The shifter and holding characters (if it contains data) are transmitted in case of read oper-

ation. In write operation, the character being transferred must be completely received before disabling.

• QUICK: SMBUS Quick Command

0: No effect.

1: If Master mode is enabled, a SMBUS Quick Command is sent.

• SWRST: Software Reset

0: No effect.

1: Equivalent to a system reset.

• HSEN: TWI High-Speed Mode Enabled

0: No effect.

1: High-speed mode enabled.

• HSDIS: TWI High-Speed Mode Disabled

0: No effect.

1: High-speed mode disabled.

• SMBEN: SMBus Mode Enabled

0: No effect.

1: If SMBDIS = 0, SMBus mode enabled.

• SMBDIS: SMBus Mode Disabled

0: No effect.

1: SMBus mode disabled.

• PECEN: Packet Error Checking Enable

0: No effect.

1: SMBus PEC (CRC) generation and check enabled.

• PECDIS: Packet Error Checking Disable

0: No effect.

1: SMBus PEC (CRC) generation and check disabled.

• PECRQ: PEC Request

0: No effect.

1: A PEC check or transmission is requested.

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• CLEAR: Bus CLEAR Command

0: No effect.

1: If Master mode is enabled, send a bus clear command.

• ACMEN: Alternative Command Mode Enable

0: No effect.

1: Alternative Command mode enabled.

• ACMDIS: Alternative Command Mode Disable

0: No effect.

1: Alternative Command mode disabled.

• THRCLR: Transmit Holding Register Clear

0: No effect.

1: Clear the Tr an sm it Holding Register and set TXRDY, TXCOMP flags.

• LOCKCLR: Lock Clear

0: No effect.

1: Clear the TWI FSM lock.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

830

32.7.2 TWI Master Mode Register

Name: TWI_MMR

Address: 0x4000C604 (0), 0x40020604 (1), 0x40024604 (2), 0x40018604 (3), 0x4001C604 (4), 0x40008604 (5),

0x40040604 (6), 0x40034604 (7)

Access: Read/Write

• IADRSZ: Internal Device Address Size

• MREAD: Master Read Direction

0: Master write direction.

1: Master read direction.

• DADR: Device Address

The device address is used to access slave devices in Read or Write mode. Those bits are only used in Master mode.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–DADR

15 14 13 12 11 10 9 8

–––MREAD–– IADRSZ

76543210

––––––––

Value Name Description

0 NONE No internal device address

1 1_BYTE One-byte inte rnal device address

2 2_BYTE Two-byte internal device address

3 3 _BYTE Three-b yte internal device address

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32.7.3 TWI Slave Mode Register

Name: TWI_SMR

Address: 0x4000C608 (0), 0x40020608 (1), 0x40024608 (2), 0x40018608 (3), 0x4001C608 (4), 0x40008608 (5),

0x40040608 (6), 0x40034608 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the TWI Write Protection Mode Register.

• NACKEN: Slave Receiver Data Phase NACK Enable

0: Normal value to be returned in the ACK cycle of the data phase in Slave Receiver mode.

1: NACK value to be returned in the ACK cycle of the data phase in Slave Receiver mode.

• SMDA: SMBus Default Address

0: Acknowledge of the SMBus Default Address disabled.

1: Acknowledge of the SMBus Default Address enabled.

• SMHH: SMBus Host Header

0: Acknowledge of the SMBus Host Header disabled.

1: Acknowledge of the SMBus Host Header enabled.

• SCLWSDIS: Clock Wait State Disable

0: No effect.

1: Clock stretching disabled in Slave mode, OVRE and UNRE will indicate overrun and underrun.

• MASK: Slave Address Mask

A mask can be applied on the slave device address in Slave mode in order to allow multiple address answer. For each bit

of the MASK field set to one the corresponding SADR bit will be masked.

If MASK field is set to 0 no mask is applied to SADR field.

• SADR: Slave Address

The slave device address is used in Slave mode in order to be accessed by master devices in Read or Write mode.

SADR must be programmed before enabling the Slave mode or after a general call. Writes at other times have no effect.

31 30 29 28 27 26 25 24

DATAMENSADR3ENSADR2ENSADR1EN––––

23 22 21 20 19 18 17 16

– SADR

15 14 13 12 11 10 9 8

– MASK

76543210

– SCLWSDIS – – SMHH SMDA – NACKEN

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

832

• SADR1EN: Slave Address 1 Enable

0: Slave address 1 matching is disabled.

1: Slave address 1 matching is enabled.

• SADR2EN: Slave Address 2 Enable

0: Slave address 2 matching is disabled.

1: Slave address 2 matching is enabled.

• SADR3EN: Slave Address 3 Enable

0: Slave address 3 matching is disabled.

1: Slave address 3 matching is enabled.

• DATAMEN: Data Matching Enable

0: Data matching on first received data is disabled.

1: Data matching on first received data is enabled.

833

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

32.7.4 TWI Internal Address Register

Name: TWI_IADR

Address: 0x4000C60C (0), 0x4002060C (1), 0x4002460C (2), 0x4 001860C (3), 0x4001C60C (4), 0x4000860C (5),

0x4004060C (6), 0x4003460C (7)

Access: Read/Write

• IADR: Internal Address

0, 1, 2 or 3 bytes depending on IADRSZ.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

IADR

15 14 13 12 11 10 9 8

IADR

76543210

IADR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

834

32.7.5 TWI Clock Waveform Generator Register

Name: TWI_CWGR

Address: 0x4000C610 (0), 0x40020610 (1), 0x40024610 (2), 0x40018610 (3), 0x4001C610 (4), 0x40008610 (5),

0x40040610 (6), 0x40034610 (7)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in TWI_WPMR.

TWI_CWGR is only used in Master mode.

• CLDIV: Clock Low Divider

The TWCK low period is defined as follows:

if BRSRCCLK = 0

if BRSRCCLK = 1

• CHDIV: Clock High Divider

The TWCK high period is defined as follows:

if BRSRCCLK = 0

if BRSRCCLK = 1

• CKDIV: Clock Divider

The CKDIV field is used to increase both TWCK high and low periods.

• BRSRCCLK: Bit Rate Source Clock

31 30 29 28 27 26 25 24

––– HOLD

23 22 21 20 19 18 17 16

– – – BRSRCCLK – CKDIV

15 14 13 12 11 10 9 8

CHDIV

76543210

CLDIV

Value Name Description

0 PERIPH_CLK The peripheral clock is the source clock for the bit rate generation.

1PMC_PCK

PMC PCKx is the source clock for the bit rate generation, thus the bit rate can be independent of the

core/peripheral clock.

tlow CLDIV(2CKDIV

×()3)+tperipheral_clock

×=

tlow CLDIV 2CKDIV

×()tPCKx

×=

thigh CHDIV(2CKDIV

×()3)+tperipheral_clock

×=

thigh CHDIV 2CKDIV

×()tPCKx

×=

835

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• HOLD: TWD Hold Time Versus TWCK Falling

If High-speed mode is selected TWD is internally modified on the TWCK falling edge to meet the I2C specified maximum

hold time, else if High-speed mode is not configured TWD is kept unchanged after TWCK falling edge for a period of

(HOLD + 3) × tperipheral clock.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

836

32.7.6 TWI Status Register

Name: TWI_SR

Address: 0x4000C620 (0), 0x40020620 (1), 0x40024620 (2), 0x40018620 (3), 0x4001C620 (4), 0x40008620 (5),

0x40040620 (6), 0x40034620 (7)

Access: Read-only

• TXCOMP: Transmission Completed (cleared by writing TWI_THR)

TXCOMP used in Master mode:

0: During the length of the current frame.

1: When both holding register and internal shifter are empty and STOP condition has been sent.

TXCOMP behavior in Master mode can be seen in Figure 32-6 and in Figure 32-8.

TXCOMP used in Slav e mo de :

0: As soon as a Start is detected.

1: After a Stop or a Repeated Start + an address different from SADR is detected.

TXCOMP behavior in Slave mode can be seen in Figure 32-34, Figure 32-35, Figure 32-36 and Figure 32-37.

• RXRDY: Receive Holding Register Ready (cleared whe n reading TWI_RHR)

0: No character has been received since the last TWI_RHR read operation.

1: A byte has been received in TWI_RHR since the last read.

RXRDY behavior in Master mode can be seen in Figure 32-8 .

RXRDY behavior in Slav e mo d e can be seen in Figure 32-32, Figure 32-35, Figure 32-36 and Figure 32-37.

• TXRDY: Transmit Holding Register Ready (cleared by writing TWI_THR)

TXRDY used in Master mode:

0: The transmit holding register has not been transferred into the internal shifter. Set to 0 when writing into TWI_THR.

1: As soon as a data byte is transferred from TWI_THR to the internal shifter or if a NACK error is detected, TXRDY is set

at the same time as TXCOMP and NACK. TXRDY is also set when MSEN is set (enables TWI).

TXRDY behavior in Master mode can be seen in Figure 32-4, Figure 32-5, and Figure 32-6.

TXRDY used in Slave mode:

0: As soon as data is written in TWI_THR, until this data has been transmitted and acknowledged (ACK or NACK).

1: Indicates that TWI_THR is empty and that data has been transmitted and acknowledged.

If TXRDY is high and if a NACK has been detected, the transmission will be stopped. Thus when TRDY = NACK = 1, the

user must not fill TWI_THR to avoid losing it.

31 30 29 28 27 26 25 24

––––––SDASCL

23 22 21 20 19 18 17 16

LOCK – SMBHHM SMBDAM PECERR TOUT – MCACK

15 14 13 12 11 10 9 8

TXBUFE RXBUFF ENDTX ENDRX EOSACC SCLWS ARBLST NACK

76543210

UNRE OVRE GACC SVACC SVREAD TXRDY RXRDY TXCOMP

837

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

TXRDY behavior in Slave mode can be seen in Figure 32-31, Figure 32-34, Figure 32-36 and Figure 32-37.

• SVREAD: Slave Read

This bit is only used in Slave mode. When SVACC is low (no slave access has been detected) SVREAD is irrelevant.

0: Indicates that a write access is performed by a master.

1: Indicates that a read access is performed by a master.

SVREAD behavior can be seen in Figure 32-31, Figure 32-32, Figure 32-36 and Figure 32-37.

• SVACC: Slave Access

This bit is only used in Slave mode.

0: TWI is not addressed. SVACC is automatically cleared after a NACK or a STOP condition is detected.

1: Indicates that the address decoding sequence has matched (A master has sent SADR). SVACC remains high until a

NACK or a STOP condition is detected.

SVACC behavior can be seen in Figure 32-31, Figure 32-32, Figure 32-36 and Figure 32-37.

• GACC: General Call Access (cleared on read)

This bit is only used in Slave mode.

0: No general call has be en de tec te d.

1: A general call has been detected. After the detection of general call, if need be, the user may acknowledge this access

and decode the following bytes and respond according to the value of the bytes.

GACC behavior can be seen in Figure 32-33.

• OVRE: Overrun Error (cleared on read)

This bit is only used if clock stretching is disab led .

0: TWI_RHR has not been loaded while RXRDY was set.

1: TWI_RHR has been loaded while RXRDY was set. Reset by read in TWI_SR when TXCOMP is set.

• UNRE: Underrun Error (cleared on read)

This bit is only used if clock stretching is disab led .

0: TWI_THR has been filled on time.

1: TWI_THR has not been filled on time.

• NACK: Not Acknowledged (cleared on read)

NACK used in Master mode:

0: Each data byte has been correctly received by the far-end side TWI slave component.

1: A data or address byte has not been acknowledged by the slave component. Set at the same time as TXCOMP.

NACK used in Slave Read mode:

0: Each data byte has been correctly received by the master.

1: In Read mode, a data byte has not been acknowledged by the master. When NACK is set the user must not fill

TWI_THR even if TXRDY is set, because it means that the master will stop the data transfer or re initiate it.

Note that in Slave Write mode all data are acknowledged by the TWI.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

838

• ARBLST: Arbitration Lost (cleared on read)

This bit is only used in Master mode.

0: Arbitration won.

1: Arbitration lost. Another master of the TWI bus has won the multi-master arbitration. TXCOMP is set at the same time.

• SCLWS: Clock Wait State

This bit is only used in Slave mode.

0: The clock is not stretched.

1: The clock is stretched. The TWI_THR / TWI_RHR buffer is not filled / emptied before the emission / reception of a new

character.

SCLWS behavior can be seen in Figure 32-34 and Figure 32-35.

• EOSACC: End Of Slave Access (cleared on read)

This bit is only used in Slave mode.

0: A slave access is being performing.

1: The Slave Access is finished. End Of Slave Access is automatically set as soon as SVACC is reset.

EOSACC behavior can be seen in Figure 32-36 and Figure 32-37.

• ENDRX: End of RX Buffer (cleared by writing TWI_RCR or TWI_RNCR)

0: The Receive Counter Register has not reached 0 since the last write in TWI_RCR or TWI_RNCR(1).

1: The Receive Counter Register has reached 0 since the last write in TWI_RCR or TWI_RNCR(1).

• ENDTX: End of TX Buffer (cleared by writing TWI_TCR or TWI_TNCR)

0: The Transmit Counter Register has not reached 0 since the last write in TWI_TCR or TWI_TNCR(1).

1: The Transmit Counter Register has reached 0 since the last write in TWI_TCR or TWI_TNCR(1).

• RXBUFF: RX Buffer Full (cleared by writing TWI_RCR or TWI_RNCR)

0: TWI_RCR or TWI_RNCR have a value other than 0(1).

1: Both TWI_RCR and TWI_RNCR have a value of 0(1).

• TXBUFE: TX Buffer Empty (cleared by writing TWI_TCR or TWI_TNCR)

0: TWI_TCR or TWI_TNCR have a value other than 0(1).

1: Both TWI_TCR and TWI_TNCR have a value of 0(1).

Note: 1. TWI_RCR, TWI_RNCR, TWI_TCR and TWI_TNCR are PDC registers.

• MCACK: Master Code Acknowledge (cleared on read)

MACK used in Slave mode:

0: No Master Code has been received.

1: A Master Code has been received.

• TOUT: Timeout Error (cleared on read)

0: No SMBus timeout occurred.

1: SMBus timeout occurred.

839

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• PECERR: PEC Error (cleared on read)

0: No SMBus PEC error occurred.

1: An SMBus PEC error occurred.

• SMBDAM: SMBus Default Address Match (cleared on read)

0: No SMBus Default Address received.

1: An SMBus Default Address was received.

• SMBHHM: SMBus Host Header Address Match (cleared on read)

0: No SMBus Host Header Address received.

1: An SMBus Host Header Address was received.

• LOCK: TWI Loc k Due to Frame Errors

0: The TWI is not locked.

1: The TWI is locked due to frame errors (see “Handling Errors in Alternative Command” on page 794).

• SCL: Serial Clock (TWCK) Line Value

0: SCL line sampled value is ‘0’.

1: SCL line sampled value is ‘1.’

• SDA: Serial Data (TWD) Line Value

0: SDA line sampled value is ‘0’.

1: SDA line sampled value is ‘1’.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

840

32.7.7 TWI SMBus Timing Register

Name: TWI_SMBTR

Address: 0x4000C638 (0), 0x40020638 (1), 0x40024638 (2), 0x40018638 (3), 0x4001C638 (4), 0x40008638 (5),

0x40040638 (6), 0x40034638 (7)

Access: Read/Write

• PRESC: SMBus Clock Pres ca le r

Used to specify how to prescale the TLOWS, TLOWM and THMAX counters in SMBTR. Counters are prescaled according

to the following formula:

• TLOWS: Slave Clock Stretch Maximum Cycles

0: TLOW:SEXT timeout check disabled.

1–255: Clock cycles in slave maximum clock stretch count. Prescaled by PRESC. Used to time TLOW:SEXT.

• TLOWM: Master Clock Stretch Maximum Cycles

0: TLOW:MEXT timeout check disabled.

1–255: Clock cycles in master maximum clock stretch count. Prescaled by PRESC. Used to time TLOW:MEXT.

• THMAX: Clock High Maximum Cycles

Clock cycles in clock high maximum count. Prescaled by PRESC. Used for bus free detection. Used to time THIGH:MAX.

31 30 29 28 27 26 25 24

THMAX

23 22 21 20 19 18 17 16

TLOWM

15 14 13 12 11 10 9 8

TLOWS

76543210

–––– PRESC

fPrescaled fMCK

2PRESC 1+()

-----------------------------

841

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

32.7.8 TWI Alternative Command Register

Name: TWI_ACR

Address: 0x4000C640 (0), 0x40020640 (1), 0x40024640 (2), 0x40018640 (3), 0x4001C640 (4), 0x40008640 (5),

0x40040640 (6), 0x40034640 (7)

Access: Read/Write

• DATAL: Data Length

0: No data to send (see Section 32.6.3.12 ”Alternative Command”).

1–255: Number of bytes to send during the transfer.

• DIR: Transfer Direction

0: Write direction.

1: Read direction.

• PEC: PEC Request (SMBus Mode only)

0: The transfer does not use a PEC byte.

1: The transfer uses a PEC byte.

• NDATAL: Next Data Length

0: No data to send (see Section 32.6.3.12 ”Alternative Command”).

1–255: Number of bytes to send for the next transfer.

• NDIR: Next Transfer Direction

0: Write direction.

1: Read direction.

• NPEC: Next PEC Request (SMBus Mode only)

0: The next transfer does not use a PEC byte.

1: The next transfer uses a PEC byte.

31 30 29 28 27 26 25 24

––––––NPECNDIR

23 22 21 20 19 18 17 16

NDATAL

15 14 13 12 11 10 9 8

––––––PECDIR

76543210

DATAL

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

842

32.7.9 TWI Filter Register

Name: TWI_FILTR

Address: 0x4000C644 (0), 0x40020644 (1), 0x40024644 (2), 0x40018644 (3), 0x4001C644 (4), 0x40008644 (5),

0x40040644 (6), 0x40034644 (7)

Access: Read/Write

• FILT: RX Digital Filter

0: No filtering applied on TWI inputs.

1: TWI input filtering is active. (Only in Standard and Fast modes)

Note: TWI digital input filtering follows a majority decision based on three samples from SDA/SCL lines at peripheral clock frequency.

• PADFEN: PAD Filter Enable

0: PAD analog filter is disabled.

1: PAD analog filter is enabled. (The analog filter must be enabled if High-speed mode is enabled .)

• PADFCFG: PAD Filter Configuration

See the electrical characteristics section for filter configuration details.

• THRES: Digital Filter Threshold

0: No filtering applied on TWI inputs.

1–7: Maximum pulse width of spikes which will be suppressed by the input filter, defined in peripheral clock cycles.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––– THRES

76543210

–––––PADFCFGPADFENFILT

843

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

32.7.10 TWI Interrupt Enable Register

Name: TWI_IER

Address: 0x4000C624 (0), 0x40020624 (1), 0x40024624 (2), 0x40018624 (3), 0x4001C624 (4), 0x40008624 (5),

0x40040624 (6), 0x40034624 (7)

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Enables the corresponding interrupt.

• TXCOMP: Transmission Completed Interrupt Enable

• RXRDY: Receive Holding Register Ready Interrupt Enable

• TXRDY: Transmit Holding Register Ready Interrupt Enable

• SVACC: Slave Access Interrupt Enable

• GACC: General Call Access Interrupt Enable

• OVRE: Overrun Error Interrupt Enable

• UNRE: Underrun Error Interrupt Enable

• NACK: Not Acknowledge Interrupt Enable

• ARBLST: Arbitration Lost Interrupt Enable

• SCL_WS: Clock Wait State Interrupt Enable

• EOSACC: End Of Slave Access Interrupt Enable

• ENDRX: End of Receive Buffer Interrupt Enable

• ENDTX: End of Transmit Buffer Interrupt Enable

• RXBUFF: Receive Buffer Full Interrupt Enable

• TXBUFE: Transmit Buffer Empty Interrupt Enable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – SMBHHM SMBDAM PECERR TOUT – MCACK

15 14 13 12 11 10 9 8

TXBUFE RXBUFF ENDTX ENDRX EOSACC SCL_WS ARBLST NACK

76543210

UNRE OVRE GACC SVACC – TXRDY RXRDY TXCOMP

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

844

• MCACK: Master Code Acknowledge Interrupt Enable

• TOUT: Timeout Error Interrupt Enable

• PECERR: PEC Error Interrupt Enable

• SMBDAM: SMBus Default Address Match Interrupt Enable

• SMBHHM: SMBus Host Header Address Match Inte rrupt Enable

845

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

32.7.11 TWI Interrupt Disable Register

Name: TWI_IDR

Address: 0x4000C628 (0), 0x40020628 (1), 0x40024628 (2), 0x40018628 (3), 0x4001C628 (4), 0x40008628 (5),

0x40040628 (6), 0x40034628 (7)

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Disables the corresponding interrupt.

• TXCOMP: Transmission Completed Interrupt Disable

• RXRDY: Receive Holding Register Ready Interrupt Dis able

• TXRDY: Transmit Holding Register Ready Interrupt Disable

• SVACC: Slave Access Interrupt Disable

• GACC: General Call Access Interrupt Disable

• OVRE: Overrun Error Interrupt Disable

• UNRE: Underrun Error Interrupt Disable

• NACK: Not Acknowledge Interrupt Disable

• ARBLST: Arbitration Lost Interrupt Disable

• SCL_WS: Clock Wait State Interrupt Dis able

• EOSACC: End Of Slave Access Interrupt Disable

• ENDRX: End of Receive Buffer Interrupt Disable

• ENDTX: End of Transmit Buffer Interrupt Disable

• RXBUFF: Receive Buffer Full Interrupt Disable

• TXBUFE: Transmit Buffer Empty Interrupt Disable

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – SMBHHM SMBDAM PECERR TOUT – MCACK

15 14 13 12 11 10 9 8

TXBUFE RXBUFF ENDTX ENDRX EOSACC SCL_WS ARBLST NACK

76543210

UNRE OVRE GACC SVACC – TXRDY RXRDY TXCOMP

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

846

• MCACK: Master Code Acknowledge Interrupt Disable

• TOUT: Timeout Error Interrupt Disable

• PECERR: PEC Error Interrupt Disable

• SMBDAM: SMBus Default Address Match Interrupt Disable

• SMBHHM: SMBus Host Header Address Match Interrupt Disable

847

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

32.7.12 TWI Interrupt Mask Register

Name: TWI_IMR

Address: 0x4000C62C (0), 0x4002062C (1), 0x4002462C (2), 0x4 001862C (3), 0x4001C62C (4), 0x4000862C (5),

0x4004062C (6), 0x4003462C (7)

Access: Read-only

The following configuration values are valid for all listed bit names of this register:

0: The corresponding interrupt is disabled.

1: The corresponding interrupt is enabled.

• TXCOMP: Transmission Completed Interrupt Mask

• RXRDY: Receive Holding Register Ready Inte rrupt Mask

• TXRDY: Transmit Holding Register Ready Interrupt Mask

• SVACC: Slave Access Interrupt Mask

• GACC: General Call Access Interrupt Mask

• OVRE: Overrun Error Interrupt Mask

• UNRE: Underrun Error Interrupt Mask

• NACK: Not Acknowledge Interrupt Mask

• ARBLST: Arbitration Lost Interrupt Mask

• SCL_WS: Clock Wait State Interrupt Mask

• EOSACC: End Of Slave Access Interrupt Mask

• ENDRX: End of Receive Buffer Interrupt Mask

• ENDTX: End of Transmit Buffer Interrupt Mask

• RXBUFF: Receive Buffer Full Interrupt Mask

• TXBUFE: Transmit Buffer Empty Interrupt Mask

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – SMBHHM SMBDAM PECERR TOUT – MCACK

15 14 13 12 11 10 9 8

TXBUFE RXBUFF ENDTX ENDRX EOSACC SCL_WS ARBLST NACK

76543210

UNRE OVRE GACC SVACC – TXRDY RXRDY TXCOMP

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

848

• MCACK: Master Code Acknowledge Interrupt Mask

• TOUT: Timeout Error Interrupt Mask

• PECERR: PEC Error Interrupt Mask

• SMBDAM: SMBus Default Address Match Interrupt Mask

• SMBHHM: SMBus Host Header Address Match Interrupt Mask

849

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

32.7.13 TWI Receive Holding Register

Name: TWI_RHR

Address: 0x4000C630 (0), 0x40020630 (1), 0x40024630 (2), 0x40018630 (3), 0x4001C630 (4), 0x40008630 (5),

0x40040630 (6), 0x40034630 (7)

Access: Read-only

• RXDATA: Master or Slave Receive Holding Data

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

RXDATA

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

850

32.7.14 TWI SleepWalking Mat ching Register

Name: TWI_SWMR

Address: 0x4000C64C (0), 0x4002064C (1), 0x4002464C (2), 0x4 001864C (3), 0x4001C64C (4), 0x4000864C (5),

0x4004064C (6), 0x4003464C (7)

Access: Read/Write

• SADR1: Slave Address 1

Slave address 1. The TWI module will match on this additional address if SADR1EN bit is enabled.

• SADR2: Slave Address 2

Slave address 2. The TWI module will match on this additional address if SADR2EN bit is enabled.

• SADR3: Slave Address 3

Slave address 3. The TWI module will match on this additional address if SADR3EN bit is enabled.

• DATAM: Data Match

The TWI module will extend the SleepWalking matching process to the first received data comparing it with DATAM if

DATAMEN bit is enabled.

31 30 29 28 27 26 25 24

DATAM

23 22 21 20 19 18 17 16

– SADR3

15 14 13 12 11 10 9 8

– SADR2

76543210

– SADR1

851

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

32.7.15 TWI Transmit Holding Register

Name: TWI_THR

Address: 0x4000C634 (0), 0x40020634 (1), 0x40024634 (2), 0x40018634 (3), 0x4001C634 (4), 0x40008634 (5),

0x40040634 (6), 0x40034634 (7)

Access: Write-only

• TXDATA: Master or Slave Transmit Holding Data

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

TXDATA

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

852

32.7.16 TWI Write Protection Mode Register

Name: TWI_WPMR

Address: 0x4000C6E4 (0), 0x400206E4 (1), 0x400246E4 (2 ), 0x400186E4 (3), 0x4001C6E4 (4), 0x400086E4 (5),

0x400406E4 (6), 0x400346E4 (7)

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x545749 (“TWI” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x545749 (“TWI” in ASCII).

See Section 32.6.7 ”TWI Register Write Protection” for the list of registers that can be write-protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x545749 PASSWD Writing any other value in this field aborts the write operation of the WPEN bit.

Always reads as 0

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32.7.17 T WI Write Protectio n Status Register

Name: TWI_WPSR

Address: 0x4000C6E8 (0), 0x400206E8 (1), 0x400246E8 (2 ), 0x400186E8 (3), 0x4001C6E8 (4), 0x400086E8 (5),

0x400406E8 (6), 0x400346E8 (7)

Access: Read-only

• WPVS: Write Protect Violation Status

0: No Write Protection Violation has occurred since the last read of TWI_WPSR.

1: A Write Protection Violation has occurred since the last read of TWI_WPSR. If this violation is an unauthorized attempt

to write a protected register, the associated violation is reported into field WPVSRC.

• WPVSRC: Write Protection Vi olation Source

When WPVS = 1, WPVSRC indicates the register address offset at which a write access has been attempted.

31 30 29 28 27 26 25 24

WPVSRC

23 22 21 20 19 18 17 16

WPVSRC

15 14 13 12 11 10 9 8

WPVSRC

76543210

–––––––WPVS

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854

33. Inter-IC Sound Controller (I2SC)

33.1 Description

The Inter-IC Sound Controller (I2SC) pr ovides a 5-wire, bidirectional, synchronous, digital audio link to external

audio devices: I2SDI, I2SDO, I2SWS, I2SCK, and I2SMCK pins.

The I2SC is compliant with the Inter-IC Sound (I2S) bus specification.

The I2SC consists of a receiver, a transmitter and a common clock generator that can be enabled separately to

provide Master, Slave or Controller modes with receiver and/or transmitter active.

Peripheral DMA Controller (PDC) channels, separate for the receiver and for the transmitter, allow a continuous

high bit rate data transfer without processor intervention to the following:

Audio CODECs in Master, Slave, or Controller mode

Stereo DAC or ADC through a dedicated I2S serial interface

The I2SC can use either a single PDC channel for both audio channe ls or one PDC channel per audio channel.

The 8- and 16-bit comp act stereo format reduces the require d PDC bandwidth by transferring the left an d right

samples within the same data word.

In Master mode, the I2SC can produce a 32 fs to 1024 fs master clock that provides an over-sampling clock to an

external audio codec or digital signal processor (DSP).

33.2 Embedded Characteristics

Compliant with Inter-IC Sound (I2S) Bus Specification

Master, Slave, and Controller Modes

Slave: Data Received/Transmitted

Master: Data Received/Transmitted And Clocks Generated

Controller: Clocks Generated

Individual Enable and Disable of Receiver, Transmitter and Clocks

Configurable Clock Generator Common to Receiver and Transmitter

Suitable fo r a Wide Rang e of Samp le Freq uencies (fs), Including 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz,

96 kHz, and 192 kHz

32 fs to 1024 fs Master Clock Generated for External Oversampling Data Converters

Support for Multiple Data Formats

32-, 24-, 20-, 18-, 16-, and 8-bit Mono or Stereo Format

16- and 8-bit Compact Stereo Format, with Left and Right Samples Packed in the Same Word to

Reduce Data Transfers

PDC Interfaces the Receiver and Transmitter to Reduce Processor Overhead

One PDC Channel for Both Audio Channels, or

One PDC Channel Per Audio Channel

Smart Holding Registers Management to Avoi d Audio Channels Mix After Overrun or Underrun

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33.3 Block Diagram

33.4 I/O Lines Description

33.5 Product Dependencies

To use the I2SC, other parts of the system must be configured correctly, as described below.

33.5.1 I/O Lines

The I2SC pins may be multiplexed with I/O Controlle r lines. The user must first program the PIO Controller to

assign the required I2SC pins to their pe ripheral function . If the I2SC I/O lines are n ot used by the application , they

can be used for other purposes by the PIO Controller. The user must enable the I2SC inputs and outputs that are

used.

Figure 33-1. I2SC Block Diagram

Clocks

Receiver

Transmitter

I2SMCK

I2SCK

I2SWS

I2SDI

I2SDO

Power

Manager

Peripheral

Bus Bridge

Peripheral

DMA

Controller

Interrupt

Controller

I2SC

Bus

Interface

PIO

Peripheral

Clock

Events

Matrix

CCFG_I2SCLKSEL

PCKx 1

Selected Clock

Table 33-1. I/O Line s Description

Pin Name Pin Description Type

I2SMCK Master Clock Output

I2SCK Serial Clock Input/Output

I2SWS I2S Word Select Input/Output

I2SDI Serial Data Input Input

I2SDO Serial Data Output Output

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856

33.5.2 Power Management

If the CPU enters a Sleep mode that disables clocks used by the I2SC, the I2SC stops functioning and resumes

operation after the system wakes up from Sleep mode.

33.5.3 Clocks

The clock for the I2SC bus interface is generated by the Power Management Controller (PMC). I2SC must be

disabled before disabling the clock to avoid freezing the I2SC in an undefined state.

33.5.4 Peripheral DMA Controller

The I2SC interfaces to the Peripheral DMA Controller (PDC). Using the I2SC DMA functionality requires the PDC

to be programmed first.

33.5.5 Interrupt Sources

The I2SC interrupt line is connected to the Interrupt Controller. Using the I2SC interrupt requires the Interrupt

Controller to be programmed first.

Table 33-2. I/O Lines

Instance Signal I/O Line Peripheral

I2SC0 I2SC0_CK PA0 A

I2SC0 I2SC0_DI0 PA2 B

I2SC0 I2SC0_DO0 PA3 B

I2SC0 I2SC0_DO0 PA17 A

I2SC0 I2SC0_MCK PA4 B

I2SC0 I2SC0_MCK PA18 A

I2SC0 I2SC0_WS PA1 A

I2SC1 I2SC1_CK PA19 B

I2SC1 I2SC1_DI0 PA22 B

I2SC1 I2SC1_DO0 PA23 A

I2SC1 I2SC1_DO0 PA25 B

I2SC1 I2SC1_MCK PA24 A

I2SC1 I2SC1_MCK PA26 B

I2SC1 I2SC1_WS PA20 B

Table 33-3. Peripheral IDs

Instance ID

I2SC0 16

I2SC1 17

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33.6 Functional Description

33.6.1 Initialization

The I2SC feat ures a receiver, a tra nsmitter and a clock generator for Master and Controller modes. Receiver and

transmitter share the same serial clock and word select.

Before enabling the I2SC, the selected configuration must be written to the I2SC M ode Regi ster (I2SC_MR) a nd to

the I2S Clock Source Selection register (CCFG_I2SCLKSEL) described in the MATRIX section. If the

I2SC_MR.IMCKMODE bit is set, the I2SC_MR.IMCKFS field must be configured as described in Section 33.6.5

”Serial Clock an d Wo rd Select Generation”.

Once the I2SC_MR has be en written, the I2SC clock generator, receiver, and transmitter can be enabled by

writing a ’1’ to the CKEN, RXEN, and TXEN bits in the Con trol Register (I2SC_CR). The clock gene rator can be

enabled alone in Controller mode to output clocks to the I2 SMCK, I2SCK, and I2SWS pins. The clock generator

must also be enabled if the receiver or the transmitter is enabled.

The clock generator, receiver, and transmitter can be disabled independently by writing a ’1’ to I2SC_CR.CXDIS,

I2SC_CR.RXDIS and/or I2SC_CR.TXDIS, respectively. Once requested to stop, they stop only when the

transmission of the pending frame transmission is completed.

33.6.2 Basic Operation

The receiver can be operated by reading the Receiver Holding Register (I2SC_RHR), whenever the Receive

Ready (RXRDY) bit in the Status Register (I2SC_SR) is set. Successive values read from RHR correspond to the

samples from the left and right audio channels for the successive frames.

The transmitter can be operated by writing to the Transmitter Holding Register (I2SC_THR), whenever the

Transmit Ready (TXRDY) bit in the I2SC_SR is set. Successive values written to THR correspond to the samples

from the left and right audio channels for the successive frames.

The RXRDY and TXRDY bits can be polled by reading the I2SC_SR.

The I2SC processor load can be reduced by enabling interrupt-driven operation. The RXRDY and/or TXRDY

interrupt requests can be enabled by writing a ’1’ to the corresponding bit in the Interrupt Enable Register

(I2SC_IER). The interrupt service routine associated to the I2SC in terrupt request is executed whenever the

Receive Ready or the Transmit Ready status bit is set.

33.6.3 Master, Controller and Slave Modes

In Master and Contro ller modes, the I2 SC provides the ma ster clock, the serial clock and the word select. I2SMCK,

I2SCK, and I2SWS pins are outputs.

In Controller mod e, the I2SC receiver and tr ansmitter are dis abled. Only the clocks are e nabled and used by an

external receiver and/or transmitter.

In Slave mode, the I2SC receives the serial clock and the word select from an external master. I2SCK and I2SWS

pins are inputs.

The mode is selected by writing the MODE field in the I2SC_MR. Since the MODE field changes the direction of

the I2SWS and I2SSCK pins, the I2SC_MR must be written when the I2SC is stopped.

33.6.4 I2S Reception and Transmission Sequence

As specified in the I2S protocol, data bits are left-justified in the word select time slot, with the MSB transmitted

first, starting one clock period after the transition on the word select line.

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858

Figure 33-2. I2S Reception and Transmission Sequence

Data bits are sent on the falling edge of the serial clock and sampled on the rising edge of the serial clock. the word

select line indicates the channel in transmission, a low level for the left cha nnel and a high level for the right

channel.

The length of transmitted words can be chosen among 8, 16, 18, 20, 24, and 32 bits by writing the

I2SC_MR.DATALENGTH field.

If the time slot allows for more data bits than written in the I2SC_MR.DATALENGTH field, zeroes are appended to

the transmitted data word or extra received bits are discarded.

33.6.5 Serial Clock and Word Select Generation

The generation of clocks in the I2SC is described in Figure 33-3 ”I2SC Clock Generation”.

In Slave mode, the serial clock and word sele ct clock are driven by an exte rnal master. I2SCK and I2SWS pins ar e

inputs.

In Master mode, the user can configure the master clock, serial clock, and word select clock through the

I2SC_MR. I2SMCK, I2SCK, and I2SWS pins are outputs and MCK is used to derive the I2SC clocks.

Audio codecs connected to the I2SC pi n s may requir e a master clock ( I2SMCK) signal with a freq uency multip le of

the audio sample frequency (fs), such as 256fs. When the I2SC is in Master mode, writing a ’1’ to

I2SC_MR.IMCKMODE outputs MCK as master clock to the I2SMCK pin, and divides MCK to cr eate th e internal bit

clock, output on the I2SCK pin. The clock division factor is defined by writing to I2SC_MR.IMCKFS and

I2SC_MR.DATALENGTH, as described in the I2SC_MR.IMCKFS field description.

The master clock (I2SMCK) frequency is [2×16 × (IMCKFS + 1)] / (IMCKDIV + 1) times the sample frequency (fs),

i.e., I2SWS frequency.

Example: If the sampling rate is 44.1 kHz with an I2S master clock (I2SMCK) ratio of 256, the core frequency must

be an integer multiple of 11 .2896 MHz. Assuming an integer multiple of 4, the IMCKDIV field must b e configured to

4; the field IMCKFS must then be set to 31.

The serial clock (I2SCK) frequency is 2 × Slot Le ngth times the sam ple frequen cy (fs), where Slot Length is d efined

in Table 33-4.

Serial clock I2SCK

Word Select I2SWS

Data I2SDI/I2SDO MSB MSBLSB

Left Channel Right Channel

In Master mo de , if th e Pe r iph er a l clock frequency is higher than 96 MHz, the PCKx clock from

PMC must be selected as I2SC input clock by writing a ’1’ in the CLKSELx bit of the

CCFG_I2CLKSEL register located in Matrix (See Figure 33-3 ”I2SC Clock Generation”).

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Warning: I2SC_MR.IMCKMODE must be written to ’1’ if the master clock frequency is strictly higher than the

serial clock.

If a master clock output is not required, the MCK clock is used as I2SCK by clearing I2SC_MR.IMCKMODE.

Alternatively, if the frequency of the MCK clock used is a multiple of the required I2SCK frequency, the I2SMCK to

I2SCK divider can be used with the ratio defined by writing the I2SC_MR.IMCKFS field.

The I2SWS pin is used as word select as described in Section 33.6.4 ”I2S Reception and Transmission

Sequence”.

Table 33-4. S lot Length

I2SC_MR.DATALENGTH Word Length Slo t Len gth

0 32 bits 32

124 bits

32 if I2SC_MR.IWS = 0

24 if I2SC_MR.IWS = 1

220 bits

318 bits

416 bits

5 16 bits compact stereo

68 bits8

7 8 bits compact stereo

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Figure 33-3. I2SC Clock Ge neration

33.6.6 Mono

When the Transmit Mono bit (TXMONO) in I2SC_MR is set, data written to the left channel is duplicated to the

right output chan n el.

When the Receive Mono bit (RXMONO) in I2SC_MR is set, data received from the left chann el is duplicated to th e

right channel.

33.6.7 Holding Registers

The I2SC user interface includes a Receive Holding Register (I2SC_RHR) and a Transmit Holding Register

(I2SC_THR). These registers are used to access audio samples for both audio channels.

When a new data word is available in I2SC_RHR, the Receive Ready bit (RXRDY) in I2SC_SR is set. Reading

I2SC_RHR clears this bit.

A receive overrun condition occurs if a new data word becomes available before the previous data word has been

read from I2 SC_ RHR. In this case, the Rece ive Ove rrun bit in I2SC_SR and bit i of the RXORCH field in I2SC_SR

are set, where i is the current receive channel number.

When I2SC_THR is empty, the Transmit Ready bit (TXRDY) in I2SC_SR is set. Writing to I2SC_THR clears this

bit.

A transmit underrun condition occurs if a new data wor d needs to be transmitted before it has been written to

I2SC_THR. In this case, the Transmit Underrun (TXUR) bit and bit i of the TXORCH field in I2SC_SR are set,

where i is the current transmit channel number. If the TXSAME bit in I2SC_MR is ’0’, then a zero data word is

I2SMCK

I2SCK

I2SWS

I2SWS_in

I2SCK_in

Peripheral

Clock

I2SC_CR.CKEN/CKDIS

I2SC_MR.IMCKDIV

I2SC_MR.IMCKMODE

I2SC_CR.CKEN/CKDIS

I2SC_MR.IMCKFS

I2SC_MR.DATALENGTH

I2SC_MR.MODE

slave

master

slave

I2SCK_in

I2SWS_in

I2SC_MR.IMCKMODE

internal

bit clock

internal

word clock

Clock

Enable

Clock

Divider

Clock

Divider

Clock

Divider

Clock

Enable

PMC.PCKx

MATRIX.CCFG_I2SCLKSEL.CLKSELx

I2SC

Selected Clock

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transmitted in case of underrun. If I2SC_MR.TXSAME is ’1’, then the previous data word for the current transmit

channel number is transmitted.

Data words are right-justified in I2SC_RHR and I2SC_THR. For the 16-b it compact stereo data format, the left

sample uses bits 15:0 and the right sam ple uses bits 31:16 of the same data word. For the 8-bit com pact stereo

data format, the left sample uses bits 7:0 and the right sam ple use s bits 15:8 of the same data word.

33.6.8 Peripheral DMA Controller Operation

All receiver audio channels can be assigned to a single PDC channel or indi vidual audio channels can be assigne d

to one PDC channel per audio channel. The same channel assignment choice applies to the transmitter audio

channels.

Channel assignment is selected by writing to the I2SC_MR.RXDMA and I2SC_MR.TXDMA bits. If a single PDC

channel is selected, all data samples use I2SC receiver or transmitter PDC channel 0.

The PDC reads from the I2SC_RHR and writes to the I2SC_THR for both audio channels successively.

The PDC transfers may use 32-bit word, 16-bit halfword, or 8-bit byte depending on the value of the

I2SC_MR.DATALENGTH field.

33.6.9 Loop-back Mode

For debug purposes, the I2SC can be configured to loop back the transmitter to the Receiver. Writing a ’1’ to the

I2SC_MR.LO OP bit inte rnally co nnects I2 SDO to I2SDI, so that the transmitted data is also received. Writing a ’0’

to I2SC_MR.LOOP restores the normal behavior with independent Receiver and Transmitter. As for other chan ges

to the Receiver or Transmitter co nfigu r ation, th e I2SC Re ceiver a nd Tra nsmitte r m ust be disab led befor e wr iting to

I2SC_MR to update I2SC_MR.LOOP.

33.6.10 Interrupts

An I2SC interru pt request can be triggere d whenever one or several of the following bits are set in I2SC_SR:

Receive Ready (RXRDY), Receive Overrun (RXOR), Transmit Ready (TXRDY) or Transmit Underrun (TXUR).

The interrupt request is generated if the corresponding bit in the Interrupt Mask Register (I2SC_IMR) is set. Bits in

I2SC_IMR are set by writing a ’1’ to the corresponding bit in I2SC_IER and cleared by writing a ’1’ to the

corresponding bit in the Interrupt Disable Register (I2SC_IDR). The interrupt request remains active until the

corresponding bit in I2SC_SR is cleared by writing a ’1’ to the corresponding bit in the Status Clear Register

(I2SC_SCR).

For debug purposes, interrupt requests can be simulated by writing a ’1’ to the corresponding bit in the Status Set

SAM G55 [DATASHEET]

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862

Figure 33-4. Interrupt Block Diagram

33.7 I2SC Application Examples

The I2SC supports several serial communication modes used in audio or high-speed serial links. Examples of

standard applications are shown in the following figures. All serial link applications supported by the I2SC are not

listed here.

Figure 33-5. Slave Transmitter I2SC Application Example

I2SC_IER

TXRDY

TXUR

RXRDY

RXOR

Set Clear

I2SC interrupt line

I2SC_IDRI2SC_IMR

Transmitter

Receiver

Interrupt

Logic

I2SCK

I2SWS

I2SDI

I2SDO

I2SC Stereo Audio

DAC

Serial Clock

Word Select

Serial Data Out

MSB LSB MSB

Serial Clock

Word Select

Serial Data Out

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Figure 33-6. Dual Microphone Application Block Diagram

Figure 33-7. Codec Application Block Diagram

Serial Clock

Word Select

Serial Data In

DendDstart

Right Channel

Left Channel

I2SCK

I2SWS

I2SDI

I2SDO

I2SC

Serial Clock

Word Select

Serial Data In

I2SMCK

I2S Microphone

for Left Channel

I2S Microphone

for Right Channel

SCK

L/R Tied to 1

SCK

L/R Tied to 0

I2SCK

I2SWS

I2SDI

I2SDO

I2SC I2S

Audio

Codec

Serial Clock

Word Select

Serial Data Out

Serial Data In

Master Clock

I2SMCK MCLK

BCLK

DAC_SDATA/DIN

LRCLK/WCLK

ADC_SDATA/DOUT

Serial Clock

Word Select

Serial Data Out

Serial Data In

Dend

Right Time Slot

Dstart

Left Time Slot

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33.8 Inter-IC Sound Controller (I2SC) User Interface

Table 33-5. Register Mapping

Offset Register Name Access Reset

0x00 Control Register I2SC_CR Write-only –

0x04 Mode Register I2SC_MR Read/Write 0x00000000

0x08 Status Register I2SC_SR Read-only 0x00000000

0x0C Status Clear Register I2SC_SCR Write-only –

0x10 St atus Set Register I2SC_SSR Write-only –

0x14 Interrupt Enable Register I2SC_IER Write-only –

0x18 Interrupt Disable Register I2SC_IDR Write-only –

0x1C Interrupt Mask Register I2SC_IMR Read-only 0x0000 0000

0x20 Receiver Holding Register I2SC_RHR Read-only 0x00000000

0x24 Transmitter Holding Register I2SC_THR Write-only –

0x28–0xFC Reserved – – –

0x100–0x124 Reserved for PDC registers for left side – – –

0x128–0x1FC Reserved – – –

0x200–0x224 Reserved for PDC registers for right side – – –

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33.8.1 Inter-IC Sound Controller Control Register

Name: I2SC_CR

Address: 0x40000000 (0), 0x40004000 (1)

Access: Write-only

• RXEN: Receiver Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit enables the I2SC receiver, if RXDIS is not one. Bit I2SC_SR.RXEN is set when the receiver is

activated.

• RXDIS: Receiver Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit disables the I2SC receiver. Bit I2SC_SR.RXEN is cleared when the receiver is stopped.

• CKEN: Clocks Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit enables the I2SC clocks generation, if CKDIS is not one.

• CKDIS: Clocks Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a zone to this bit disables the I2SC clock generation.

• TXEN: Transmitter Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit enables the I2SC transm itter, if TXDIS is not one. Bit I2SC_SR.TXEN is set when the Transmitter

is started.

• TXDIS: Transmitter Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit disables the I2SC transmitter. Bit I2SC_SR.TXEN is cleared when the Transmitter is stopped.

• SWRST: Software Reset

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit resets all the registers in the I2SC. The I2SC is disabled after the reset.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

SWRST – TXDIS TXEN CKDIS CKEN RXDIS RXEN

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866

33.8.2 Inter-IC Sound Controller Mode Register

Name: I2SC_MR

Address: 0x40000004 (0), 0x40004004 (1)

Access: Read/Write

The I2SC_MR must be written when the I2SC is stopped. The proper sequence is to write to I2SC_MR, then write to

I2SC_CR to enable the I2SC or to disable the I2SC before writing a new value to I2SC_MR.

• MODE: Inter-IC Sound Controller Mode

• DATALENGTH: Data Word Length

• FORMAT: Data Format

31 30 29 28 27 26 25 24

IWS IMCKMODE IMCKFS

23 22 21 20 19 18 17 16

– – IMCKDIV

15 14 13 12 11 10 9 8

– TXSAME TXDMA TXMONO – RXLOOP RXDMA RXMONO

76543210

FORMAT – DATALENGTH – MODE

Value Name Description

0 SLAVE I2SCK and i2SWS pin inputs used as bit clock and word select/frame synchronization.

1MASTER Bit clock and word select/frame synchronization generated by I2SC from MCK and output to I2SCK

and I2SWS pins. MCK is output as master clock on I2SMCK if I2SC_MR.IMCKMODE is set.

Value Name Description

0 32_BITS Data length is set to 32 bits

1 24_BITS Data length is set to 24 bits

2 20_BITS Data length is set to 20 bits

3 18_BITS Data length is set to 18 bits

4 16_BITS Data length is set to 16 bits

5 16_BITS_COMPACT Data length is set to 16-bit compact stereo. Left sample in bits 15:0 and right sample in bits 31:16 of

same word.

6 8_BITS Data length is set to 8 bits

7 8_BITS_COMPACT Data length is set to 8-bit comp act stereo. Lef t sample in bit s 7:0 and right sample in bits 15:8 of the

same word.

Value Name Description

0I2S I2S format, stereo with I2SWS low for left channel, and MSB of sample starting one I2SCK period

after I2SWS edge

1LJ Left-justified format, stereo with I2SWS high for left channel, and MSB of sample starting on I2SWS

edge

2– Reserved

3– Reserved

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• RXDMA: Single or Multiple PDC Channels for Receiver

0: The receiver uses only one PDC channel for all audio channels.

1: The receiver uses one PDC channel per audio channel.

• RXMONO: Receive Mono

0: Stereo

1: Mono, with left audio samples duplicated to right audio channel by the I2SC.

• RXLOOP: Loop-back Test Mode

0: Normal mode

1: I2SDO output of I2SC is internally connected to I2SDI input.

• TXMONO: Transmit Mono

0: Stereo

1: Mono, with left audio samples duplicated to right audio channel by the I2SC.

• TXDMA: Single or Multiple PDC Channels for Transmitter

0: The transmitter uses only one PDC channel for all audio channels.

1: The transmitter uses one PDC channel per audio channel.

• TXSAME: Transmit Data when Underrun

0: Zero sample transmitted when underrun.

1: Previous sample transmitted when underrun

• IMCKDIV: Selected Clock to I2SC Master Clock Ratio

I2SMCK Master clock output freque ncy is Selected Clock divided by (IMCKDIV + 1). Refer to the IMCKFS field description.

Notes: 1. This field is write-only. Always read as ‘0’.

2. Do not write a ‘0’ to this field.

• IMCKFS: Master Clock to fs Ratio

Master clock frequency is [2 x 16 × (IMCKFS + 1)] / (IMCKDIV + 1) times the sample rate, i.e., I2SWS frequency.

Value Name Description

0 M2SF32 Sample frequency ratio set to 32

1 M2SF64 Sample frequency ratio set to 64

2 M2SF96 Sample frequency ratio set to 96

3 M2SF128 Sample frequency ratio set to 128

5 M2SF192 Sample frequency ratio set to 192

7 M2SF256 Sample frequency ratio set to 256

11 M2SF384 Sample frequency ratio set to 384

15 M2SF512 Sample frequency ratio set to 512

23 M2SF768 Sample frequency ratio set to 768

31 M2SF1024 Sample frequency ratio set to 1024

47 M2SF1536 Sample frequency ratio set to 1536

63 M2SF2048 Sample frequency ratio set to 2048

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868

• IMCKMODE: Master Clock Mode

0: No master clock generated (Selected Clock drives I2SCK output).

1: Master clock generated (internally generated clock is used as I2SMCK output).

Warning: If I2SMCK frequency is th e same as I2SCK, IMCKMODE must be cleared. Refer to Section 33.6.5 ”Serial Clock

and Word Select Generation” and Table 33-4 “Slot Length”.

• IWS: I2SWS Slot Width

0: I2SWS slot is 32 bits wide for DATALENGTH = 18/20/24 bits.

1: I2SWS slot is 24 bits wide for DATALENGTH = 18/20/24 bits.

Refer to Table 33-4 “Slot Length”.

869

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33.8.3 Inter-IC Sound Controller Status Register

Name: I2SC_SR

Address: 0x40000008 (0), 0x40004008 (1)

Access: Read-only

• RXEN: Receiver Enabled

0: This bit is cleared when the receiver is disabled, following a RXDIS or SWRST request in I2SC_CR.

1: This bit is set when the receiver is enabled, following a RXEN request in I2SC_CR.

• RXRDY: Receive Ready

0: This bit is cleared when I2SC_RHR is read.

1: This bit is set when received data is present in I2SC_RHR.

• RXOR: Receive Overrun

0: This bit is cleared when the corresponding bit in I2SC_SCR is written to ’1’.

1: This bit is set when an overrun error occurs on I2SC_RHR or when the corresponding bit in I2SC_SSR is written to ’1’.

• ENDRX: End of Receiver Transfer

0: This bit is set when PDC has completed the receive transfer.

1: This bit is cleared when a new receive transfer is programmed into the PDC.

• TXEN: Transmitter Enabled

0: This bit is cleared when the transmitter is disabled, following a I2SC_CR.TXDIS or I2SC_CR.SWRST request.

1: This bit is set when the transmitter is enabled, following a I2 SC_CR.TXEN request.

• TXRDY: Transmit Ready

0: This bit is cleared when data is written to I2SC_THR.

1: This bit is set when I2SC_THR is empty and can be written with new data to be transmitted.

• TXUR: Transmit Underrun

0: This bit is cleared when the corresponding bit in I2SC_SCR is written to ’1’.

1: This bit is set when an underrun error occurs on I2SC_THR or when the corresponding bit in I2SC_SSR is written to ’1’.

• ENDTX: End of Transmitter Transfer

0: This bit is set when the PDC has completed the transmit transfer.

1: This bit is cleared when a new transmit transfer is programmed into the PDC.

31 30 29 28 27 26 25 24

TXBUFE–––––––

23 22 21 20 19 18 17 16

– – TXURCH RXBUFF – – –

15 14 13 12 11 10 9 8

–––––– RXORCH

76543210

ENDTX TXUR TXRDY TXEN ENDRX RXOR RXRDY RXEN

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870

• RXORCH: Receive Overrun Channel

This field is cleared when I2SC_SCR.RXOR is written to ’1’.

Bit i of this field is set when a receive overrun error occurred in channel i (i = 0 for first channel of the frame).

• RXBUFF: Receive Buffer Full

0: This bit is set when received data is present in I2SC_RHR.

1: This bit is cleared when I2SC_RHR is read and no more received data is present.

• TXURCH: Transmit Underrun Channel

0: This field is cleared when I2SC_SCR.TXUR is written to ’1’.

1: Bit i of this field is set when a transmit underrun error occurred in channel i (i = 0 for first channel of the frame) .

• TXBUFE: Transmit Buffer Empty

0: This bit is set when I2SC_THR is empty and can be written with new data to be transmitted.

1: This bit is cleared when data is written to I2SC_THR and is being transmitted .

871

SAM G55 [DATASHEET]

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33.8.4 Inter-IC Sound Controller Status Clear Register

Name: I2SC_SCR

Address: 0x4000000C (0), 0x4000400C (1)

Access: Write-only

• RXOR: Receive Overrun Status Clear

Writing a ’0’ to this bit has no effect.

Writing a ’1’ to this bit clears the stat us bit .

• TXUR: Transmit Underrun Status Clear

Writing a ’0’ to this bit has no effect.

Writing a ’1’ to this bit clears the stat us bit .

• RXORCH: Receive Overrun Per Channel Status Clear

Writing a ’0’ has no effect.

Writing a ’1’ to any bit in this field clea rs th e cor re sp o ndi ng bit in the I2SC_SR and the corresponding interrupt request.

• TXURCH: Transmit Underrun Per Channel Status Clear

Writing a ’0’ has no effect.

Writing a ’1’ to any bit in this field clea rs th e cor re sp o ndi ng bit in the I2SC_SR and the corresponding interrupt request.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – TXURCH ––––

15 14 13 12 11 10 9 8

–––––– RXORCH

76543210

–TXUR–––RXOR––

SAM G55 [DATASHEET]

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872

33.8.5 Inter-IC Sound Controller Status Set Register

Name: I2SC_SSR

Address: 0x40000010 (0), 0x40004010 (1)

Access: Write-only

• RXOR: Receive Overrun Status Set

Writing a ’0’ to this bit has no effect.

Writing a ’1’ to this bit sets the status bit.

• TXUR: Transmit Underrun Status Set

Writing a ’0’ to this bit has no effect.

Writing a ’1’ to this bit sets the status bit.

• RXORCH: Receive Overrun Per Channel Status Set

Writing a ’0’ has no effect.

Writing a ’1’ to any bit in this field sets the corresponding bit in I2SC_SR and the corresponding interrupt request.

• TXURCH: Transmit Underrun Per Channel Status Set

Writing a ’0’ has no effect.

Writing a ’1’ to any bit in this field sets the corresponding bit in I2SC_SR and the corresponding interrupt request.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

– – TXURCH ––––

15 14 13 12 11 10 9 8

–––––– RXORCH

76543210

–TXUR–––RXOR––

873

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33.8.6 Inter-IC Sound Controller Interrupt Enable Register

Name: I2SC_IER

Address: 0x40000014 (0), 0x40004014 (1)

Access: Write-only

• RXRDY: Receiver Read y In te rrupt Enab le

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit sets the corresponding bit in I2SC_IMR.

• RXOR: Receiver Overrun Interrupt Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit sets the corresponding bit in I2SC_IMR.

• ENDRX: End of Reception Interrupt Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit sets the corresponding bit in the I2SC_IMR.

• TXRDY: Transmit Ready Interrupt Enable

0: Writing a ’0’ to this bit as no effect.

1: Writing a ’1’ to this bit sets the corresponding bit in I2SC_IMR.

• TXUR: Transmit Underflow Interrupt Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit sets the corresponding bit in I2SC_IMR.

• ENDTX: End of Transmission Interrupt Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit sets the corresponding bit in I2SC_IMR.

• RXFULL: Receive Buffer Full Interrupt Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit sets the corresponding bit in I2SC_IMR.

• TXEMPTY: Transmit Buffer Empty Interrupt Enable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit sets the corresponding bit in I2SC_IMR.

31 30 29 28 27 26 25 24

TXEMPTY–––––––

23 22 21 20 19 18 17 16

––––RXFULL–––

15 14 13 12 11 10 9 8

––––––––

76543210

ENDTX TXUR TXRDY – ENDRX RXOR RXRDY –

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874

33.8.7 Inter-IC Sound Controller Interrupt Disable Register

Name: I2SC_IDR

Address: 0x40000018 (0), 0x40004018 (1)

Access: Write-only

• RXRDY: Receiver Ready Interrupt Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit clears the corresponding bit in I2SC_IMR.

• RXOR: Receiver Overrun Interrupt Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit clears the corresponding bit in I2SC_IMR.

• ENDRX: End of Reception Interrupt Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit clears the corresponding bit in I2SC_IMR.

• TXRDY: Transmit Ready Interrupt Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit clears the corresponding bit in I2SC_IMR.

• TXUR: Transmit Underflow Interrupt Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit clears the corresponding bit in I2SC_IMR.

• ENDTX: End of Transmission Interrupt Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit clears the corresponding bit in I2SC_IMR.

• RXFULL: Receive Buffer Full Interrupt Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit clears the corresponding bit in I2SC_IMR.

• TXEMPTY: Transmit Buffer Empty Interrupt Disable

0: Writing a ’0’ to this bit has no effect.

1: Writing a ’1’ to this bit clears the corresponding bit in I2SC_IMR.

31 30 29 28 27 26 25 24

TXEMPTY–––––––

23 22 21 20 19 18 17 16

––––RXFULL–––

15 14 13 12 11 10 9 8

––––––––

76543210

ENDTX TXUR TXRDY – ENDRX RXOR RXRDY –

875

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33.8.8 Inter-IC Sound Controller Interrupt Mask Register

Name: I2SC_IMR

Address: 0x4000001C (0), 0x4000401C (1)

Access: Write-only

• RXRDY: Receiver Ready Interrupt Disable

0: The corresponding interrupt is disabled. This bit is cleared when the corresponding bit in I2SC_IDR is written to ’1’.

1: The correspo nd in g inte r ru pt is enable d. T his bit is set when the corresponding bit in I2SC_IER is written to ’1’.

• RXOR: Receiver Overrun Interrupt Disable

0: The corresponding interrupt is disabled. This bit is cleared when the corresponding bit in I2SC_IDR is written to ’1’.

1: The correspo nd in g inte r ru pt is enable d. T his bit is set when the corresponding bit in I2SC_IER is written to ’1’.

• ENDRX: End of Reception Interrupt Disable

0: The corresponding interrupt is disabled. This bit is cleared when the corresponding bit in I2SC_IDR is written to ’1’.

1: The correspo nd in g inte r ru pt is enable d. T his bit is set when the corresponding bit in I2SC_IER is written to ’1’.

• TXRDY: Transmit Ready Interrupt Disable

0: The corresponding interrupt is disabled. This bit is cleared when the corresponding bit in I2SC_IDR is written to ’1’.

1: The correspo nd in g inte r ru pt is enable d. T his bit is set when the corresponding bit in I2SC_IER is written to ’1’.

• TXUR: Transmit Underflow Interrupt Disable

0: The corresponding interrupt is disabled. This bit is cleared when the corresponding bit in I2SC_IDR is written to ’1’.

1: The correspo nd in g inte r ru pt is enable d. T his bit is set when the corresponding bit in I2SC_IER is written to ’1’.

• ENDTX: End of Transmission Interrupt Disable

0: The corresponding interrupt is disabled. This bit is cleared when the corresponding bit in I2SC_IDR is written to ’1’.

1: The correspo nd in g inte r ru pt is enable d. T his bit is set when the corresponding bit in I2SC_IER is written to ’1’.

• RXFULL: Receive Buffer Full Interrupt Disable

0: The corresponding interrupt is disabled. This bit is cleared when the corresponding bit in I2SC_IDR is written to ’1’.

1: The correspo nd in g inte r ru pt is enable d. T his bit is set when the corresponding bit in I2SC_IER is written to ’1’.

• TXEMPTY: Transmit Buffer Empty Interrupt Disable

0: The corresponding interrupt is disabled. This bit is cleared when the corresponding bit in I2SC_IDR is written to ’1’.

1: The correspo nd in g inte r ru pt is enable d. T his bit is set when the corresponding bit in I2SC_IER is written to ’1’.

31 30 29 28 27 26 25 24

TXEMPTY–––––––

23 22 21 20 19 18 17 16

––––RXFULL–––

15 14 13 12 11 10 9 8

––––––––

76543210

ENDTX TXUR TXRDY – ENDRX RXOR RXRDY –

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876

33.8.9 Inter-IC Sound Controller Receiver Holding Registe r

Name: I2SC_RHR

Address: 0x40000020 (0), 0x40004020 (1)

Access: Read-only

• RHR: Receiver Holding Register

This field is set by hardware to the last received data word. If I2SC_MR.DATALENGTH specifies fewer than 32 bits, data is

right justified in the RHR field.

31 30 29 28 27 26 25 24

RHR

23 22 21 20 19 18 17 16

RHR

15 14 13 12 11 10 9 8

RHR

76543210

RHR

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33.8.10 Inter-IC Sound Controller Transmitter Holding Register

Name: I2SC_THR

Address: 0x40000024 (0), 0x40004024 (1)

Access: Write-only

• THR: Transmitter Holding Register

Next data word to be transmitted after the current word if TXRDY is not set. If I2SC_MR.DATALENGTH specifies fewer

than 32 bits, data is right-justified in the THR field.

31 30 29 28 27 26 25 24

THR

23 22 21 20 19 18 17 16

THR

15 14 13 12 11 10 9 8

THR

76543210

THR

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878

34. Pulse Density Modulation Interface Controller (PDMIC)

34.1 Description

The Pulse Density Modulation Interface Controller (PDMIC) is a PDM interface controller and decode r that suppo rt

both mono and stereo PDM formats. It integrates a clock generator drivin g the PDM microphones and embeds

filters which decimat e th e inco mi ng bitstream to ob tain most comm o n au dio rates.

34.2 Embedded Characteristics

Multiplexed PDM Input Support

16-bit Resolution

PDC Support

Up to 4 Conversions Stored

PDM Clock Source can be Independent from Core Clock

Register Write Protection

34.3 Block Diagram

Figure 34-1. PDMIC Block Diagram

PDMIC Interrupt

Control

Logic

User

Interface

Interrupt

Controller

APB

PDC

System Bus

PDM Interface Controller

Digital

Filter

Data, to second PDM Interface Controller

Clock, from second PDM Interface Controller

Configuration, from second PDM Interface Controller

PDM

Data

Sampling

Peripheral Bridge

PCKx Clock

Peripheral Clock

CLKS

PMC

PDMIC_DAT

PDMIC_CLK

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34.4 Signal Description

34.5 Product Dependencies

34.5.1 I/O Lines

The pins used for int erfacing the PDMIC are multip lexed with PIO lines. The prog rammer must first program the

PIO controllers to assign the peripheral functions to PDMIC pins.

34.5.2 Power Management

The PDMIC is not continuously clocked. The user must first enable the PDMIC peripheral clock in the Power

Management Controller (PMC) before using the controller.

34.5.3 Interrupt Sources

The PDMIC in terrupt line is conne cted on on e of the in ternal s ources of th e Inter rupt Contr oller. Us ing the PD MIC

interrupt requires the Interrupt Controller to be programmed first.

Table 34-1. PDMIC Pin Description

Pin Name Description Type

PDMIC_CLK Pulse Density Modulation Bitstream Sampling Clock Output

PDMIC_DAT Pulse Density Modulation Multiplexed Data Input

Table 34-2. I/O Lines

Instance Signal I/O Line Peripheral

PDMIC0 PDMIC0_CLK PA10 B

PDMIC0 PDMIC0_DAT PA9 B

Table 34-3. Peripheral IDs

Instance ID

PDMIC0 13

PDMIC1 18

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34.6 Functional Description

34.6.1 PDM Interface

34.6.1.1 Description

The PDM clock (PDMIC_CLK) is used to sample the PDM bitstream.

The field PRESCAL in the Mode Register (PDMIC_MR) m ust be programmed in order to provide a PDMIC_CLK

frequency compliant with the microphone parameters.

34.6.1.2 Start-up Sequence

To start processing the bitstream coming from the PDM interface, follow the steps below:

1. Clear all bits in the Control Register (PDMIC_CR) or compute a soft reset using the SWRST bit of

PDMIC_CR.

2. Configure the PRESCAL field in PDMIC_MR according to the microphone spe cifications.

3. Enable the PDM mode and start the conversions using the ENPDM bit in PDMIC_CR.

34.6.1.3 Restrictions

The external PDM data sampling module is shared with two PDMIC modules. When two PDM microphones are

connected on the PDMIC_DAT line, both PDMICs must be enabled and the steps below must be followed:

1. Clear all bits in PDMIC_CR or compute a soft reset using the SWRST bit of PDMIC_CR in both PDMIC

modules.

2. Configur e th e PMC to provide the same c lock to both PDMIC modules (clock frequencies should be the

same).

3. Configure the PRESCAL field in PDMIC_MR according to the microphone specifications (the PRESCAL

value should be the sam e in bo th PDMI C).

4. Enable the PDM mode and start the conversions using the ENPDM bit in PDMIC_CR in the PDMIC0.

5. Enable the PDM mode and start the conversions using the ENPDM bit in PDMIC_CR in the PDMIC1.

To stop the conversions, follow the steps below:

1. Disable the PDM mode or compute a software reset in PDMIC1.

2. Disable the PDM mode or compute a software reset in PDMIC0.

The bitstream sampled on the rising edge of PDMIC_CLK is routed to PDMIC0 and the bitstream sampled on the

falling edge of PDMIC_CLK is routed to PDMIC1.

34.6.2 Digital Signal Processing (Digital Filter)

34.6.2.1 Description

The PDMIC includes a DSP section containing a decimation filter, a droop compensation filter, a sixth-order low

pass filter, a first-order high pass filter and an offset and gain compensation stage. A block diagram of the DSP

section is represented in Figure 34-2 “DSP Block Diagram”.

Data processed by the filtering section are two’s complement signals defined on 24 bits.

The filtering of the decimation stage is performed by a fourth-order sinc-based filter whose zeros are placed in

order to minimize aliasing effects of the decimation. The decimation ratio of this filter is either 32 or 64. The droop

induced by this filter can be compensated by the droop compensation stage.

The sixth-order low pass filter is used to decimate the sinc filter output by a ratio of 2.

The PDMIC_CLK frequency range is between peripher al clock/2 and peripheral clock/256 or between

PCKx clock/2 and PCKx clock/256, depending on the selected clock source.

The PCKx clock frequency must always be at least three times lower than the peripheral clock

frequency.

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An optional first-order high pass filter is implemented in order to eliminate the DC component of the incoming

signal.

The overall decimation ratio of this DSP section is either 64 or 128. This fits an audio sampling rate of 48 kHz with

a PDM microphone sampling frequency of either 3.072 or 6.144 MHz. The frequency response of the filters

optimizes the gain flatness between 0 and 20 kHz (when the droop compensation filter is implemented and the

high pass filter is bypassed) and highly reduces the aliasing effects of the decima tion.

Figure 34-2. DSP Block Diagram

34.6.2.2 Decimation Filter

The sigma-delta architecture of the PDM microphone implies a filtering and a decimation of the bitstream at the

output of the microphone bitstream. The decima tion filter de cimates the bitstream by either 32 or 64. T o perform

this operation, a fourth-order sinc filter with an Over-Sampling Ratio (OSR) of 32 or 64 is implemente d with the

following transfer function:

The DC gain of this filter is unity and does not depend on its OSR. However, as it generates a fourth-order zero at

Fs/OSR frequency multiples (Fs being the sampling frequency of the microphone), the frequency response of the

decimation filter depends o n the OSR parameter . See Section 34.6.2.3 “Droop Compensatio n” for freq uency p lots.

Its non-flat frequency response can be compensated over the 0 to 20 kHz band by using the droop compensation

filter when the decimated frequency is set to 48 kHz. See Section 34.6.2.3 “Droop Compensation”.

If the decimated sampling rate is modified, the frequency response of this filter is scaled proportionally to the new

frequency.

In Figure 34-3 and F igure 34-4, Fs is the sampling rate of the PDM microphone.

324

32/64

SINC Filter

Decimation

offset * 28

gain

data0

data

Droop Compensation Low Pass Filter

sincc_byp

shiftscale

24 32

...

0101

signed

right shift

{

...

010111

16 LSBs

signed

right shift

16 or 32

bits

High Pass Filter

Decimation

hpf_byp

Hz() 1

OSR4

--------------zi–

i0=

OSR 1–









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Figure 34-3. Spectral mask of an OSR = 32, Fs = 6.144 MHz, Fourth-Order Sinc Filter: Overall Response (continuous

line) and 0 to 20 kHz Bandwidth Response (dashed line)

The zeros of this filter are located at multiples of Fs/32

Figure 34-4. Spectral Mask of an OSR = 64, Fs = 3.072 MHz, Fourth-order Sinc Filter: Overall Response (continuou s

line) and 0 to 20 kHz Bandwidth Response (dashed line)

The zeros of this filter are located at multiples of Fs/64.

34.6.2.3 Droop Compensation

The droop effect introduced by the sinc filter can be compensated in the 0 to 20 kHz by the droop compensation

filter (see Figure 34-5). This is a second-order IIR filter which is applied on the signal output by the sinc. The

default coefficients of the droo p compensation filter are comp uted to optimize the droop of the sinc filter with the

decimated frequency equal to 48 kHz.

This filter compensates the droop of the sinc filter regardless of the OSR value.

If the decimated sampling rate is modified, the frequency response of this filter is scaled proportionally to the new

frequency.

This filter can be bypassed by setting the SINBYP bit in the PDMIC DSP Configuration Register 0

(PDMIC_DSPR0).

0 Fs/16 2*Fs/16 3*Fs/16 4*Fs/16 5*Fs/16 6*Fs/16 7*Fs/16 8*Fs/16

-120

-96

-72

-48

-24

frequency (Hz), overall mask

gain (dB), overall mask

0 2.5 5 7.5 10 12.5 15 17.5 20

-0.7

-0.56

-0.42

-0.28

-0.14

frequency (kHz), base band, output sampling rate = 48 kHz

gain (dB), base band

0 Fs/16 2*Fs/16 3*Fs/16 4*Fs/16 5*Fs/16 6*Fs/16 7*Fs/16 8*Fs/16

-120

-96

-72

-48

-24

frequency (Hz), overall mask

gain (dB), overall mask

-3

-2.4

-1.8

-1.2

-0.6

gain (dB), base band

frequency (kHz), base band, output sampling rate = 48 kHz

0 2.5 5 7.5 10 12.5 15 17.5 20

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Figure 34-5. Droop Compensation Filter Overall Frequency Response

Figure 34-6. Droop Compensation Filter 0 to 20 kHz Band Flatness

34.6.2.4 Low Pass Filter

The PDMIC includes a sixth-o rder IIR filter that performs a low pass transfer func tion and decimates by 2 the

output of the sinc filter. The coefficients are computed for a decimated sampling rate of 48 kHz and optimize the 0

to 20 kHz band flatness while rejecting the aliasing of the PDM microphone by at least 60 dB in the 28 to 48 kHz

band.

If the decimated sampling rate is modified, the frequency response of this filter is scaled proportionally to the new

frequency.

Figure 34-7 and Figure 34-8 are drawn for an output sampling frequency of 48 kHz.

01234 5 6 7 89 10

x 104

-10

-8

-6

-4

-2

2droop compensation overall response

frequency (Hz)

gain (dB)

sinc filter response

sinc filter+droop compensation response

0 0.2 0.4 0.6 0.81 1.2 1.4 1.6 1.82

x 104

-2

-1

2x 10-4 droop compensation flatness in 0-20kHz band

frequency (Hz)

gain (dB)

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Figure 34-7. Low Pass Filter Spectral Mask

Figure 34-8. Low Pass Filter Ripple in the 0 to 20 kHz Band

34.6.2.5 High Pass Filter

The PDMIC include s an optional first-o rder IIR filter performing a high pass transfer functio n after the low pa ss

filter and before the decimation. The coefficients are computed for a decimated sampling rate of 48 kHz to obtain a

-3dB cutoff frequency at 15 Hz.

If the decimated sampling rate is modified, the frequency response of this filter is scaled proportionally to the new

frequency.

This filter can be bypassed by setting the HPFBYP bit in PDMIC_DSPR0 (see Section 34.7.8 “PDMIC DSP

Configuration Register 0”).

Figure 34-9 is drawn for an output sampling frequency of 48 kHz.

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

x 104

-120

-100

-80

-60

-40

-20

Low pass filter spectral mask

frequency (Hz)

gain (dB)

0 0.2 0.4 0.6 0.81 1.2 1.4 1.6 1.82

x 104

-0.05

-0.04

-0.03

-0.02

-0.01

0.01

0.02

0.03

0.04

0.05 Low pass filter 0-20kHz ripple

frequency (Hz)

gain (dB)

885

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 34-9. High Pass Filter Spectral Mask in the 0 to 100 Hz Band

34.6.2.6 Gain and Offset Compensation

An offset, a gain, a scaling factor and a shift can be applied to a converted PDM microphone value using the

following operation:

where:

data0 is a signed integer defined on 24 bits. It is the output of the filtering channel.

offset is a signed integer defined on 16 bits (see PDMIC DSP Configuration Register 1). It is multiplied by 28

to have the same weight as data0.

dgain is an unsigned integer defined on 15 bits (see PDMIC DSP Configuration Register 1). Only the 32

MSBs of the multiplication operation are used for scaling and shifting operations. dgain defaults to 0 after

reset, which forces CDR to 0. It mus t be programmed to a non-zero value to read non-zero data into the

PDMIC_CDR register.

scale is an unsigned integer defined on 4 bits (see PDMIC DSP Configuration Register 0). It shifts the

multiplication operation result by scale bits to the right. Maxim um allowed value is 15.

shift is an unsigned integer defined on 4 bits (see PDMIC DSP Configuration Register 0). It shifts the

multiplication operation result by shift bits to the right. Maximum allowed value is 15.

If the data transfer is configured in 3 2-bit mod e (see PDMIC DSP Configuration Register 0), the 2shift division is not

performed and the 32-bit result of the remaining operation is sent.

If the data transfer is configured in 16-bit mode, the 2 shift division is performed. The result is then saturated to be

within ±(215-1) and the 16 LSBs of this saturation operation are sent to the controller as the result of the PDM

microphone conversion.

Default parameters are defined to output a 16-bit result whatever the data transfer configuration may be.

34.6.3 Conversion Results

When a conversion is completed, the resulting 16-bit digital value is stored in the PDMIC Converted Data Register

(PDMIC_CDR).

The DRDY bit in the Interrupt Status Register (PDMIC_ISR) is set. In the case of a connected PDC channel,

DRDY rising triggers a data transfer request. In any case, DRDY can trigger an interrupt.

Reading PDMIC_CDR clears the DRDY flag.

0 10 20 30 40 50 60 70 80 90 100

-30

-25

-20

-15

-10

-5

0High pass filter spectral mask

frequency (Hz)

gain (dB)

data data0offset 28

×+()dgain×

2scale shift 8++

-------------------------------------------------------------------------

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

886

Figure 34-10. DRDY Flag Behavior

If PDMIC_CDR is not read before further incoming data is converted, the Overrun Error (OVRE) flag is set in

PDMIC_ISR. Likewise, new data converted when DRDY is high sets the OVRE bit (Overrun Error) in PDMIC_ISR.

In case of overrun, the newly converted data is lost.

The OVRE flag is automatically cleared when PDMIC_ISR is read.

34.6.4 Register Write Protection

To prevent any single software error from corrupting PDMIC behavior, certain registers in the address space can

be write-protected by setting the WPEN bit in the PDMIC Write Protection Mode Register (PDMIC_WPMR).

If a write access to a write-protected register is detected, the WPVS flag in the PDMIC Write Protection Status

attempted.

The WPVS bit is automatically cleared after reading PDMIC_WPSR.

The following registers can be write-protected:

PDMIC Mode Register

PDMIC DSP Configuration Register 0

PDMIC DSP Configuration Register 1

Read the PDMIC_CDR

DRDY

Read the PDMIC_CDR

(PDMIC_SR)

Write the PDMIC_CR

with ENPDM = 1

887

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

34.7 Pulse Density Modulation Interface Controller (PDMIC) User Interface

Notes: 1. If an offset is not listed in the table, it must be considered as “reserved”.

Table 34-4. Register Mapping

Offset(1) Register Name Access Reset

0x00 Control Register PDMIC_CR Read/Write 0x00000000

0x04 Mode Register PDMIC_MR Read/Write 0x00F00000

0x08–0x10 Reserved – – –

0x14 Converted Data Register PDMIC_CDR Read-only 0x00000000

0x18 Interrupt Enable Register PDMIC_IER Write-only –

0x1C Interrupt Disable Register PDMIC_IDR Write-only –

0x20 Interrupt Mask Register PDMIC_IMR Read-only 0x00000000

0x24 Interrupt Status Register PDMIC_ISR Read-only 0x00000000

0x28–0x54 Reserved – – –

0x58 DSP Configuration Regi ster 0 PDMIC_DSPR0 Read/Write 0x00000000

0x5C DSP Configuration Register 1 PDMIC_DSPR1 Read/Write 0x00000001

0x60–0xE0 Reserved – – –

0xE4 Write Protection Mode Register PDMIC_WPMR Read/Write 0x00000000

0xE8 Write Protection Status Register PDMIC_WPSR Read-only 0x00000000

0xEC–0xFC Reserved – – –

0x100–0x124 Reserved for PDC Registers – – –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

888

34.7.1 PDMIC Control Register

Name: PDMIC_CR

Address: 0x4002C000 (0), 0x40030000 (1)

Access: Read/Write

• SWRST: Software Reset

0: No effect.

1: Resets the PDMIC, simulating a hardware reset.

Warning: The read value of this bit is always 0.

• ENPDM: Enable PDM

0: Disables the PDM and stops the conversions.

1: Enables the PDM and starts the conversions.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––ENPDM–––SWRST

889

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

34.7.2 PDMIC Mode Register

Name: PDMIC_MR

Address: 0x4002C004 (0), 0x40030004 (1)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the PDMIC Write Protection Mode Register.

• CLKS: Clock Source Selection

0: Peripheral clock selected

• PRESCAL: Prescaler Rate Selection

PRESCAL determines the frequency of the PDM bitstream sampling clock (PDMIC_CLK ):

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

– PRESCAL

76543210

–––CLKS––––

1: PCKx clock selected (This clock source can be independent of the processor clock.)

where SELCK is either fperipheral clock or fPC K x cl oc k depending on the value of bit CLKS (fperipheral clock or fPCKx clock is the clock frequency in

Hz).

PRESCAL SELCK

PDMIC_CLK

-------------------------------------- 1–=

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

890

34.7.3 PDMIC Converted Data Register

Name: PDMIC_CDR

Address: 0x4002C014 (0), 0x40030014 (1)

Access: Read-only

• DATA: Data Converted

The filtered output data is placed into this register at the end of a conver sio n an d re main s un til it is read.

31 30 29 28 27 26 25 24

DATA

23 22 21 20 19 18 17 16

DATA

15 14 13 12 11 10 9 8

DATA

76543210

DATA

891

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

34.7.4 PDMIC Interrupt Enable Register

Name: PDMIC_IER

Address: 0x4002C018 (0), 0x40030018 (1)

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Enables the corresponding interrupt.

• DRDY: Data Ready Int errupt Enable

• OVRE: Overrun Error Interrupt Enable

• ENDRX: End of Receive Buffer Interrupt Enable

• RXBUFF: Receive Buffer Full Interrupt Enable

31 30 29 28 27 26 25 24

– – – RXBUFF ENDRX – OVRE DRDY

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

892

34.7.5 PDMIC Interrupt Disable Register

Name: PDMIC_IDR

Address: 0x4002C01C (0), 0x4003001C (1)

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Disables the corresponding interrupt.

• DRDY: Data Ready Interrupt Disable

• OVRE: General Overrun Error Interrupt Disable

• ENDRX: End of Receive Buffer Interrupt Disable

• RXBUFF: Receive Buffer Full Interrupt Disable

31 30 29 28 27 26 25 24

– – – RXBUFF ENDRX – OVRE DRDY

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––––

893

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

34.7.6 PDMIC Interrupt Mask Register

Name: PDMIC_IMR

Address: 0x4002C020 (0), 0x40030020 (1)

Access: Read-only

The following configuration values are valid for all listed bit names of this register:

0: The corresponding interrupt is disabled.

1: The corresponding interrupt is enabled.

• DRDY: Data Ready Interrupt Mask

• OVRE: General Overrun Error Interrupt Mask

• ENDRX: End of Receive Buffer Interrupt Mask

• RXBUFF: Receive Buffer Full Interrupt Mask

31 30 29 28 27 26 25 24

– – – RXBUFF ENDRX – OVRE DRDY

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

894

34.7.7 PDMIC Interrupt Status Register

Name: PDMIC_ISR

Address: 0x4002C024 (0), 0x40030024 (1)

Access: Read-only

• FIFOCNT: FIFO Count

Number of conversions available in the FIFO (not a source of interrupt).

• DRDY: Data Ready (cleared by reading PDMIC_CDR)

0: No data has been converted since the last read of PDMIC_CDR.

1: At least one data has been converted and is available in PDMIC_CDR.

• OVRE: Overrun Error (cleared on read)

0: No overrun error has occurred since the last read of PDMIC_ISR.

1: At least one overrun error has occurred since the last read of PDMIC_ISR.

• ENDRX: End of RX Buffer (cleared by writing PDMIC_RCR or PDMIC_RNCR)

0: The Receive Counter register has not reached 0 since the last write in PDMIC_RCR or PDMIC_RNCR.

1: The Receive Counter register has reached 0 since the last write in PDMIC_RCR or PDMIC_RNCR.

Note: PDMIC_RCR and PDMIC_RNCR are located in the Peripheral DMA Controller (PDC).

• RXBUFF: RX Buffer Full (cleared by writing PDMIC_RCR or PDMIC_RNCR)

0: PDMIC_RCR or PDMIC_RNCR has a value other than 0.

1: Both PDMIC_RCR and PDMIC_RNCR have a value of 0.

Note: PDMIC_RCR and PDMIC_RNCR are located in the Peripheral DMA Controller (PDC).

31 30 29 28 27 26 25 24

– – – RXBUFF ENDRX – OVRE DRDY

23 22 21 20 19 18 17 16

FIFOCNT

15 14 13 12 11 10 9 8

––––––––

76543210

––––––––

895

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

34.7.8 PDMIC DSP Configuration Register 0

Name: PDMIC_DSPR0

Address: 0x4002C058 (0), 0x40030058 (1)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the PDMIC Write Protection Mode Register.

• HPFBYP: High-Pass Filter Bypass

0: High-pass filte r en ab le d.

1: Bypasses the high-pass filter.

• SINBYP: SINCC Filter Bypass

0: Droop compensation filter enabled.

1: Bypasses the droop compensation filter.

•SIZE: Data Size

0: Converted data size is 16 bits.

1: Converted data size is 32 bits.

• OSR: Global Oversampling Ratio

Note: Values not listed are reserved.

• SCALE: Data Scale

Shifts the multiplication operation result by SCALE bits to the right.

•SHIFT: Data Shift

Shifts the scaled result by SHIFT bits to the right.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

SHIFT SCALE

76543210

– OSR SIZE SINBYP HPFBYP –

Value Name Description

0 128 Glob al Oversampling ratio is 128 (SINC filter oversampling ratio is 64)

1 64 Global Oversampling ratio is 64 (SINC filter oversampling ratio is 32)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

896

34.7.9 PDMIC DSP Configuration Register 1

Name: PDMIC_DSPR1

Address: 0x4002C05C (0), 0x4003005C (1)

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the PDMIC Write Protection Mode Register.

• DGAIN: Gain Correction

Gain correction to apply to the final result.

• OFFSET: Offset Correction

Offset correction to apply to the final result.

DGAIN and OFFSET values can be determined using the formula in Section 34.6.2.6 “Gain and Offset Compensation”.

31 30 29 28 27 26 25 24

OFFSET

23 22 21 20 19 18 17 16

OFFSET

15 14 13 12 11 10 9 8

–DGAIN

76543210

DGAIN

897

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

34.7.10 PDMIC Write Protection Mode Register

Name: PDMIC_WPMR

Address: 0x4002C0E4 (0), 0x400300E4 (1)

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY corresponds to 0x414443 (“ADC” in ASCII).

1: Enables the write protection if WPKEY corresponds to 0x414443 (“ADC” in ASCII).

See Section 34.6.4 “Register Write Protection” for the list of registers that can be write-protected.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x414443 PASSWD Writing any other value in this field aborts the write operation of the WPEN bit.

Always reads as 0.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

898

34.7.11 PDMIC Write Protection Status Register

Name: PDMIC_WPSR

Address: 0x4002C0E8 (0), 0x400300E8 (1)

Access: Read-only

• WPVS: Write Protection Violation Status

0: No write protec tion v iola tio n ha s oc curred since the last read of PDMIC_WPSR.

1: A write protection violation has occurred since the last read of PDMIC_WPSR. If this violation is an unautho rized attempt

to write a protected register, the associated violation is reported into field WPVSRC.

• WPVSRC: Write Protection Vi olation Source

When WPVS = 1, WPVSRC indicates the register address offset at which a write access has been attempted.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

WPVSRC

15 14 13 12 11 10 9 8

WPVSRC

76543210

–––––––WPVS

899

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35. Cyclic Redundancy Check Calculation Unit (CRCCU)

35.1 Description

The Cyclic Redundancy Check Calculation Unit (CRCCU) has its own DMA which functions as a Master with the

Bus Matrix. Three different polynomials are av ailable: CCITT802.3, CASTAGNOLI and CCITT16.

The CRCCU is designed to perform data integrity checks of off-/on-chip memories as a background task without

CPU intervention.

35.2 Embedded Characteristics

Data Integrity Check of Off-/On-Chip Memories

Background Task Without CPU Intervention

Performs Cyclic Redundancy Check (CRC) Operation on Programmable Memory Area

Programmable Bus Burden

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

900

35.3 CRCCU Block Diagram

Figure 35-1. Block Diagram

35.4 Product Dependencies

35.4.1 Power Management

The CRCCU is clocked thro ugh the Power Man agement Cont roller (PMC), the pr ogrammer must first configu re the

CRCCU in the PMC to enable the CRCCU clock.

35.4.2 Interrupt Source

The CRCCU has an interrupt line connected to the Interrupt Controller. Handling the CRCCU interrupt requires

programming the Interrupt Controller before configuring the CRCCU.

AHB-Layer

Context FSM

AHB Interface

Host

Interface

APB Bus

AHB SRAM

TR_ADDR

HRDATA

HTRANS

HSIZE

TR_CRC

Flash

External

Bus Interface

901

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.5 CRCCU Functional Description

35.5.1 CRC Calculation Unit

The CRCCU integrates a d edicated Cycli c Re dundancy Check (C RC) engine. Whe n configured a nd activate d, this

CRC engine performs a checksum computation on a memory area. CRC computation is performed from the LSB

to MSB. Three differe nt polynomials are available: CC ITT802.3, CASTAGNOLI and CCITT16 (see field description

“PTYPE: Primitive Polynomial” in Section 35.7.10 “CRCCU Mode Register” for details).

35.5.2 CRC Calculation Unit Operation

The CRCCU has a DMA controller that supports programmable CRC memory checks. When enabled, the DMA

channel reads a programmable amount of data and computes CRC on the fly.

The CRCCU is controlled by two registers, TR_ADDR and TR_CTRL, which need to be mapped in the internal

SRAM. The addresses of these two registers are pointed to by the CRCCU_DSCR.

TR_ADDR defines the start address of memory area targeted for CRC calculation.

TR_CTRL defines the buffer transfer size, the tra nsfer width (byte , halfword, word) an d the transfer-com pleted

interrupt enab le .

To start the CRCCU, set the CRC enable bit (ENABLE) and configure the mode of operation in the CRCCU Mode

(DMAEN) in the CRCCU DMA Enable Register (CRCCU_DMA_EN).

When the CRCCU is enabled, the CRCCU reads the predefined amount of data (defined in TR_CTRL) located

from TR_ADDR start address and computes the checksum.

The CRCCU_SR contains the temporary CRC value.

The BTSIZE field located in the TR_CTRL register (lo cated in memory), is automatically decr emented if its value is

different from zero. Once the value of the BTSIZE field is equal to zero, the CRCCU is disabled by hardware. In

this case, the relevant CRCCU DMA Status Register bit DMASR is automatically cleared.

If the COMPARE field of the CRCCU_MR is set to true, the TR _CRC (Transfer Reference Register) is compared

with the last CRC computed. If a mismatch occurs, an error flag is set and an interrupt is raised (if unmasked).

The CRCCU accesses the memory by single access (TRWIDTH size) in order not to limit the bandwidth usage of

the system, but the DIVIDER field of the CRCCU Mode Register can be used to lower it by dividing the frequency

of the single accesses.

The CRCCU scrolls the defined memory area using ascending addresses.

In order to compute the CRC for a memory size larger than 256 Kbytes or for non-contiguous memory area, it is

possible to re-enable the CRCCU on the new memory area and the CRC will be updated accordingly. Use the

RESET field of the CRCCU_CR to reset the CRCCU Status Register to its default value (0xFFFFFFFF).

Table 35-1. CRCCU Descriptor Memory Mapping

SRAM Memory

CRCCU_DSCR+0x0 ----> TR_ADDR

CRCCU_DSCR+0x4 ----> TR_CTRL

CRCCU_DSCR+0x8 ----> Reserved

CRCCU_DSCR+0xC ----> Reserved

CRCCU_DSCR+0x10 ----> TR_CRC

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

902

35.6 Transfer Control Registers Memory Mapping

Note: These registers are memory mapped.

Table 35-2. Transfer Control Register Memory Mapping

Offset Register Name Access Reset

CRCCU_DSCR + 0x0 CRCCU Transfer Address Register TR_ADDR Read/Write 0x00000000

CRCCU_DSCR + 0x4 CRCCU T ransfer Control Register TR_CTRL Read/Write 0x00000000

CRCCU_DSCR + 0xC–0x10 Reserved – – –

CRCCU_DSCR+0x10 CRCCU Transfer Reference Register TR_CRC Read/Write 0x0000000 0

903

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.6.1 Transfer Address Register

Name: TR_ADDR

Access: Read/Write

• ADDR: Transfer Address

31 30 29 28 27 26 25 24

ADDR

23 22 21 20 19 18 17 16

ADDR

15 14 13 12 11 10 9 8

ADDR

76543210

ADDR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

904

35.6.2 Transfer Control Register

Name: TR_CTRL

Access: Read/Write

• BTSIZE: Buffer Transfer Size

• TRWIDTH: Transfer Width Register

• IEN: Context Done Interrupt Enable (Active Low)

0: Bit DMAISR of CRCCU_DMA_ISR is set at the end of the current descriptor transfer.

1: Bit DMAISR of CRCCU_DMA_ISR remains cleared.

31 30 29 28 27 26 25 24

––––IEN– TRWIDTH

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

BTSIZE

76543210

BTSIZE

Value Name Description

0 BYTE The data size is 8-bit

1 HALFWORD The data size is 16-bit

2 WORD The data size is 32-bit

905

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.6.3 Transfer Reference Register

Name: TR_CRC

Access: Read/Write

• REFCRC: Reference CRC

When Compare mode is enabled, the checksum is compared with this field.

31 30 29 28 27 26 25 24

REFCRC

23 22 21 20 19 18 17 16

REFCRC

15 14 13 12 11 10 9 8

REFCRC

76543210

REFCRC

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

906

35.7 Cyclic Redundancy Check Calculation Unit (CRCCU) User Interface

Table 35-3. Register Mapping

Offset Register Name Access Reset

0x000 CRCCU Descriptor Base Register CRCCU_DSCR Read/Write 0x00000000

0x004 Reserved – – –

0x008 CRCCU DMA Enable Register CRCCU_DMA_EN Write-only –

0x00C CRCCU DMA Disable Register CRCCU_DMA_DIS Write-only –

0x010 CRCCU DMA Status Register CRCCU_DMA_SR Read-only 0x00000000

0x014 CRCCU DMA Interrupt Enable Register CRCCU_DMA_IER Write-only –

0x018 CRCCU DMA Interrupt Disable Register CRCCU_DMA_IDR Write-only –

0x001C CRCCU DMA Interrupt Mask Register CRCCU_DMA_IMR Read-only 0x00000000

0x020 CRCCU DMA Interrupt Status Register CRCCU_DMA_ISR Read-only 0x00000000

0x024–0x030 Reserved – – –

0x034 CRCCU Control Register CRCCU_CR Write-only –

0x038 CRCCU Mode Register CRCCU_MR Read/Write 0x00000000

0x03C CRCCU Status Register CRCCU_SR Read-only 0xFFFFFFFF

0x040 CRCCU Interrupt Enable Register CRCCU_IER Write-only –

0x044 CRCCU Interrupt Disable Register CRCCU_IDR Write-only –

0x048 CRCCU Interrupt Mask Register CRCCU_IMR Read-only 0x00000000

0x004C CRCCU Interrupt Status Register CRCCU_ISR Read-only 0x00000000

0x050–0x0FC Reserved – – –

907

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.7.1 CRCCU Descriptor Base Address Register

Name: CRCCU_DSCR

Address: 0x40048000

Access: Read/Write

• DSCR: Descriptor Base Address

DSCR needs to be aligned with 512-byte boundaries.

31 30 29 28 27 26 25 24

DSCR

23 22 21 20 19 18 17 16

DSCR

15 14 13 12 11 10 9 8

DSCR –

76543210

––––––––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

908

35.7.2 CRCCU DMA Enable Register

Name: CRCCU_DMA_EN

Address: 0x40048008

Access: Write-only

• DMAEN: DMA Enable

0: No effect

1: Enable CRCCU DMA channel

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––DMAEN

909

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.7.3 CRCCU DMA Disable Register

Name: CRCCU_DMA_DIS

Address: 0x4004800C

Access: Write-only

• DMADIS: DMA Disable

0: No effect

1: Disable CRCCU DMA channel

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––DMADIS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

910

35.7.4 CRCCU DMA Status Register

Name: CRCCU_DMA_SR

Address: 0x40048010

Access: Read-only

• DMASR: DMA Status

0: DMA channel disabled

1: DMA channel enabled

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––DMASR

911

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.7.5 CRCCU DMA Interrupt Enable Register

Name: CRCCU_DMA_IER

Address: 0x40048014

Access: Write-only

• DMAIER: Interrupt Enable

0: No effect

1: Enable interrupt

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––DMAIER

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

912

35.7.6 CRCCU DMA Interrupt Disable Register

Name: CRCCU_DMA_IDR

Address: 0x40048018

Access: Write-only

• DMAIDR: Interrupt Disable

0: No effect

1: Disable interrupt

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––DMAIDR

913

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.7.7 CRCCU DMA Interrupt Mask Register

Name: CRCCU_DMA_IMR

Address: 0x4004801C

Access: Read-only

• DMAIMR: Interrupt Mask

0: Buffer Transfer Completed interrupt disabled

1: Buffer Transfer Completed interrupt enabled

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––DMAIMR

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

914

35.7.8 CRCCU DMA Interrupt Status Register

Name: CRCCU_DMA_ISR

Address: 0x40048020

Access: Read-only

• DMAISR: Interrupt Status

0: DMA buffer transfer has not yet started or transfer still in progress

1: DMA buffer transfer has terminated. This flag is reset after read.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––DMAISR

915

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.7.9 CRCCU Control Register

Name: CRCCU_CR

Address: 0x40048034

Access: Write-only

• RESET: CRC Computation Reset

0: No effect

1: Sets the CRCCU_SR to 0xFFFFFFFF

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––RESET

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916

35.7.10 CRCCU Mode Register

Name: CRCCU_MR

Address: 0x40048038

Access: Read/Write

• ENABLE: CRC Enable

Always write a 1 to this bit.

• COMPARE: CRC Compare

If set to one, this bit indicates that the CRCCU DMA will compare the CRC computed on the data stream with the value

stored in the TR_CRC reference register. If a mismatch occurs, the ERRISR bit in the CRCCU_ISR is set.

• PTYPE: Primitive Polynomial

• DIVIDER: Request Divider

CRCCU DMA performs successive transfers. It is possible to reduce the bandwidth drained by the CRCCU DMA by pro-

gramming the DIVIDER field. The transfer request frequency is divided by 2^(D IVIDER+1).

• BITORDER: Precomputation Bit Swap Operation of the CRC

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––BITORDER–

15 14 13 12 11 10 9 8

––––––––

76543210

DIVIDER PTYPE COMPARE ENABLE

Value Name Description

0 CCITT8023 Polynom 0x04C11DB7

1 CASTAGNOLI Polynom 0x1EDC6F41

2 CCITT16 Polynom 0x102 1

Value Name Description

0 MSBFIRST CRC computation is performed from the mo st significant bit to the least significant bit

1 LSBFIRST CRC computation is performed from the least significant bit to the most significant bit

917

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35.7.11 CRCCU Status Register

Name: CRCCU_SR

Address: 0x4004803C

Access: Read-only

• CRC: Cyclic Redundancy Check Value

This register can not be read if the COMPARE bit in the CRCCU_MR is set to true.

31 30 29 28 27 26 25 24

CRC

23 22 21 20 19 18 17 16

CRC

15 14 13 12 11 10 9 8

CRC

76543210

CRC

SAM G55 [DATASHEET]

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918

35.7.12 CRCCU Interrupt Enable Register

Name: CRCCU_IER

Address: 0x40048040

Access: Write-only

• ERRIER: CRC Error Interrupt Enable

0: No effect

1: Enable interrupt

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––ERRIER

919

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35.7.13 CRCCU Interrupt Disable Register

Name: CRCCU_IDR

Address: 0x40048044

Access: Write-only

• ERRIDR: CRC Error Interrupt Disable

0: No effect

1: Disable interrupt

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––ERRIDR

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

920

35.7.14 CRCCU Interrupt Mask Register

Name: CRCCU_IMR

Address: 0x40048048

Access: Read-only

• ERRIMR: CRC Error Interrupt Mask

0: Interrupt disabled

1: Interrupt enabled

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––ERRIMR

921

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

35.7.15 CRCCU Interrupt St atus Register

Name: CRCCU_ISR

Address: 0x4004804C

Access: Read-only

• ERRISR: CRC Error Interrupt Status

0: Interrupt disabled

1: Interrupt enabled

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–––––––ERRISR

SAM G55 [DATASHEET]

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922

36. USB Host Port (UHP)

36.1 Description

The USB Host Port (UHP) interfaces the USB with the host app lication. It handles the Open HCI protocol (O pen

Host Controller Interface) as well as USB v2.0 Full-speed and Low-speed protocols.

The USB Host Port integrates a root hub and transceivers on downstream ports. It provides several high-speed

half-duplex serial communication ports at a baud rate of 12 Mbit/s. Up to 127 USB devices (printer, camera,

mouse, keyboard, disk, etc.) and th e USB hub can be connec ted to the USB host in the USB “tiere d star” topology.

The USB Host Port controller is fully compliant with the OpenHCI specification. The USB Host Port User Interface

(registers description) can be found in the Open HCI Rev 1.0 Specification.

This means that all standard class devices are automatically detected and available to the user application. As an

example, integr ating an HID (Human Interface Device) class driver provides a plug & play feature for all USB

keyboards and mouses.

36.2 Embedded Characteristics

Compliant with OpenHCI Rev 1.0 Specification

Compliant with USB V2.0 Full-speed an d Lo w- sp ee d Specification

Supports Both Low-speed 1.5 Mbps and Full-speed 12 Mbps USB Devices

Root Hub Integrated with 1 Downstream USB Ports

Embedded USB Transceivers

Supports Power Management

36.3 Block Diagram

Figure 36-1. Block Diagram

PORT S/M

USB transceiver

Embedded USB

v2.0 Full-speed Transceiver

Root Hub

and

Host SIE

List Processor

Block

FIFO 64 x 8

HCI

Slave Block

OHCI

Registers

OHCI Root

Hub Registers

AHB

ED & TD

Regsisters

Control

HCI

Master Block

Data

uhp_int

MCK

UHPCK

AHB

Slave

Master

923

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Access to the USB host operational registers is achieved through the AHB bus slave interface. The OpenHCI host

controller initializes master DMA transfers through the ASB bus master interface as follows:

Fetches endpoint descriptors and transfer descriptors

Access to endpoint data from system memory

Access to the HC communication area

Write status and retire transfer Descriptor

Memory access errors (abort, misalignment) lead to an “UnrecoverableError” indicated by the corresponding flag

in the host controller operational registers.

The USB root hub is integrated in the USB host. Several USB downstream ports are available. The number of

downstream ports can be determined by the software driver reading the root hub’s operational registers. Device

connection is automatically detected by the USB host port logic.

USB physical transceivers are integrated in the product and driven by the root hub’s ports.

36.4 Product Dependencies

36.4.1 I/O Lines

DPs and DMs are not controlled by any PIO controllers. The embedded USB physical transceivers are controlled

by the USB host controller.

36.4.2 Power Management

The USB host controlle r requ ires a 48 MHz cloc k. This clock must be generated by a PLL with a correct accuracy

of ± 0.25%.

Thus the USB device peripheral receives two clocks from the Power Management Controller (PMC): the Master

clock (MCK) used to drive the per ipheral user interf ace (MCK domain) and the UHPCLK 48 MHz clock used to

interface with the bus USB signals (Recovered 12 MHz domain).

36.4.3 Interrupt Sources

The USB host inter face has an interrup t line connected to the interrupt controller.

Handling USB host interrupts requires programming the interrupt controller before configuring the UHP.

Table 36-1. Peripheral IDs

Instance ID

UHP 47

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924

36.5 Functional Description

Refer to the Open Host Controller Interface Specification for USB Rele a se 1. 0. a.

36.5.1 Host Controller Interface

There are two communication channels between the Host Controller and the Host Controller Driver. The first

channel uses a set of operational regist ers located on th e USB Host Controller. The Host Control ler is the tar get for

all communications on this channel. The operational registers contain control, status and list pointer registers.

They are mapped in the me mory mapped area . Within the op er ational register set there is a pointer to a location in

the processor address space named the Host Controller Communication Area (HCCA). The HCCA is the second

communication channel. The host controller is the master for all communication on this channel. The HCCA

contains the head pointer s to th e interrupt End point Descrip tor lists, the hea d pointer to the d one queue a nd status

information associated with start-of-frame processing.

The basic building blocks for communication across the interface are End point Descriptors (ED, 4 double words)

and Transfer Descriptors (TD, 4 or 8 double words). The host controller assigns an Endpoint Descriptor to each

endpoint in the system. A queue of Transfer Descriptors is linked to the Endpoint Descriptor for the specific

endpoint.

Figure 36-2. USB Host Communication Channels

Operational

Registers

Mode

HCCA

Status

Event

Frame Int

Ratio

Control

Bulk

Host Controller

Communications Area

Interrupt 0

Interrupt 1

Interrupt 2

Interrupt 31

Done

. . .

Open HCI

Shared RAM

Device Register

in Memory Space

Device Enumeration

= Transfer Descriptor = Endpoint Descriptor

. . .

925

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.5.2 Host Controller Driver

Figure 36-3. USB Host Drivers

USB Handling is done through several layers as follows:

Host controller hardware and serial engine—Transmits and receives USB data on the bus.

Host controller driver—Drives the Host controller hardware and handles the USB protocol.

USB Bus driver and hub driver—Hand les USB commands and enumera tion. Offers a hardware indepe ndent

interface.

Mini driver—Handles device specific commands.

Class driver—Handles standard devices. This acts as a generic dr iver for a class of devices, e.g., the HID

driver.

36.6 Typical Connection

Figure 36-4. Board Schematic to Interface UHP Device Controller

A termination serial resistor m ust be conn ected to HDP and HDM. Refer to the section “Electrical Characteristics”

for definition of the resistor value (REXT).

Host Controller Hardware

HUB Driver

Host Controller Driver

USB Driver

Mini Driver Class Driver Class Driver

User Application

Kernel Drivers

User Space

Hardware

REXT

HDMA

HDMB

HDPA

HDPB

10nF

100nF10μF

5V 0.20A

Type A Connector

REXT

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

926

36.7 USB Host Port (UHP) User Interface

Most of the host controller (HC) registers are OHCI operational registers, defined by the OHCI Specification for

USB. Four additional registe rs not specified by the OHCI Specification for USB provid e additional information

about the USB1.1 host controller state. The USB1.1 host controller registers can be accessed in user and

supervisor modes.

To enhance code reusa bility with possible future versions of the USB1.1 host controller, reads and writes to

reserved USB1.1 host controller register addresses are to be avoided. Unless otherwise specif ied, when writing

registers that have reserved bits, read-modify-write operations must be used so that the reserved bits are written

with their previous values.

Notes: 1. Restrictions apply to the physical addresses used in these registers.

2. Connected to the integrated USB1.1 phy pin s (DM, DP).

3. Although the controller implements two ports, the second port cannot be used.

Table 36-2. Register Mapping

Offset Register Name Access Reset

0x00 OHCI Revision Number Register UHP_ HCREVISION Read-only 0x0000 0010

0x04 HC Operating Mode Register UHP_HCCONTROL Read/Write 0x0000 0000

0x08 HC Command and Status Register UHP_HCCOMMANDSTATUS Read/Write 0x0000 0000

0x0C HC Interrupt and Status Register UHP_HCINTERRUPTSTATUS Read/Write 0x0000 0000

0x10 HC Interrupt Enable Register UHP_HCINTERRUPTENABLE Read/Write 0x0000 0000

0x14 HC Interrupt Disable Register UHP_HCINTERRUPTDISABLE Read/Write 0x0000 0000

0x18 HC HCCA Address Register(1) UHP_HCHCCA R ead/Write 0x0000 0000

0x1C HC Current Periodic Register (1) UHP_HCPERIODCURRENTED Read-only 0x0000 0000

0x20 HC Head Control Register(1) UHP_HCCONTROLHEADED Read/Write 0x0000 0000

0x24 HC Current Control Register(1) UHP_HCCONTROLCURRENTED Read/Write 0x0000 0000

0x28 HC Head Bulk Register(1) UHP_HCBULKHEADED R ead/Write 0x0000 0000

0x2C HC Current Bulk Register(1) UHP_HCBULKCURRENTED Read/Write 0x000 0 0000

0x30 HC Head Done Register(1) UHP_HCDONEHEAD Read-only 0x0000 0000

0x34 HC Frame Interval Register UHP_HCF MINT ERVAL Read/Write 0x0000 2EDF

0x38 HC Frame Remaining Register UHP_HCFMREMAINING Read-only 0x0000 0000

0x3C HC Frame Numb er Register UHP_HCFMNU MBER Read-only 0x0000 0000

0x40 HC Periodic Start Register UHP_HCPERIODICSTART R ead/Write 0x0000 0000

0x44 HC Low-Speed Threshold Register UHP_HCLSTHRESHOLD Read/Write 0x0000 0628

0x48 HC Root Hub A Register UHP_HCRHDESCRIPTORA Read/Write 0x0A00 1203

0x4C HC Root Hub B Register UHP_HCRHDESCRIPTORB Read/Write 0x0000 0000

0x50 HC Root Hub Status Register UHP_HCRHSTATUS Read/Write 0x0000 0000

0x54 HC Port 1 Status and Control Register(2) UHP_ HCRHPORTSTATUS1 Read/Write 0x0000 0100

0x58 HC Port 2 Status and Control Register(3) UHP_ HCRHPORTSTATUS2 Read/Write 0x0000 0100

927

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36.7.1 UHP OHCI Revision Number Register

Name: UHP_HCREVISION

Address: 0x4004C000

Access: Read-only

• REV: OHCI Revision Number

10h: This read-only field co ntains the BCD representation of the version of the HCI specification that is implemented by this

HC. For example, a value of 11h corresponds to version 1.1. All of the HC implementations that are compliant with this

specification will have a value of 10h.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

REV

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928

36.7.2 UHP HC Operating Mode Register

Name: UHP_HCCONTROL

Address: 0x4004C004

Access: Read/Write

This register controls the operating mode of the USB1.1 host controller.

• CBSR: Control/Bulk Service Ratio

Specifies the ratio between control and bulk EDs processed in a frame.

0: 1 control ED per bulk ED.

1h: 2 control EDs per bulk ED.

2h: 3 control EDs per bulk ED.

3h: 4 control EDs per bulk ED.

• PLE: Periodic List Enable

0: Periodic ED lists are not processed. Periodic list processing is disabled beginning with the next frame.

1: Enables processing of the periodic ED lists. Periodic list processing begins in the next frame.

• IE: Isochronous Enable

0: Isochronous EDs are not processed. The USB1.1 host controller checks this bit every time it finds an isochronous ED in

the periodic list.

1: Enables processing of isochronous EDs in the next frame, if not in the current frame.

• CLE: ControL List Enable

0: The control ED list is not proc e sse d in the ne xt 1 ms frame. The host cont ro ller driv er can m od ify th e con tr ol ED list. If

the driver removes the ED pointed to by the UHP_HCCONTROLCURRENTED register from the ED list, it must update the

UHP_HCCONTROLCURRENTED register to point to a current ED before it reenables the control list.

1: Enables processing of the control ED list. The UHP_HCCONTROLHEADED register must be 0 or point to a valid ED

before setting this bit. The UHP_HCCONTROLCURRENTED register must be 0 or point to a valid ED before setting this

bit.

• BLE: Bulk List Enable

0: The bulk ED list is not processed in the next 1 ms frame. The host controller driver can modify the bulk ED list. If the

driver removes the ED pointed to by the UHP_HCBULKCURRENTED register from the ED list, it must update the

UHP_HCBULKCURRENTED register to point to a current ED before it reenables the bulk list.

1: Enables processing of the bulk ED list. The UHP_HCBULKHEADED r egister m ust be 0 or poin t to a valid ED before set-

ting this bit. The UHP_HCBULKCURRENTED register must be 0 or point to a valid ED before setting this bit.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––––RWE RWC IR

76543210

HCFS BLE CLE IE PLE CBSR

929

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• HCFS: Host Controller Functional State

A transition to USB operational causes SOF generation to begin in 1 ms. The USB1.1 host controller can automatically

transition from USB suspend to USB resume, if a downstream resume is received. The USB1.1 host controller enters USB

suspend after a software reset. The USB1.1 host controller enters USB reset after a hardware reset. The USB reset state

resets the root hub and causes downstream signaling of USB reset.

0: USB reset.

1h: USB resume.

2h: USB operational.

3h: USB suspend.

• IR: Interrupt Routing

0: The USB1.1 host controller does not provide an SMI interrupt. This bit must be 0 to allow the USB1.1 host controller

interrupt to propagate to the MPU level 2 interrupt controller.

• RWC: Remote Wakeup Connected

0–1: This bit indicates whether HC supports remote wakeup signaling. If remote wakeup is supported and used by the sys-

tem it is the responsibility of system firmware to set this bit during POST. HC clears the bit upon a hardware reset but does

not alter it upon a softwar e re set. Remo te wakeup signalin g of the host system is host-bus-specific and is not d escr ibe d in

this specification.

• RWE: Remote Wakeup Enable

0–1: This bit is used by HCD to enable or disable the remote wakeup feature upon the detection of upstream resume sig-

naling. When this bit is set and the ResumeDete cted bit in HcInterruptStatus is set, a r emote wakeup is signaled to the host

system. Setting this bit has no impact on the generation of hardware interrupt.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

930

36.7.3 UHP HC Command and Status Register

Name: UHP_HCCOMMANDSTATUS

Address: 0x4004C008

Access: Read/Write

This register shows the current state of the host controller and accepts commands from the host controller driver.

• HCR: Host Controller Reset (read/write)

0: No effect.

1: Initiates a software reset of the USB1.1 host controller. This transitions the USB1.1 host controller to the USB suspend

state. This resets most USB1.1 host controller OHCI registers. OHCI register accesses must not be attempted until a read

of this bit returns a 0. A write of 1 to this b it does not reset the roo t hub and does not signal USB reset to down stream USB

functions.

• CLF: Control List Filled (read/write)

0–1: The host controller driver must set this bit if it modifies the control list to include new TDs. If the

UHP_HCCONTROLHEADED register is 0, the USB1.1 host controller does not begin processing control list EDs unless

this bit is set. When the USB1.1 host controller sees this bit set and begins processing the control list, it clears this bit to 0.

• BLF: Bulk List Filled (read/write)

0–1: The host controller driver must set this bit if it modifies the bulk list to include new TDs. If the

UHP_HCBULKCURRENTED register is 0, the USB1.1 host controller does not begin processing bulk list EDs unless this

bit is set. When the USB1.1 host controller sees this bit set and begins processing the bulk list, it clears this bit to 0.

• OCR: Ownership Change Request (read/write)

0–1: The host controller driver sets this bit to gain ownership of the host controller. The processor does not support SMI

interrupts, so no ownership change interrupt occurs.

• SOC: Scheduling Overrun Count (read-only)

0–3: Counts the number of times a scheduling overrun occurs. This count is incremented even if the host controller driver

has not acknowledged any previous pending scheduling overrun interrupt.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––SOC

15 14 13 12 11 10 9 8

––––––––

76543210

––––

OCR BLF CLF HCR

931

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36.7.4 UHP HC Interrupt and Status Register

Name: UHP_HCINTERRUPTSTATUS

Address: 0x4004C00C

Access: Read/Write

This register reports the status of the USB1.1 host controller internal interrupt sou rces.

• SO: Scheduling Overrun (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: A scheduling overrun has not occurred.

1: A scheduling overrun has occurred.

• WDH: Write Done Head (read/write, write ‘1’ to clear)

The host controller driver must read the value from the UHP_HCDONEHEAD register before writing 1 to this bit. A write of

1 clears this bit; a write of 0 has no effect.

0: USB1.1 host controller has not updated the UHP_HCDONEHEAD register.

1: USB1.1 host controller has updated the UHP_HCDONEHEAD register.

• SF: Start of Frame (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: A SOF has not been issued.

1: A SOF has been issued.

• RD: Resume Detected (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: A downstream device has not issued a resume request.

1: A downstream device has issued a resume request.

• UE: Unrecoverable Error (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: An unrecoverable error has not occurred.

1: An unrecoverable error has occurred on the OCPI bus, or that an isochronous TD PSW field condition code was not set

to Not Accessed when the USB1.1 host controller attempted to perform a transfer using that PSW/offset pair.

31 30 29 28 27 26 25 24

–OC––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–RHSC FNO UE RD SF WDH SO

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

932

• FNO: Frame Number Overflow (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: A frame number overflow has not occurred.

1: A frame number overflow has occurred.

• RHSC: Root Hub Status Change (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: A root hub status change has not occurred.

1: A root hub status change has occurred.

• OC: Ownership Change (read-only)

0–1: This bit is set by HC when HCD sets the OwnershipChangeRequest field in UHP_HCCOMMANDSTATUS. This

event, when unmasked, will always generate an System Management Interrupt (SMI) immediately. This bit is tied to 0

when the SMI pin is not imple m en te d.

933

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36.7.5 UHP HC Interrupt Enable Register

Name: UHP_HCINTERRUPTENABLE

Address: 0x4004C010

Access: Read/Write

This register enables various OHCI interrupt sources to generate interrupts to the level 2 interrupt controller.

• SO: Scheduling Overrun (read/write, write ‘1’ to set)

A write of 1 sets this bit; a writ e of 0 ha s no effe ct . A write of 1 to the co rr es po nd in g bit in th e

UHP_HCINTERRUPTDISABLE register clears this bit.

0: Scheduling overrun interrupts do not propagate.

1: When MIE is 1, allows scheduling overrun interrupts to propagate to the level 2 interrupt controller .

• WDH: Write Done Head (read/write, write ‘1’ to set)

A write of 1 sets this bit; a writ e of 0 ha s no effe ct . A write of 1 to the co rr es po nd in g bit in th e

UHP_HCINTERRUPTDISABLE register clears this bit.

0: Write done head interrupts do not propagate.

1: When MIE is 1, allows write done head interrupts to propag ate to the level 2 interrupt controller.

• SF: Start of Frame (read/write, wr ite ‘1’ to set)

A write of 1 sets this bit; a writ e of 0 ha s no effe ct . A write of 1 to the co rr es po nd in g bit in th e

UHP_HCINTERRUPTDISABLE register clears this bit.

0: Start of frame interrupts do not propagate.

1: When MIE is 1, allows start of frame interrupts to propagate to the level 2 interrupt controller.

• RD: Resume Detected (read/write, write ‘1’ to set)

A write of 1 sets this bit; a writ e of 0 ha s no effe ct . A write of 1 to the co rr es po nd in g bit in th e

UHP_HCINTERRUPTDISABLE register clears this bit.

0: Resume detected interrupts do not propagate.

1: When MIE is 1, allows resume detected interrupts to propagate to the level 2 interrupt controller.

• UE: Unrecoverable Error (read/write, write ‘1’ to set)

A write of 1 sets this bit; a writ e of 0 ha s no effe ct . A write of 1 to the co rr es po nd in g bit in th e

UHP_HCINTERRUPTDISABLE register clears this bit.

0: Unrecoverable error interrupts do not propagate.

1: When MIE is 1, allows unrecoverable error interrupts to propagate to the level 2 interru pt controller.

31 30 29 28 27 26 25 24

MIE OC ––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–RHSC FNO UE RD SF WDH SO

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

934

• FNO: Frame Number Overflow (read/write, write ‘1’ to set)

A write of 1 sets this bit; a writ e of 0 ha s no effe ct . A write of 1 to the co rr es po nd in g bit in th e

UHP_HCINTERRUPTDISABLE register clears this bit.

0: Frame number overflow interrupts do not propagate.

1: When MIE is 1, allows frame number overflow interrupts to propagate to the level 2 interrupt controller.

• RHSC: Root Hub Status Change (read/write, write ‘1’ to set)

A write of 1 sets this bit; a writ e of 0 ha s no effe ct . A write of 1 to the co rr es po nd in g bit in th e

UHP_HCINTERRUPTDISABLE register clears this bit.

0: Root hub status change interrupts do not propagate.

1: When MIE is 1, allows root hub status change interrupts to propagate to the level 2 interrupt controller.

• OC: Ownership Change (read-only)

0: Ignore.

1: Enable interrupt generation due to Ownership Change.

• MIE: Master Interrupt Enable (read/write, write ‘1’ to set)

A write of 1 sets this bit; a writ e of 0 ha s no effe ct . A write of 1 to the co rr es po nd in g bit in th e

UHP_HCINTERRUPTDISABLE register clears this bit.

0: OHCI interrupt sources are ignored and USB1.1 host controller interrupts are not propagated to the level 2 interrupt

controller.

1: Allows other enabled OHCI interrupt sources to propagate to the level 2 interrupt controller.

935

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.6 UHP HC Interrupt Disable Register

Name: UHP_HCINTERRUPTDISABLE

Address: 0x4004C014

Access: Read/Write

This register is used to clear bits in the UHP_HCINTERRUPTENABLE register.

• SO: Scheduling Overrun (read/write)

Read always returns 0.

0: No effect.

1: Clears the SO bit in the UHP_HCINTERRUPTENABLE register.

• WDH: Write Done Head (read/write)

Read always returns 0.

0: No effect.

1: Clears the WDH bit in the UHP_HCINTERRUPTENAB LE register.

• SF: Start of Frame (read/write)

Read always returns 0.

0: No effect.

1: Clears the SF bit in the UHP_HCINTERRUPTENABLE register.

• RD: Resume Detected (read/write)

Read always returns 0.

0: No effect.

1: Clears the RD bit in the UHP_HCINTERRUPTENABLE register.

• UE: Unrecoverable Error (read/write)

Read always returns 0.

0: No effect.

1: Clears the UE bit in the UHP_HCINTERRUPTENABLE register.

• FNO: Frame Number Overflow (read/write)

Read always returns 0.

0: No effect.

1: Clears the FNO bit in the UHP_HCINTERRUPTENABLE register.

31 30 29 28 27 26 25 24

MIE OC ––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

–RHSC FNO UE RD SF WDH SO

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

936

• RHSC: Root Hub Status Change (read/write)

Read always returns 0.

0: No effect.

1: Clears the RHSC bit in the UHP_HCINTERRUPTENABLE register.

• OC: Ownership Change (read-only)

0: Ignore.

1: Disable interrupt generation due to Ownership Change.

• MIE: Master Interrupt Enable (read/write)

Read always returns 0.

0: No effect.

1: Clears the MIE bit in the UHP_HCINTERRUPTENABLE register.

937

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.7 UHP HC HCCA Address Register

Name: UHP_HCHCCA

Address: 0x4004C018

Access: Read/Write

This register defines the physical address of the beginning of the HCCA.

• HCCA: Physical Address of the Beginning of the HCCA

0–FF FFFFh: This is the base address of the Host Controller Communication Area.

31 30 29 28 27 26 25 24

HCCA

23 22 21 20 19 18 17 16

HCCA

15 14 13 12 11 10 9 8

HCCA

76543210

––––––––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

938

36.7.8 UHP HC Current Periodic Register

Name: UHP_HCPERIODCURRENTED

Address: 0x4004C01C

Access: Read-only

This register defines the physical address of the next endpoint descriptor (ED) on the periodic ED list.

• PCED: Physical Address of the Current ED on the Periodic ED list

0–FFF FFFFh: This field represents bits 31:4 of the physical address of the next ED on the periodic ED list. EDs are

assumed to begin on a 16-byte aligned address, so bits 3:0 of this pointer are assumed to be 0.

31 30 29 28 27 26 25 24

PCED

23 22 21 20 19 18 17 16

PCED

15 14 13 12 11 10 9 8

PCED

76543210

PCED – –––

939

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.9 UHP HC Head Control Register

Name: UHP_HCCONTROLHEADED

Address: 0x4004C020

Access: Read/Write

This register defines the physical address of the head endpoint descriptor (ED) on the control ED list.

• CHED: Physical Address of the Head ED on the Control ED list

0–FFF FFFFh: This field represents bits 31:4 of the physical address of the head ED on the control ED list. EDs are

assumed to begin on a 16-byte aligned address, so bits 3:0 of this pointer are assumed to be 0.

31 30 29 28 27 26 25 24

CHED

23 22 21 20 19 18 17 16

CHED

15 14 13 12 11 10 9 8

CHED

76543210

CHED – –––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

940

36.7.10 UHP HC Current Control Register

Name: UHP_HCCONTROLCURRENTED

Address: 0x4004C024

Access: Read/Write

This register defines the physical address of the next endpoint descriptor (ED) on the control ED list.

• CCED: Physical Address of the Current ED on the Control ED List

0–FFF FFFFh: This field represents bits 31:4 of the physical address of the next ED on the control ED list. EDs are

assumed to begin on a 16-byte aligned address, so bits 3:0 of this pointer are assumed to be 0.

A value of 0 indicates that the USB1.1 host controller has reached the end of the control ED list without finding any trans-

fers to process. This register is automatically updated by the USB1.1 host controller.

31 30 29 28 27 26 25 24

CCED

23 22 21 20 19 18 17 16

CCED

15 14 13 12 11 10 9 8

CCED

76543210

CCED – –––

941

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.11 UHP HC Head Bulk Register

Name: UHP_HCBULKHEADED

Address: 0x4004C028

Access: Read/Write

This register defines the physical address of the head endpoint descriptor (ED) on the bulk ED list.

• BHED: Physical Address of the Head ED on the Bulk ED List

0–FFF FFFFh: This field represents bi ts 31:4 of the physical add ress of the head ED on the bulk ED list. EDs are assumed

to begin on a 16-byte aligned address, so bits 3:0 of this pointer are assumed to be 0.

31 30 29 28 27 26 25 24

BHED

23 22 21 20 19 18 17 16

BHED

15 14 13 12 11 10 9 8

BHED

76543210

BHED – –––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

942

36.7.12 UHP HC Current Bulk Register

Name: UHP_HCBULKCURRENTED

Address: 0x4004C02C

Access: Read/Write

This register defines the physical address of the next endpoint descriptor (ED) on the bulk ED list.

• BCED: Physical Address of the Current ED on the Bulk ED List

0–FFF FFFFh: This fiel d rep rese nts bits 3 1:4 o f the ph ysical addr ess of the n ext ED on the bulk ED list. EDs are assumed

to begin on a 16-byte aligned address, so bits 3:0 of this pointer are assumed to be 0.

A value of 0 indicates that the USB1.1 host controller has reached the end of the bulk ED list without finding any transfers

to process. This register is automatically updated by the USB1.1 host controller.

31 30 29 28 27 26 25 24

BCED

23 22 21 20 19 18 17 16

BCED

15 14 13 12 11 10 9 8

BCED

76543210

BCED – –––

943

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.13 UHP HC Head Done Register

Name: UHP_HCDONEHEAD

Address: 0x4004C030

Access: Read-only

This register defines the physical address of the current head of the done TD queue.

• DH: Physical Address of the Last TD that has added to the done queue

0–FFF FFFFh: This field represents bits 31:4 of the physical address of the top TD on the done TD queue. TDs are

assumed to begin on a 16-byte aligned address, so bits 3:0 of this pointer are assumed to be 0.

A value of 0 indicates that there are no TDs on the don e queu e. This register is automatically up dated by the USB1 .1 host

controller.

31 30 29 28 27 26 25 24

23 22 21 20 19 18 17 16

15 14 13 12 11 10 9 8

76543210

DH – –––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

944

36.7.14 UHP HC Frame Interval Register

Name: UHP_HCFMINTERVAL

Address: 0x4004C034

Access: Read/Write

This register defines the number of 12-MHz clock pulses in each USB frame.

• FRAMEINTERVAL: Frame Interval

0–3FFFh: Number of 12 -MHz clo cks in the USB fra me. Nomina lly, th is is set to 11,999 (2EDFh) to give a 1-ms frame. The

host controller driver can make minor changes to this field to attempt to manually synchronize with another clock source.

• FSMPS: Largest Data Packet

0–7FFFh: Larg e s t data pac k et size allo we d for full-sp ee d pa ck ets, in bit times.

• FIT: Frame Interval Toggle

0–1: The host controller driver must toggle this bit any time it changes the frame interval field.

31 30 29 28 27 26 25 24

FIT FSMPS

23 22 21 20 19 18 17 16

FSMPS

15 14 13 12 11 10 9 8

––FRAMEINTERVAL

76543210

FRAMEINTERVAL

945

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.15 UHP HC Frame Remaining Register

Name: UHP_HCFMREMAINING

Address: 0x4004C038

Access: Read-only

This register reports the number of full-speed bit times remaining in the current frame.

• FR: Frame Remaining

0–3FFFh: The number of full-speed bit times remaining in the current frame. This field is automatically reloaded with the

frame interval (FI) value in the UHP_HCFMINTERVAL register at the beginning of every frame.

• FRT: Frame Remaining Toggle

0–1: This bit is loaded with the frame interval to gg le bit every time the USB1.1 host co ntro ller loads the fra me interval field

into the frame remaining field.

31 30 29 28 27 26 25 24

FRT – ––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––FR

76543210

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

946

36.7.16 UHP HC Frame Number Register

Name: UHP_HCFMNUMBER

Address: 0x4004C03C

Access: Read-only

This register reports the current USB frame number.

• FN: Frame Number

0–FFFFh: This field reports the current USB frame number. It is incremented when the frame remaining field is reloaded

with the frame interval (FI) value in the UHP_HCFMINTERVAL register. Frame number automatically rolls over from

FFFFh to 0. After frame number is incremented, its new value is written to the HCCA and the USB1.1 host controller sets

the SOF interrupt status bit and begins processing the ED lists.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

76543210

947

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.17 UHP HC Periodic Start Register

Name: UHP_HCPERIODICSTART

Address: 0x4004C040

Access: Read/Write

This register defines the position within the USB frame where endpoint descriptors (EDs) on the periodic list have priority

over EDs on the bulk and control lists.

• PS: Periodic Start

0–3FFFh: The host controller driver must program this value to be about 10% le ss than the frame interval (FI) value in the

UHP_HCFMINTERVAL register, so that control and bulk EDs have pr iority for the first 10% of the frame; then periodic EDs

have priority for the remaining 90% of the frame.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––PS

76543210

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

948

36.7.18 UHP HC Low-Speed Threshold Register

Name: UHP_HCLSTHRESHOLD

Address: 0x4004C044

Access: Read/Write

This register defines the latest time in a frame that the USB1.1 host controller can begin a low-speed packet.

• LST: Low-Speed Threshold

0–3FFFh: This field defines the number of full-speed bit times in the frame after which the USB1.1 host controller cannot

start an 8-byte low-speed packet. The USB1.1 host controller only begins a low-speed transaction if the frame re maining

(FR) value in the UHP_HCFMREMAINING register is greater than the low-speed threshold.

The host controller driver must set this field to a value that ensures that an 8-byte low-speed TD comple tes be fore the end

of the frame. When set, the host controller driver must not change the value.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––LST

76543210

LST

949

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.19 UHP HC Root Hub A Register

Name: UHP_HCRHDESCRIPTORA

Address: 0x4004C048

Access: Read/Write

This register defines several aspects of the USB1.1 host controller root hub functionality.

• NDP: Number of Downstream Ports (read-only)

0–FFh: The USB signal multiplexing mode and top-level pin mu ltiplexing features can p lace the device in a mode where 0,

1, 2, or 3 of the USB1.1 host controller downstream ports are usable. This register reports three ports, regardless of USB

signal multiplexing mode and top-level pin multiplexing mode.

• PSM: Power Switching Mode (read/write)

0: Because the device does not provide signals fr om the USB1.1 host controller to control external VBUS switching, this bit

defaults to 0 that indicates that all ports are powered at the same time.

• NPS: No Power Switching (read/write)

1: Because the device does not provide connections from the USB1.1 host controller to control external VBUS switching,

this bit defaults to 1 that indicates that VBUS power switching is not supported and that power is available to all down-

stream ports when the USB1.1 host controller is powered. This bit has no relationship to the OTG controller register bits

that relate to VBUS. System software can update this register to simplify h ost controller driver and/or OTG driver coding.

• DT: Device Type (read-only)

0: This bit is always 0, which indicates that the USB1.1 host controller implemented is not a compound device.

• OCPM: Overcurrent Protection Mode (read/write)

0: Because the device does not provide host controller overcurrent protection input signals, this bit has no effect. This bit

has no relationship to the OTG controller register bits that relate to VBUS.

• NOCP: No Overcurrent Protection (read/write)

1: Because the device do es not provide signal s to allow connection of external over current indication signals to the USB1.1

host controller, this bit defaults to 1 that indicates that the USB1.1 host controller does not implement overcurrent protec-

tion inputs. This bit has no relationship to the OTG controller register bits that relate to VBUS.

31 30 29 28 27 26 25 24

POTPG

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––NOCP

OCPM DT NPS PSM

76543210

NDP

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

950

• POTPG: Power-On to Power-good Time (read/write)

0–FFh: Defines the minimum amount of time (2 ms x POTPG) between the USB1.1 host controller turning on power to a

downstream port and when the USB1.1 host can access the downstream device. This field has no effect on USB1.1 host

controller operation. After turning on power to a port, the USB1.1 host controller driver must delay the amount of time

implied by POTPG before attempting to reset a n attached downstream d evice. The requ ired amount of time is implementa-

tion-specific and must be calcu lated ba sed on the amou nt of time th e VBUS supply takes to provide valid VBUS to a wo rst-

case downstream USB function controller. The implementation- specific value must be computed and then written to this

register before the USB1.1 host controller driver is initialized. Because the device do es not provide a dire ct control from the

USB1.1 host controller to switch VBUS on and off, this value must take into account any delays caused by other methods

of controlling VBUS externally. This field has no relationship to the OTG controller register bits that relate to VBUS. System

software can update this register to simplify host controller driver and/or OTG driver coding.

951

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.20 UHP HC Root Hub B Register

Name: UHP_HCRHDESCRIPTORB

Address: 0x4004C04C

Access: Read/Write

This register defines several aspects of the USB1.1 host controller root hub functionality.

Note: The device does not provid e connections from the USB1.1 host controller to pins to provide external port power switching.

Systems that implement port power switching must use other mechanisms to control port power.

• DR0: Device Removable

Reserved.

• DR1: Device Removable Bit for Downstream Port 1

Defines whether downstream port 1 has a removable or nonremo vable device.

0: Downstream port 1 may have a removable device attached.

1: Downstream port 1 has a nonremovable device attached.

• DR2: Device Removable Bit for Downstream Port 2

Defines whether downstream port 2 has a removable or nonremo vable device.

0: Downstream port 2 may have a removable device attached.

1: Downstream port 2 has a nonremovable device attached.

• DR3: Device Removable Bit for Downstream Port 3

Defines whether downstream port 3 has a removable or nonremo vable device.

0: Downstream port 3 may have a removable device attached.

1: Downstream port 3 has a nonremovable device attached.

• DRx[x=4..15]: Device Removable

Reserved.

• PPCM0: Port Power Control Mask

Reserved.

• PPCM1: Port Power Control Mask for Downstream Port 1

Defines whether downstream port 1 has port power contr olled by the global power control. System software can update

these bits to simplify host controller driver and/or OTG dr iver coding.

0: Global power control is implemented for downstream port 1.

1: Per-port power control is implemented for downstream port 1.

31 30 29 28 27 26 25 24

PPCM15 PPCM14 PPCM13 PPCM12 PPCM11 PPCM10 PPCM9 PPCM8

23 22 21 20 19 18 17 16

PPCM7 PPCM6 PPCM5 PPCM4 PPCM3 PPCM2 PPCM1 PPCM0

15 14 13 12 11 10 9 8

DR15 DR14 DR13 DR12 DR11 DR10 DR9 DR8

76543210

DR7 DR6 DR5 DR4 DR3 DR2 DR1 DR0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

952

• PPCM2: Port Power Control Mask for Downstream Port 2

Defines whether downstream port 2 has port power contr olled by the global power control. System software can update

these bits to simplify host controller driver and/or OTG dr iver coding.

0: Global power control is implemented for downstream port 2.

1: Per-port power control is implemented for downstream port 2.

• PPCM3: Port Power Control Mask for Downstream Port 3

Defines whether downstream port 3 has port power contr olled by the global power control. System software can update

these bits to simplify host controller driver and/or OTG dr iver coding.

0: Global power control is implemented for downstream port 3.

1: Per-port power control is implemented for downstream port 3.

• PPCMx[x=4..15]: Port Power Control Mask

Reserved.

953

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

36.7.21 UHP HC Root Hub Status Register

Name: UHP_HCRHSTATUS

Address: 0x4004C050

Access: Read/Write

This register reports the USB1.1 host controller root hub status.

• LPS: Local Power Status (read/write)

0: Because the root hub doe s not support the local power status feature, this bit defa ults to 0 and has no effect. This bit has

no relationship to the OTG controller register bits that relate to VBUS. System software can update this register to simplify

host controller driver and/or OTG driver coding.

• OCI: Overcurrent Indicator (read-only)

0: Because the device does not provide signals for external hardware to report overcurrent status to the USB1.1 host con-

troller, this bit is always 0. This bit has no relationship to the OTG controller regis ter bits that relate to VBUS.

• DRWE: Device Remote Wakeup Enable (read/write)

0: A write of 0 has no effect. Connect status change events do not cause a transition from USB suspend to USB resume

state and the resume detected interrupt is not changed.

1: A write of 1 sets the device remote wake up enable bit. This b it enables a connect status change even t to be treated as a

resume event, which causes a transition from USB suspend to USB resume state and sets the resume detected interrupt

status bit.

• LPSC: Local Power Status Change (read/write)

0: Because the root hub doe s not support the local power status feature, this bit defa ults to 0 and has no effect. This bit has

no relationship to the OTG controller register bits that relate to VBUS. System software can update this register to simplify

host controller driver and/or OTG driver coding.

• OCIC: Overcurrent Indication Change (read/write)

This bit is automatically set when the overcurrent indicator bit changes. This bit has no relationship to the OTG contro ller

register bits that relate to VBUS. System software can update this register to simplify host controller driver and/or OTG

driver coding.

0: No effect.

1: Clears this bit.

• CRWE: Clear Remote Wakeup Enable (read/write)

0: No effect.

1: Clears the device remote wakeup enable bit.

31 30 29 28 27 26 25 24

CRWE – ––––––

23 22 21 20 19 18 17 16

––––––

OCIC LPSC

15 14 13 12 11 10 9 8

DRWE – ––––––

76543210

––––––

OCI LPS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

954

36.7.22 UHP HC Port 1 Status and Control Register

Name: UHP_HCRHPORTSTATUS1

Address: 0x4004C054

Access: Read/Write

This register reports and controls the state of USB1.1 host port 1.

• CCS/CPE: Port 1 Current Connection Status/clear Port Enable (read/write)

If the DR[1] bit in the UHP_HCRHDESCRIPTORB register is set to 1 to indicate a nonremovable USB device on port 1, this

bit is set after a root hub reset to inform the system that the device is attached. A write of 1 clears th is bit; a write of 0 has

no effect.

0: No USB device is attached to port 1.

1: USB device is attached to port 1.

• PES/SPE: Port 1 Port Enable Status/set Port Enable (read/write)

A write of 1 to this bit when port 1 curr ent con nect status is 1 sets the po rt 1 por t ena ble status bit; a writ e of 1 wh en por t 1

current connect status is 0 ha s no effe ct; a write of 0 has no effect. This bit is automatically set at com pletion of port 1 USB

reset, if it was not already set before the USB reset completed; and this bit is automatically set at the end of a USB sus-

pend, if the port was not enabled when the USB resume completed.

0: Port 1 is disabled.

1: Port 1 is enabled.

• PSS/SPS: Port 1 Port Suspend Status/set Port Suspend (read/write)

A write of 1 to this bit when port 1 cur re n t connect status is 1 sets the port 1 port suspend status bit and places port 1 in

USB suspend state; a write of 1 when port 1 current connect status is 0 sets the connect status change to inform the

USB1.1 host controller driver software of an attempt to suspend a disconnected device; a write of 0 has no effect. This bit

is cleared automatically at the end of the USB resume sequence and also at the end of the USB reset sequence.

0: Port 1 is not in the USB suspend state.

1: Port 1 is in the USB suspend state or is in the resume sequence.

• POCI/CSS: Port 1 port Overcurrent Indicator/clear Suspend Status (read/write)

A write of 1 to this bit when port 1 port suspend status is 1 causes resume signaling on por t 1; a write of 1 when por t 1 port

suspend status is 0 has no effect; a writ e of 0 has no effect. The device does not pr ovide inputs for signalin g exte rnal over -

current indication to the USB1.1 host controller. Overcurrent monitoring, if required, must be handled throug h some other

mechanism.

0: Port 1 port overcurrent condition has not occurred.

1: Port 1 port overcurrent condition has occurred.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––PRSC OCIC PSSC PESC CSC

15 14 13 12 11 10 9 8

–––––– LSDA/CPP PPS/SPP

76543210

–––

PRS/SPR POCI/CSS PSS/SPS PES/SPE CCS/CPE

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• PRS/SPR: Port 1 port Reset Status/set Port Reset (read/write)

A write of 1 to this bit sets the port 1 port reset status bit an d ca us es th e USB1 .1 host controller to begin signaling USB

reset to port 1; a write of 0 ha s no effe ct .

0: USB reset is not being sent to port 1.

1: Port 1 is signaling the USB reset.

• PPS/SPP: Port 1 Port Power Status/set Port Power (read/write)

The host contro ller drive r ca n writ e a 1 to this bit to se t the port 1 port power status bit; a write of 0 has no effect. The

device does not p rovide sign als from the USB1 .1 host con troll er to contr ol external port po wer, so if required, USB1.1 host

port power control signals must be controlled through other means. Software can track the current power state using the

port power status bit and other power control bits, but those bits have no direct effect on external port power control. This

bit has no relationship to the OTG controller register bits that relate to VBUS. System software can update this register to

simplify host controller driver and/or OTG driver coding.

0: Port 1 power is disabled.

1: Port 1 power is enabled.

• LSDA/CPP: Port 1 Low-speed Device Attached/clear Port Power (read/write)

This bit is valid only when port 1 current connect status is 1. The host controller driver can write a 1 to this bit to clear the

port 1 port power status bit; a write of 0 has no effect. The USB1.1 host controller does not control external port power

using OHCI mechanisms, so, if required, USB1.1 host port power must be controlled through other means. This bit has no

relationship to the OTG controller register bits that relate to VBUS. System software can update this register to simplify

host controller driver and/or OTG driver coding.

0: Full-speed device is attached to port 1.

1: Low-speed device is attached to port 1.

• CSC: Port 1 Connect Status Change (read/write, write ‘1’ to clear)

If the DR[1] bit in the UHP_HCRHDESCRIPTORB register is set to 1 to indicate a nonremovable USB device on port 1, this

bit is set only after a root hub reset to inform the system that the device is attached. A write of 1 clears this bit; a write of 0

has no effect.

0: Port 1 current connect status has not changed.

1: Port 1 current connect status has changed due to a connect or disconnect event. If current connect status is 0 when a

set port reset, set port enable, or set port suspend write occurs, then this bit is set.

• PESC: Port 1 Enable Status Change (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: Port 1 port enable status has not changed.

1: Port 1 port enable status has changed.

• PSSC: Port 1 Suspend Status Change (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: Port 1 port suspend status has not changed.

1: Port 1 port suspend status has changed. Suspend status is considered to have changed only after the resume pulse,

low-speed EOP, and 3-ms synchronization delays have been completed.

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• OCIC: Port 1 Overcurrent Indicator Change (read/write)

0: Because the device does not provide inputs for signaling extern al overcurrent indi cation to the USB1.1 host controller,

this bit is always 0. Overcurrent monitoring, if required, must be handled through some other mechanism. This bit has no

relationship to the OTG controller register bits that relate to VBUS.

• PRSC: Port 1 Reset Status Change (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: Port 1 port reset status bit has not changed.

1: Port 1 port reset status bit has changed.

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36.7.23 UHP HC Port 2 Status and Control Register

Name: UHP_HCRHPORTSTATUS2

Address: 0x4004C058

Access: Read/Write

This register reports and controls the state of USB1.1 host port 2.

• CCS/CPE: Port 2 Current Connection Status/clear Port Enable (read/write)

When read as 1, indica te s tha t po rt 2 curr en tly ha s a USB device attached. When 0, indicates that no USB device is

attached to port 2. This bit is set to 1 after root hub reset if the UHP_HCRHDESCRIPTORB.DR[2] bit is set to indicate a

non-removable device on port 2.

0: A write of 0 to this bit has no effect.

1: A write of 1 to this bit clears the port 2 port enable bit.

• PES/SPE: Port 2 Current Connection Status/clear Port Enable (read/write)

When read as 1, indicates that port 2 is enabled. When read as 0, this bit indicates that port 2 is not enabled. This bit is

automatically set at completion of port 2 USB reset if it was not alre ady set before the USB reset completed and is auto-

matically set at the end of a USB suspend if the port was not enabled when the USB resume completed.

0: A write of 0 has no effect.

1: A write of 1 to this bi t when port 2 cu rrent connect status is 1 se ts the port 2 po rt enable status bit. A write of 1 when p ort

2 current connect status is 0 has no effect.

• PSS/SPS: Port 2 Port Suspend Status/set Port Suspend (read/write)

When read as 1, indicates that port 2 is in the USB suspend state, or is in the resume sequence. When 0, indicates that

port 2 is not in the USB suspend state. This bit is cleared automatically at the end of the USB resume sequence and also

at the end of the USB reset sequence.

0: A write of 0 to this bit has no effect.

1: If port 2 current connect status is 1, a write of 1 to this bit sets the port 2 port suspend status bit and place s port 2 in USB

suspend state. If current connect status is 0, a write of 1 instead sets connect status change to inform the USB1.1 host

controller driver software of an attempt to suspend a disconnected device.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

–––PRSC OCIC PSSC PESC CSC

15 14 13 12 11 10 9 8

–––––– LSDA/CPP PPS/SPP

76543210

–––

PRS/SPR POCI/CSS PSS/SPS PES/SPE CCS/CPE

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• POCI/CSS: Port 2 Port Overcurrent Indicator/clear Suspend Status (read/write)

When read as 1, indicates that a port 2 port overcurrent condition has occurred. When 0, no port 2 po rt ove rcu rr en t co nd i-

tion has occurred. The device does not provide inputs for signaling external overcurrent indication to the USB1.1 host

controller. Overcurrent monitoring, if required, must be handled through some other me ch an ism . T his bit has no rela tio n -

ship to the OTG controller register bits that relate to VBUS.

0: A write of 0 has no effect.

1: A write of 1 to this bit when port 2 port suspend status is 1 causes resume signaling on port 2. A write of 1 when port 2

port suspend status is 0 has no effect.

• PRS/SPR: Port 2 Port Reset Status/set Port Reset (read/write)

When read as 1, indicates that port 2 is sending a USB reset. When read as 0, USB reset is not being sent to port 2.

0: A write of 0 to this bit has no effect.

1: A write of 1 to this bit sets the port 2 port reset status bit and causes the USB1.1 host controller to begin signaling USB

reset to port 2.

• PPS/SPP: Port 2 Port Power Status/set Port Power (read/write)

This bit indicates, when read as 1, that the port 2 power is enabled. When read as 0, port 2 power is not enabled. The

device does not provide signals from the USB1.1 host controller to control external port power, so, if required, USB1.1 host

port power control signals must be controlled through other means. Software can track the current power state using the

port power status bit and other power control bits, but those bits have no direct effect on external port power control. This

bit has no relationship to the OTG controller register bits that relate to VBUS. System software can update this register to

simplify host controller driver and/or OTG driver coding.

0: A write of 0 has no effect.

1: A write of 1 to this bit sets the port 2 port power status bit.

• LSDA/CPP: Port 2 Low-speed Device Attached/clear Port Power (read/write)

This bit indicates, when read as 1, that a low-speed device is attached to port 2. A 0 in this bit indicates a fu ll-speed device.

This bit is valid only when port 2 current connect status is 1. The USB1.1 host controller does not control external port

power using OHCI mechanisms, so, if required, USB1.1 host port power must be controlled through other means.

0: A write of 0 to this bit has no effect.

1: The host controller driver can write a 1 to this bit to clear the port 2 port power status.

• CSC: Port 2 Connect Status Change (read/write)

If the DR[2] bit in the UHP_HCRHDESCRIPTORB register is set to 1 to indicate a nonremovable USB device on port 2, this

bit is set only after a root hub reset to inform the system that the device is attached. A write of 1 clears this bit; a write of 0

has no effect.

0: Port 2 current connect status has not changed.

1: Port 2 current connect status has changed due to a connect or disconnect event. If current connect status is 0 when a

set port reset, set port enable, or set port suspend write occurs, then this bit is set.

• PESC: Port 2 enable status change (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: Port 2 port enable status has not changed.

1: Port 2 port enable status has changed.

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• PSSC: Port 2 suspend status changed (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: Port 2 port suspend status has not changed.

1: Port 2 port suspend status has changed. Suspend status is considered to have changed only after the resume pulse,

low-speed EOP, and 3-ms synchronization delays have been completed.

• OCIC: Port 2 Overcurrent Indicator Change (read/write)

0: Because the device does not provide inputs for signaling extern al overcurrent indi cation to the USB1.1 host controller,

this bit is always 0. Overcurrent monitoring, if required, must be handled through some other mechanism. This bit has no

relationship to the OTG controller register bits that relate to VBUS.

• PRSC: Port 2 Reset Status Change (read/write, write ‘1’ to clear)

A write of 1 clears this bit; a write of 0 has no effect.

0: Port 2 port reset status bit has not changed.

1: Port 2 port reset status bit has changed.

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37. USB Device Port (UDP)

37.1 Description

The USB Device Port (UDP) is compliant with the Universal Serial Bus (USB) 2.0 full-speed device specification.

Each endpoint can be configured in one of several USB transfer types. It can be associated with one or two banks

of a dual-port RAM used to store the current data payload. If two banks are used, one DPR b ank is read or written

by the processor, while the other is read or written by the USB device per ipheral. This feature is mandatory for

isochronous endpoints. Thus the device maintains the maximum bandwidth (1 Mbyte/s) by working with endpoints

with two banks of DPR.

Note: 1. The Dual-Bank function provides two banks for an endpoint. This feature is used for ping-pong mode.

Suspend and resume are automatically detected by the USB device, which notifies the processor by raising an

interrupt. Depending on the product, an external signal can be used to send a wakeup request to the USB host

controller.

37.2 Embedded Characteristics

USB 2.0 Full-speed Compliant, 12 Mbit/s

Embedded USB 2.0 Full-speed Transceiver

Integrated Pull-up on DDP

Integrated Pull-down on DDM

6 Endpoints

Embedded Dual-port RAM for Endpoints

Suspend/Resume Logic

Ping-pong Mode (2 Memory Banks) for Isochronous and Bulk Endpoints

Table 37-1. USB Endpoint Description

End point No. Mnemonic Dual-Ban k(1) Max. Endpoint Size Endpoint Type

0 EP0 No 64 Control/Bulk/Interrupt

1 EP1 Yes 128 Bulk/Iso/Interrupt

2 EP2 Yes 128 Bulk/Iso/Interrupt

3 EP3 No 64 Control/Bulk/Interrupt

4 EP4 Yes 512 Bulk/Iso/Interrupt

5 EP5 Yes 512 Bulk/Iso/Interrupt

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37.3 Block Diagram

Figure 37-1. Block Diagram

Access to the UDP is via the APB bus interface. Read and write to the data FIFO are done by reading and writing

8-bit values to APB registers.

The UDP peripheral requires two clocks: one peripheral clock used by the Master Clock domain (MCK) and a 48

MHz clock (UDPCK) used by the 12 MHz domain.

A USB 2.0 full-speed pad is embedded and controlled by the Serial Interfa ce Eng ine (SIE) .

The signal external_resume is optional. It allows the UDP peripheral to wake up once in system mode. The host is

then notified that the device asks for a resume. This optional feature must also be negotiated with the host during

the enumeration.

37.3.1 Signal Description

Atmel Bridge

12 MHz

Suspend/Resume Logic

Serial

Interface

Engine

SIE

MCK

Master Clock

Domain

Dual

Port

RAM

FIFO

UDPCK

Recovered 12 MHz

Domain

udp_int

(interrupt line)

USB Device

Embedded

USB

Transceiver

DDP

DDM

APB

MCU

Bus

txoen

eopn

txd

rxdm

rxd

rxdp

Wrapper

User

Interface

Table 37-2. Signal Names

Signal Name Description Type

UDPCK 48 MHz clock Input

MCK Master clock Input

udp_int Interrupt line connected to the Interrupt Controller Input

DDP USB D+ line I/O

DDM USB D- line I/O

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37.4 Product Dependencies

For further details on the USB Device hardware imp lementation, see the specific Product Properties document.

The USB physical transceiver is integrated into the product. The bidirectional differential signals DDP and DDM

are available from the product boundary.

One I/O line may be used by the application to check that VBUS is still available from the host. Self- powered

devices may use this entry to be notified that the host has been powered off. In this case, the pull-up on DDP must

be disabled in order to prevent feeding current to the host. The application should disconnect the transcei ve r, then

remove the pull-up.

37.4.1 I/O Lines

The USB pins are shared with PIO lines. By default, the DDP/DDM pins are configured as PIOs.

37.4.2 Power Management

The USB device peripheral requires a 48 MHz clock. This clock must be generated by a PLL driven by a clock

source with an accuracy of ± 0.25% (note that the fast RC oscillator cannot be used).

Thus, the USB device receives two clocks from the Power Management Controller (PMC):

Master clock, MCK, used to drive the peripheral user interface

UDPCK, used to interface with the bus USB signals (recovered 12 MHz domain)

WARNING: T he UDP peripheral clock in the PMC must be enabled before any read/write operations to the UDP

registers including the Transceiver Control Register (UDP_TXVC).

37.4.3 Interrupt Sources

The USB device interface has an interrupt line conne cted to the Interrupt Controller.

Handling the USB device inte rr up t re qu ire s pr og ra m m ing the Interrupt Controller before configuring the UDP.

37.5 Typical Connection

Figure 37-2. Board Schematic to Interface Device Peripheral

Table 37-3. Peripheral IDs

Instance ID

UDP 48

REXT

DDM

DDP

PIO 27 K

47 K

Type B

Connector

5V Bus Monitoring

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37.5.1 USB Device Transceiver

The USB device transceiver is embedded in the product. However, discrete components are required for each of

the following actions:

to monitor VBUS voltage

for line termination

to disconnect the host for reduced power consumption

37.5.2 VBUS Monitoring

VBUS monitoring is required to detect host connection. VBUS monitoring is done using a standard PIO with

internal pull-up disabled. When the host is switched off, it should be considered as a disconnect, the pull-up must

be disabled in order to prevent powering the host through the pull-up resistor.

When the host is disconnected and the transceiver is enabled, then DDP and DDM are floating. This may lead to

over consumption. A solution is to enable the integrated pull-down by disabling the transceiver

(UDP_TXVC.TXVDIS = 1) and then remove the pull-up (UDP_TXVC.PUON = 0).

A termination serial resistor must be connected to DDP and DDM. The resistor value is defined in the electrical

characteristics of the product (REXT).

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37.6 Functional Description

37.6.1 USB 2.0 Full-speed Introduction

The USB 2.0 full-speed provides commu nication services between host and attached USB devices. Each device is

offered with a collection of communication flows (pipes) associated with each endpoint. Software on the host

communicates with a USB device through a set of communication flows.

Figure 37-3. Example of USB 2. 0 Full-speed Communic a tio n Control

The Control Transfer endp oint EP0 is always used when a USB device is first configured (USB 2.0 specifica tions).

37.6.1.1 USB 2.0 Full-speed Transfer Types

A communication flow is carried over one of four transfer types defined by the USB device.

37.6.1.2 USB Bus Transactions

Each transfer results in one or more transactions over the USB bus. There are three kinds of transactions flowing

across the bus in packets:

Setup Transaction

Data IN Transaction

Data OUT Transaction

EP0

USB Host V2.0

Software Client 1 Software Client 2

Data Flow: Bulk Out Transfer

Data Flow: Bulk In Transfer

Data Flow: Control Transfer

EP1

EP2

USB Device 2.0

Block 1

USB Device 2.0

Block 2

EP5

EP4

EP0

Data Flow: Isochronous In Transfer

Data Flow: Isochronous Out Transfer

USB Device endpoint configuration requires that

in the first instance Control Transfer must be EP0.

Table 37-4. USB Co mmunication Flow

Transfer Direction Bandwidth Supported

Endpoint Size Error Detection Retrying

Control Bidirectional Not guaranteed 8, 16, 32, 64 Yes Automatic

Isochronous Unidirectional Guaranteed 512 Yes No

Interrupt Unidirectional Not guaranteed ≤ 64 Yes Yes

Bulk Unidirectiona l Not guaranteed 8, 16, 32, 64 Yes Yes

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37.6.1.3 USB Transfer Event Definitions

As indicated below, transfers are sequential events carried out on the USB bus.

Notes: 1. Control transfer must use endpoints with no ping-pong attributes.

2. Isochronous transfers must use endpoints with ping-pong attributes.

3. Control transfers can be aborted using a stall handshake.

A status transaction is a special type of host-to-device tran saction used only in a control transfer. The control

transfer must be performed using endpoints with no ping-pong attributes. According to the control sequence (read

or write), the USB device sends or receives a status transaction.

Figure 37-4. Control Read and Write Sequences

Notes: 1. During the Status IN stage, the host waits for a zero length packet (Data IN transaction with no data) from the

device using DATA1 PID. Refer to Chapter 8 of the Universal Serial Bus Specification, Rev. 2.0, for more

information on the protocol layer.

2. During the Status OUT stage, the host emits a zero length packet to the device (Data OUT transaction with no

data).

Table 37-5. USB T ransfer Events

Transfer

TransactionDirection Type

CONTROL (bidirectional) Control(1)(3)

Setup transaction → Data IN transactions → Status OUT transaction

Setup transaction → Data OUT transactions → Status IN transaction

Setup transaction → Status IN transaction

IN (device toward host)

Interrupt IN

Data IN transaction → Data IN transactionIsochronous IN(2)

Bulk IN

OUT (host toward device)

Interrupt OUT

Data OUT transaction → Data OUT transactionIsochronous OUT(2)

Bulk OUT

Control Read Setup TX Data OUT TX Data OUT TX

Data Stage

Control Write

Setup Stage

Setup TX

No Data Control

Data IN TX Data IN TX

Status Stage

Status IN TX

Status OUT TX

Status IN TX

Data Stage

Setup Stage Status Stage

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37.6.2 Handling Transactions with USB 2.0 Device Peripheral

37.6.2.1 Setup Transaction

Setup is a special type of host-to-device transaction us ed during control transfers. Control transfers must be

performed using endpoints with no ping-pong attributes. A setup transaction needs to be handled as soon as

possible by the fir mware. It is used to transmit request s from the host to the device. Th ese requests are then

handled by the USB device and m ay require more arguments. The arguments are sent to the device by a Data

OUT transaction which follows the setup transaction. These requests may also return data. The data is carried out

to the host by the next Data IN transaction which follows the setup transaction. A status transaction ends the

control transfer.

When a setup transfer is received by the USB endpoint:

The USB device automatically acknowledges the setup packet

RXSETUP is set in the corresponding Endpoint Control and Status Register x (UDP_CSRx)

An endpoint interrupt is generated while the RXSETUP is not cleared. This interrupt is carried out to the

microcontr olle r if inte rr up ts are enab le d for this endpoint.

Thus, firmware must detect the RXSETUP polling the UDP_CSRx or catching an interrupt, read the setup packet

in the FIFO, then clear the RXSETUP. RXSETUP cannot be cleared before the setup packet has been read in the

FIFO. Otherwise, the USB device would accept the next Data OUT transfer and overwrite the setup packet in the

FIFO.

Figure 37-5. Setup Transaction Followed by a Data OUT Transaction

37.6.2.2 Data IN Transaction

Data IN transactions are used in control, isochronous, bulk and interrupt transfers and conduct the transfer of data

from the device to the host. Data IN transactions in isochronous transfer must be done u sing en dpoint s with pin g-

pong attributes.

Using Endpoints Without Ping-pong Attributes

To perform a Data IN transaction using a non ping-pong endpoint:

1. The application checks if it is possible to write in the FIFO by polling TXPKTRDY in the endpoint’s

UDP_CSRx (TXPKTRDY must be cleared).

2. The application writes the first packet of data to be sent in the endpoint’s FIFO, writing zero or more byte

values in the endpoint’s FIFO Data Register x (UDP_FDRx).

RX_Data_BKO

(UDP_CSRx)

ACK

PID

Data OUT

PID

NAK

PID

ACK

PID

Data SetupSetup PID

USB

Bus Packets

RXSETUP Flag

Set by USB Device Cleared by Firmware Set by USB

Device Peripheral

FIFO (DPR)

Content Data Setup Data

XX XX OUT

Interrupt Pending

Setup Received Setup Handled by Firmware Data Out Received

Data OUT

PID

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3. The application notifies the USB peripheral it has finished by setting the TXPKTRDY in the endpoint’s

UDP_CSRx.

4. The application is notified that the end point ’ s FIFO has been r eleased by the USB device when TXCOMP in

the endpoint’s UDP_CSRx has been set. Then an interrupt for the corresponding endpoint is pending while

TXCOMP is set.

5. The microcontroller writes the second packet of data to be sent in the endpoint’s FIFO, writing zero or more

byte values in the endpoint’s UDP_FDRx.

6. The microcontroller notifies the USB peripheral it has finished by setting the TXPKTRDY in the endpoint’s

UDP_CSRx.

7. The application clears the TXCOMP in the endpoint’s UDP_CSRx.

After the last packet has been sent, the application must clear TXCOMP once this has been set.

TXCOMP is set by the USB device when it has received an ACK PID signal for the Data IN packet. An interrupt is

pending while TXCOMP is set.

Warning: TX_COMP must be cleared after TX_PKTRDY has been set.

Note: Refer to Chapter 8 of the Universal Serial Bus Specification, Rev 2.0, for more information on the Data IN protocol

layer.

Figure 37-6. Data IN Transfer for Non Ping-pong Endpoint

Using Endpoints With Ping-pong Attribute

The use of an endpoint with ping-pong attributes is necessary during isochronous transfer. This also allows

handling the maximum bandwidth defined in the USB specification during bulk transfer. To be able to guarantee a

constant or the maximum bandwidth, the microcontroller must prepare the next data payload to be sent while the

current one is being sent by the USB device. Thus two banks of memory are used. While one is available for the

microcontroller, the other one is locked by the USB device.

USB Bus Packets Data IN 2

Data IN NAK

ACK

Data IN 1

FIFO (DPR)

Content Data IN 2Load In ProgressData IN 1

Cleared by Firmware

DPR access by the firmware

Payload in FIFO

TXCOMP Flag

(UDP_CSRx)

TXPKTRDY Flag

(UDP_CSRx)

PID

Data IN Data IN

PIDPID PIDPID ACK

PID

Prevous Data IN TX Microcontroller Load Data in FIFO Data is Sent on USB Bus

Interrupt

Pending

Interrupt Pending

Set by the firmware Set by the firmware

Cleared by

Firmware

Cleared by HW

DPR access by the hardware

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Figure 37-7. Bank Swapping Data IN Transfer for Ping-pong Endpoints

When using a ping-pong endpoint, the following procedures are required to perform Data IN transactions:

1. The microcontroller checks if it is possible to write in the FIFO by polling TXPKTRDY to be cleared in the

endpoint’s UDP_CSRx.

2. The microcontroller writes the first data payload to be sent in the FIFO (Bank 0), writing zero or more byte

values in the endpoint’s UDP_FDRx.

3. The microcontroller notifies the USB peripheral it has finished writing in Bank 0 of the FIFO by setting the

TXPKTRDY in the endpoint’s UDP_CSRx.

4. Without waiting for TXPKTRDY to be cleared, the microcontroller writes the second data payload to be sent

in the FIFO (Bank 1), writing zero or more byte values in the endpoint’s UDP_FDRx.

5. The microcontroller is notified that the first Bank has been rele ased by the USB device when TXCOMP in the

endpoint’s UDP_CSRx is set. An interrupt is pending while TXCOMP is being set.

6. Once the microcontroller has received TXCOMP for the first Bank, it notifies the USB device that it has

prepared the second Bank to be sent, raising TXPKTRDY in the endpoint’s UDP_CSRx.

7. At this step, Bank 0 is available and the microcontroller can prepare a third data payload to be sent.

USB Device USB Bus

Read

Write

1st Data Payload

2nd Data Payload

3rd Data Payload

2nd Data Payload

1st Data Payload

Data IN Packet

Microcontroller

Endpoint 1

Bank 0

Endpoint 1

Bank 1

Endpoint 1

Bank 0

Endpoint 1

Bank 0

Endpoint 1

Bank 0

Endpoint 1

Bank 1

Simultaneous

Write and Read

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Figure 37-8. Data IN Transfer for Ping-pong Endpoint

Warning: There is software critical path due to the fact that once the second bank is filled, the driver has to wait for

TX_COMP to set TX_PKTRDY. If the delay between receiving TX_COMP is set and TX_PKTRDY is set too long,

some Data IN packets may be NACKed, reducing the bandwidth.

Warning: TX_COMP must be cleared after TX_PKTRDY has been set.

37.6.2.3 Data OUT Transaction

Data OUT transactions are used in control, isochronous, bulk and interrupt transfers and conduct the transfer of

data from the host to the device. Data OUT transa ctions in isochronous transf ers must be done using en dpoints

with ping-pong attributes.

Data OUT Transaction Without Ping-pong Attributes

To perform a Data OUT transaction, using a non ping-pong endpoint:

1. The host ge n er ates a Data OUT packet.

2. This packet is received by the USB device endpoint. While the FIFO associated to this endpoint is being

used by the microcontroller, a NAK PID is returned to the host. Once the FIFO is available, data are written

to the FIFO by the USB device and an ACK is automatically carried out to the host.

3. The microcontroller is notified that the USB device has received a dat a payload polling RX_DA TA_BK0 in the

endpoint’s UDP_CSRx. An interrupt is pending for this endpoint while RX_DATA_BK0 is set.

4. The number of bytes available in the FIFO is made available by reading RXBYTECNT in the endpoint’s

UDP_CSRx.

5. The microcontroller carries out data received from the endpoint’s memory to its memory. Data received is

available by reading the endpoint’s UDP_FDRx.

6. The microcontroller notifies the USB devi ce that it has finished the tr ansfer by cleari ng RX_DATA_BK0 in the

endpoint’s UDP_CSRx.

7. A new Data OUT packet can be accepted by the USB device.

Data INData IN

Read by USB Device

FIFO (DPR)

Bank 0

TXCOMP Flag

(UDP_CSRx) Interrupt Cleared by Firmware

Set by USB

Device

TXPKTRDY Flag

(UDP_MCSRx)

ACK

PID Data IN

PID ACK

PID

Set by Firmware,

Data Payload Written in FIFO Bank 1

Cleared by USB Device,

Data Payload Fully Transmitted

Data IN

PID

USB Bus

Packets

Set by USB Device

Set by Firmware,

Data Payload Written in FIFO Bank 0

Written by MCU

FIFO (DPR)

Bank 1

Written by MCU Written by MCU

Microcontroller

Load Data IN Bank 0 Microcontroller Load Data IN Bank 1

USB Device Send Bank 0 Microcontroller Load Data IN Bank 0

USB Device Send Bank 1

Interrupt Pending

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Figure 37-9. Data OUT Transfer for Non Ping-pong Endp oints

An interrupt is pending while the flag RX_DATA_BK0 is set. Memory transfer between the USB device, the FIFO

and microcontroller memory is not possible after RX_DATA_BK0 has been cleared. Otherwise, the USB device

would accep t th e ne xt Data OU T tran sfer and overwrite the current Data OUT packet in the FIFO .

Using Endpoints With Ping-pong Attributes

During isochronous transfer, using an endpoint with p ing-pong attributes is obligatory. To be able to guarantee a

constant bandwidth, the microcontroller must read the previous data payload sent by the host, while the current

data payload is received by the USB device. Thus two banks of memory are used. Wh ile one is available for the

microcontroller, the other one is locked by the USB device.

Figure 37-10. Bank Swap pin g in Data OUT Transfers for Ping-pong Endpoints

When using a ping-pong endpoint, the following procedures are required to perform Data OUT transactions:

1. The host ge n er ates a Data OUT packet.

2. This packet is received by the USB device endpoint. It is written in the endpoint’s FIFO Bank 0.

3. The USB device sends an ACK PID packet to the host. The ho st can imm edia tel y send a se co nd Da ta OUT

packet. It is accepted by the device and copied to FIFO Bank 1.

4. The microcontroller is notified that the USB device has received a data p ayload, polling RX_DATA_BK0 in

the endpoint’s UDP_CSRx. An interrupt is pending for this endpoint while RX_DATA_BK0 is set.

ACK

PID

Data OUTNAK PIDPIDPIDPIDPID Data OUT2ACKData OUT Data OUT 1

USB Bus

Packets

RX_DATA_BK0

Set by USB Device Cleared by Firmware,

Data Payload Written in FIFO

FIFO (DPR)

Content Written by USB Device Microcontroller Read

Data OUT 1 Data OUT 1 Data OUT 2

Host Resends the Next Data Payload

Microcontroller Transfers Data

Host Sends Data Payload

Data OUT2 Data OUT2

Host Sends the Next Data Payload

Written by USB Device

(UDP_CSRx) Interrupt Pending

USB Device USB Bus

Read

Write

Simultaneous

Write and Read

1st Data Payload

2nd Data Payload

3rd Data Payload

2nd Data Payload

1st Data Payload

Data IN Packet

Microcontroller

Endpoint 1

Bank 0

Endpoint 1

Bank 1

Endpoint 1

Bank 0

Endpoint 1

Bank 0

Endpoint 1

Bank 0

Endpoint 1

Bank 1

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5. The number of bytes available in the FIFO is made available by reading RXBYTECNT in the endpoint’s

UDP_CSRx.

6. The microcontroller transfers out data received from the end point’ s memory to the microcontroller’s memory.

Data received is made available by reading the endpoint’s UDP_FDRx.

7. The microcontroller notifies the USB peripheral device that it has finished the transfer by clearing

RX_DATA_BK0 in the endpoint’s UDP_CSRx.

8. A third Data OUT packet can be accepted by the USB peripheral device and copied in the FIFO Bank 0.

9. If a second Data OUT packet has been received, the microcontroller is notified by the flag RX_DATA_BK1

set in the endpoint’s UDP_CSRx. An interrupt is pending for this endpoint while RX_DATA_BK1 is set.

10. The microcontroller transfers out data received from the endpoint’ s memory to the microcontr oller’s memory.

Data received is available by reading the endpoint’s UDP_FDRx.

11. The microcontroller notifies the USB device it has finished the transfer by clearing RX_DATA_BK1 in the

endpoint’s UDP_CSRx.

12. A fourth Data OUT packet can be accepted by the USB device and copied in the FIFO Bank 1.

Figure 37-11. Data OUT Tr ansfer for Ping-pong Endpoint

Note: An interrupt is pending whil e the RX_DATA_BK0 or RX_DATA_BK1 flag is set.

Warning: When RX_DATA_BK0 and RX_DATA_BK1 are both set, there is no way to determine which one to

clear first. Thus the software must keep an internal counter to be sure to clear alternatively RX_DATA_BK0 then

RX_DATA_BK1. This situation may occur when the software application is busy elsewhere and the two banks are

filled by the USB host. Once the application comes back to the USB driver, the two flags are set.

37.6.2.4 Stall Handshake

A stall handshake can be used in one of two distinct occasions. (For more information on the stall handshake, refer

to Chapter 8 of the Universal Serial Bus Specification, Rev 2.0.)

A functional stall is used when the halt feature associated with the endpoint is set. (Refer to Chapter 9 of the

Universal Serial Bus Specification, Rev 2.0, for more information on the halt feature.)

To abort the current request, a protocol stall is used, but uniquely with control transfer.

Data OUT PID

ACK Data OUT 3

Data OUT

Data OUT 2

Data OUT

Data OUT 1

PID

Data OUT 3Data OUT 1Data OUT1

Data OUT 2 Data OUT 2

PID PID PID

ACK

Cleared by Firmware

USB Bus

Packets

RX_DATA_BK0 Flag

RX_DATA_BK1 Flag

Set by USB Device,

Data Payload Written

in FIFO Endpoint Bank 1

FIFO (DPR)

Bank 0

Bank 1

Write by USB Device Write In Progress

Read By Microcontroller

Set by USB Device,

Data Payload Written

in FIFO Endpoint Bank 0

Host Sends First Data Payload Microcontroller Reads Data1 in Bank 0,

Host Sends Second Data Payload Microcontroller Reads Data2 in Bank 1,

Host Sends Third Data Payload

Cleared by Firmware

Write by USB Device

FIFO (DPR)

(UDP_CSRx)

Interrupt Pending

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The following procedure generates a stall packet:

1. The microcontroller sets the FORCESTALL flag in the UDP_CSRx endpoint’s register.

2. The host receives the stall packet.

3. The microcontroller is notified that the device has sent the stall by polling the STALLSENT to be set. An

endpoint interrupt is pending while STALLSENT is set. The microcontroller must clear STALLSENT to clear

the interrupt.

When a setup transaction is received after a stall handshake, STALLSENT must be clea red in order to prevent

interrupts due to STALLSENT being set.

Figure 37-12. Sta ll Han dsh ake (Data IN Transfer)

Figure 37-13. Sta ll Han dsh ake (Data OUT Transfer)

Data IN Stall PIDPID

USB Bus

Packets

Cleared by Firmware

Set by Firmware

FORCESTALL

STALLSENT Set by

USB Device

Cleared by Firmware

Interrupt Pending

Data OUT PID Stall PID

Data OUT

USB Bus

Packets

Cleared by Firmware

Set by Firmware

FORCESTALL

STALLSENT

Set by USB Device

Interrupt Pending

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37.6.2.5 Transmit Data Cancellation

Some endpoints have dual-banks whereas some endpoints have only one bank. The procedure to cancel

transmission data held in these banks is described below.

To see the organization of dual-bank availability refer to Table 37-1 ”USB Endpoint Description”.

Endpoints Without Dual-Banks

The cancellation procedure depends on the TXPKTRDY flag value in the UDP_CSR:

TXPKTRDY is not set:

Reset the endpoint to clear the FIFO (pointers). (See Section 37.7.9 ”UDP Reset Endpoint Register”.)

TXPKTRDY has already been set:

Clear TXPK TR DY s o that no packet is read y to be sen t

Reset the endpoint to clear the FIFO (pointers). (See Section 37.7.9 ”UDP Reset Endpoint Register”.)

Endpoints With Dual-Banks

The cancellation procedure depends on the TXPKTRDY flag value in the UDP_CSR:

TXPKTRDY is not set:

Reset the endpoint to clear the FIFO (pointers). (See Section 37.7.9 ”UDP Reset Endpoint Register”.)

TXPKTRDY has already been set:

Clear TXPKTRDY and read it back until actually read at 0.

Set TXPKTRDY and read it back until actually read at 1.

Clear TXPK TR DY s o that no packet is read y to be sen t.

Reset the endpoint to clear the FIFO (pointers). (See Section 37.7.9 ”UDP Reset Endpoint Register”.)

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37.6.3 Controlling Device States

A USB device has several possible states. Refer to Chapter 9 of the Universal Serial Bus Specification, Rev 2.0.

Figure 37-14. USB Device State Diagram

Movement from one state to another depends on the USB bus state or on standard requests sent through control

transactions via the default endpoint (endpoint 0).

After a period of bus inactivity, the USB device enters Suspend Mode. Accepting Suspend/Resume requests from

the USB host is mandato ry. Constraints in Suspend Mode are very strict for bus-powered applications; devices

must not consume more than 2.5 mA on the USB bus.

While in Suspend Mode, the host may wake up a device by sending a resume signal (bus activity) or a USB device

may send a wakeup request to the host, e.g., waking up a PC by moving a USB mouse.

The wakeup feature is not mandatory for all devices and must be negotiated with the host.

37.6.3.1 Not Powered State

Self powered devices can detect 5V VBUS using a PIO as described in the typical connection section. When the

device is not connected to a host, device power consumption can be reduced by disabling MCK for the UDP,

disabling UDPCK and disabling the transceiver . DDP and DDM lines are pulled down by 330 KΩ resistors.

Attached

Suspended

Hub Reset

Deconfigured

Hub

Configured

Bus Inactive

Bus Activity

Bus Inactive

Bus Activity

Bus Inactive

Bus Activity

Bus Inactive

Bus Activity

Reset

Address

Assigned

Device

Deconfigured Device

Configured

Powered

Default

Address

Configured

Power

Interruption

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37.6.3.2 Entering Attached State

To enable integrated pull-up, the PUON bit in the UDP_TXVC register must be set.

Warning: To write to the UDP_TXVC register, MCK cloc k must be enabled on the UDP. This is done in the PMC.

After pull-up connectio n, th e device enter s the po were d st ate. In this state, the UDPCK and MCK must be enabled

in the PMC. The transceiver can remain disabled.

37.6.3.3 From Powered State to Default State

After its connection to a USB host, the USB device waits for an end-of-bus reset. The unmaskable flag

ENDBUSRES is set in the Interrupt Status Register (UDP_ISR) and an interrupt is triggered.

Once the ENDBUSRES interrupt has been triggered, the device enters Default State. In this state, the UDP

software must:

Enable the default endpoint, setting the EPEDS flag in the UDP_CSR0 and, optionally, enabling the interrupt

for endpoint 0 by writing 1 to the Interrupt Enable Register (UDP_IER). The enumeration then begins by a

control transfer.

Configure the Interrupt Mask Register (UDP_IMR) which has been reset by the USB reset detection

Enable the transceiver clearing the TXVDIS flag in the UDP_TXVC register.

In this state UDPCK and MCK must be enabled.

Warning: Each time an ENDBUSRES interrupt is triggered, the UDP_IMR and UDP_CSRs have been reset.

37.6.3.4 From Default State to Address State

After a set address standard device request, the USB host peripheral enters the address state.

Warning: Before the device enters in address state, it must achieve the Status IN transaction of the control

transfer, i.e., the UDP device sets its new address once the TXCOMP flag in the UDP_CSR0 has been received

and cleared.

To move to address state, the driver software sets the FADDEN flag in the Global State Register

(UDP_GLB_STAT), sets its new address, and sets the FEN bit in the Function Address Re gister (UDP_FADDR).

37.6.3.5 From Address State to Configured State

Once a valid Set Configuration standard request has been received and acknowledged, the device enables

endpoints corresponding to the current configuration. This is done by setting the EPEDS and EPTYPE fields in the

UDP_CSRx and, optionally, enabling corresponding interrupts in the UDP_IER.

37.6.3.6 Entering in Suspend State

When a Suspend (no bus activity on the USB bus) is detected, the RXSUSP signal in the UDP_ISR is set. This

triggers an interrupt if the corresponding bit is set in the UDP_IMR. This flag is cleared by writing to the Interrupt

Clear Register (UDP_ICR) and the device then enters Suspend mode.

In this state bus powered devices must drain no more than 2.5 mA from the 5V VBUS. As an example, the

microcontroller switches to slow clock, disables the PLL and main oscillator, and goes into Idle mode. It may also

switch off other devices on the board.

The USB device peripheral clocks can be switched off. Resume event is asynchronously detected. MCK and

UDPCK can be switched off in the PMC and the USB transceiver can be disabled by setting the TXVDIS bit in the

UDP_TXVC register.

Warning: Read, write operations to the UDP registers are allowed only if MCK is enabled for the UDP peripheral.

Switching off MCK for the UDP peripheral m ust be one of the last operations after writing to the UDP_TXVC

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37.6.3.7 Receiving a Host Resume

In suspend mode, a resume event on the USB bus lin e is detected asynchronously, transceiver and clocks are

disabled (however the pull-up shall not be removed).

Once the resume is detected on the bus, the WAKEUP signal in the UDP_ISR is set. It may generate an interrupt

if the corresponding bit in the UDP_IMR is set. T his interrupt may be used to wake up the core , enable PLL and

main oscillators and configure clocks.

Warning: Read, write operations to the UDP registers are allowed only if MCK is enabled for the UDP peripheral.

MCK for the UDP must be enabled before clearing the WAKEUP bit in the UDP_ICR and clearing TXVDIS in the

UDP_TXVC register.

37.6.3.8 Sending a Device Remote Wakeup Request

In Suspend state it is possible to wake up the host sending an external resume.

The device must wait at least 5 ms after being entered in suspend before sending an external resume.

The device has 10 ms from the moment it starts to drain current and it forces a K state to resume the host.

The device must force a K state from 1 to 15 ms to resume the host

Before sending a K state to the host, MCK, UDPCK and the transceiver must be enabled. The n to enable the

remote wakeup feature, the RMWUPE bit in the UDP_GLB_STAT register must be enabled. To force the K state

on the line, a transition of the ESR bit from 0 to 1 has to be done in the UDP_GLB_STAT register by first writing a

0 in the ESR bit and then writing a 1.

The K state is automatically generated and released accordin g to the USB 2.0 spe cification.

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37.7 USB Device Port (UDP) User Interface

WARNING: The UDP pe ripheral clock in the PMC must be enabled before a ny read/write operation s to the UDP registers,

including the UDP_TXVC register.

Notes: 1. Reset values are not defined for UDP_ISR or UDP_FDRx. UDP_FDRs reflect Dual Port RAM me mory locations which are

not affected by any reset signals.

2. See Warning above Table 37-6 ”Register Mapping”.

Table 37-6. Register Mapping

Offset Register Name Access Reset

0x000 Frame Number Register UDP_FRM_NUM Read-only 0x0000_0000

0x004 Global State Register UDP_GLB_STAT Read/Write 0x0000_0010

0x008 Function Address Register UDP_FADDR Read/Write 0x0000_0100

0x00C Reserved – – –

0x010 Interrupt Enable Register UDP_IER Write-only

0x014 Interrupt Disable Register UDP_IDR Write-only

0x018 Interrupt Mask Register UDP_IMR Read-only 0x0000_1200

0x01C Interrupt Status Register UDP_ISR Read-only –(1)

0x020 Interrupt Clear Register UDP_ICR Write-only

0x024 Reserved – – –

0x028 Reset Endpoint Register UDP_RST_EP Read/Write 0x0000_0000

0x02C Reserved – – –

0x030 Endpoint Control and Status Register 0 UDP_CSR0 Read/Write 0x0000_0000

... ... ... ... ...

0x030 + 0x4 * 5 Endpoint Control and Status Register 5 UDP_CSR5 Read/Write 0x0000_0000

0x050 Endpoint FIFO Data Register 0 UDP_FDR0 Read/Write –(1)

... ... ... ... ...

0x050 + 0x4 * 5 Endpoint FIFO Data Register 5 UDP_FDR5 Read/Write –(1)

0x070 Reserved – – –

0x074 Transceiver Control Register UDP_TXVC(2) Read/Write 0x0000_0100

0x078–0x0FC Reserved – – –

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37.7.1 UDP Frame Number Register

Name: UDP_FRM_NUM

Address: 0x40044000

Access: Read-only

• FRM_NUM: Frame Number as Defined in the Packet Field Formats

This 11-bit value is incremented by the host on a per frame basis. This value is updated at each start of frame.

Value updated at the SOF_EOP (Start of Frame End of Packet).

• FRM_ERR: Frame Error

This bit is set at SOF_EOP when the SOF packet is received containing an error.

This bit is reset upon receipt of SOF_PID.

• FRM_OK: Frame OK

This bit is set at SOF_EOP when the SOF packet is received without any error.

This bit is reset upon receipt of SOF_PID (Packet Identification).

In the Interrupt Status Register, the SOF interrupt is updated upon receiving SOF_PID. This bit is set without waiting for

EOP.

Note: In the 8-bit Register Interface, FRM_OK is bit 4 of FRM_NUM_H and FRM_ERR is bit 3 of FRM_NUM_L.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––FRM_OKFRM_ERR

15 14 13 12 11 10 9 8

––––– FRM_NUM

76543210

FRM_NUM

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37.7.2 UDP Global State Register

Name: UDP_GLB_STAT

Address: 0x40044004

Access: Read/Write

This register is used to get and set the device state as specified in Cha pter 9 of the USB Serial Bus Specification, Rev.2.0.

• FADDEN: Function Address Enable

Read:

0: Device is not in address state

1: Device is in address state

Write:

0: No effect, only a reset can bring back a device to th e de fa ult state .

1: Sets device in address state. This occurs after a successful Set Address request. Beforehand, the UDP_FADDR must

have been initialized with Set Address parameters. Set Address must complete the Status Stage before setting FADDEN.

Refer to chapter 9 of the Universal Serial Bus Specification, Rev. 2.0 for more details.

• CONFG: Configured

Read:

0: Device is not in configured state

1: Device is in configured state

Write:

0: Sets device in a non configured state

1: Sets device in configured state

The device is set in configured state when it is in address state and receives a successful Se t Configuration r equest. Refer

to Chapter 9 of the Universal Serial Bus Specification, Rev. 2.0 for more details.

• ESR: Enable Send Resume

0: Mandatory value prior to starting any Remote Wakeup procedure

1: Starts the Remote Wakeup procedure if this bit value was 0 and if RMWUPE is enabled

• RMWUPE: Remote Wa keup Enable

0: The Remote Wakeup feature of the device is disabled.

1: The Remote Wakeup feature of the device is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – – RMWUPE RSMINPR ESR CONFG FADDEN

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37.7.3 UDP Function Address Register

Name: UDP_FADDR

Address: 0x40044008

Access: Read/Write

• FADD: Function Address Value

The Function Address Value must be programmed by firmware once the device receives a set address request from the

host, and has achieved the status stage of the no-data control seque nce. Refer to the Universal Serial Bus Specification,

Rev. 2.0 for more information. After power up or reset, the function address value is set to 0.

• FEN: Function Enable

Read:

0: Function endpoint disabled

1: Function endpoint enabled

Write:

0: Disables function endpoint

1: Default value

The Function Ena b le bit (F EN) allow s the micr oc on tr olle r to e nable or disable the function endpoints. The microcontroller

sets this bit after receipt of a reset from the host. Once this bit is set, the USB device is able to accept and transfer data

packets from and to the host.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

–––––––FEN

76543210

–FADD

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37.7.4 UDP Interrupt Enable Register

Name: UDP_IER

Address: 0x40044010

Access: Write-only

• EP0INT: Enable Endpoint 0 Interrupt

• EP1INT: Enable Endpoint 1 Interrupt

• EP2INT: Enable Endpoint 2Interrupt

• EP3INT: Enable Endpoint 3 Interrupt

• EP4INT: Enable Endpoint 4 Interrupt

• EP5INT: Enable Endpoint 5 Interrupt

0: No effect

1: Enables corresponding Endpoint Interrupt

• RXSUSP: Enable UDP Suspend Interrupt

0: No effect

1: Enables UDP Suspend Interrupt

• RXRSM: Enable UDP Resume Interrupt

0: No effect

1: Enables UDP Resume Interrupt

• SOFINT: Enable St art Of Frame Interrupt

0: No effect

1: Enables Start Of Frame Interrupt

• WAKEUP: Enable UDP Bus Wakeup Interrupt

0: No effect

1: Enables USB bus Interrupt

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

– – WAKEUP – SOFINT EXTRSM RXRSM RXSUSP

76543210

EP5INT EP4INT EP3INT EP2INT EP1INT EP0INT

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37.7.5 UDP Interrupt Disable Register

Name: UDP_IDR

Address: 0x40044014

Access: Write-only

• EP0INT: Disable Endpoint 0 Interrupt

• EP1INT: Disable Endpoint 1 Interrupt

• EP2INT: Disable Endpoint 2 Interrupt

• EP3INT: Disable Endpoint 3 Interrupt

• EP4INT: Disable Endpoint 4 Interrupt

• EP5INT: Disable Endpoint 5 Interrupt

0: No effect

1: Disables corresponding Endpoint Interrupt

• RXSUSP: Disable UDP Suspend Interrupt

0: No effect

1: Disables UDP Suspend Interrupt

• RXRSM: Disable UDP Resume Interrupt

0: No effect

1: Disables UDP Resume Interrupt

• SOFINT: Disable Start Of Frame Interrupt

0: No effect

1: Disables Start Of Frame Interrupt

• WAKEUP: Disable USB Bus Interrupt

0: No effect

1: Disables USB Bus Wakeup Interrupt

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

– – WAKEUP – SOFINT EXTRSM RXRSM RXSUSP

76543210

EP5INT EP4INT EP3INT EP2INT EP1INT EP0INT

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37.7.6 UDP Interrupt Mask Register

Name: UDP_IMR

Address: 0x40044018

Access: Read-only

• EP0INT: Mask Endpoint 0 Interrupt

• EP1INT: Mask Endpoint 1 Interrupt

• EP2INT: Mask Endpoint 2 Interrupt

• EP3INT: Mask Endpoint 3 Interrupt

• EP4INT: Mask Endpoint 4 Interrupt

• EP5INT: Mask Endpoint 5 Interrupt

0: Corresponding Endpoint Interrupt is disabled

1: Corresponding Endpoint Interrupt is enabled

• RXSUSP: Mask UDP Suspend Interrupt

0: UDP Suspend Interrupt is disabled

1: UDP Suspend Interrupt is enabled

• RXRSM: Mask UDP Resume Interrupt.

0: UDP Resume Interrupt is disabled

1: UDP Resume Interrupt is enabled

• SOFINT: Mask Start Of Frame Interrupt

0: Start of Frame Interrupt is disabled

1: Start of Frame Interrupt is enabled

• BIT12: UDP_IMR Bit 12

Bit 12 of UDP_IMR cannot be masked and is always read at 1.

• WAKEUP: USB Bus Wakeup Interrupt

0: USB Bus Wakeup Interrupt is disabled

1: USB Bus Wakeup Interrupt is enabled

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

– – WAKEUP BIT12 SOFINT EXTRSM RXRSM RXSUSP

76543210

EP5INT EP4INT EP3INT EP2INT EP1INT EP0INT

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Note: When the USB block is in suspend mode, the application may power down the USB logic. In this case, any USB HOST resume

request that is made must be taken into account and, thus, the reset value of the RXRSM bit of the register UDP_IMR is enabled.

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37.7.7 UDP Interrupt Status Register

Name: UDP_ISR

Address: 0x4004401C

Access: Read-only

• EP0INT: Endpoint 0 Interrupt Status

• EP1INT: Endpoint 1 Interrupt Status

• EP2INT: Endpoint 2 Interrupt Status

• EP3INT: Endpoint 3 Interrupt Status

• EP4INT: Endpoint 4 Interrupt Status

• EP5INT: Endpoint 5 Interrupt Status

0: No Endpointx Interrupt pending

1: Endpointx Interrupt has been raised

Several signals can generate this interrupt. The reason can be found by re ading UDP_CSR0:

RXSETUP set to 1

RX_DATA_BK0 set to 1

RX_DATA_BK1 set to 1

TXCOMP set to 1

STALLSENT set to 1

EP0INT is a sticky bit. Interrupt remains valid until EP0INT is cleared by writing in the corresponding UDP_CSR0 bit.

• RXSUSP: UDP Suspend Interrupt Status

0: No UDP Suspend Interrupt pending

1: UDP Suspend Interrupt has been raised

The USB device sets this bit when it detects no activity for 3 ms . The USB device enters Suspend mode.

• RXRSM: UDP Resume Interrupt Status

0: No UDP Resume Interrupt pending

1: UDP Resume Interrupt has been raised

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

– – WAKEUP ENDBUSRES SOFINT EXTRSM RXRSM RXSUSP

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EP5INT EP4INT EP3INT EP2INT EP1INT EP0INT

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The USB device sets this bit when a UDP resume signal is detected at its port.

After reset, the state of this bit is undefined, the application must clear this bit by setting the RXRSM flag in the UDP_ICR.

• SOFINT: Start of Frame Interrupt Status

0: No Start of Frame Interrupt pending

1: Start of Frame Interrupt has been raised

This interrupt is raised each time a SOF token has been detected. It can be used as a synchronization signal by using iso-

chronous endpoints.

• ENDBUSRES: End of BUS Reset Interrupt Status

0: No End of Bus Reset Interrupt pending

1: End of Bus Reset Interrupt has be en rais ed

This interrupt is raised at the end of a UDP reset sequence. The USB device must prepare to receive requ ests on the end-

point 0. The host starts the enumeration, then performs the configura tion.

• WAKEUP: UDP Resume Interrupt Status

0: No Wakeup Interrupt pending

1: A Wakeup Interrupt (USB Host Sent a RESUME or RESET) occurred since the last clear.

After reset the state of this bit is undefined; the application must clear this bit by setting the WAKEUP flag in the UDP_ICR.

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37.7.8 UDP Interrupt Clear Register

Name: UDP_ICR

Address: 0x40044020

Access: Write-only

• RXSUSP: Clear UDP Suspend Interrupt

0: No effect

1: Clears UDP Suspend Interrupt

• RXRSM: Clear UDP Resume Interrupt

0: No effect

1: Clears UDP Resume Interrupt

• SOFINT: Clear Start Of Frame Interrupt

0: No effect

1: Clears Start Of Frame Interrupt

• ENDBUSRES: Clear End of Bus Reset Interrupt

0: No effect

1: Clears End of Bus Reset Interrupt

• WAKEUP: Clear Wakeup Interrupt

0: No effect

1: Clears Wakeup Interrupt

31 30 29 28 27 26 25 24

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23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

– – WAKEUP ENDBUSRES SOFINT EXTRSM RXRSM RXSUSP

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37.7.9 UDP Reset Endpoint Register

Name: UDP_RST_EP

Address: 0x40044028

Access: Read/Write

• EP0: Reset Endpoint 0

• EP1: Reset Endpoint 1

• EP2: Reset Endpoint 2

• EP3: Reset Endpoint 3

• EP4: Reset Endpoint 4

• EP5: Reset Endpoint 5

This flag is used to reset the FIFO associated with the endpoint and the bit RXBYTECOUNT in the UDP_CSRx. It also

resets the data toggle to DATA0. It is useful after removing a HALT condition on a BULK endpoint. Refer to Chapter 5.8.5

in the USB Serial Bus Specification, Rev.2.0.

Warning: This flag must be cleared at the end of the reset. It does not clear UDP_CSRx flags.

0: No reset

1: Forces the corresponding endpoint FIF0 pointers to 0, therefore RXBYTECNT field is read at 0 in UDP_CSRx

Resetting the endpoint is a two-step operation:

1. Set the corresponding EPx field.

2. Clear the corr esponding EPx field.

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23 22 21 20 19 18 17 16

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15 14 13 12 11 10 9 8

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EP5 EP4 EP3 EP2 EP1 EP0

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37.7.10 UDP Endpoint Control and Status Register (CONTROL_BULK)

Name: UDP_CSRx [x = 0..5] (CONTROL_BU LK)

Address: 0x40044030

Access: Read/Write

WARNING: Due to synchronization between MCK and UDPCK, the software application must wa it fo r the end of the write

operation before executing another write by polling the bits which must be set/cleared.

As an example, to perform a control operation on the endpoint without modifying the status flags while accessing the con-

trol bits and fields of this register, the status flag bits must first be defined with the “No effect” value ‘1’. Once the overall

UDP_CSR value is defined, the register can be written and then the synchronization wait procedure must be execu ted.

//! Bitmap for all status bits in CSR that are not affected by a value 1.

#define UDP_REG_NO_EFFECT_1_ALL (UDP_CSR_RX_DATA_BK0 |\

UDP_CSR_RX_DATA_BK1 |\

UDP_CSR_STALLSENT |\

UDP_CSR_RXSETUP |\

UDP_CSR_TXCOMP)

/*! Sets specified bit(s) in the UDP_CSR.

* \param ep Endpoint number.

* \param bits Bitmap to set to 1.

#define udp_set_csr(ep, bits) \

do { \

volatile uint32_t reg; \

volatile uint32_t nop_count; \

reg = UDP->UDP_CSR[ep]; \

reg |= UDP_REG_NO_EFFECT_1_ALL; \

reg |= (bits); \

UDP->UDP_CSR[ep] = reg; \

for (nop_count = 0; nop_count < 20; nop_count ++) {\

__NOP(); \

} \

} while (0)

31 30 29 28 27 26 25 24

––––– RXBYTECNT

23 22 21 20 19 18 17 16

RXBYTECNT

15 14 13 12 11 10 9 8

EPEDS – – – DTGLE EPTYPE

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DIR RX_DATA_BK1 FORCESTALL TXPKTRDY STALLSENT RXSETUP RX_DATA_ BK0 TXCOMP

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/*! Clears specified bit(s) in the UDP_CSR.

* \param ep Endpoint number.

* \param bits Bitmap to set to 0.

#define udp_clear_csr(ep, bits) \

do { \

volatile uint32_t reg; \

volatile uint32_t nop_count; \

reg = UDP->UDP_CSR[ep]; \

reg |= UDP_REG_NO_EFFECT_1_ALL; \

reg &= ~(bits); \

UDP->UDP_CSR[ep] = reg; \

for (nop_count = 0; nop_count < 20; nop_count ++) {\

__NOP(); \

} \

} while (0)

In a preemptive environment, set or clear the flag and wait for a time of 1 UDPCK clock cycle and 1peripheral clock cycle.

However, RX_DATA_BK0, TXPKTRDY, RX_DATA_BK1 require wait times of 3 UDPCK clock cycles and 5 peripheral

clock cycles before accessing DPR.

• TXCOMP: Generates an IN Packet with Data Previously Written in the DPR

This flag generates an interrupt while it is set to one.

Write (cleared by the firmware):

0: Clear the flag, clear the interrupt

1: No effect

Read (Set by the USB peripheral):

0: Data IN transaction has not been acknowledged by the Host

1: Data IN transaction is achieved, acknowledged by the Host

After having issued a Data IN transaction setting TXPKTRDY, the device firmware waits for TXCOMP to be sure that the

host has acknowledged the transaction.

• RX_DATA_BK0: Rece ive Data Bank 0

This flag generates an interrupt while it is set to one.

Write (cleared by the firmware):

0: Notify USB peripheral device that data have be en read in the FIFO’s Bank 0.

1: To leave the read value unchanged.

Read (Set by the USB peripheral):

0: No data packet has been received in the FIFO’s Bank 0.

1: A data packet has been received, it has been stored in the FIFO’s Bank 0.

When the device firmware has polled this bit or has been interrupted by this signal, it must transfer data from the FIFO to

the microcontroller memory. The number of bytes received is available in RXBYTCENT field. Bank 0 FIFO values are read

through the UDP_FDRx. Once a transfer is done, the device firmware must release Bank 0 to the USB peripheral device

by clearing RX_DATA_BK0.

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After setting or clearing this bit, a wait time of 3 UDPCK clock cycles and 3 peripheral clock cycles is required before

accessing DPR.

• RXSETUP: Received Setup

This flag generates an interrupt while it is set to one.

Read:

0: No setup packet available.

1: A setup data packet has been sent by the host and is available in the FIFO.

Write:

0: Device firmware notifies the USB peripheral device that it has read the setup data in the FIFO.

1: No effect.

This flag is used to notify the USB device firmware that a valid Setup data packet has been sent by the host and success-

fully received by the USB de vice . Th e USB de vice firm wa re may tra nsf er Setu p da ta from th e FI FO by re ad ing the

UDP_FDRx to the microcontroller memory. Once a transfer has been done, RXSETUP must be cleared by the device

firmware.

Ensuing Data OUT transaction is not accepted while RXSETUP is set.

• STALLSENT: Stall Sent

This flag generates an interrupt while it is set to one.

This ends a STALL handshake.

Read:

0: Host has not acknowledged a stall

1: Host has acknowledged the stall

Write:

0: Resets the STALLSENT flag, clears the interrupt

1: No effect

This is mandatory for the device firmware to clear this flag. Otherwise the interrupt remains.

Refer to chapters 8.4.5 and 9.4.5 of the Universal Serial Bus Specification, Rev. 2.0 for more information on the STALL

handshake.

• TXPKTRDY: Transmit Packet Ready

This flag is cleared by the USB device.

This flag is set by the USB device firmware.

Read:

0: There is no data to send.

1: The data is waiting to be sent upon reception of token IN.

Write:

0: Can be used in the procedur e to can cel tran sm ission data. ( See Section 37.6.2.5 “Transmit Data Cancellation” on page

973)

1: A new data payload has been written in the FIFO by the firmware and is ready to be sent.

This flag is used to generate a Data IN transaction (device to host). Device firmware checks that it can write a data payload

in the FIFO, checking that TXPKTRDY is cleared. Transfer to the FIFO is done by writing in the UDP_FDRx. Once the data

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payload has been transfe rred to the FIFO, the firmware n otifies the USB device setting TXPKTRDY to one. USB bus trans-

actions can start. TXCOMP is set once the data payload has been received by the host.

After setting or clearing this bit, a wait time of 3 UDPCK clock cycles and 3 peripheral clock cycles is required before

accessing DPR.

• FORCESTALL: Force Stall (used by Control, Bulk and Isochronous Endpoints)

Read:

0: Normal state

1: Stall state

Write:

0: Return to normal state

1: Send STALL to the host

Refer to chapters 8.4.5 and 9.4.5 of the Universal Serial Bus Specification, Rev. 2.0 for more information on the STALL

handshake.

Control endpoints: During the data stage and status stage, this bit indicates that the microcontroller cannot complete the

request.

Bulk and interrupt endpoints: This bit notifies the host that the endpoint is halted.

The host acknowledges the STALL, device firmware is notified by the STALLSENT flag.

• RX_DATA_BK1: Receive Data Bank 1 (only used by endpoints with ping-pong attributes)

This flag generates an interrupt while it is set to one.

Write (cleared by the firmware):

0: Notifies USB device that data have been read in the FIFO’s Bank 1.

1: To leave the read value unchanged.

Read (Set by the USB peripheral):

0: No data packet has been received in the FIFO’s Bank 1.

1: A data packet has been received, it has been stored in FI FO ’s Ban k 1.

When the device firmware has polled this bit or has been interrupted by this signal, it must transfer data from the FIFO to

microcontroller memory. The number of bytes received is available in RXBYTECNT field. Bank 1 FIFO values are read

through UDP_FDRx. Once a transfer is done, the device firmware must release Bank 1 to the USB device by clearing

RX_DATA_BK1.

After setting or clearing this bit, a wait time of 3 UDPCK clock cycles and 3 peripheral clock cycles is required before

accessing DPR.

• DIR: Transfer Direction (only available for control endpoints) (Read/Write)

0: Allows Data OUT transactions in the control data stage.

1: Enables Data IN transactions in the control data stage.

Refer to Chapter 8.5.3 of the Universal Serial Bus Specification, Rev. 2.0 for more information on the control data stage.

This bit must be set before UDP_CSRx/RXSETUP is cleared at the end of the setup stage. According to the request sent

in the setup data packet, the d ata stage is either a device to host (DIR = 1) or host to device (DIR = 0) data transfer. It is not

necessary to check this bit to reverse direction for the status stage.

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• EPTYPE: Endpoint Type (Read/Write)

• DTGLE: Data Toggle (Read-only)

0: Identifies DATA0 packet

1: Identifies DATA1 packet

Refer to Chapter 8 of the Universal Serial Bus Specification, Rev. 2.0 for more information on DATA0, DATA1 packet

definitions.

• EPEDS: Endpoint Enable Disable

Read:

0: Endpoint disabled

1: Endpoint enabled

Write:

0: Disables endpoint

1: Enables endpoint

Control endpoints are always enabled. Reading or writing this field has no effect on control endpoints.

Note: After reset, all endpoints are configured as control endpoints (zero).

• RXBYTECNT: Number of Bytes Availa ble in the FIFO (Read-only)

When the host sends a data packet to the device, the USB device stores the data in the FIFO and notifies the microcon-

troller. The microcontroller can load the data from the FIFO by reading RXBYTECENT bytes in the UDP_FDRx.

Value Name Description

0 CTRL Control

1 ISO_OUT Isochronous OUT

2 BULK_OUT Bulk OUT

3 INT_OUT Interrupt OUT

4– Reserved

5 ISO_IN Isochronous IN

6 BULK_IN Bulk IN

7 INT_IN Interrupt IN

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37.7.11 UDP Endpoint Control and Status Register (ISOCHRONOUS)

Name: UDP_CSRx [x = 0..5] (ISOCHRONOUS)

Address: 0x40044030

Access: Read/Write

• TXCOMP: Generates an IN Packet with Data Previously Written in the DPR

This flag generates an interrupt while it is set to one.

Write (cleared by the firmware):

0: Clear the flag, clear the interrupt.

1: No effect.

Read (Set by the USB peripheral):

0: Data IN transaction has not been acknowledged by the Host.

1: Data IN transaction is achieved, acknowledged by the Host.

After having issued a Data IN transaction setting TXPKTRDY, the device firmware waits for TXCOMP to be sure that the

host has acknowledged the transaction.

• RX_DATA_BK0: Rece ive Data Bank 0

This flag generates an interrupt while it is set to one.

Write (cleared by the firmware):

0: Notify USB peripheral device that data have be en read in the FIFO’s Bank 0.

1: To leave the read value unchanged.

Read (Set by the USB peripheral):

0: No data packet has been received in the FIFO’s Bank 0.

1: A data packet has been received, it has been stored in the FIFO’s Bank 0.

When the device firmware has polled this bit or has been interrupted by this signal, it must transfer data from the FIFO to

the microcontroller memory. The number of bytes received is available in RXBYTCENT field. Bank 0 FIFO values are read

through the UDP_FDRx. Once a transfer is done, the device firmware must release Bank 0 to the USB peripheral device

by clearing RX_DATA_BK0.

After setting or clearing this bit, a wait time of 3 UDPCK clock cycles and 3 peripheral clock cycles is required before

accessing DPR.

31 30 29 28 27 26 25 24

––––– RXBYTECNT

23 22 21 20 19 18 17 16

RXBYTECNT

15 14 13 12 11 10 9 8

EPEDS – – – DTGLE EPTYPE

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DIR RX_DATA_BK1 FORCESTALL TXPKTRDY ISOERROR RXSETUP RX_DATA_ BK0 TXCOMP

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• RXSETUP: Received Setup

This flag generates an interrupt while it is set to one.

Read:

0: No setup packet available.

1: A setup data packet has been sent by the host and is available in the FIFO.

Write:

0: Device firmware notifies the USB peripheral device that it has read the setup data in the FIFO.

1: No effect.

This flag is used to notify the USB device firmware that a valid Setup data packet has been sent by the host and success-

fully received by the USB de vice . Th e USB de vice firm wa re may tra nsf er Setu p da ta from th e FI FO by re ad ing the

UDP_FDRx to the microcontroller memory. Once a transfer has been done, RXSETUP must be cleared by the device

firmware.

Ensuing Data OUT transaction is not accepted while RXSETUP is set.

• ISOERROR: A CRC error has been detected in an isochronous transfer

This flag generates an interrupt while it is set to one.

Read:

0: No error in the previous isochronous transfer.

1: CRC error has been detected, data available in the FIFO are corrupted.

Write:

0: Resets the ISOERROR flag, clears the interrupt.

1: No effect.

• TXPKTRDY: Transmit Packet Ready

This flag is cleared by the USB device.

This flag is set by the USB device firmware.

Read:

0: There is no data to send.

1: The data is waiting to be sent upon reception of token IN.

Write:

0: Can be used in the procedur e to can cel tran sm ission data. ( See Section 37.6.2.5 “Transmit Data Cancellation” on page

973)

1: A new data payload has been written in the FIFO by the firmware and is ready to be sent.

This flag is used to generate a Data IN transaction (device to host). Device firmware checks that it can write a data payload

in the FIFO, checking that TXPKTRDY is cleared. Transfer to the FIFO is done by writing in the UDP_FDRx. Once the data

payload has been transfe rred to the FIFO, the firmware n otifies the USB device setting TXPKTRDY to one. USB bus trans-

actions can start. TXCOMP is set once the data payload has been received by the host.

After setting or clearing this bit, a wait time of 3 UDPCK clock cycles and 3 peripheral clock cycles is required before

accessing DPR.

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• FORCESTALL: Force Stall (used by Control, Bulk and Isochronous Endpoints)

Read:

0: Normal state.

1: Stall state.

Write:

0: Return to normal state.

1: Send STALL to the host.

Refer to chapters 8.4.5 and 9.4.5 of the Universal Serial Bus Specification, Rev. 2.0 for more information on the STALL

handshake.

Control endpoints: During the data stage and status stage, this bit indicates that the microcontroller cannot complete the

request.

Bulk and interrupt endpoints: This bit notifies the host that the endpoint is halted.

The host acknowledges the STALL, device firmware is notified by the STALLSENT flag.

• RX_DATA_BK1: Receive Data Bank 1 (only used by endpoints with ping-pong attributes)

This flag generates an interrupt while it is set to one.

Write (cleared by the firmware):

0: Notifies USB device that data have been read in the FIFO’s Bank 1.

1: To leave the read value unchanged.

Read (set by the USB peripheral):

0: No data packet has been received in the FIFO’s Bank 1.

1: A data packet has been received, it has been stored in FI FO ’s Ban k 1.

When the device firmware has polled this bit or has been interrupted by this signal, it must transfer data from the FIFO to

microcontroller memory. The number of bytes received is available in RXBYTECNT field. Bank 1 FIFO values are read

through UDP_FDRx. Once a transfer is done, the device firmware must release Bank 1 to the USB device by clearing

RX_DATA_BK1.

After setting or clearing this bit, a wait time of 3 UDPCK clock cycles and 3 peripheral clock cycles is required before

accessing DPR.

• DIR: Transfer Direction (only available for control endpoints) (Read/Write)

0: Allows Data OUT transactions in the control data stage.

1: Enables Data IN transactions in the control data stage.

Refer to Chapter 8.5.3 of the Universal Serial Bus Specification, Rev. 2.0 for more information on the control data stage.

This bit must be set before UDP_CSRx/RXSETUP is cleared at the end of the setup stage. According to the request sent

in the setup data packet, the d ata stage is either a device to host (DIR = 1) or host to device (DIR = 0) data transfer. It is not

necessary to check this bit to reverse direction for the status stage.

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• EPTYPE: Endpoint Type (Read/Write)

• DTGLE: Data Toggle (Read-only)

0: Identifies DATA0 packet

1: Identifies DATA1 packet

Refer to Chapter 8 of the Universal Serial Bus Specification, Rev. 2.0 for more information on DATA0, DATA1 packet

definitions.

• EPEDS: Endpoint Enable Disable

Read:

0: Endpoint disabled

1: Endpoint enabled

Write:

0: Disables endpoint

1: Enables endpoint

Control endpoints are always enabled. Reading or writing this field has no effect on control endpoints.

Note: After reset, all endpoints are config ured as control endpoints (zero).

• RXBYTECNT: Number of Bytes Availa ble in the FIFO (Read-only)

When the host sends a data packet to the device, the USB device stores the data in the FIFO and notifies the microcon-

troller. The microcontroller can load the data from the FIFO by reading RXBYTECENT bytes in the UDP_FDRx.

Value Name Description

0 CTRL Control

1 ISO_OUT Isochronous OUT

2 BULK_OUT Bulk OUT

3 INT_OUT Interrupt OUT

4– Reserved

5 ISO_IN Isochronous IN

6 BULK_IN Bulk IN

7 INT_IN Interrupt IN

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37.7.12 UDP FIFO Data Register

Name: UDP_FDRx [x = 0..5]

Address: 0x40044050

Access: Read/Write

• FIFO_DATA: FIFO Data Value

The microcontroller can push or pop values in the FIFO through this register.

RXBYTECNT in the corresponding UDP_CSRx is the number of bytes to be read from the FIFO (sent by the host).

The maximum number of bytes to write is fixed by the Max Packet Size in the Standar d Endpoint Descriptor. It can not be

more than the physical memory size associated to the endpoint. Refer to the Universal Serial Bus Specification, Rev. 2.0

for more information.

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FIFO_DATA

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37.7.13 UDP Transceiver Control Register

Name: UDP_TXVC

Address: 0x40044074

Access: Read/Write

WARNING: The UDP peripheral clock in the PMC must be enabled before any read/write operations to the UDP regi sters

including the UDP_TXVC register.

• TXVDIS: Tra n sc ei ve r Disa ble

When UDP is disabled, power consumption can be reduced significantly by disabling the embedded transceiver. This can

be done by setting TXVDIS bit.

To enable the transceiver, TXVDIS must be cleared.

• PUON: Pull-up On

0: The 1.5KΩ integrated pull-up on DDP is disconnected.

1: The 1.5 KΩ integrated pull-up on DDP is connected.

Note: If the USB pull-up is not connected on DDP, the user should not write in any UDP register other than the UDP_TXVC register . This

is because if DDP and DDM are floating at 0, or pulled down, then SE0 is received by the device with the consequence of a USB

Reset.

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23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––

PUON TXVDIS

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38. Analog-to-Digital Converter (ADC)

38.1 Description

The ADC is based on a 12-bit Analog-to-Digital Converter (ADC) managed by an ADC Controller providing

enhanced resolution up to 16 bits. Refer to Figure 38-1 “Analog-to-Digital Converter Block Diagram”. It also

integrates a 8-to-1 analog multiple xer, making possible the analog-to-digital conversions of 8 analog lines. The

conversions extend from 0V to VDDIO.

Conversion results are reported in a common register for all channels, as well as in a channel-dedicated register.

The 13-bit,14-bit,15-bit and 16-bit resolution modes are obtained by averaging multiple samples to decrease

quantization noise. For the 13-bit mode, 4 samples are used, which gives a real sample rate of 1/4 of the actual

sample frequency. For the 14-bit mode, 16 samples are used, giving a real sample rate of 1/16 of the actual

sample frequency. For the 15-bit and 16-bit mod es, respectively 64 and 256 sa mples are used, giving a real

sample rate of resp ectively 1/64 and 1/256 of the a ctual sample frequency. T his arrangement allows conversion

speed to be traded for better accuracy.

Software trigger, external trigge r on r ising edge of the ADTRG pin or intern al trigge rs from Timer Coun ter output( s)

are configurable.

The last channel can be converted at a rate different from oth er channels to improve conversion and processing

efficiency in case of a device which provides very low frequency variations such as a temperature sensor. A

dedicated comparison circuitry on the last channel allows specific processing and interrupt.

The main comparison circuitry allows autom atic detection of values below a thr eshold, higher than a threshold, in a

given range or outside the range, thresholds and ranges being fully configurable.

The ADC also integrates a Sleep mode and a conversion sequencer and connects with a PDC channel. These

features reduce both power consumption and processor intervention.

This ADC has a selectable single-ended or full differential input.

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38.2 Embedded Characteristics

12-bit Resolution with Enhanced Mode up to 16 bits

500 ksps Conversion Rate

Digital Averaging Function providing Enhanced Resolution Mode up to 16 bits

Wide Range of Power Supply Operation

Selectable Single-Ended or Differential Input Voltage

Integrated Multiplexer Offering Up to 8 Independent Analog Inputs

Individual Enable and Disable of Each Channel

Hardware or Software Trigger from:

External Trigger Pin

Timer Counter Outputs (Corresponding TIOA Trigger)

Up to 2 Trigger Events With Independent Rates

PDC Support

Two Sleep Modes (Automatic Wakeup on T rigger)

Lowest Power Consumption (Voltage Reference OFF Between Conversions)

Fast Wakeup Time Response on Trigger Event (Voltage Reference ON Between Conversions)

Channel Sequence Customization

Automatic Window Comparison of Converted Values

Asynchronous Partial Wakeup (SleepWalking) on external trigger

Register Write Protection

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38.3 Block Diagram

Figure 38-1. Analog-to-Digital Converter Block Diagram

38.4 Signal Description

ADC Interrupt

ADTRG

VDDIO

GND

Trigger

Selection

Control

Logic

Successive

Approximation

Analog-to-Digital

Converter

Timer

Counter

Channels

User

Interface

Interrupt

Controller

Peripheral Bridge

APB

PDC

System Bus

nalog Inputs

Multiplexed

with I/O lines

PIO

AD-

ADC Controller

Peripheral Clock

ADC Cell

CHx

RTC

RTCOUT1

RTCOUT0

PMC

Bus Clock

ADCCLK

all channels trigger

last channel

trigger

Table 38-1. ADC Pin Description

Pin Name Description

AD0–AD7 Analog input Channels

ADTRG External Trigger

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38.5 Product Dependencies

38.5.1 Power Management

The ADC Controller is not continuously clocked. The programmer must first enable the ADC Controller peripheral

clock in the Power Management Co ntroller (PMC) before using the ADC Controller. However, if the application

does not require ADC operations, the ADC Controller clock can be stopped when not needed and restarted when

necessary. Configuring the ADC Controller does not require the ADC Controller clock to be enabled.

38.5.2 Interrupt Sources

The ADC interrupt line is connected on one of the internal sources of the Interrupt Controller. Using the ADC

interrupt requires the interrupt controller to be programmed first.

38.5.3 I/O Lines

The digital input ADTRG is multiplexed with digital functions on the I/O line and the selection of ADTRG is made

using the PIO cont ro ller .

The analog inputs ADC_ADx are multiplexed with digital functions on the I/O lines. ADC_ADx inputs are selected

as inputs of the ADCC when writing a one in the corres ponding CHx bit of ADC_CHER an d the digital functions are

not selected.

38.5.4 Hardware Triggers

The ADC can use internal signals to start conversions. Refer to the ADC_MR.TRGSEL field description for exact

wiring of internal triggers.

Table 38-2. Peripheral IDs

Instance ID

ADC 29

Table 38-3. I/O Lines

Instance Signal I/O Line Peripheral

ADC ADTRG PA8 B

ADC AD0 PA17 X1

ADC AD1 PA18 X1

ADC AD2 PA19 X1

ADC AD3 PA20 X1

ADC AD4 PB0 X1

ADC AD5 PB1 X1

ADC AD6/WKUP12 PB2 X1

ADC AD7/WKUP13 PB3 X1

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38.6 Functional Description

38.6.1 Analog-to-Digital Conversion

Once the programmed startup time (ADC_MR.STARTUP) h as elapsed , ADC conver sions are sequenced by three

operating times:

Tracking time—the time for the ADC to charge its input sampling capacitor to the input voltage. When

several channels are converted consecutively, the inherent tracking time is six ADC clock cycles. However,

the tracking time can be increased using the TRACKTIM field in the Mode Register (ADC_MR).

ADC inherent conversion time—the time for the ADC to convert the sampled analog voltage. This time is

constant and is defined from start of conversion to end of conversion.

Channel conversion period—the effective time between the end of the current channel conversion and the

end of the next channel conversion.

Figure 38-2. Sequence of Consecutive ADC Conversions with TRACKTIM = 0

ADCCLK

LCDR

ADC_ON

ADC_SEL

DRDY

ADC_Start

CH0 CH1

CH0

Start Up Time

(and start CH0 tracking)

A to D for CH0 A to D for CH1

CH0 tracking

CH1 Tracking = 6 ADCCLK

CH1

CH0 conversion period CH1 conversion period

CH2

5 ADCCLK

ADC_eoc

Trigger event

(Hard or Soft)

Analog cell IOs

1005

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Figure 38-3. Sequence of Consecutive ADC Conversions with TRACKTIM = 15

38.6.2 ADC Clock

The ADC uses the ADC clock (ADCCLK) to perform conversions. The ADC clock frequency is selected in the

PRESCAL field of ADC_MR.

To generate the ADC clock, the prescaler has two clock sources: the peripheral clock and the PMC_PCKx clock.

This clock source is selected using the SRCCLK bit in the Extended Mode Register (ADC_EMR).

If PMC_PCKx is selected as a source clock, the ADC clock frequency is independent of the processor/bus clock.

At reset, the peripheral clock is selected.

If the SRCCLK bit in ADC_EMR is cleared, then th e prescaler clock (presc_clk) is driven by peripheral_clock. If the

SRCCLK bit in ADC_EMR is set to 1, the prescaler clock is driven by PMC_PCKx. The ADC clock frequency is

between fpresc_clk and fpresc_clk/512, if PRESCAL is set to 255 (0xFF).

PRESCAL must be programmed to pro vide the ADC clock f requency parameter given in the se ction “Electrical

Characteristics”.

38.6.3 ADC Reference Voltage

The conversion is performed on a full range between 0V and the reference voltage connected to VDDIO.

Analog inputs between these voltages convert to values based on a linear conve rsion.

38.6.4 Conversion Resolution

The ADC analog cell features a 12-bit resolution.

The ADC digital controller provides enhanced resolution up to 16 bits.

If ADTRG is asynchronous to the ADC peripheral clock, the internal resynchronization introduces a jitter of 1

peripheral clock. This jitter may reduce the resolution of the converted signal.

The same applies when using the independent clock (ADC_MR.SRCCLK = 1), if the provided clock is

asynchronous to ADC peripheral clock.

ADCCLK

LCDR

ADC_ON

ADC_SEL

DRDY

ADC_Start

CH0 CH1

CH0

Start Up Time

(and start CH0 tracking)

A to D for CH0 A to D for CH1

CH0 tracking

CH1 Tracking = 7 × ADCCLK

CH1

CH0 conversion period CH1 conversion period

CH2

5 × ADCCLK

CH2 Tracking

= 7 × ADCCLK

TRACKTIM=15 Effect TRACKTIM=15 Effect

ADC_eoc

Trigger event

(Hard or Soft)

Analog cell IOs

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38.6.5 Conversion Results

When a conversion is completed, the resulting digital value is stored in the Channel Data Registe r (ADC_CDRx) of

the current channel and in the ADC Last Converted Data Register (ADC_LCDR). By setting the TAG option in the

Extended Mode Register (ADC_EMR), ADC_LCDR presents the channel number associated with the last

converted data in the CHNB field.

When a conversion is completed, the channel EOC bit and the DRDY bit in the Interrupt Status Register

(ADC_ISR) ar e set. In the ca se of a connected PDC channel, DRDY rising triggers a data request. In any case,

either EOC and DRDY can trigger an interrupt.

Reading one of the ADC_CDRx clears the corresponding EOC bit. Reading ADC_LCDR clears the DRDY bit.

Figure 38-4. EOCx and DRDY Flag Behavior

If ADC_CDR is not read before further incoming data is converted, the corresponding OVREx flag is set in the

Overrun Status Register (ADC_OVER).

New data converted when DRDY is high sets the GOVRE bit in ADC_ISR.

The OVREx flag is automatically cleared when ADC_OVER is read, and the GOVRE flag is automatically cleared

when ADC_ISR is read.

Read the ADC_CDRx

EOCx

DRDY

Read the ADC_LCDR

CHx

(ADC_CHSR)

(ADC_ISR)

Write the ADC_CR

with START = 1

Write the ADC_CR

with START = 1

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Figure 38-5. EOCx, OVREx and GOVREx Fl ag Behavior

Warning: If the corresponding channel is disabled du ring a conversion or if it is disabled and then reenabled during a con-

version, its associated data and co rrespo nding EOCx and GOVRE flags i n ADC_ISR and OVREx fla gs in ADC_OVER are

unpredictable.

EOC0

GOVRE

CH0

(ADC_CHSR)

(ADC_ISR)

Trigger event

EOC1

CH1

(ADC_CHSR)

(ADC_ISR)

OVRE0

(ADC_OVER)

Undefined Data Data A Data B

ADC_LCDR

Undefined Data Data A

ADC_CDR0

Undefined Data Data B

ADC_CDR1

Data C

Conversion C

Conversion A

DRDY

(ADC_ISR)

Read ADC_CDR1

Read ADC_CDR0

Conversion B

Read ADC_OVER

Read ADC_ISR

OVRE1

(ADC_OVER)

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38.6.6 Conversion Triggers

Conversions of the active analog channels are started with a software or hardware trigger. The software trigger is

provided by writing the Control Register (ADC_CR) with the START bit at 1.

The list of external/internal events is provided in Section 38.7.2 “ADC Mode Register”. The hardware trigger is

selected using the TRGSEL field in ADC_MR. When the TRGEN bit is set in ADC_MR, the selected hardware

trigger is enabled and the software trigger is disabled.

The ADC also provides a dual trigger mode (ADC_LCTM R.DUALTRIG=1) in which the higher index channel can

be sampled at a rhythm different from the other channels. The trigger of the last channel is generated by the RTC.

Refer to Section 38.6.11 “Last Channel Specific Measurement Trigger”.

If a hardware trigger is selected, the start of a conversion is triggered after a delay starting at each rising edge of

the selected signal. Due to asynchronous handling, the delay may vary in a range of two peripheral clock periods

to one ADC clock per iod. This delay introd uces sampling jitter in th e A/D conversion pr ocess and may the refore

degrade the conversion performance (e.g., SNR, THD).

Figure 38-6. Hardware Trigger Delay

If one of the TIOA outputs is selected, the corresponding Timer Counter channel must be programmed in

Waveform mode.

Only one start command is ne cessary to initiate a conversion sequ ence on all the channels. The ADC hard ware

logic automatically pe rforms the conver sions on the active chann els, then waits for a new reque st. The Channel

Enable (ADC_CHER) and Channel Disable (ADC_CHDR) registers enable the analog channels to be enabled or

disabled independently.

If the ADC is used with a PDC, only th e tran sfer s of con verte d data fr om en able d chann els are perform ed a nd the

resulting data buffers should be interprete d accordingly.

38.6.7 Sleep Mode and Conversion Sequencer

The ADC Sleep mode maximizes power saving by automatically deactivating the ADC when it is no t being used for

conversions. Sleep mode is selected by setting the SLEEP bit in ADC_MR.

Sleep mode is managed by a conversion sequencer, which automatically processes the conversions of all

channels at lowest power consumption.

This mode can be used when the minimum period of time between two successive trigger events is greater than

the startup period of the ADC. See section “Electrical Characteristics”.

When a start conversion request occurs, the ADC is automatically activated. As the analog cell requires a startup

time, the logic waits during this time and starts the conversion on the enabled channels. When all conversions are

complete, the ADC is deactivated until the next trigger. Triggers occurring during the sequence are ignored.

A Fast wakeup mode is available in ADC_MR as a compromise between power-saving strategy and

responsiveness. Setting the FWUP bit enables the Fast wakeup mode. In Fast wakeup mode, the ADC cell is not

fully deactivated while no conversion is requested, thereby providing less power saving but faster wakeup.

The conversion sequencer allows automatic processing with minimum processor inte rvention and optim ized power

consumption. Conversion sequences can be performed periodically using a Timer/Counter output. The periodic

trigger

start

delay

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acquisition of several samples can be processed automatically without any intervention of the processor via the

PDC.

The sequence can be customized by programming the Sequence Channel Register ADC_SEQR1 and setting the

USEQ bit of the Mode Register (ADC_MR). The user can choose a specific or der of ch annels an d ca n p rogra m u p

to 8 conversions by seq uence. The user is free to create a persona l sequence by w riting channel numbers in

ADC_SEQR1. Not only can channel numbers be written in any sequence, channel numbers can be repeated

several times. When the bit USEQ in ADC_MR is set, the fields USCHx in ADC_SEQR1 are used to define the

sequence. Only enabled USCHx fields will be part of the sequence. Each USCHx field has a corresponding

enable, CHx-1, in ADC_CHER.

Note: The reference voltage pins always remain connected in Normal mode as in Sleep mode.

38.6.8 Comparison Window

The ADC Controller features automatic comparison functions. It compares converted values to a low threshold, a

high threshold or both, depending on the value of the CMPMODE bit in ADC_EMR. The comparison can be done

on all channels or only on the channel specified in the CMPSEL field of ADC_EMR. To compare all channels, the

CMPALL bit of ADC_EMR must be set.

If set to 1, the CMPTYPE bit of ADC_EMR can be used to discard all conversion results that do not match the

comparison conditions. Once a conversion result matches the comparison conditions, all the subsequent

conversion results are stored in ADC_LCDR ( even if these r esults do not m eet the co mparison cond itions) . Writing

a 1 to the CMPRST bit in ADC_CR im mediately stops the conversion result storage until the next comparison

match.

If the CMPTYPE bit in ADC_EMR is cleared, all conversions ar e stored in ADC_LCD R. Only the conv ersions tha t

match the comparison conditions trigger the COMPE flag in ADC_ISR.

Moreover , a filtering op tion can be set by writing t he number of consecutive comparison matches needed to raise

the flag. This number can be written and read in the CMPFILTER field of ADC_EMR. The filtering option is

dedicated to reinfor ce the d etection of an a nalog signal overpa ssing a pre defined thresho ld. The filte r is cleared as

soon as ADC_ISR is read, so this filtering function must be used with peripheral DMA controller and works only

when using Interrupt mode (no polling).

The flag can be read on the COMPE bit of the Interrupt Status Register (ADC_ISR) and can trigger an interrupt.

The high threshold and the low threshold can be read/write in the Compare Window Register (ADC_CWR).

38.6.9 Differential and Single-ended Input Modes

The ADC can be configured to operate in the following input voltage modes:

Single-ended—ADC_COR.DIFFx = 0. This is the default mode after a reset.

Differential—ADC_COR.DIFFx = 1 (see Figure 38-7). In Differential mode, the ADC requires differential

input signals having a VDD/2 common mode voltage (refer to the “Electrical Characteristics” section).

The following equations give the ADC input-output transfer function in each mode(1).

Single-ended mode:

Differential mode:

Note: 1. Equations assume ADC_EMR.OSR = 1

ADC_LCDR.LDATA ADx GND–

ADVREF GND–

------------------------------------------- 212

×=

ADC_LCDR.LDATA 1 ADx ADx+1–

ADVREF GND–

-------------------------------------------





211

×=

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If the ANACH bit is set in ADC_MR, the ADC can manage both differential channels and single-ended channels. If

the ANACH bit is cleared, the parameters defined in ADC_CGR, ADC_COR are applied to all channels.

Table 38-4 gives the in tern al pos itive an d ne gativ e ADC inputs assignment with respect to the programmed mode

(ADC_COR.DIFFx). If Differential mode is enabled, the odd channel index is routed to the negative input.

For example, if Differential mode is required on channel 0, input pins AD0 and AD1 are used. In this case, only

channel 0 must be enabled by writing a 1 to ADC_CHER.CH0.

Figure 38-7. Analog Full Scale Ranges in Single-Ended and Differential Appl icatio ns

38.6.10 ADC Timings

The ADC startup time is programmed through the STARTUP field in ADC_MR. See section “Electrical

Characteristics”.

The ADC controller provides a tracking time of six ADC clock cycles.

It is possible to add one more ADC clock to the ADC tracking time by programming the TRACKTIM field in

ADC_MR.When the offset or differential input parameters of the analog cell change betwee n two channels, the

analog cell may need a specific settling time before starting the tracking phase. In that case, the controller

automatically waits during the settling time defin ed in ADC_MR. Obviously, if the ANACH option is not set, this

time is unused.

Warning: No input buffer amplifier to isolate the source is included in the ADC. This must be taken into

consideration. See section “Electrical Characteristics”.

Table 38-4. Input Pins and Channel Numbers

Input Pin

Channel Number

Single-ended Mode Differential Mode

AD0 CH0 CH0

AD1 CH1

AD2 CH2 CH2

AD3 CH3

AD4 CH4 CH4

AD5 CH5

AD6 CH6 CH6

AD7 CH7

Single-ended

se0fd1 = 0

VIN+VIN+

VIN-

(¾) VADVREF

VADVREF

½)VADVREF

)

½)VADVREF

)

(¼) VADVREF

Full differential

se0fd1 = 1

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38.6.11 Last Channel Specific Measurement Trigger

The last channel (higher index available) embeds a specific mode allowing a measurement trigger period which

differs from other active channels. This allows efficient management of the conversions especially if the channel is

driven by a device with a varia tion of a different frequency fro m other converted channels (for example, but no t

limited to, temper at ur e se ns or ).

The last channel can be sampled in different ways through the ADC controller. The different methods of sampling

depend on the configuration bit TRGEN in ADC_MR and bit CH7 in ADC_CHSR.

The last channel measure can be triggered like the other channels by enabling its associated conversion channel

index 7, writing 1 in CH7 of ADC_CHER.

The manual start can only be performed if bit TRGEN is cleared. When the START bit in ADC_CR is set, the last

channel conversion is scheduled together with the other enabled channels (if any). The result of the conversion is

placed in ADC_CDR7 register and the associated flag EOC7 is set in ADC_ISR.

If the last channel is enabled in ADC_CHSR, DUALTRIG is cleared and bit TRGEN = 1, the last channel is

periodically converted together with the other enabled channels and the result is placed in the ADC_LCDR and

ADC_CDR7 registers. Thus the last channel conversion result is part of the Peripheral DMA C ontroller buffer (s ee

Figure 38-8).

When the conversion result match es the conditions defined in the ADC_LCTMR and ADC_LCCWR, the LCCHG

flag is set in ADC_ISR.

Figure 38-8. Same Trigger for All Channels (ADC_CHSR[LCI] = 1 and ADC_MR.TRGEN = 1)

Base Address (BA)

BA + 0x02

ADC_CDR[LCI]0

ADC_CDR[0]0

ADC_CDR[0]0BA + 0x04

ADC_CDR[0]0

ADC_CDR[LCI]0

BA + 0x06

BA + 0x08

BA + 0x0A

Assuming ADC_CHSR[0] = 1 and ADC_CHSR[LCI] = 1

trig.event1

DMA Buffer

Structure

trig.event2

DMA Transfer

trig.event3

Internal/External

Trigger Event

(Defined by TRGSEL field)

ADC_SEL CLC C CC

Notes: ADC_SEL: Command to the ADC analog cell

Cx: All ADC channel values except the last channel (highest index)

LCx: Last channel value

LCI: Last channel index

ADC_CDR[LCI] LC1 LC2LC0

ADC_CDR[0] C0 C1 C2 C3 C4 C5

LC3 LC4 LC5

ADC_LCDR C0 C1 C2 C3 C4LC1 LC2LC0 LC3 LC4 LC5

LC LC LC LC

ADC_LCTMR.DUALTRIG = 1

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If the last channel is driven by a device with a slower variation compared to other channels (temperature sensor for

example), the channel can be enabled/disabled at any time. However, this may not be optimal for downstream

processing.

The ADC controller allows a different way of triggering the measuremen t when DUALTRIG is set in the Last

Channel Trigger Mode Register (ADC_LCTMR) but CH7 is not set in ADC_CHSR.

Under these conditions, the last channel conversion is triggered with a period defined by the OUT1 field in the

RTC_MR (Real-time Clock Mode Register) while other channels are still active. OUT1 configures an internal

trigger generated by the RTC, totally independent of the internal/external triggers. The RTC event will be

processed on the next internal/external trigger event as described in Figure 38-9. The internal/external trigger for

other channels is selected through the TRGSEL field of ADC_MR.

When DUALTRIG = 1, the result of each conversion of channel 7 is only uploaded in the ADC_CDR7 register and

not in ADC_LCDR (see Figure 38-9). Therefore ther e is no change in the st ructure of th e peripheral DMA contr oller

buffer due to the conversion of the last channel: only the enabled channels are kept in the buffer. The end of

conversion of the last channel is reported by the EOC7 flag in ADC_ISR.

Figure 38-9. Independent Trigger Measu rement for Last Channel (ADC_CHSR[LCI] = 0 and ADC_MR.TRGEN = 1)

If DUALTRIG = 1 and b it ADC_MR.TRGEN is cleared and none of th e channels are enabled in ADC_CHSR

(ADC_CHSR = 0), then only channel 7 is converted at a rate defined by the trigger event signal that can be

configured in RTC_MR.OUT1 (see Figure 38-10).

This mode of opera tion, when combined with the Slee p mode operation of the ADC Controller, provides a low-

power mode fo r last channel measure. T his assumes there is no other ADC conversion to schedule a t a high

sampling rate or no other channel to convert.

Base Address (BA)

BA + 0x02

ADC_CDR[0]0

BA + 0x04

ADC_CDR[0]0

trig.event1

DMA Buffer Structure

trig.event2

DMA Transfer

trig.event3

ADC_SEL CLC CCLC

ADC_LCTMR.DUALTRIG = 1

ADC_CDR[0]0

Internal RTC

Trigger event

ADC_CDR[LCI] LC1 LC2LC0

ADC_CDR[0]

and ADC_LCDR C0 C1 C2 C3 C4 C5

period defined by RTC_MR.OUT1

Internal/External

Trigger Event

(Defined by TRGSEL)

Assuming ADC_CHSR[0] = 1

Notes: ADC_SEL: Command to the ADC analog cell

Cx: All ADC channel values except the last channel (highest index)

LCx: Last channel value

LCI: Last channel index

LC conversion scheduled

on TRGSEL trigger event

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Figure 38-10. Only Last Channel Measurement Trigg ered at Low Speed (ADC_CHSR[LCI] = 0 and ADC_MR.TRGEN =

38.6.12 Enhanced Resolution Mode and Digital Averaging Function

38.6.12.1 Enhanced Resolution Mode

The Enhanced Resolution mode is enabled if the OSR field is configured to 1, 2, 3 or 4 in ADC_EMR. The

enhancement is based on a digital averaging function.

FREERUN in ADC_MR must be cleared when digital averaging is used (OSR ≠ 0 in ADC_EMR).

There is no averaging on the last index channel if the measure is triggered by an RTC event.

In this mode, the ADC Controller will trade off conversion speed against accuracy by averaging multiple samples,

thus providing a digital low-pass filter function.

The selected oversampling ratio applies to all enabled channels except for the last channel when triggered by an

RTC event.

where N and M are given in the table below.

The average result is valid in ADC_CDRx (x corresponds to the index of the channel) only if the EOCn flag is set in

ADC_ISR and if the OVREn flag is cleared in ADC_OVER. The average result for all channels is valid in

ADC_LCDR only if DRDY is set and GOVRE is cleared in ADC_ISR.

ADC_SEL

Internal RTC

Trigger Event

period defined by RTC_MR.OUT1

LCI

ADC_CDR[LCI] LC1 LC2LC0

DC_LCTMR.DUALTRIG = 1

Notes: ADC_SEL: Command to the ADC analog cell

LCx: Last channel value

LCI: Last channel index

LCI

ADC_LCDR.LDATA 1

-----

kN1–=

k0=

×ADC k()=

Table 38-5. Digital Averaging Function Configuration versus OSR Values

ADC_EMR.OSR Value ADC_LCDR .LDATA Length N Value M Value Full Scale Value Maximum Value

0 12 bits 1 1 4095 4095

1 13 bits 4 2 8191 8190

2 14 bits 16 4 16383 16381

3 15 bits 64 8 32767 32761

4 16 bits 256 16 65535 65521

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Note that ADC_CDRs are not buffered. Therefore, when an averaging sequence is ongoing, the value in these

registers changes after each averaging sample. However, overrun flags in ADC_OVER rise as soon as the first

sample of an av eraging sequence is rece ived. Thus the previous averaged value is not read, even if the new

averaged value is not ready.

Consequently, when an overrun flag rises in ADC_OVER, it means that the previous unrea d data i s lost but it d oes

not mean that this data has been overwritten by the new averaged va lue as the averaging sequence concerning

this channel can still be ongoing.

When an oversamp ling is performed, the m aximum value that can be read on ADC_CDRx or ADC_LCDR is not

the full-scale value, even if the maximum voltage is supplied on the analog input. Refer to Table 38-5 “Digital

Averaging Function Configuration versus OSR Values”.

38.6.12.2 Averaging Function versus Trigger Events

The samples can be defined in different ways for the averaging function depending on the configuration of the

ASTE bit in ADC_EMR and the USEQ bit in ADC_MR.

When USEQ = 0, there are two possible ways to generate the averaging thr ough the trigge r even t. If AST E = 0 in

ADC_EMR, every trigger event generates one sample for each enabled channel as described in Figure 38-11.

Therefore four trigger events are requested to get the result of averaging if OSR = 1.

Figure 38-11. Digital Averaging Function Waveforms Over Multiple Trigger Events

If ASTE = 1 in ADC_EMR and USEQ = 0 in ADC_MR, the sequence to be converted, defined in ADC_CHSR, is

automatically repeated n times (where n corresponds to the oversampling ratio defined in the OSR field in

ADC_EMR). As a result, only one trigger is required to obtain the result of the averaging function as described in

Figure 38-12.

Internal/External

Trigger Event

ADC_SEL 01

DC_EMR.OSR = 1, ASTE = 0, ADC_CHSR[1:0] = 0x3 and ADC_MR.USEQ = 0

ADC_CDR[1]

ADC_CDR[0] CH0_0

ADC_LCDR

0i1

01010101

0i2 0i3 CH0_1 0i1

CH1_0 1i1 1i2 1i3 CH1_1 1i1

EOC[0]

Read ADC_CDR[1]

CH1_1CH0_1

EOC[1]

Read ADC_LCDR

DRDY

Notes: ADC_SEL: Command to the ADC analog cell

0i1, 0i2, 0i3, 1i1, 1i2, 1i3 are intermediate results and CH0_0, CH0_1, CH1_0 and CH1_1 are final results of

average function.

Read ADC_CDR[0]

Read ADC_CDR[1]

OVR[0]

CH1_0

Read ADC_LCDR

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Figure 38-12. Dig ital Averaging Function Waveforms on a Single Trigger Event

When USEQ = 1, the user can define the channel sequence to be converted by configuring ADC_SEQRx and

ADC_CHER so that channels are not interleaved during the averaging period. Under these conditions, a sample is

defined for each end of conversion as described in Figure 38-13.

When USEQ = 1 and ASTE = 1, OSR can be only configured to 1. Up to three channels can be converted in this

mode. The averaging result will be pl aced in the corresponding ADC_CDRx and in ADC_LCDR for each trigger

event. The ADC real sample rate remains the maximum ADC sample rate divided by 4.

It is important that the user sequence follows a specific pattern. The user sequence must be programmed in such

a way that it generates a stream of conversion, where a same channel is successively converted.

Table 38-6. Example Sequen ce Configurations (USEQ = 1, ASTE = 1, OSR = 1)

Number of Channels Non-interleaved Averaging - Register Value

1 (e.g., CH0) 2 (e.g., CH0, CH1) 3 (e.g., CH0, CH1, CH2)

ADC_CHSR 0x0000_000F 0x0000_00FF 0x0000_0FFF

ADC_SEQR1 0x0000_0000 0x1111_0000 0x1111_0000

ADC_SEQR2 0x0000_0000 0x0000_0000 0x0000_2222

Internal/External

Trigger Event

ADC_SEL 0

ADC_EMR.OSR = 1, ASTE = 1, ADC_CHSR[1:0] = 0x3 and ADC_MR.USEQ = 0

ADC_CDR[1]

ADC_CDR[0] CH0_0

ADC_LCDR

0i1

0i2 0i3 CH0_1

EOC[0]

Read ADC_CDR[0]

Read ADC_CDR[1]

CH1_1CH0_1

EOC[1]

Read ADC_LCDR

DRDY

011100

CH1_0 1i1 1i2 1i3 CH1_1

Note: ADC_SEL: Command to the ADC analog cell

0i1, 0i2, 0i3, 1i1, 1i2, 1i3 are intermediate results and CH0_0, CH0_1, CH1_0 and CH1_1 are final

results of average function.

01 11

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1016

Figure 38-13. Dig ital Averaging Function Waveforms on a Single Trigger Event, Non-interle aved

38.6.13 Asynchronous and Partial Wakeup (SleepWalking)

This operating m od e is a me an s o f data pre - pr oc es sing that qualifies an incoming event, thus allowing the ADC to

decide whet her or not to wake up the system. Asynchronous and partial wakeup is mainly used when the system

is in Wait mode (see the PMC section for further details). It can also be enabled when the system is fully running.

Once the Asynchronous and partial wakeup mode is enabled, no access must be performed in the ADC before a

Wakeup is performed by the ADC.

When the Asynchronous and partial wakeup mode is enabled for the ADC (see the PMC section), the PMC

decodes a clock request from the ADC. The clock request is generated as soon as a trigger event occurs. Only a

trigger from RTC or ADTRG pin can be used in partial wakeup mo de. The sele ction between RTC or ADT RG pin is

performed through the ADC_MR.TRGSEL field.

If the system is in Wait mode (processor and peripheral clocks switched off), the PMC restarts the fast RC

oscillator and provides the clock only to the ADC.

To perform a conversion at regular intervals with RTC trigger, the RTC must be configured with the following

settings: RTC_MR.OUT0=7 and RTC_MR.THIGH=7. The period of the trigger can be defined in

RTC_MR.TPERIOD.

To trigger a conversion using the ADTRG pin, the minimum high level duration of the ADTRG signal must be

greater than 2 clock periods of the fast RC oscillator. The maximum duration of the high level must be limited to the

amount of startup and conversion time.

As soon as the clock is provided by the PMC, the ADC processes the co nversions and comp ares the converted

values with LOWTHRES and HIGHTHRES field values in ADC_CWR.

Internal/External

Trigger Event

ADC_SEL 0

DC_EMR.OSR = 1, ASTE = 1, ADC_CHSR[7:0] = 0xFF and ADC_MR.USEQ = 1

ADC_CDR[1]

ADC_CDR[0] CH0_0

ADC_LCDR

0i1

0i2 0i3 CH0_1

EOC[0] Read ADC_CDR[0]

Read ADC_CDR[1]

CH1_1CH0_1

EOC[1]

Read ADC_LCDR

DRDY

01111 0000

CH1_0 1i1 1i2 1i3 CH1_1

Note: ADC_SEL: Command to the ADC analog cell

0i1, 0i2, 0i3, 1i1, 1i2, 1i3 are intermediate results and CH0_0, CH0_1, CH1_0 and CH1_1 are final

results of average function.

DC_SEQR1 = 0x1111_0000

1017

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

The ADC instructs the PMC to disable the clock if the converted value do es not meet the conditions defined by

LOWTHRES and HIGHTHRES field values in ADC_CWR.

If the converted value meets the conditions, the ADC instructs the PMC to exit the full system from Wait mode.

If the processor and peripherals are running, the ADC c an be configured in Asynchronous and partial wakeup

mode by enabling the PMC_SLPWK_ER (see the PMC section). When a trigger event occurs, the ADC requests

the clock from the PMC and the comparison is performed. I f there is a comparison match, the ADC continues to

request the clock. If there is no match, the clock is switched off for the ADC only, until a new trigger event is

detected.

It is recommended to write a ‘1’ to the SLEEP bit to reduce the power consumption of the analog part of the ADC

when the system is waiting for a trigger event.

38.6.14 Buffer Structure

The PDC read channel is triggered each time a new data is stored in ADC_LCDR. The same structure of data is

repeatedly stored in ADC_LCDR each time a trigger event occurs. Depending on user mode of operation

(ADC_MR, ADC_CHSR, ADC_SEQR1) the structure differs. Each data read to PDC buffer, carried on a half-word

(16-bit), consists of last converted data right aligned and when TAG is set in ADC_EMR, the four most significant

bits are carrying the channel number thus allowing an easier post-processing in the PDC buffer or better checking

the PDC buffer integrity.

Figure 38-14. Buffer Structure

Base Address (BA)

BA + 0x02

ADC_CDR66

ADC_CDR55

ADC_CDR88BA + 0x04

ADC_CDR66

ADC_CDR55

ADC_CDR88

BA + 0x06

BA + 0x08

BA + 0x0A

ADC_CDR66

ADC_CDR55

ADC_CDR88

BA + [(N-1) * 6]

BA + [(N-1) * 6]+ 0x02

BA + [(N-1) * 6]+ 0x04

Assuming ADC_CHSR = 0x000_01600

ADC_EMR.TAG = 1

trig.event1

ADC_CDR60

ADC_CDR50

ADC_CDR80

ADC_CDR60

ADC_CDR50

ADC_CDR80

ADC_CDR60

ADC_CDR50

ADC_CDR80

Assuming ADC_CHSR = 0x000_01600

ADC_EMR.TAG = 0

DMA Buffer

Structure DMA Buffer

Structure

trig.event2

trig.event1

trig.event2

trig.eventN

DMA Transfer

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1018

38.6.15 Register Write Protection

To prevent any single softwar e error from cor rupting ADC be havior, cer tain registe rs in the address sp ace can be

write-protected by setting the bit WPEN in the “ADC Write Protection Mode Register” (ADC_WPMR).

If a write access to the protected registers is detected, the WPVS flag in the “ADC Write Protection Status

attempted.

The WPVS flag is automatically reset by reading ADC_WPSR.

The following registers are write-protected when WPEN is set in ADC_WPMR:

ADC Mode Register

ADC Channel Sequence 1 Register

ADC Channel Enable Register

ADC Channel Disable Register

ADC Last Channel Trigger Mode Register

ADC Last Channel Compare Window Register

ADC Extended Mode Register

ADC Compare Window Register

ADC Channel Differential Input Register

ADC Analog Control Register

38.6.16 Autotest Function

The ADC_ACR.AUTOTEST field configures the autotest modes of the analog cell. When configured for an

autotest mode, a conversion must be started on a given channel to observe the gain and offset errors. At the end

of the conversion, the value read on ADC_CDR is used to compute the gain and offset errors by comparison with

the expected values. There is no automatic correction, and gain and offset errors must be corrected by software.

Refer to the section “Electrical Characteristics” for expected values under autotest.

1019

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7 Analog-to-Digital (ADC) User Interface

Note: Any offset not listed in the table must be considered as “reserved”.

Table 38-7. Register Mapping

Offset Register Name Access Reset

0x00 Control Register ADC_CR Write-only –

0x04 Mode Register ADC_MR Read/Write 0x00000000

0x08 Channel Sequence Register 1 ADC_SEQR1 Read/Write 0x00000000

0x0C Reserved – – –

0x10 Channel Enable Register ADC_CHER Write-only –

0x14 Channel Disable Register ADC_CHDR Write-only –

0x18 Channel Status Register ADC_CHSR Read-only 0x00000000

0x1C Reserved – – –

0x20 Last Converted Data Register ADC_LCDR Read-only 0x00000000

0x24 Interrupt Enable Register ADC_IER Write-only –

0x28 Interrupt Disable Register ADC_IDR Write-only –

0x2C Interrupt Mask Register ADC_IMR Read-only 0x00000000

0x30 Interrupt Status Register ADC_ISR Read-only 0x00000000

0x34 Last Channel Trigger Mode Register ADC_LCTMR Read/Write 0x00000000

0x38 Last Channel Compare Window Register ADC_LCCWR Read/Write 0x00000000

0x3C Overrun S tatus Register ADC_OVER Read-only 0x00000000

0x40 Extended Mode Register ADC_EMR Read/Write 0x00000000

0x44 Compare Window Register ADC_CWR Read/Write 0x00000000

0x48 Reserved – – –

0x4C Channel Differential Input Register ADC_COR Read/Write 0x00000000

0x50 Channel Data Register 0 ADC_CDR0 Read-only 0x00000000

0x54 Channel Data Register 1 ADC_CDR1 Read-only 0x00000000

... ... ... ... ...

0x6C Channel Data Register 7 ADC_CDR7 Read-only 0x00000000

0x70–0x90 Reserved – – –

0x94 Analog Control Register ADC_ACR Read/Write 0x00080000

0x98–0xAC Reserved – – –

0xC4–0xE0 Reserved – – –

0xE4 Write Protection Mode Register ADC_WPMR Read/W rite 0x00000000

0xE8 Write Protection Status Register ADC_WPSR Read-only 0x00000000

0xEC–0xFC Reserved – – –

0x100–0x124 Reserved for PDC registers – – –

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1020

38.7.1 ADC Control Register

Name: ADC_CR

Address: 0x40038000

Access: Write-only

• SWRST: Software Reset

0: No effect.

1: Resets the ADC, simulating a hardware reset.

• START: Start Conversion

0: No effect.

1: Begins analog-to-digital conversion.

• CMPRST: Comparison Restart

0: No effect.

1: Stops the conve rs i on res ult stor age un til th e ne xt co mp a riso n m atc h.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – – CMPRST – – START SWRST

1021

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7.2 ADC Mode Register

Name: ADC_MR

Address: 0x40038004

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• TRGEN: Trigger Enable

• TRGSEL: Trigger Selection

• SLEEP: Sleep Mode

• FWUP: Fast WakeUp

31 30 29 28 27 26 25 24

USEQ TRANSFER TRACKTIM

23 22 21 20 19 18 17 16

ANACH – SETTLING STARTUP

15 14 13 12 11 10 9 8

PRESCAL

76543210

FREERUN FWUP SLEEP – TRGSEL TRGEN

Value Name Description

0 DIS Hardware triggers are disabled. Starting a conversion is only possible by software.

1 EN Hardware trigge r selected by TRGSEL fi eld is enabled.

Value Name Description

0 ADC_TRIG0 ADTRG External trigger

1 ADC_TRIG1 TIOA0 Output of the Timer Counter Channel 0

2 ADC_TRIG2 TIOA1 Output of the Timer Counter Channel 1

3 ADC_TRIG3 TIOA2 Output of the Timer Counter Channel 2

4 ADC_TRIG4 RTCOUT0

5 ADC_TRIG5 RTT 16-Bit prescaler output

6 ADC_TRIG6 RTTEVENT

7 ADC_TRIG7 –

Value Name Description

0 NORMAL Normal Mode: The ADC core and reference voltage circuitry are kept ON between conversions.

1 SLEEP Sleep Mode: The wakeup time can be modified by programming the FW UP bit.

Value Name Description

0 OFF If SLEEP is 1, then both ADC core and reference voltage circuitry are OFF between conversions

1ON If SLEEP is 1, then Fast Wakeup Sleep mode: The voltage reference is ON between conversions and ADC

core is OFF

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1022

• FREERUN: Free Run Mode

Note: FREERUN must be cleared when digital averaging is used (OSR ≠ 0 in ADC_EMR).

• PRESCAL: Prescaler Rate Selection

PRESCAL = (fperipheral clock / (2 × fADCCLK)) – 1.

• STARTUP: Startup Time

• SETTLING: Analog Settling Time

• ANACH: Analog Change

Value Name Description

0OFF Normal Mode

1 ON Free Run Mode: Never wait for any trigger.

Value Name Description

0 SUT0 0 periods of ADCCLK

1 SUT8 8 periods of ADCCLK

2 SUT16 16 periods of ADCCLK

3 SUT24 24 periods of ADCCLK

4 SUT64 64 periods of ADCCLK

5 SUT80 80 periods of ADCCLK

6 SUT96 96 periods of ADCCLK

7 SUT112 112 periods of ADCCLK

8 SUT512 512 periods of ADCCLK

9 SUT576 576 periods of ADCCLK

10 SUT640 640 periods of ADCCLK

11 SUT704 704 periods of ADCCLK

12 SUT768 768 periods of ADCCLK

13 SUT832 832 periods of ADCCLK

14 SUT896 896 periods of ADCCLK

15 SUT960 960 periods of ADCCLK

Value Name Description

0 AST3 3 periods of ADCCLK

1 AST5 5 periods of ADCCLK

2 AST9 9 periods of ADCCLK

3 AST17 17 periods of ADCCLK

Value Name Description

0 NONE No analog change on channel switching: DIFF0, and OFF0 are used for all chan nels.

1 ALLOWED All ows different analog settings for each channel. See ADC_COR register.

1023

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• TRACKTIM: Tracking Time

• TRANSFER: Transfer Time

The TRANSFER field must be set to 2 to guarantee the optimal transfer time.

• USEQ: Use Sequence Enable

Value Name Description

0 ADCCLK6 The tracking time is 6 ADC clock cycles.

1–14 – The tracking time is 6 ADC clock cycles.

15 ADCCLK7 The tracking time is 7 ADC clock cycles.

Value Name Description

0 NUM_ORDER Normal Mode: The controller converts channels in a simple numeric order depending only on the channel

index.

1 REG_ORDER User Sequence Mode: The sequence respects what is defined in ADC_SEQR1 register and can be used to

convert the same channel several times.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1024

38.7.3 ADC Channel Sequence 1 Register

Name: ADC_SEQR1

Address: 0x40038008

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• USCHx: User Sequence Number x

The allowed range is 0 up to 7, thus only the sequencer fr om CH0 to CH7 can be used.

This register activates only if the USEQ field in ADC_MR field is set to ‘1’.

Any USCHx field is processed only if the CHx-1 it in ADC_CHSR reads logical ‘1’, else any value written in USCHx does

not add the corresponding channel in the conversion sequence.

Configuring the same value in different fields leads to multiple samples of the same channel du ring the conversion

sequence. This can be done consecutively, or not, according to user needs.

When configuring consecutive fie lds with the same value, the associated channe l is samp led as m any time a s th e n umber

of consecutive values, this part of the conversion sequence being triggered by a unique event.

31 30 29 28 27 26 25 24

– USCH7

23 22 21 20 19 18 17 16

USCH6 USCH5

15 14 13 12 11 10 9 8

USCH4 USCH3

76543210

USCH2 USCH1

1025

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7.4 ADC Channel Enable Register

Name: ADC_CHER

Address: 0x40038010

Access: Write-only

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• CHx: Channel x Enable

0: No effect.

1: Enables the corresponding channel.

Note: If USEQ = 1 in ADC_MR, CHx corresponds to the enable of sequence number x+1 described in ADC_SEQR1 (e.g. CH0 enables

sequence number USCH1).

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1026

38.7.5 ADC Channel Disable Register

Name: ADC_CHDR

Address: 0x40038014

Access: Write-only

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• CHx: Channel x Disable

0: No effect.

1: Disables the corresponding channel.

Warning: If the corresponding channel is disabled du ring a conversion or if it is disabled and then reenabled during a con-

version, its associated data and co rrespo nding EOCx and GOVRE flags i n ADC_ISR and OVREx fla gs in ADC_OVER are

unpredictable.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0

1027

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7.6 ADC Channel Status Register

Name: ADC_CHSR

Address: 0x40038018

Access: Read-only

• CHx: Chan ne l x Status

0: The corresponding channel is disabled.

1: The corresponding channel is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1028

38.7.7 ADC Last Converted Data Register

Name: ADC_LCDR

Address: 0x40038020

Access: Read-only

• LDATA: Last Data Converted

The analog-to-digital conversion data is placed into this register at the end of a conversion and remain s until a new conver-

sion is completed.

If OSR = 0 and TAG = 1 in ADC_EMR, the 4 MSB of LDATA carry the channel number in order to get a packed system

memory buffer made of 1 converted data stored in a halfword (16-bit) instead of 1 converted data in a 32-bit word, thus

dividing by 2 the size of the memory buffer.

• CHNBOSR: Channel Number in Oversampling Mode

Indicates the last converted channel when the TAG bit is set in ADC_EMR and the OSR field is not equal to 0 in

ADC_EMR0. If the TAG bit is not set, CHNBOSR = 0.

31 30 29 28 27 26 25 24

––– CHNBOSR

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

LDATA

76543210

LDATA

1029

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7.8 ADC Interrupt Enable Register

Name: ADC_IER

Address: 0x40038024

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Enables the corresponding interrupt.

• EOCx: End of Conversion Interrupt Enable x

• LCCHG: Last Channel Change Interrupt Enable

• DRDY: Data Ready Int errupt Enable

• GOVRE: General Overrun Error Interrupt Enable

• COMPE: Comparison Event Interrupt Enable

• ENDRX: End of Receive Buffer Interrupt Enable

• RXBUFF: Receive Buffer Full Interrupt Enable

31 30 29 28 27 26 25 24

– – – RXBUFF ENDRX COMPE GOVRE DRDY

23 22 21 20 19 18 17 16

––––LCCHG–––

15 14 13 12 11 10 9 8

––––––––

76543210

EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1030

38.7.9 ADC Interrupt Disable Register

Name: ADC_IDR

Address: 0x40038028

Access: Write-only

The following configuration values are valid for all listed bit names of this register:

0: No effect.

1: Disables the corresponding interrupt.

• EOCx: End of Conversion Interrupt Disable x

• LCCHG: Last Channel Change Interrupt Disable

• DRDY: Data Ready Interrupt Disable

• GOVRE: General Overrun Error Interrupt Disable

• COMPE: Comparison Event Interrupt Disable

• ENDRX: End of Receive Buffer Interrupt Disable

• RXBUFF: Receive Buffer Full Interrupt Disable

31 30 29 28 27 26 25 24

– – – RXBUFF ENDRX COMPE GOVRE DRDY

23 22 21 20 19 18 17 16

––––LCCHG–––

15 14 13 12 11 10 9 8

––––––––

76543210

EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0

1031

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7.10 ADC Interrupt Mask Register

Name: ADC_IMR

Address: 0x4003802C

Access: Read-only

The following configuration values are valid for all listed bit names of this register:

0: The corresponding interrupt is disabled.

1: The corresponding interrupt is enabled.

• EOCx: End of Conversion Interrupt Mask x

• LCCHG: Last Channel Change Interrupt Mask

• DRDY: Data Ready Interrupt Mask

• GOVRE: General Overrun Error Interrupt Mask

• COMPE: Comparison Event Interrupt Mask

• ENDRX: End of Receive Buffer Interrupt Mask

• RXBUFF: Receive Buffer Full Interrupt Mask

31 30 29 28 27 26 25 24

– – – RXBUFF ENDRX COMPE GOVRE DRDY

23 22 21 20 19 18 17 16

––––LCCHG–––

15 14 13 12 11 10 9 8

––––––––

76543210

EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1032

38.7.11 ADC Interrupt Status Register

Name: ADC_ISR

Address: 0x40038030

Access: Read-only

• EOCx: End of Conversion x (automatically set / cleared)

0: The corresponding analog channel is disabled, or the conversion is not finished. This flag is cleared when reading the

corresponding ADC_CDRx registers.

1: The corresponding analog channel is enabled and conversion is complete.

• LCCHG: Last Channel Change (cleared on read)

0: There is no comparison match (defined in the Last Channel Compare Window Register (ADC_LCCWR) since the last

read of ADC_ISR.

1: The temperature value reported on ADC_CDR7 has changed since the last read of ADC_ISR, according to what is

defined in the Last Channel Trigger Mode Register (ADC_LCTMR) and Last Channel Compare Window Register

(ADC_LCCWR).

• DRDY: Data Ready (automa tically set / cleared)

0: No data has been converted since the last read of ADC_LCDR.

1: At least one data has been converted and is available in ADC_LCDR.

• GOVRE: General Overrun Error (cleared on read)

0: No general overrun error occurred since the last read of ADC_ISR.

1: At least one general overrun error has occurred since the last read of ADC_ISR.

• COMPE: Comparison Event (cleared on read)

0: No comparison event since the last read of ADC_ISR.

1: At least one comparison event (defined in ADC_EMR and ADC_CWR) has occurred since the last read of ADC_ISR.

• ENDRX: End of Receive Transfer (cleared by writing ADC_RCR or ADC_RNCR)

0: The Receive Counter Register has not reached 0 since the last write in ADC_RCR or ADC_RNCR(1).

1: The Receive Counter Register has reached 0 since the last write in ADC_RCR or ADC_RNCR(1).

• RXBUFF: Receive Buffer Full (cleared by writing ADC_RCR or ADC_RNCR)

0: ADC_RCR or ADC_RNCR(1) has a value other than 0.

1: Both ADC_RCR and ADC_RNCR(1) have a value of 0.

Note: 1. ADC_RCR and ADC_RNCR are PDC registers

31 30 29 28 27 26 25 24

– – – RXBUFF ENDRX COMPE GOVRE DRDY

23 22 21 20 19 18 17 16

––––LCCHG–––

15 14 13 12 11 10 9 8

––––––––

76543210

EOC7 EOC6 EOC5 EOC4 EOC3 EOC2 EOC1 EOC0

1033

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7.12 ADC Last Channel Trigger Mode Register

Name: ADC_LCTMR

Address: 0x40038034

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• DUALT R IG: Dual Trigger ON

0: All channels are triggered by event defined by TRGSEL in ADC_MR.

1: Last channel (higher index) trigger period is defined by OUT1 in RTC_MR.

• CMPMOD: Last Channel Comparison Mode

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

– – CMPMOD – – – DUALTRIG

Value Name Description

0LOW Generates the LCCHG flag in ADC_ISR when the converted data is lower than the low threshold of the

window.

1 HIGH Generates the LCCHG flag in ADC_ISR when the converted data is higher than the high threshold of the

window.

2 IN Generates the LCCHG flag in ADC_ISR when the converted data is in the comparison window.

3 OUT Generates the LCCHG flag in ADC_ISR when the converted data is out of the comparison window.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1034

38.7.13 ADC Last Channel Compare Window Register

Name: ADC_LCCWR

Address: 0x40038038

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• LOWTHRES: Low Threshold

Low threshold associated to compare settings of ADC_LCTMR.

• HIGHTHRES: High Threshold

High threshold associated to compare settings of ADC_LCTMR.

31 30 29 28 27 26 25 24

–––– HIGHTHRES

23 22 21 20 19 18 17 16

HIGHTHRES

15 14 13 12 11 10 9 8

–––– LOWTHRES

76543210

LOWTHRES

1035

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7.14 ADC Overrun Status Register

Name: ADC_OVER

Address: 0x4003803C

Access: Read-only

• OVREx: Overrun Error x

0: No overrun error on the corresponding channel since the last read of ADC_OVER.

1: An overrun error has occurred on the corresponding channel since the last read of ADC_OVER.

Note: An overrun error does not always mean that the unread data has been replaced by a new vali d data. Refer to Section 38.6.12

“Enhanced Resolution Mode and Digital Averaging Function” for details.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

OVRE7 OVRE6 OVRE5 OVRE4 OVRE3 OVRE2 OVRE1 OVRE0

SAM G55 [DATASHEET]

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1036

38.7.15 ADC Extended Mode Register

Name: ADC_EMR

Address: 0x40038040

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• CMPMODE: Comparison Mode

• CMPTYPE: Comparison Type

• CMPSEL: Comparison Selected Channel

If CMPALL = 0: CMPSEL indicates which channel has to be compared.

If CMPALL = 1: No effect.

• CMPALL: Compare All Channels

0: Only channel indicated in CMPSEL field is compared.

1: All channels are compared.

• CMPFILTER: Compare Event Filtering

Number of consecutive compare events necessary to raise the flag = CMPFILTER+1

When programmed to 0, the flag rises as soon as an event occurs.

Refer to Section 38.6.8 “Comparison Window” when using filtering option (CMPFILTER > 0).

31 30 29 28 27 26 25 24

–––––––TAG

23 22 21 20 19 18 17 16

– – SRCCLK ASTE – OSR

15 14 13 12 11 10 9 8

– – CMPFILTER – – CMPALL –

76543210

CMPSEL – CMPTYPE CMPMODE

Value Name Description

0LOW When the converted data is lower than the low threshold of the window , generates the COMPE flag in

ADC_ISR or, in Partial Wakeup mode, defines the conditions to exit system from Wait mode.

1 HIGH When the converted data is higher than the high threshold of the window, generates the COMPE flag in

ADC_ISR or, in Partial Wakeup mode, defines the conditions to exit system from Wait mode.

2IN When the converted data is in the comparison window, generates the COMPE flag in ADC_ISR or, in Partial

Wakeup mode, defines the conditions to exit system from Wait mode.

3OUT When the converted data is out of the comparison window, generates the COMPE flag in ADC_ISR or, in

Partial Wakeup mode, defines the conditions to exit system from Wait mode.

Value Name Description

0 FLAG_ONLY Any conversion is performed and comparison function drives the COMPE flag.

1 START_CONDITION Comparison conditions must be met to start the storage of all conversions until the CMPRST bit is

set.

1037

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

• OSR: Oversampling Rate

Note: FREERUN (see ADC_MR) must be cleared when digital averaging is used.

• ASTE: Averaging on Single Trigger Event

• SRCCLK: External Clock Selection

0 (PERIPH_CLK): The peripheral clock is the source for the ADC prescaler.

1 (PMC_PCKx): PMC_PCKx is the source clock for the ADC prescaler, thus the ADC clock can be independent of the

core/peripheral clock.

• TAG: Tag of ADC_LCDR

0: Sets CHNB field to zero in ADC_LCDR.

1: Appends the channel number to the conversion result in ADC_LCDR.

Value Name Description

0 NO_AVERAGE No averaging. ADC sample rate is maximum.

1 OSR4 1-bit enha nced resolution by averaging. ADC sample rate divided by 4.

2 OSR16 2-bit enhanced resolution by averaging. ADC sample rate divided by 16.

3 OSR64 3-bit enhanced resolution by averaging. ADC sample rate divided by 64.

4 OSR256 4-bit enhanced resolution by averaging. ADC sample rate di vided by 256.

Value Name Description

0 MULTI_TRIG_AVERAGE The average requests several trigger events.

1 SINGLE_TRIG_AVERAGE The average requests only one trigger event.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1038

38.7.16 ADC Compare Window Re gister

Name: ADC_CWR

Address: 0x40038044

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• LOWTHRES: Low Threshold

Low threshold associated to compare settings of ADC_EMR.

• HIGHTHRES: High Threshold

High threshold associated to compare settings of ADC_EMR.

31 30 29 28 27 26 25 24

HIGHTHRES

23 22 21 20 19 18 17 16

HIGHTHRES

15 14 13 12 11 10 9 8

LOWTHRES

76543210

LOWTHRES

1039

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

38.7.17 ADC Channel Differential Input Register

Name: ADC_COR

Address: 0x4003804C

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• DIFFx: Differential Inputs for Channel x

0: Corresponding channel is set in Single-ended mode.

1: Corresponding channel is set in Differential mode.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

DIFF7 DIFF6 DIFF5 DIFF4 DIFF3 DIFF2 DIFF1 DIFF0

15 14 13 12 11 10 9 8

––––––––

76543210

––––––––

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1040

38.7.18 ADC Channel Data Register

Name: ADC_CDRx [x=0..7]

Address: 0x40038050

Access: Read/Write

• DATA: Converted Data

The analog-to-digital conversion data is placed into this register at the end of a conversion and remain s until a new conver-

sion is completed. ADC_CDRx is only loaded if the corresponding analog channel is enabled.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

DATA

76543210

DATA

1041

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38.7.19 ADC Analog Control Register

Name: ADC_ACR

Address: 0x40038094

Access: Read/Write

This register can only be written if the WPEN bit is cleared in the ADC Write Protection Mode Register.

• AUTOTEST: ADC Autotest Modes

31 30 29 28 27 26 25 24

AUTOTEST ––––––

23 22 21 20 19 18 17 16

––––––––

15 14 13 12 11 10 9 8

––––––––

76543210

––––––––

Value Name Description

0 NO_AUTOTEST No auto test, normal mode of operation

1 OFFSET_ ERROR Offset Error test (see electrical characteristics)

2 GAIN_ERROR_HIGH Gain Error (high code) test (see electrical characteristics)

3 GAIN_ERROR_LOW Gain Error (low code) test (see electrical characteristics)

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1042

38.7.20 ADC Write Protection Mode Register

Name: ADC_WPMR

Address: 0x400380E4

Access: Read/Write

• WPEN: Write Protec ti on Ena b le

0: Disables the write protection if WPKEY value corresponds to 0x414443 (“ADC” in ASCII).

1: Enables the write protection if WPKEY value corresponds to 0x414443 (“ADC” in ASCII).

See Section 38.6.15 “Register Write Protection” for the list of write-protected registers.

• WPKEY: Write Protection Key

31 30 29 28 27 26 25 24

WPKEY

23 22 21 20 19 18 17 16

WPKEY

15 14 13 12 11 10 9 8

WPKEY

76543210

–––––––WPEN

Value Name Description

0x414443 PASSWD Writing any other value in this field aborts the write operation of the WPEN bit.

Always reads as 0

1043

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38.7.21 ADC Write Protection Status Register

Name: ADC_WPSR

Address: 0x400380E8

Access: Read-only

• WPVS: Write Protection Violation Status

0: No write protec tion v iola tio n ha s oc curred since the last read of ADC_WPSR.

1: A write protection violation has occurred since the last read of ADC_WPSR. If this violation is an unauthorized attempt to

write a protected register, the associated violation is reported into field WPVSRC.

• WPVSRC: Write Protection Vi olation Source

When WPVS = 1, WPVSRC indicates the register address offset at which a write access has been attempted.

31 30 29 28 27 26 25 24

––––––––

23 22 21 20 19 18 17 16

WPVSRC

15 14 13 12 11 10 9 8

WPVSRC

76543210

–––––––WPVS

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1044

39. Electrical Characteristics

39.1 Absolute Maximum Ratings

39.2 Recommended Operating Conditions

Notes: 1. The VDDCORE range is defined for all conditions (process and temperature). The value may be different than the one used

with the internal regulator which is trimmed in production.

2. To run at fMCK = 120 MHz, the Internal regul ator needs to be trimmed, using the code read in the Unique Identifier on th e

Flash. Refer to Section 8.3.1.5 “Unique Identifier”.

Table 39-1. Absolute Maximum Ratings*

Storage temperature . . . . . . . . . . . . . . . . . . .-60°C to + 150°C *Notice: Stresses beyond those listed under “Absolute

Maximum Ratings” may cause permanent

damage to the device. This is a stress rating only

and functional operation of the device at these or

other conditions beyond those indicated in the

operational sections of this specification is not

implied. Exposure to absolute maximum

rating condit ions for extended periods may

affect device reliability.

Voltage on input pi ns

with respect to ground. . . . . . . . . . . . . . . . . . . . .-0.3V to + 4V

Absolute maximum voltage (VDDIO) . . . . . . . . . . . . . . . . . 4V

Total DC output current on all I/O lines:

49-lead WLCSP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mA

64-lead packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mA

Table 39-2. Recommended Operating Condition s

Symbol Parameter Conditions Min Typ Max Unit

TAAmbient Temperature Range — -40 — +85 °C

VDDCORE DC Supply Core Connected to VDDOUT — — 1.32 V

VDDCOREXT100(1) External DC Supply Core To run @100 MHz 1.15 — 1.32 V

VDDCOREXT120(1) External DC Supply Core To run @120 MHz 1.25 — 1.32 V

VDDCOREXT_WM External DC Supply Core in Wait mode Internal regulator in Wait mode 1.2 — 1.32 V

VDDIO DC Supply I/Os — 1.62 3.3 3.6 V

VDDIO_RIPPLE Supply Ripple Voltage RMS value 10 kHz to 10 MHz — — 30 mV

RMS value > 10 MHz — — 10

Supply Ripple Voltage when ADC used RMS value, 10 kHz to 20 MHz — — 20 mV

VDDIO_SLOPE Slope on VDDIO In Active mode — — 1.5 V/ms

fMCK Master Clock Frequency — — 100 120 (2) MHz

1045

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

39.3 DC Characteristics

The following characteristics are applicable to the operating temperature range: TA = -40°C to 85°C, unless

otherwise specified.

Table 39-3. DC Characteristics

Symbol Parameter Conditions Min Typ Max Unit

VIL Low-level Input Voltage PA21–PA22 (1) ——0.8

All others, NRST -0.3 — 0.3 × VDDIO

VIH High-level Input Voltage PA21–PA22(2) 2.0 — — V

All others, NRST 0.7 × VDDIO —V

DDIO + 0.3V

VOH High-level Output

Voltage

PA21–PA22 (1) VDDIO - 0.4V — —

PA3–PA4, PA14 (IOH = 6.0 mA) VDDIO - 0.4V — —

All others, Drive Low (IOH = 2.0 mA),

NRST VDDIO - 0.4V — —

All others, Drive High (IOH = 4.0 mA),

NRST VDDIO - 0.4V — —

VOL Low-level Output Voltage

PA21–PA22 (1) ——0.4

PA3–PA4, PA14 (IOL = 6.0 mA) — — 0.4

All others Drive Low (IOH = 2.0 mA),

NRST ——0.4

All others Drive High (IOH = 4.0 mA),

NRST ———

VHYS Hysteresis Voltage PA21–PA22 (1) 0.2 — — mV

All others, NRST 0.15 — — mV

IOH Source Current

VOH = VDDIO - 0.4

PA3–PA4, PA14 — — -6

PA21–PA22 (1) ——-20

All others, Drive High — — -4

All others, Drive Low — — -2

NRST — — -4 mA

IOL Sink Current

VOH = VDDIO - 0.4

PA3–PA4, PA14 — — 6

PA21–PA22 (1) ——20

All other Drive High — — 4

All others Drive Low — — 2

VOL = 0.4V

NRST — — 4 mA

IIL Low-level Input Current

Pull-up ON on PA21–PA22 11 33 72 µA

Pull-up OFF -1 – 1 µA

Pull-up ON on all other 10 – 50

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1046

Notes: 1. Using PA21–PA22 (USB pads) requires an external resistor REXT = 33 ohms. Voltage required for USB pads: VDDIO min is

3.0V and max is 3.6V.

2. Except PA3–PA4–PA14 (no pull-down on PA3–PA4–PA14).

Notes: 1. A 4.7 µF or higher ceramic capacitor must be connected between VDDIO and the closest GND pin of the device.

This large decoupling capacitor is mandatory to reduce startup current, thus improving transient response and noise

rejection.

2. To ensure stability, an external 1 µF output capacitor CDOUT must be connected between the VDDOUT and the closest GND

pin of the device. The ESR (Equivalent Series Resistance) of the capacitor must be in the range 20 to 200 mΩ. Multilayer

ceramic capacitors are suitable as output capacitors.

IIH Input High Pull-down OFF -1 – 1 µA

Pull-down ON on all except PA21–PA22 10 – 50

RPULLUP Pull-up Resistor

PA21–PA22 in the following modes:

- As PIO

- PA22 In Full Speed mode

- PA21 In Low Speed Mode

50 100

150 kΩ

Pull-up Resistor All others, NRST 70 100 140 kΩ

RPULLDOWN Pull-down Resistor

PA21–PA22 in the following modes:

- As PIO

- FS/HS 14.25 20

20 24.8 kΩ

All others, NRST (2) 70 100 140 kΩ

Table 39-4. VDDCORE Voltage Regulator Characteristics

Symbol Parameter Conditions Min Typ Max Unit

VDDIO DC Input Voltage Range — 1.62 3.3 3.60 V

VDDOUT DC Output Voltage

Running mo de @1 0 0 MH z(3) 1.08 — 1.32

VRunning mo de @1 2 0 MH z(3) 1.2 — 1.32

Wait mode 0.85 — 1.32

VACCURACY Output Voltage Accuracy Initial output voltage accuracy -5.5 — 5.5 %

ILOAD Maximum DC Output

Current At 1.2V

At 0.95V 10 µ — 60 m A

VLINE Line Regulation VDDIO from 1.62V to 3.6V; ILOAD max — — 30 mV

VLINE-TR Transient Line Regulation VDDIO from 1.62V to 3.6V ; tR = tF = 1 ms; ILOAD

max ——80mV

VLOAD Load Regulation ILOAD = 20% to 80% at ILOAD max — — 20 mV

VLOAD-TR Transient Load Regul ation ILOAD = 20% to 80% at max; tR = tF = 20 µs — — 80 mV

IQQuiescent Current ILOAD = 0 mA at 2V — 1.03 1.8 µA

ILOAD = 0 mA at 3.6V — 2.1 2.6

CDIN Input Decoupling Capacitor (1) ———µF

CDOUT Output Decoupling

Capacitor (2) —1—µF

tON Turn-on Time for Standby

to Normal Mode — — — 600 µs

Table 39-3. DC Characteristics (Continued)

Symbol Parameter Conditions Min Typ Max Unit

1047

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

A 100 nF bypass capacitor between VDDOUT and the closest GND pin of the device helps to decrease output noise and

improves the load transient response.

3. The voltage range value is given for a regulator that is not trimmed. To have the trimmed value of the regulator , please refer

to Unique ID value in Section 8.3.1.5 “Unique Identifier”.

Figure 39-1. Core Brownout Output Waveform

Table 39-5. Core Power Supply Brownout Detector Characteristics

Symbol Parameter Conditions Min Typ Max Unit

VTH- Supply Falling Threshold — 0.71 0.9 1.02 V

VHYST Hysteresis — 10 60 110 mV

VTH+ Supply Rising Threshold — 0.79 1.0 1.08 V

IDDON Current Consumption on VDDCORE Brownout detector enabled — 3.6 6 µA

IDDOFF Brownout detector disabled — — 1

IDDIOON Current Consumption on

VDDIO

Brownout detector enabled — 2.9 5 µA

IDDIOOFF Brownout detector disabled — — 1

tD- VTH- Detection Propagation Time — — 1 15 µs

tSTART Startup Time F rom disabled state to enabled state — — 600 µs

Table 39-6. VDDIO Supply Monitor

Symbol Parameter Conditions Min Typ Max Unit

VTH Supply Monitor Threshold 16 selectable steps 1.6 — 3.4 V

TACCURACY Threshold Level Accuracy -40°C to +85°C -2.5 — 2.5 %

VHYST Hysteresis — — 20 30 mV

IDD Current Consumption Normal mode, -40°C to +85°C — — 10 µA

Standby mode, -40°C to +85°C — — 1

tSTART S t artup Time From disabled state to enabled state — — 600 µs

VDDCORE

VTH-

VTH+

BOD OUTPUT

tD+

tD-

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1048

The threshold is selected through the SUPC_SMMR in the Supply Controller.

Figure 39-2. VDDIO Supply Monitor

Table 39-7. Thresh old Selection

Digital Code Threshold min (V) Threshold typ (V) Threshold max (V)

0000 — 1.6 —

0001 — 1.72 —

0010 — 1.84 —

0011 — 1.96 —

0100 — 2.08 —

0101 — 2.20 —

0110 — 2.33 —

0111 — 2.45 —

1000 — 2.57 —

1001 — 2.69 —

1010 — 2.81 —

1011 — 2.93 —

1100 — 3.05 —

1101 — 3.17 —

1110 — 3.29 —

1111 — 3.41 —

Table 39-8. Power-on Reset Characteristics

Symbol Parameter Conditions Min Typ Max Unit

VTH+ Threshold Voltage Rising At startup 1.49 1.5 4 1.595 V

VTH- Threshold Voltage Falling — 1.39 1.46 1.53 V

VHYST Hysteresis — 50 80 130 mV

tRES Reset Timeout Period — 120 320 800 µs

IPOR Current Consumption — — 300 499 nA

HYST

VDDIO

Reset

TH+

1049

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Figure 39-3. Power-on Reset Characteristics

TH-

TH+

VDDIO

Reset

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1050

39.4 Power Consumption

This section provides information on:

Power consumption of the device in Low-power mode (Wait mode), Sleep mode and Active mode.

Power consumption by peripheral: calculated as the difference in current measurement after enabling then

disabling the co rr es po nd in g cloc k.

39.4.1 Backup Mode Current Consumption

The Backup mode configuration and measurements are defined as follows.

The Backup mode values are the same in Single supply or Dual supply.

Figure 39-4. Backup Mode Measurement Setup

39.4.1.1 Configuration A: Embedded Slow Clock RC Oscillator Enabled

Single supply

Supply Monitor on VDDIO is disabled (SUPC_SMMR.SMSMPL = 0)

RTC is running

RTT is enabled on 1Hz mode

BOD disabled

One WKUPx enabled

Current measurement on AMP1 (see Figure 39-4)

VDDIO

VDDOUT

VDDCORE

Voltage

Regulator

VDDPLL

1.8V

AMP1

Table 39-9. Typical Power Consumption for Backu p Mode

Backup

Total Consumption @25°C

Unit Conditions (AMP1)

Configuration A

VDDIO = 3.6V 2.6 µA

VDDIO = 3.3V 2.1 µA

VDDIO = 3.0V 1.8 µA

VDDIO = 2.5V 1.5 µA

VDDIO = 2.0V 1.3 µA

VDDIO = 1.8V 1.12 µA

VDDIO = 1.6V 1.08 µA

1051

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39.4.2 Wait Mode Power Consumption

Wait mode configuration and measurements are defined below.

39.4.2.1 Wait Mode Single Supply

Figure 39-5. Wait Mode Measuremen t Setup (Single Supply)

Core clock and master clock stopped

There is no activity on the I/O s of the device.

Current measurement as shown in the above figure

All peripheral clocks deactivated

RAM can be powered by block of 8/16/32 Kbytes in Wait mode

BOD disabled



DDIO

= 1.8V (Single supply)

VDDCORE = internal voltage regulator used with default settings

Temperature = 25°C

Table 39-10 provides current consumption in Wait mode under typical conditions.

Table 39-11 provides timing wakeup from RAM in Wait mode under typical conditions.

Table 39-10. Typical Current Consumption in Wait Mode (Single Supply)

Wait Mode Consumption

Refer to Figure 39-5 Typical Value

DDIO

= 1.8V

UnitRAM Powered Flash Conditions VDDOUT Consumption

(AMP1) Total Consumption

(AMP2)

All RAM + 16 Kbytes

SRAM I/D Cache In Deep-power-down mode

20.7 22.0

µA

All RAM powered 17.5 19.6

8 Kbytes powered 10 12.2

Table 39-11. Typical Wa keup Timing in Wait Mode

Wait Mode Wakeup Time

Refer to Figure 39-5

Wakeup Time UnitFast RC Oscillator (MHz) Flash Conditio ns

24 MHz trimmed

All RAM

4.9

µs16 MHz trimmed 6.5

8 MHz 13

VDDIO

VDDOUT

VDDCORE

Voltage

Regulator

AMP1

AMP2

1.8V

SAM G55 [DATASHEET]

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1052

39.4.2.2 Wait Mode Dual Supply

Figure 39-6. Wait Mode Measurement Setup (Dual Supply)

Core clock and master clock stopped

There is no activity on the I/O s of the device.

Current measurement as shown in the above figure

All peripheral clocks deactivated

RAM can be powered by block of 8/16/32 Kbytes in Wait mode

BOD disabled



DDIO

= 1.8V (Dual supply)

VDDCORE = VDDCOREEXT120

Temperature = 25°C

Table 39-10 provides current consumption in Wait mode under typical conditions.

Table 39-12. Typical Current Consumption in Wait Mode (Dual Supply)

Wa it Mode Consumption

Refer to Figure 39-5 Typical Value

DDIO

= 1.8V

UnitRAM Powered Flash Conditions VDDOUT Consumption

(AMP1) Total Consumption

(AMP2)

All RAM powered In Deep-power-down mode 44 48 µA

VDDIO

Voltage

Regulator

Configured

as 120 MHz

VDDOUT

1.8V

VDDCORE

(3.0V–3.6V)

DC/DC

VIN

VOUT

ENA

AMP1

VDDUSB

(only on 64-pin

packages)

AMP2

1053

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39.4.3 Sleep Mode Power Consumption

Sleep mode configuration and measurements are defined below.

Figure 39-7. Measurement Setup for Sleep Mode

Core clock off



DDIO

= 1.8V or 3.3V (single supply)

Master clock (MCK) running at various frequencies with PLLA or the fast RC oscillator

Fast startup through pins WKUP 0– 15

All peripheral clocks deactivated

Temperature = 25°C

Table 39-13 provides current consumption in Sleep mode under typical conditions.

Table 39-13. T ypical Current Consumption in Sleep Mode versus Master Clock (MCK) Variation with PLLA or Fast

Sleep Mode

Consumption Typical Va lue

VDDIO = 1.8V Typical V alue

VDDIO = 3.3V

UnitMCK (MHz) PLLA or Fast RC Total Consumption

(AMP2) Total Consumption

(AMP2)

120 PLL 8.5 8.6

100 PLL 7.2 7.2

96 PLL 6.9 6.9

48 PLL 3.6 3.6

24 PLL 2.0 2.0

24 Fast RC 1.8 1.8

16 Fast RC 1.2 1.2

8 Fast RC 0.7 0.7

VDDIO

VDDOUT

VDDCORE

Voltage

Regulator

AMP1

AMP2

1.8V

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1054

39.4.4 Active Mode Power Consumption

Active mode power configuration and measurements are as follows for all tables:

Temperature = 25°C

Fibonacci or CoreMark algorithm runs from Flash memory with 128-b it access mode or from SRAM

All peripheral clocks ar e de a ctiva te d

Peripheral clocks are divided by 8

PLLB clock source is PCK (PMC_USB.USBS = 1)

Peripheral clock PCK3 is used by timers 0 and 1

All interrupts, MPU and FPU are disabled

Flash is OFF (PMC_FSMR.FFLPM = 1 and PMC_FSMR.FLPM = 0x1)

Master Clock (MCK) runs at various frequencies with PLLA or the fast RC oscillator

Current measurement on AMP1 (VDDCORE) and total current on AMP2

Figure 39-8. Active Mode Measurement Setup

Table 39-14 and Table 39-16 provide active mode current con sumption under typical conditions running the

Fibonacci algorithm.

Table 39-15 and Table 39-17 provide active mode current con sumption under typical conditions running the

CoreMark algorithm.

VDDIO

VDDOUT

VDDCORE

Voltage

Regulator

AMP1

AMP2

1.8V

1055

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Active mode power configuration and measurements are as follows for Table 39-14 and Table 39-15:

VDDIO = 3.3V (single supply)

VDDCORE = value of internal voltage regulator with settings @120 MHz

Table 39-14. Typical Current Consumption Running at VDDIO = 3.3V

MCK (MHz) PLL or Fast RC Wait State

Fibonacci Alg orithm

Unit

128-bit Flash Access SRAM

AMP1 AMP2 AMP2

120 PLL 5 14.9 15.0 13.9

100 PLL 4 12.5 12.6 11.6

48 PLL 2 5.9 6.0 5.5

24 PLL 1 3.0 3.0 2.8

24 Fast RC 1 3.0 3.0 2.8

16 Fast RC 0 2.1 2.1 1.9

8 Fast RC 0 1.1 1.1 1.0

Table 39-15. T ypical Active Current Consumption at VDDIO = 3.3V

MCK (MHz) PLL or Fast RC Wait State

CoreMark Algorithm

Unit

128-bit Flash Access

Cache Di sabled 128-bit Flas h Access

Cache Enabled SRAM

AMP2 AMP2 AMP2

120 PLL 5 24.2 23.6 18.2

100 PLL 4 21.0 19.8 15.3

48 PLL 2 11.5 9.6 7.3

24 PLL 1 6.1 4.9 3.7

24 Fast RC 1 5.9 4.9 3.7

16 Fast RC 0 3.9 3.3 2.5

8 Fast RC 0 2.2 1.7 1.4

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1056

Active mode power configuration and measurements are as follows for Table 39-16 and Table 39-17:

VDDIO = 1.8V (single supply)

VDDCORE = value of internal voltage regulator with settings @120 MHz

Table 39-16. Typical Current Consumption Running at VDDIO = 1.8V

MCK (MHz) PLL or Fast RC Wait State

Fibonacci Algorithm

Unit

128-bit Flash Access SRAM

AMP1 AMP2 AMP2

120 PLL 5 14.7 14.8 13.7

100 PLL 4 12.3 12.4 11.5

48 PLL 2 5.9 6.0 5.5

24 PLL 1 3.0 3.0 2.8

24 Fast RC 1 3 .0 3.0 2.8

16 Fast RC 0 2 .1 2.1 1.9

8 Fast RC 0 1.1 1.1 1.0

Table 39-17. T ypical Active Current Consumption at VDDIO = 1.8V

MCK (MHz) PLL or Fast RC Wait S tate

CoreMark Algorithm

Unit

128-bit Flash Access

Cache Di s abled 128-bit Flas h Access

Cache Enabled SRA M

AMP2 AMP2 AMP2

120 PLL 5 24.1 23.4 18.1

100 PLL 4 20.9 19.6 15.2

48 PLL 2 11.4 9.5 7.3

24 PLL 1 6.1 4.9 3.6

24 Fast RC 1 5.9 4.8 3.5

16 Fast RC 0 3.9 3.2 2.5

8 F ast RC 0 2.1 1.7 1.3

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39.4.5 Peripheral Power Consumption in Active Mode

The peripheral consumption configuration and measurements are as follows:

VDDIO = 1.8V or 3.0V

VDDCORE = value of inte rnal voltage regulator with default settings

Temperature = 25°C

Frequency = 120 MHz

Table 39-18. Power Consumption on VDDCORE

Peripheral Consumption (Typ)

at 1.8V Consumption (Typ)

at 3.0V Unit

PIO Controller A (PIOA)

PIO Controller B (PIOB)

2.6 2.7

µA/MHz

1.0 1.1

UHP 7.2 7.3

UDP 1.8 1.9

CRCCU 0.01 0.01

Timer Counter (TC0_CH0)

Timer Counter (TC0_CH1)

Timer Counter (TC0_CH2)

Timer Counter (TC1_CH3)

Timer Counter (TC1_CH4)

Timer Counter (TC1_CH5)

1.6

0.9

1.4

0.9

1.7

0.9

1.5

0.9

ADC 2.4 2.5

PDM0

PDM1 10.7

11.7 10.8

11.8

MEM2MEM 0.67 0.73

I2SC0

I2SC1 2.6

2.4 2.7

2.5

FLEXCOM0 in USART0

FLEXCOM1 in USART1

FLEXCOM2 in USART2

FLEXCOM3 in TWI3

FLEXCOM4 in TWI4

FLEXCOM5 in SPI5

FLEXCOM6 in TWI6

FLEXCOM7 in SPI7

2.4

2.6

3.2

2.6

1.6

2.6

1.5

2.5

2.8

3.2

2.7

1.7

2.7

1.6

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39.5 Oscillator Characteristics

39.5.1 32 kHz RC Oscillator Characteristics

39.5.2 8/16/24 MHz RC Oscillators Characteristics

Notes: 1. The frequency range can be configur ed in the Supply Controller registers.

2. Only if VDDCORE is connected to VDDOUT.

3. Not trimmed from factory.

4. After trimming from factory; for Wait mode and [-40°C : +85°C].

5. After trimming from factory; for Functional mode and [-40°C : +85°C]

6. After trimming from factory; for typical VDDCORE (internal regulator) and [-40°C : +85°C]

7. With VDDCORE @1.2V and TA = 25°C. For more information on bit MOSCRCEN, refer to the PMC Clock Generator Main

Oscillator register (CKGR_MOR).

The Total Accuracy of the RC 16/24 MHz is: ACC accuracy at 25°C + ACC temperature accuracy.

Table 39-19. 32 kHz RC Oscillator Characteristics

Symbol Parameter Conditions Min Typ Max Unit

— RC Oscillator Frequency — 20 32 44 kHz

— Frequency Supply Dependency Typical at VDDIO = 3V -3 — 3 %/V

— Frequency Temperature Dependency [-40°C : +85°C] versus 25°C -10 — 10 %

Duty Duty Cycle — 45 50 55 %

tON Startup Time — — — 100 µs

IDDON Current Consumption After startup time — 540 860 nA

IDDSTDBY Standby Current Consumption After startup time — 10 150 nA

Table 39-20. 8/16/24 MHz RC Oscillator Characteristics

Symbol Parameter Conditions Min Typ Max Unit

fRANGE RC Oscillator Frequency Range (1) 81624MHz

ACC ACC accuracy at 25°C 16 MHz or 24 MHz output selected (2) -1.5 1.5 %

ACC88 MHz Total Accuracy 8 MHz output selected (1)(3) -30 — 30 %

ACC16 16 MHz Temperature Accuracy

16 MHz output selected (1)(4) -11 — 3

%16 MHz output selected (1)(5) -6 — 3

16 MHz output selected (1)(6) -3.5 — 3

ACC24 24 MHz Temperature Accuracy

24 MHz output selected (1)(4) -11 — 3

%24 MHz output selected (1)(5) -6 — 3

24 MHz output selected (1)(6) -3.5 — 3

Duty Duty Cycle — 45 50 55 %

tON Startup Time Time after MOSCRCEN is set(7) when

90% of frequency is reached. 3—5.5µs

tONTRIM Stabilizing T ime — — 5 — µs

IDDON Active Current Consumption(4)

8 MHz — 95 150

µA16 MHz — 130 200

24 MHz — 180 250

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Example: Total Accuracy of RC 16 MHz : ACCT = ACC+ ACC16 (with VDDCORE = internal regulator

VDDOUT)

ACCT at VDDCore typ. = -5%/+4.5% .

The 16/24 MHz fast RC oscillator is calibrated in producti on. This calibration can be read through the Get CALIB

Bit command (see Sectio n 23. “Enhanced Embedded Flash Controller (EEF C)”) . The frequency ca n be trimmed by

software through the Power Management Controller (PMC).

39.5.3 32.768 kHz Crystal Oscillator Characteristics

Note: 1. RS is the series resistor.

Figure 39-9. 32.268 kHz Crystal Oscillator Schematic

CLEXT = 2 × (CCRYSTAL – CPARA – CPCB).

where CPCB is the capacitance of the printed circuit board (PCB) track layout from the crystal to the SAM G55 pin.

Table 39-21. 32.768 kHz Crystal Oscillator Charac teristics

Symbol Parameter Conditions Min Typ Max Unit

fFREQ Operating Frequency Normal mode with crystal 25 32.768 40 kHz

Duty Duty Cycle — 40 50 60 %

tON Startup Time

RS(1) < 50 kΩCCRYSTAL = 12.5 pF — — 900

CCRYSTAL = 6 pF — — 300

RS(1) < 100 kΩCCRYSTAL = 12.5 pF — — 1200

CCRYSTAL = 6 pF — — 500

IDDON

Current Consumption Wi thout Trimming

RS(1) < 50 kΩCCRYSTAL = 12.5 pF — — 850

CCRYSTAL = 6 pF — — 800

RS(1) < 100 kΩCCRYSTAL = 12.5 pF — — 1100

CCRYSTAL = 6 pF — — 1200

Current Consumption After Trimming

RS(1) < 50 kΩCCRYSTAL = 12.5 pF — — 680

CCRYSTAL = 6 pF — — 650

RS(1) < 100 kΩCCRYSTAL = 12.5 pF — — 650

CCRYSTAL = 6 pF — — 750

PON Drive Level — — — 0.2 µW

RFInternal Resistor Betwe en XIN32 and XOUT32 — 10 — MΩ

CLEXT Maximum External Capacitor on XIN32 and

XOUT32 ———24pF

CPARA Internal Parasitic Capacitance — 0.4 0.5 0.6 pF

XIN32 XOUT32

LEXT

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1060

39.5.4 32.768 kHz Crystal Characteristics

39.5.5 32.768 kHz XIN32 Clock Input Characteristics in Bypass Mode

Figure 39-10. XIN32 Clock Timing

Table 39-22. Cr ystal Characteristics

Symbol Parameter Conditions Min Typ Max Unit

ESR Equivalent Series Resistor (RS) Crystal at 32.768 kHz — 50 100 kΩ

CmMotional Capacitance Crystal at 32.768 kHz 0.6 — 3 fF

CSHUNT Shunt Capacitance Crystal at 32.768 kHz 0.6 — 2 pF

CLOAD Load Capacitance Crystal at 32.768 kHz

Max external capacitor 20 pF 6 — 12.5 pF

Table 39-23. XIN32 Cloc k Electrical Characteristics (In Bypass Mode)

Symbol Parameter Conditions Min Max Unit

1/(tCPXIN32) XIN32 Clock Frequency 32.768 kHz crystal oscillator in

Bypass mode (i.e., when

SUPC_MR.OSCBYPASS = 1 and

SUPC_CR.XTALSEL = 1)

44 kHz

tCPXIN32 XIN32 Clock Period 22 µs

tCHXIN32 XIN32 Clock High Half-period 11 µs

tCLXIN32 XIN32 Clock Low Half-period 11 µs

tCLCH Rise Time 400 ns

tCHCL Fall Time 400 ns

CiXIN32 Input Capacitance 6 pF

RIN XIN32 Pull-down Resistor 3 5 MΩ

VXIN32_IL VXIN32 Input Low-level Voltage -0.3 0.3 × VDDIO V

VXIN32_IH VXIN32 Input High-level Voltage 0.7 × VDDIO VDDIO + 0.3 V

CPXIN32

CLXIN32

CHXIN32

CLCH

CHCL

XIN32_IL

XIN32_IH

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39.5.6 3 to 20 MHz Crystal Oscillator Charact eristics

Notes: 1. RS is the series resistor.

2. RS = 100–200 Ω; CSHUNT = 2.0–2.5 pF; Cm = 2 fF typ, 1.5 fF worst case, using 1 kΩ serial resistor on XOUT.

3. RS = 50–100 Ω; C SHUNT = 2.0–2.5 pF; Cm = 4 fF typ, 3 fF worst case.

4. RS = 25–50 Ω; CSHUNT = 2.5–3.0 pF; Cm = 7 fF typ, 5 fF worst case.

5. RS = 20–50 Ω; CSHUNT = 3.2–4.0 pF; Cm = 10 fF typ, 8 fF worst case.

6. For more information on the bit MOSCXTEN, refer to the PMC Clock Generator Main Oscillator Register (CKGR_MOR).

Table 39-24. 3 to 20 MHz Crystal Oscillator Characteristics

Symbol Parameter Conditions Min Typ Max Unit

freq Operating Frequency Normal mode with crystal 3 16 20 MHz

VDDIO Supply Voltage — 1.62 3.3 3.60 V

VDDCORE Supply Voltage Supplied by voltage regulator or

VDDCOREXT100 or VDDCOREXT120 — — 1.32 V

Duty Duty Cycle — 40 50 60 %

tON Startup Time

3 MHz, CSHUNT = 3 pF — — 14.5

8 MHz, CSHUNT = 7 pF with Cm = 3 fF — — 5

12MHz, CSHUNT = 7 pF with Cm = 3 fF — — 3.8

16 MHz, CSHUNT = 7 pF with Cm = 8 fF — — 1.4

16 MHz, CSHUNT = 7 pF with Cm = 1.6 fF — — 4.5

20 MHz, CSHUNT = 7 pF — — 4.5

IDD_ON

Current Consumption

(on VDDIO)

3 MHz(2)

8 MHz(3)

12 MHz

16 MHz(4)

20 MHz(5)

—

230

300

350

390

450

350

400

470

560

µA

Current Consumption

(on VDDCORE)

3 MHz(2)

8 MHz(3)

12 MHz

16 MHz(4)

20 MHz(5)

—

µA

PON Drive Level

3 MHz — — 15

µW8 MHz — — 30

12 MHz, 16 MHz, 20 MHz — — 50

RfInternal Resistor Between XIN and XOUT — 0.5 — MΩ

CINTLOAD Internal Load Capacitance Integrated load capacitance ((XIN)

(GND) and (XOUT)(GND) in series) 7.5 9 10.5 pF

CCrystal Maximum External Capacitor

on XIN and XOUT Integrated load capacitance

(XIN and XOUT in series) 12.5 — 17.5 pF

CPARABYPASS Internal Parasitic During Bypass On XIN — 5.5 6.3 pF

On XOUT — 2.9 3.3

RPARASTANDBY Internal Impedance During Standby MOSCXT EN = 0 (6) —300—Ω

SAM G55 [DATASHEET]

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Figure 39-11. 3 to 20 MHz Crystal Oscillator Schematic

CLEXT = 2 × (CCRYSTAL – CINTLOAD – CPCB)

Where CPCB is the capacitance of the printed circuit board (PCB) track layout from the crystal to the SAM G55 pin.

39.5.7 3 to 20 MHz Crystal Characteristics

39.5.8 3 to 20 MHz XIN Clock Input Characteristics in Bypass Mode

XIN XOUT

LEXT

CRYSTAL

SAM G55

R = 1K if Crystal Frequency

is lower than 8 MHz

Table 39-25. Crystal Characteris tics

Symbol Parameter Conditions Min Typ Max Unit

ESR Equivalent Series Resistor (RS)

Fundamental at 3 MHz

Fundamental at 8 MHz

Fundamental at 16 MHz

Fundamental at 20 MHz

—

200

100

CmMotional Capacitance — 3 — 8 fF

CSHUNT Shunt Capacitance — — — 7 pF

CLOAD Load Capacitance Max external capacitors: 17 pF 12.5 — 17.5 pF

Table 39-26. XIN Clock Electrical Charac teristics (In Bypass Mode)

Symbol Parameter Conditions Min Typ Max Unit

1/(tCPXIN) XIN Clock Frequency

3–20 MHz crystal

oscillator is in Bypass

mode

——50MHz

tCPXIN XIN Clock Period 20 — — ns

tCHXIN XIN Clock High Half-period 8 — — ns

tCLXIN XIN Clock Low Half-period 8 — — ns

tCLCH Rise Time 2.2 — — ns

tCHCL Fall Time 2.2 — — ns

VXIN_IL XIN Low-level Input Voltage -0.3 — Min

[0.8V, 0.3 × VDDIO]V

VXIN_IH XIN High-level Input Voltage Min

[2.0V, 0.7 × VDDIO]—V

DDIO + 0.3V V

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Figure 39-12. XIN Clock Timing

39.5.9 Crystal Oscillator Design Considerations

39.5.9.1 Choosing a Crystal

When choosing a crystal for the 32.768 kHz slow clock oscillator or for the 3–20 MHz oscillator, several

parameters must be taken into account. Imp ortant pa rameters between crystal and SAM G55 specifications are as

follows:

Load Capacitance

CCRYSTAL is the equivalent capacitor value the oscillator must “show” to the crystal in order to oscillate

at the target fre quency. The crystal mu st be selected according to the internal load cap acit ance (CL) of

the on-chip oscillator. A mismatch of the load capacitance will result in a frequency drift.

Drive Level

Crystal drive level ≥ Oscillator drive level. A crystal drive level lower than the oscillator specification

may damage the crystal.

Equivalent Series Resistor (ESR)

Crystal ESR ≤ Oscillator ESR Max. A crystal with ESR value higher than that of the oscillator may

cause the oscillator to not start.

Shunt Capacitance

Max. crystal shunt capacitance ≤ Oscillator shunt capacitance (CSHUNT). Having a crystal with ESR

value higher than that of the oscillator may cause the oscillator to not start.

tCPXIN

tCPXIN tCHXIN

tCLCH tCHCL

VXIN_IL

VXIN_IH

SAM G55 [DATASHEET]

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39.6 PLLA Characteristics

39.7 PLLB Characteristics

39.8 12-bit ADC Characteristics

Table 39-27. PLLA Characteristics

Symbol Parameter Conditions Min Typ Max Unit

fIN Input Frequency — 20 — 300 kHz

fOUT Output Frequency — 48 — 120 MHz

IPLLON Current Consumption PLL is in Active mode — — 14 µ A/MHz

IPLLOFF Current Consumption PLL is in Standby mode — — 500 nA

tLOCK Lock PLL after Startup Time Lock PLL — — 1.5 ms

Table 39-28. PLLB Characteristics

Symbol Parameter Conditions Min Typ Max Unit

fIN Input Frequency — 20 — 100 kHz

fOUT Output Frequency — 24 — 48 MHz

IPLLON Current Consumption PLL is in Active mode — — 12 µ A/MHz

IPLLOFF Current Consumption PLL is in Standby mode @ 25°C — — 500 nA

PLL is in Standby mode — — 5 µA

tLOCK Lock PLL after Startup Time Lock PLL — — 1.5 ms

Table 39-29. Analog Power Supply Characteristics

Symbol Parameter Conditions Min Typ Max Unit

VDDIO ADC Analog Supply — 1.62 1.8 3.60 V

VDDCORE ADC Digital Supply Internal voltage regulator or

VDDCOREXT100 or VDDCOREXT120 — — 1.32

IVDDIO Current Consumption Sleep mode (Clock off) — 2 4 µA

Normal mode — 1.5 2.0 mA

IVDDCORE Current Consumption Sleep mode (Clock off) — 1 2 µA

Normal mode — 40 80

Table 39-30. Channel Conversion Time and ADC Clock

Symbol Parameter Conditions Min Typ Max Unit

fADC ADC Clock Frequency No missing code 0.1 — 10 MHz

tCP_ADC ADC Clock Period — 100 — 10000 ns

tCONV ADC Conversion Time — 1 — — tcp_ADC

fSAMPLE Sampling Rate 12-bit mode — — 500 ksps

tSTART ADC Startup Time From OFF to Normal mode — — 4 µs

—ADC Inherent Conversion Time (from

start of conversion to end of conversion) —20

ADCCLCK

cycles

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39.8.1 ADC Resolution

39.8.1.1 Differential Mode Conditions

Temperature = 25°C

fADC = 10 MHz

OSR: Number of av er ag e d sam p les

Differential Mode

VDDIO = 1.8V or 3.0V

VDDCORE = value of inte rnal voltage regulator

Table 39-31. ADC Resolution Following Digital Averaging (Typical Value) at 1.8V

Parameter Averaging

Resolution

(ADC_EMR.OSR) Oversampling

Ratio Mode

(bits) INL

(LSB) DNL

(LSB) SNR

(dB) THD

(dB) ENOB

(bits)

OSR = 0 1 12 +/-0.5 -0.5/+0.3 68.4 -86.7 11.1

OSR = 1 4 13 -0.9/+1 -0.6/0.5 72.1 -86.8 11.7

OSR = 2 16 14 +/-1.7 +/-0.7 75.2 -88.1 12.2

OSR = 3 64 15 -3.5/3.4 -1.4/1.6 76.5 -88.1 12.4

OSR = 4 256 16 -8/7.3 -4.3/4.4 76.9 -87.9 12.4

Table 39-32. ADC Resolution Following Digital Averaging (Typical Value ) at 3.0V

Parameter Averaging

Resolution

(ADC_EMR.OSR) Oversampling

Ratio Mode

(bits) INL

(LSB) DNL

(LSB) SNR

(dB) THD

(dB) ENOB

(bits)

OSR = 0 1 12 +/-0.4 -0.4/0.2 70 .7 -84.7 11.4

OSR = 1 4 13 + /-0.9 +/-0.7 74.2 -86.7 12.0

OSR = 2 16 14 -1.7/1.9 -1/1.3 77.6 -87.9 12.5

OSR = 3 64 15 -3.6/3.5 -1.8/1.9 79.1 -88.2 12.8

OSR = 4 256 16 -8.1/6.8 -4.8/4.1 79.6 -88 12.8

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39.8.1.2 Single Mode Conditions

Temperature = 25°C

fADC = 10 MHz

OSR: Number of av er ag e d sam p les

Single Mode

VDDIO = 1.8V or 3.0V

VDDCORE = value of inte rnal voltage regulator

Table 39-33. ADC Resolution Following Digital Averaging (Typical Value ) at 1.8V

Parameter Averaging

Resolution

OSR (ADC_EMR) Oversampling

Ratio Mode

(bits) INL

(LSB) DNL

(LSB) SNR

(dB) THD

(dB) ENOB

(bits)

OSR = 0 1 12 -0.8/+0.9 -0.6/0+ .4 57.4 -73.7 9.2

OSR = 1 4 13 +/-1.6 -0.8/+1 67.8 -73.7 10.8

OSR = 2 16 14 -3.2/+3.1 +/-0.9 70.2 -73.8 11.1

OSR = 3 64 15 -6.3/+6.4 +/-1.9 69 -73.6 11.0

OSR = 4 256 16 -12 .3/+ 12.9 -3.0/+3.6 72.6 -76.7 11.5

Table 39-34. ADC Resolution Following Digital Averaging (Typical Value ) at 3.0V

Parameter Averaging

Resolution

OSR (ADC_EMR) Oversampling

Ratio Mode

(bits) INL

(LSB) DNL

(LSB) SNR

(dB) THD

(dB) ENOB

(bits)

OSR = 0 1 12 -0.8/+0.7 -0.5/+0 .3 58.9 -75.7 9.5

OSR = 1 4 13 -1.6/1+.3 -0.8/+0.6 70.5 -75.4 11.2

OSR = 2 16 14 -3/+2.6 +/-0.9 73.2 -75.4 11.5

OSR = 3 64 15 -6.1/+5.2 -1.1/+1.4 70.7 -75.6 11.2

OSR = 4 256 16 -12.2/+9.8 -2/+2.3 75.9 -78 12.0

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39.8.2 Static Performance Characteristics

39.8.3 Dynamic Performance Characteristics

Note: 1. ADC Clock (fADC) = 10 MHz, fSAMPLE = 500 ksps, fIN = 62 kHz, FFT using 512 points or more, frequency band = [1 kHz,

250 kHz] – Nyquist conditions fulfilled.

Note: 1. ADC Clock (fADC) = 10 MHz, fSAMPLE = 500 ksps, fIN = 62 kHz, FFT using 1024 points or more, frequency band = [1 kHz,

250 kHz] – Nyquist conditions fulfilled.

Table 39-35. Static Performance Characteristics 12-bit Mode INL, DNL

Parameter Conditions Min Typ Max Unit

Native ADC Resolution — — — 12 bit

Resolution with Digital Averaging See Analo g - to -D igital Co nverter (ADC) — — 16 bit

Integral Non-linearity (INL) Single mode -2.5 +/-1 +2.5 LSB

Differential Mode -2 +/-1 +2

Differential Non-linearity (DNL) Single Mode -1 +/-0.5 +1 LSB

Differential Mode -1 +/-0.5 +1

Table 39-36. Static Performance Characteristics Gain and Error Offset 12-bit Mode

Parameter Conditions Min Typ Max Unit

Offset Error Single Mode -3 +/-1 +3

LSB

Differential Mode -2 +/-1 +2

Gain Error Single Mode -3 +/-1 +3

Differential Mode -2 +/-1 +2

Table 39-37. Dynamic Performance Characteristics in Single Mode 12-bit Mode (1)

Parameter Conditions Min Typ Max Unit

Signal to Noise Ratio (SNR) — — 64 — dB

Total Harmonic Distortion (THD) — — -70 — dB

Signal to Noise and Distortion (SINAD) — — 63 — dB

Effective Number of Bits (ENOB) — — 10 — bit

Table 39-38. Dynamic Performance Characteristics in Differential Mode 12-bit Mode (1)

Parameter Conditions Min Typ Max Unit

Signal to Noise Ratio (SNR) — — 70 — dB

Total Harmonic Distortion (THD) — — -74 — dB

Signal to Noise and Distortion (SINAD) — — 68 — dB

Effective Number of Bits (ENOB) — — 11 — bit

SAM G55 [DATASHEET]

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39.8.4 External Reference Voltage

VADVREF is an external reference voltage applied on the pin ADVREF (available on 64-pin packages only). If ADC

not used it is recommended to connect it to VDDIO.

The quality of the reference voltage VADVREF is critical to the performance of the ADC. A DC variation of the

reference voltage VADVREF is converted to a gain error by the ADC. The noise generated by VADVREF is converted

by the ADC to count noise.

Notes: 1. When the ADC is in Sleep mode, the ADVREF impedance has a minimum of 1 MΩ.

39.8.5 Track and Hold Time versus Source Out put Impedance

Figure 39-13 shows a simplified acquisition path.

Figure 39-1 3. Simplified Acquisition Path

During the tracking phase, the ADC must track the input signal during the tracking time shown below:

12-bit mode: tTRACKTIM = 0.12 × ZSOURCE + 250

With tTRACKTIM expressed in ns and ZSOURCE expressed in ohms.

Note: 1. Input voltage range can be up to VDDIO without destruction or over-consumption.

39.8.6 Autotest Values

Table 39-39. ADVREF Electrical Characteristics

Symbol Parameter Conditions Min Typ Max Unit

VADVREF ADVREF Voltage Range Full operational 1.62 – 3.6 V

VnInput Voltage Noise Bandwidth from 1 kHz to 1 MHz – – 100 µVrms

RADVREF ADVREF Input DC Impedance Reference resistor bridge(1) 5811kΩ

Table 39-40. Analog Inputs

Parameter Min Typ Max Unit

Input Voltage Range 0 — VDDIO —

Input Capacitance — 5 6 pF

Input Source Impedance — 50 2000 Ω

Sample & HoldMux.

Zsource Ron

Csample

ADC

Input12-bit

ADC

Core

Table 39-41. Autotest Mode Values

ADC_ACR.AUTOTEST Configuration Code

NO_AUTOTEST –

OFFSET_ ERROR 2048

GAIN_ERROR_HIGH 3840

GAIN_ERROR_LOW 256

1069

SAM G55 [DATASHEET]

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39.9 AC Characteristics

39.9.1 External Reset

39.9.2 I/O Characteri stics

Criteria used to define the maximum frequency of the I/Os are:

Output duty cycle (40%–60%)

Minimum output swing: 100 mV to VDDIO - 100 mV

Addition of rising and falling time inferior to 75% of the period

Notes: 1. Pin Group 1 = PA21, 22 if USB used is Full Speed mode

2. Pin Group 2 = All ot hers, NRST

3. Pin Group 3 = PA3, PA4, PA14

Table 39-42. I/O Characteristics

Symbol Parameter Conditions Min Max Unit

tEXT Minimum reset pulse width (pulse to apply

on NRST pin to guarantee the reset) 1—SCLK

Table 39-43. I/O Characteristics

Symbol Parameter Conditions Min Max Unit

FreqMax1 Pin Group 1(1) Maximum Output Frequency

25 pF

—25MHz

PulseminH1Pin Group 1 (1) High Level Pulse Width 20 — ns

PulseminL1Pin Group 1 (1) Low Level Pulse Width 20 —

FreqMax2

Pin Group 2(2)Maximum Output Frequency with Drive HIGH 10 pF — 40 MHz

25 pF — 20

Pin Group 2(2)Maximum Output Frequency with Drive LOW 10 pF — 65 MHz

25 pF — 33

PulseminH2

Pin Group 2(2) High Level Pulse Width with Drive HIGH 10 pF 12.5 — ns

25 pF 25 —

Pin Group 2(2) High Level Pulse Width with Drive LOW 10 pF 7.7 — ns

25 pF 15 —

PulseminL2

Pin Group 2(2) Low Level Pulse Wi dth with Drive HIGH 10 pF 12.5 — ns

25 pF 25 —

Pin Group 2(2) Low Level Pulse Wi dth with Driv e LOW 10 pF 7.7 — ns

25 pF 15 —

FreqMax3 Pin Group 3(3) Maximum Output Frequency 10 pF — 65 MHz

30 pF — 40

PulseminH3Pin Group 3(3) High Level Pulse Width 10 pF 7.7 — ns

30 pF 12.5 —

PulseminL3Pin Group 3(3) Low Level Pulse Width 10 pF 7.7 — ns

30 pF 12.5 —

SAM G55 [DATASHEET]

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1070

39.9.3 PDM Characteristics

Figure 39-14. PDM Mode

Notes: 1. 1.8V domain: VDDIO from 1.62V to 2V, maximum external capacitor = 20 pF

2. 3.3V domain: VDDIO from 2.85V to 3.60, maximum external capacitor = 20 pF

Table 39-44. PDM Characteristics

Symbol Parameter Conditions Min Max Unit

PDMCLK Clock Frequency — 1 4 MHz

PDM0Data Setup Falling Edge 1.8V domain 4.0 — ns

3.3V domain 4.0 — ns

PDM1Data Hold Falling Edge 1.8V domain 0 — ns

3.3V domain 0 — ns

PDM2Data Setup Rising Edge 1.8V domain 4.0 — ns

3.3V domain 4.0 — ns

PDM3Data Hold Rising Edge 1.8V domain 0 — ns

3.3V domain 0 — ns

PDMCLK

PDMDAT0

PDM2 PDM3

PDMDAT0

PDM0 PDM1

1071

SAM G55 [DATASHEET]

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39.9.4 SPI Characteristics

In Figure 39-16 “SPI Master Mode with (CPOL = NCPHA = 0) or (CPOL = NCPHA = 1)” and Figure 39-17 “SPI

Master Mode with (CPOL = 0 and NCPHA=1) or (CPOL = 1 and NCPHA = 0)” below, the MOSI line shifting edge

is represen ted with a hol d time = 0. Howe ver, it is important to note that for this device, the MISO line is sampled

prior to the MOSI line shifting edge. As shown in Figure 39-15 “MISO Capture in Master Mode”, the device

sampling point extends the propagation delay (tp) for slave and routing delays to more than half the SPI clock

period, wherea s th e com m o n sam p ling point allows only less than half the SPI clock period.

As an example, an SPI Slave working in Mode 0 is safely driven if the SPI Master is configured in Mode 0.

Figure 39-15. MISO Capture in Master Mode

Figure 39-16. SPI Master Mode with (CPOL = NCPHA = 0) or (CPOL = NCPHA = 1)

Figure 39-17. SPI Master Mode with (CPOL = 0 and NCPHA=1) or (CPOL = 1 and NCPHA = 0)

MISO

(slave answer)

SPCK

(generated

by the master)

MISO cannot be provided

before the edge

Bit N Bit N+1

0 < delay < SPI0 or SPI3

Bit N

Internal

shift register

Safe margin,

always >0

Common sampling point Device sampling point

Extended t

SPCK

MISO

MOSI

SPI

SPCK

MISO

MOSI

SPI5

SPI3SPI4

SAM G55 [DATASHEET]

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1072

Figure 39-18. SPI Slave Mode with (CPOL = 0 and NCPHA = 1) or (CPOL = 1 and NCPHA = 0)

Figure 39-19. SPI Slave Mode with (CPOL = NCPHA = 0) or (CPOL = NCPHA = 1)

SPCK

MISO

MOSI

SPI6

SPI7SPI8

NPCSS

SPI12 SPI13

SPCK

MISO

MOSI

SPI9

SPI10 SPI11

NPCS0

SPI14

SPI15

1073

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39.9.4.1 Maximum SPI Frequency

The following formulae give maximum SPI frequency in master Read and Write modes and in slave Read and

Write modes.

Master Write Mode

The SPI sends data only to a slave device, e.g., to an LCD. The limit is given by SPI2 (or SPI5) timing. The

SPI provides a maximum frequency greater than the maximum pad speed (see Section 39.9.2 “I/O

Characteristics”) and thus the maximum SPI frequency is equivalent to the maximum pad speed.

Master Read Mode

tVALID is the slave time response to output data after detecting an SPCK edge. For a non-volatile memory

with tVALID (or tV) = 12 ns Max.

fSPCKmax = 34.7 MHz @ VDDIO = 3.3V.

Slave Read Mode

In Slave mode, SPCK is the input clock for the SPI. The maximum SPCK frequency is given by setup and

hold timings SPI7/SPI8(or SPI10/SPI11). Since this gives a frequency well above the pad limit, the limit in

slave Read mode is given by SPCK pad.

Slave Write Mode

For I/O domain and SPI6, fSPCKMax = 20 MHz. tSETUP is the setup time from the master be fore sampling data.

fSPCKMax 1

SPI0orSPI3

()tVALID

----------------------------------------------------------

fSPCKMax 1

2xS(PI6max orSPI9max

()tSETUP

--------------------------------------------------------------------------------------

SAM G55 [DATASHEET]

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1074

39.9.4.2 SPI Timings

Notes: 1. 1.8V domain: VDDIO fro m 1.62 V to 2V, maximum external capacitor = 20 pF.

2. 3.3V domain: VDDIO from 2.85V to 3.60V, maximum external capacitor = 40 pF.

Note that in SPI master mode, the SAM G55 does not sample the data (MISO) on the edge opposite from where

data clocks out (MOSI) but on the same edge. This is shown in Figure 39-16 and Figure 39-17.

Table 39-45. SPI Timings

Symbol Parameter Conditions Min Max Unit

SPI0MISO Setup time before SPCK rises (master) 1.8V domain(1) 19.3 — ns

3.3V domain(2) 16.8 — ns

SPI1MISO Hold time after SPCK rises (master) 1.8V domain(1) 0—ns

3.3V domain(2) 0—ns

SPI2SPCK rising to MOSI Delay (master) 1.8V domain(1) 04.8ns

3.3V domain(2) 03.2ns

SPI3MISO Setup time before SPCK falls (master) 1.8V domain(1) 21.6 — ns

3.3V domain(2) 17.7 — ns

SPI4MISO Hold time after SPCK falls (master) 1.8V domain(1) 0—ns

3.3V domain(2) 0—ns

SPI5SPCK falling to MOSI Delay (master) 1.8V domain(1) 06.1ns

3.3V domain(2) 04.1ns

SPI6SPCK falling to MISO Delay (slave) 1.8V domain(1) 4.6 20.3 ns

3.3V domain(2) 4.0 16.3 ns

SPI7MOSI Setup time before SPCK rises (slave) 1.8V domain(1) 2.6 — ns

3.3V domain(2) 2.4 — ns

SPI8MOSI Hold time after SPCK rises (slave) 1.8V domain(1) 4.1 — ns

3.3V domain(2) 4.1 — ns

SPI9SPCK rising to MISO Delay (slave) 1.8V domain(1) 4.6 20.6 ns

3.3V domain(2) 4.2 16.9 ns

SPI10 MOSI Setup time before SPCK falls (slave) 1.8V domain(1) 3.0 — ns

3.3V domain(2) 3.0 — ns

SPI11 MOSI Hold time after SPCK falls (slave) 1.8V domain(1) 4.0 — ns

3.3V domain(2) 3.7 — ns

SPI12 NPCS setup to SPCK rising (slave) 1.8V domain(1) 6.0 — ns

3.3V domain(2) 6.0 — ns

SPI13 NPCS hold after SPCK falling (slave) 1.8V domain(1) 3.7 — ns

3.3V domain(2) 3.7 — ns

SPI14 NPCS setup to SPCK falling (slave) 1.8V domain(1) 6.4 — ns

3.3V domain(2) 6.4 — ns

SPI15 NPCS hold after SPCK falling (slave) 1.8V domain(1) 3.9 — ns

3.3V domain(2) 3.9 — ns

1075

SAM G55 [DATASHEET]

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39.9.5 USART in SPI Mode Timings

Figure 39-20. USART SPI Master Mode

Figure 39-21. USART SPI Slave Mode (Mode 1 or 2)

NSS

SPI0

MSBLSB

SPI1

CPOL=1

CPOL=0

MISO

MOSI

SCK

SPI5

SPI2

SPI3

SPI4

• the MOSI line is driven by the output pin TXD

• the MISO line drives the input pin RXD

• the SCK line is driven by the output pin SCK

• the NSS line is driven by the output pin RTS

SCK

MISO

MOSI

SPI6

SPI7SPI8

NSS

SPI12 SPI13

• the MOSI line drives the input pin RXD

• the MISO line is driven by the output pin TXD

• the SCK line drives the input pin SCK

• the NSS line drives the input pin CTS

SAM G55 [DATASHEET]

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1076

Figure 39-22. USART SPI Slave Mode (Mode 0 or 3)

SPCK

MISO

MOSI

SPI9

SPI10 SPI11

NPCS0

SPI14

SPI15

1077

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Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

39.9.5.1 USART SPI TImings

Notes: 1. 1.8V domain: VDDIO from 1.62V to 2V, maximum external capacitor = 20 pF

2. 3.3V domain: VDDIO from 2.85V to 3.60V, maximum external capacitor = 40 pF

Table 39-46. USART SPI Timings

Symbol Parameter Conditions Min Max Unit

Master Mode

SPI0SCK Period 1.8V domain(1) MCK/6 — ns

3.3V domain(2) MCK/6 — ns

SPI1Input Data Setup Time 1.8V domain(1) 0.5 × MCK + 4.2 — ns

3.3V domain(2) 0 .5 × MCK + 4.2 — ns

SPI2Input Data Hold Time 1.8V domain(1) 1.5 × MCK — ns

3.3V domain(2) 1.5 × MCK — ns

SPI3Chip Select Active to Serial Clock 1.8V domain(1) 1.5 × SPCK - 3 — ns

3.3V domain(2) 1.5 × SPCK - 2.5 — ns

SPI4Output Data Setup Time 1.8V domain(1) 0 12.4 ns

3.3V domain(2) 010ns

SPI5Serial Clock to Chip Select Inacti ve 1.8V domain(1) 1 × SPCK - 1.8 — ns

3.3V domain(2) 1 × SPCK - 1.5 — ns

Slave Mode

SPI6SCK falling to MISO 1.8V domain(1) 421ns

3.3V domain(2) 3.4 14.5 ns

SPI7MOSI Setup time before SCK rises 1.8V domain(1) 2 × MCK + 2.3 — ns

3.3V domain(2) 2 × MCK + 2.0 — ns

SPI8MOSI Hold time after SCK rises 1.8V domain(1) 1.5 — ns

3.3V domain(2) 1.5 — ns

SPI9SCK rising to MISO 1.8V domain(1) 4.0 19.5 ns

3.3V domain(2) 3.5 14.5 ns

SPI10 MOSI Setup time before SCK falls 1.8V domain(1) 2 × MCK + 2.8 — ns

3.3V domain(2) 2 × MCK + 2.8 — ns

SPI11 MOSI Hold time after SCK falls 1.8V domain(1) 0.8 — ns

3.3V domain(2) 0.5 — ns

SPI12 NPCS0 setup to SCK rising 1.8V domain(1) 2.5 × MCK + 0.3 — ns

3.3V domain(2) 2 .5 × MCK + 0.2 — ns

SPI13 NPCS0 hold after SCK falling 1.8V domain(1) 1.5 × MCK + 1.3 — ns

3.3V domain(2) 1 .5 × MCK + 1.0 — ns

SPI14 NPCS0 setup to SCK falling 1.8V domain(1) 2.5 × MCK + 0.6 — ns

3.3V domain(2) 2 .5 × MCK + 0.5 — ns

SPI15 NPCS0 hold after SCK rising 1.8V domain(1) 1.5 × MCK +1.9 — ns

3.3V domain(2) 1.5 × MCK +1.8 — ns

SAM G55 [DATASHEET]

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1078

39.9.6 Two-wire Serial Interface Characteristics

Table 39-47 provides the requirements for devices connected to the Two-wire Serial Bus and the compliance of the device

with them. For timing symbols, refer to Figure 39-23.

Notes: 1. CB = capacitance of one bus line in pF. Per I2C standard, CB max = 400 pF

2. The TWCK low period is defined as follo ws: tLOW = ((CLDIV × 2CKDIV) + 4 ) × tMCK

3. The TWCK high period is defined as follows: tHIGH = ((CHDIV × 2CKDIV) + 4 ) × tMCK

4. The field HOLD is defined in the TWI Clock Waveform Generator Register (TWI_CWGR). tCP_MCK = MCK bus period.

Figure 39-23. Two-wire Serial Bus Timing

Table 39-47. Two-wire Serial Bus Requirements

Symbol Parameter Condition Min Max Unit

VHYST Hysteresis of Schmitt Trigger Inputs — 0.150 — V

VOL Low-level Output Voltage 3 mA sink current — 0.4 V

tRRise Time for both TWD and TWC K — 20 + 0.1CB(1) 300 ns

tOF Output Fall Time from VIHmin to VILmax 10 pF < Cb < 400 pF

See Figure 39-23 20 + 0.1CB(1) 250 ns

Ci(1) Capacitance for each I/O Pin — — 10 pF

fTWCK TWCK Clock Frequency — 0 400 kHz

RPValue of Pull-up Resistor

fTWCK ≤ 100 kHz Ω

fTWCK > 100 kHz Ω

tLOW Low Period of the TWCK Clock — (2) —µs

tHIGH High Period of the TWCK Clock — (3) —µs

tHD;STA Hold Time (repeated) START Condition — tHIGH —µs

tSU;STA Setup Time for a Repeated Start

Condition —t

HIGH —µs

tHD;DAT Data Hol d Time — 0 (HOLD +3) ×

tCP_MCK(4) µs

tSU;DAT Data Setup Time — tLOW - ((HOLD +3) ×

tCP_MCK(4))—ns

tSU;STO Setup Time for STOP Condition — t HIGH —µs

tHD;STA Hold Time (repeated) START Condition — tHIGH —µs

VVDDIO 0.4V–

3mA

-------------------------------------

1000ns

-----------------

VVDDIO 0.4V–

3mA

-------------------------------------

300ns

--------------

tSU;STA

tLOW

tHIGH

tLOW

tof

tHD;STA tHD;DAT tSU;DAT tSU;STO

tBUF

TWCK

TWD

1079

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

39.9.7 High-speed Two-wire Serial Interface Characteristics

Table 39-48 provides the requirements for devices connected to the Two-wire Serial Bus.

For timing symbols, refer to Figure 39-23.

Note: 1. For bus li ne loads CB between 100 pF and 400 pF, the timing parameters must be linearly interpolated.

Table 39-48. High-Speed Two-wire Serial Bus Requirements

Symbol Parameter Condition Min Max Unit

fTWCK TWCK Clock Frequency

Capacitive load

CB = 100 pF (max) — 3.4 MHz

CB = 400 pF(1) —1.7

VHYST Hysteresis of Schmitt T rigger Inputs — 0.1 × VDDIO —V

VOL Low-level Output Voltage — — 0.2 × VDDIO V

tRd Rise T ime for both TWD/TWCK (After

Acknowledge)

Capacitive load

CB = 100 pF (max) 10 80 ns

CB = 400 pF(1) 20 160

tOF Output Fall Time from VIHmin to VILmax

Capacitive load

CB =100 pF (max) 10 40 ns

CB = 400 pF(1) 20 80

CICapacitance for Each I/O Pin — — 10 pF

RPValue of Pull-up Resistor

CB ≤ 100 pF Ω

100 pF < CB ≤ 400 pF Ω

tHD;DAT Data Hold Time

Capacitive load from

10 pF to 100 pF 070µs

Capacitive load

CB = 400 pF(1) 0150µs

tSU;DAT Data Setup Time

Capacitive load from

10 pF to 100 pF 10 — ns

Capacitive load

CB = 400 pF(1) 10 — ns

VVDDIO 0.4V–

3mA

-------------------------------------

1000ns

-----------------

VVDDIO 0.4V–

3mA

-------------------------------------

300ns

--------------

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1080

39.9.8 Embedded Flash Characteristics

The maximum operating frequency is given in Table 39-49 below but is limited by the embedded Flash access time when

the processor is fetching code out o f it. Table 39-49 and Ta ble 39-50 below give the de vice maximum and typical operating

frequency depending on the field FWS of the EEFC Flash Mode Register (EEFC_FMR). This field defines the number of

wait states required to access the embedded Flash memory.

The following char ac te rist ics ar e ap p lic ab le at 25°C unless otherwise specified.

Table 39-49. Embedded Flash Wait State at VDDIO 1.62V (Max Value)

FWS Read Operations Maximum Operating Frequency (MHz)

0 1 cycle 20

1 2 cycles 40

2 3 cycles 60

3 4 cycles 80

4 5 cycles 100

5 6 cycles 120

Table 39-50. AC Flash Characteristics

Symbol Parameter Conditions Min Typ Max Unit

ICC Flash Active Current on

VDDCORE

Random 128-bit read at max frequency — 16 20

Random 64-bit read at max frequency — 8 10

Program — 3 5

Erase — 3 5

ICC20 Flash Active Current on

VDDIO

Random 128-bit read at max frequency — 6 10

Random 64-bit read at max frequency — 6 10

Program — 10 15

Erase — 10 15

– Program/Erase Cycle Time

Write page (512 bytes) — 1.5 3 ms

Write word

– 64-bit word

– 128-bit word —20

40 40

80 µs

Erase page mode — 10 50 ms

Erase block mode (by 8Kbytes) — 80 200 ms

Erase sector mode

(Sector of 112/128 Kbytes) — 800 1500 ms

Lock/Unlock time per region — — — ms

– Full Chip Erase 512 Kbytes — 3 6 s

– Data Retention Not powered or powered — 20 years

– Erase Pin Debounce Time Erase pin at high level 200 — — ms

– Endurance Write/Erase cycles per page, block or

sector at temp = 85°C 10K — cycles

1081

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

40. Mechanical Characteristics

40.1 49-lead WLCSP Package

Figure 40-1. 49-lead WLCSP Package Mechanical Drawing

This package respects the recommendations of the NEMI User Group.

Table 40-1. Device and 49-ball WLCSP Package Maximum Weigh t

SAMG55 8.444 mg

Table 40-2. Package Reference

JEDEC Drawing Reference na

JESD97 Classification e1

Table 40-3. 49-ball WLCSP Package Characteristics

Moisture Sensitivity Level 1

Backside coating : 0.025 min

0.040 max

SAM G55 [DATASHEET]

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1082

40.2 64-lead QFN Package

Figure 40-2. 64-lead QFN Package Mechanical Drawing

This package respects the recommendations of the NEMI User Group.

Table 40-4. Device and 64-lead QFN Package Maximu m Weight

160 mg

Table 40-5. Package Reference

JEDEC Drawing Reference MO-220

JESD97 Classification e3

Table 40-6. 64-lead QFN Package Characteristics

Moisture Sensitivity Level 3

1083

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

40.3 64-lead LQFP Mechanical Characteristics

Figure 40-3. 64-lead LQFP Package Drawing

This package respects the recommendations of the NEMI User Group.

Table 40-7. Device and 64-lead LQFP Packa ge Maximum Weight

88.62 mg

Table 40-8. LQFP Package Reference

JEDEC Drawing Reference MS-026

J-STD-609 Classification e3

Table 40-9. 64-lead LQFP Package Characte ristics

Moisture Sensitivity Level 3

CONTROL DIMENSIONS ARE IN MILLIMETERS

Millimeter Inch

Symbol

Min. Nom. Max. Min. Nom. Max.

Symbol Millimeter Inch

Min. Nom. Max. Min. Nom. Max.

Tolerances of form and position

Drawing No.: R-LQ064_N

Rev.: A

Date: 11/22/2013

Jedec Code: MS-026

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1084

40.4 Soldering Profile

Table 40-10 gives the recommended soldering profile from J-STD-020C.

Note: The package is certified to be backward compatible with Pb/Sn soldering profile.

A maximum of three reflow passes is allowed per component.

40.5 Packaging Resources

Land Pattern Definition.

Refer to the following IPC Standards:

IPC-7351A and IPC-782 (Generic Requirements for Surface Mount Design and Land Pattern Standards)

http://landpatterns.ipc.org/default.asp

Atmel Green and RoHS Policy and Package Material Declaration Data Sheet http://www.atmel.com/green/

Table 40-10. Soldering Profile

Profile Feature Green Package

Average Ramp-up Rate (217°C to Peak) 3°C/sec. max.

Preheat Temperature 175°C ±25°C 180 sec. max.

Temperature Maintained Above 217°C 60 sec. to 150 sec.

Time within 5°C of Actual Peak Temperature 20 sec. to 40 sec.

Peak Temperature Range 260°C

Ramp-down Rate 6°C/sec. max.

Time 25°C to Peak Temperature 8 min. max.

1085

SAM G55 [DATASHEET]

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41. Marking

All devices are marked with the Atmel logo and the ordering code.

Additional marking may be in one of the following formats:

where

“YY”: manufactory year

“WW”: manufactory week

“V”: revision

“XXXXXXXXX”: lot number

YYWW V

XXXXXXXXX ARM

SAM G55 [DATASHEET]

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1086

42. Ordering Information

Table 42-1. SAM G55 Ordering Information

Ordering Code MRL Package Carrier Type Operating Temperature

Range

ATSAMG55G19A-UUT A WLCSP49 Reel Industrial

-40°C to 85°C

ATSAMG55G19B-UUT B

ATSAMG55J19A-MU A

QFN64

Tray Industrial

-40°C to 85°C

ATSAMG55J19B-MU B

ATSAMG55J19A-MUT A Reel

ATSAMG55J19B-MUT B

ATSAMG55J19A-AU A

LQFP64

Tray Industrial

-40°C to 85°C

ATSAMG55J19B-AU B

ATSAMG55J19A-AUT A Reel

ATSAMG55J19B-AUT B

1087

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43. Errata

Errata is described in the following sections:

Section 43.1 “Revision A Parts”

Section 43.2 “Revision B Parts”

43.1 Revision A Parts

Errata in this section is applicable to the devices listed in the following table:

43.1.1 USB

Issue: USB functionality not guaranteed over the whole temperature range

The USB device and host functionalities are guaranteed only in a commercial temp er at ur e ra ng e 0°C to +70°C.

Workaround: None.

43.1.2 Analog-to-Digital Converter (ADC)

Issue: INL and DNL values at 25°C

In Single-ended mode at 25°C, the INL and DNL values are as follows:

Workaround: None.

Issue: INL and DNL values from 40°C to 85°C

In Single-ended mode from 40°C to 85°C, the INL and DNL values are as follows:

Workaround: None.

Ordering Code

ATSAMG55G19A-UUT

ATSAMG55J19A-MU

ATSAMG55J19A-MUT

ATSAMG55J19A-AU

ATSAMG55J19A-AUT

Table 43-1. Static Performan ce Characteristics 12-bit Mode INL, DNL

Parameter Conditions Min Typ Max Unit

Integral Non-linearity (INL) Single-ended mode -3.3 ±0.8 +3.4 LSB

Differential Non-linearity (DNL) -2 -0.7 / +0.4 +1.2 LSB

Table 43-2. Static Performan ce Characteristics 12-bit Mode INL, DNL

Parameter Conditions Min Typ Max Unit

Integral Non-linearity (INL) Single-ended mode -5.5 ±0.8 +5.5 LSB

Differential Non-linearity (DNL) -2 -0.7 / +0.4 +1.2 LSB

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1088

43.1.3 Asynchronous Partial Wakeup (SleepWalking) (PMC)

Issue: SleepWalking limitation

If a wakeup request from the WKUP pins, an RTT event or an RTC event occurs simultaneously with the wakeup

of a peripheral that has SleepWalking enabled and simultaneously entering wait mode, the device is not able to

wake up.

Workaround: None.

Issue: PMC Asynchronous Wakeup

Using more than one wakeup event (WKUP or internal event such as RTC, etc.) may lead to a system deadlock.

Workaround: None

43.1.4 SUPC

Issue: No Write Protect ion On SUPC_WUIR

The System Controller Write Protection Mode register (SYSC_WPMR) does not work on the Supply Controller

Wakeup Inputs Register (SUPC_WUIR). The SUPC_WUIR is not write-protected.

Workaround: None

43.1.5 TWI/TWIHS

Issue: TWI/TWIHS Clear command does not work

Bus reset using the “CLEAR” bit of the TWIHS control register does not work correctly during a bus busy state.

Workaround:

When the TWI master detects the SDA line stuck in low state, the procedure to recover is:

1. Reconfigure the SDA/SCL lines as PIO.

2. Try to assert a logic 1 on the SDA line (PIO output = 1) .

3. Read the SDA line state. If the PIO state is a logic 0 then generate a clock pulse on SCL (1-0-1 transition).

4. Read the SDA line state. If the SDA line = 0, go to Step 3; if SDA = 1, go to Step 5

5. Generate a STOP condition.

6. Reconfig ur e SDA/S CL PIOs as peripheral.

43.1.6 CMCC

Issue: RAM CMCC usage limitation

The 16 Kbytes of cache RAM cannot be allocated simultaneously to the RAM Cache and to the SRAM on I/D bus.

If the cache is used, up to 14 Kbytes can be unusable (depending on the selected cache size). If the cache

function is required to optimize the device performances, the size must be set to 8 Kbytes.

Workaround: None

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43.2 Revision B Parts

Errata in this section is applicable to the de vice s liste d in th e followin g ta ble :

43.2.1 SUPC

Issue: No write protection on SUPC_WUIR

The System Controller Write Protection Mode register (SYSC_WPMR) does not work on the Supply Controller

Wakeup Inputs Register (SUPC_WUIR). The SUPC_WUIR is not write-protected.

Workaround: None

43.2.2 TWI/TWIHS

Issue: TWI/TWIHS Clear command does not work

Bus reset using the “CLEAR” bit of the TWIHS control register does not work correctly during a bus busy state.

Workaround:

When the TWI master detects the SDA line stuck in low state the procedure to recover is:

1. Reconfigure the SDA/SCL lines as PIO.

2. Try to assert a Logic 1 on the SDA line (PIO output = 1).

3. Read the SDA line state. If the PIO state is a Logic 0 then ge nerates a clock pulse on SCL (1-0-1 tr ansition ).

4. Read the SDA line state. If the SDA line = 0, go to Step 3; if SDA = 1, go to Step 5.

5. Generate a STOP condition.

6. Reconfig ur e SDA/S CL PIOs as peripheral.

43.2.3 CMCC

Issue: RAM CMCC usage limitation

The 16 Kbytes of cache RAM cannot be allocated simultaneously to the RAM Cache and to the SRAM on I/D bus.

If the cache is used, up to 14 Kbytes can be unusable (depending on the selected cache size). If the cache

function is required to optimize the device performances, the size must be set to 8 Kbytes.

Workaround: None

Ordering Code

ATSAMG55G19B-UUT

ATSAMG55J19B-MU

ATSAMG55J19B-MUT

ATSAMG55J19B-AU

ATSAMG55J19B-AUT

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44. Revision History

In the tables that follow, the most recent version of the document appears first.

Table 44-1. SAM G55 Datasheet Rev. 11289F Revision History

Issue Date Changes

27-May-16

Minor editorial and formatting changes th roughout

”Features”

“USB 2.0 Device” changed to “Crystal-less USB 2.0 Device”

Section 1. “Configuration Summa r y”

Table 1-1 “Configuration Summary”: removed instance of “TWIHS”

Section 2. “Block Diagram”

Figure 2-1 “SAM G55 Block Diagram”: repositioned ‘VUSB’ input and renamed to ‘VDDUSB’

Section 3. “Signal Description”

Table 3-1 “Signal Description List”: renamed ‘VUSB’ to ‘VDDUSB’; inse rted row “Pulse Density Modulation Interfac e

Controller - PDMICx”; “USB OHCI/FS/IC” changed to “USB OHCI/FS”

Section 5. “Power Considerations”

Updated Figure 5-2 “Single Supply”, Figure 5-3 “Dual Supply” and Table 5-1 “Low-power Mode Configuration Summary”

Section 6. “Product Mapping”

Figure 6-1 “SAM G55 Product Mapping”: updated addresses for Internal SRAM blocks

Section 8. “Memories”

Figure 8-2 “Flash Sector Organization”: “A sector size is 64 KBytes” changed to “A sector size is 128 Kbytes”

Updated Section 8.3.1.8 “Calibration Bits”

Section 11. “Debug and Test Features”

Section 11.6.4 “Debug Architecture”: in first paragraph, “four functional units” corrected to “fivie functi onal units”

Updated Section 11.6.9 “IEEE 1149.1 JTAG Boundary Scan”

Section 11.6.10 “ID Code Register”: updated descriptions for bit [0] and for field PART NUMBER

Section 12. “Chip Identifier (CHIPID)”

Updated Table 12-1 “SAM G55 Chip ID Registers” with MRL B chip identifiers

Section 14. “Cortex-M Cache Controller (CMCC)”

Section 14.2 “Embedded Characteristics”: bullet “Write through cache operations, read allocate” changed to “Write

accesses forwarded, cache state not modified. Allocate on read.”

Section 15. “Bus Matrix (MATRIX)”

Section 15.2 “Embedded Characteristics”: added bullet “Automatic clock-off mode for power reduction”

Section 15.6.1.4 “Fixed Priority Arbitration”: in last sentence, deleted instance of “and MATRIX_PRBS”

Table 15-4 “Register Mapping”:

- added registers MATRIX_MCFG3, MATRIX_MCFG4, MATRIX_SCFG4 and MATRIX_PRAS4

- defined offset range 0x00A4–0x010C as “reserved”

Section 15.9.1 “Bus Matrix Master Configuration Registers”: index [x = 0..2] updated to [x = 0..4]

Section 15.9.2 “Bus Matrix Slave Configuration Registers”: index [x = 0..3] updated to [x = 0..4]

Section 15.9.3 “Bus Matrix Priority Registers A For Slaves”: modified title (was “Bus Matrix Priority Registers For

Slaves”); index MATRIX_PRAS0..MATRIX_PRAS3 updated to MATRIX_PRAS0..MATRIX_PRAS4; ad ded field M4PR

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Section 16. “Parallel Input/Output Controller (PIO)”

Table 16-4 “Register Mapping”:

- “Peripheral Select Register 1” corrected to “Peripheral ABCD Select Register 1”

- “Peripheral Select Register 2” corrected to “Peripheral ABCD Select Register 2”

Section 16.6.24 “PIO Peripheral ABCD Select Register 1”: added addresses

Section 16.6.25 “PIO Peripheral ABCD Select Register 2”: corrected addresses

Section 19. “Reset Controller (RSTC)”

‘Slow crystal’ changed to ‘32.768 kHz crystal’ throughout; instances of “is set” changed to “is written to 1”; instances of “is

reset” changed to “is written to 0”

Reworked Section 19.1 “Description” and Section 19.2 “Embed ded Characteristics”

Updated Figure 19-1 “Reset Controller Bl ock Diagra m” and Figure 19-3 “General Reset Timing Diagram”

Updated Section 19.4.2.1 “N RST Signal or Interrupt”

Updated Section 19.4.3.3 “32.768 kHz Crystal Oscillator Failure Detection Reset” and Section 19.4.3.4 “W atchdog

Reset”

Updated Figure 19-6 “Software Reset Timing Diagram” and Figure 19-7 “User Reset Timing Diagram”

Section 20. “Watchdog Timer (WDT)”

Section 20.4 “Functional Description”: changed “To prevent a software deadlock that continuously triggers the watchdog,

the reload of the watchdog must occur . ..” to read “The reload of the watchdog must occur...”

Section 23. “Enhanced Emb edded Flash Controller (EEFC)”

Section 23.4.3.6 “Calibration Bit”: changed information on oscillators that are calibrated in production

Section 24. “Timer Counter (TC)”

Reformatted and renamed Table 24-2 “Channel Signal Description”

Updated Section 24.6.3 “Clock Selection” and Section 24.6.9 “Transfe r with PDC in Capture Mode”

Section 25. “Supply Controller (SUPC)”

Table 25-2 “Register Mapping”: SUPC_MR reset value 0x00E0_ 5A00 corrected to 0x00E0_5400

Added “This register can only be written if the WPEN bit is cleared in the System Controller Write Protection Mode

Supply Monitor Mode Register”

Section 25.5.5 “Supply Contro ller Mode Register”:

- added “This register can only be written if the WPEN bit is cleared in the System Controller Write Protection Mode

- added note “Bits 23 and 14 must always be written to ‘1’.”

- in bitmap cell 23, renamed “ONE” to “ONEA” and added corresponding bit description

- added bit ONE in bitmap cell 14

- modified VDDSEL bit description

Section 25.5.9 “Supply Controlle r Power Mode Register”: modified ECPWRS bit description

Section 26. “Real-time Clock (RTC)”

Updated Section 26.5.6 “Updating Time/Calendar”

Reworked Figure 26-5 “Calibration Circuitry Waveforms”

AD channel index ‘7’ replaced with generic ‘n’ in Section 26.5.8 “Waveform Generation”

Modified Figure 26-6 “Waveform Ge neration for ADC Trigger Event”

Section 26.6.1 “RTC Control Register”: added ‘3’ to CALEVSEL field values

Section 26.6.2 “RTC Mode Register”: added fields TPERIOD and THIGH

Table 44-1. SAM G55 Datasheet Rev. 11289F Revision History (Continued)

Issue Date Changes

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27-May-16

Section 28. “General Purpose Backup Regi sters (GPBR)”

Updated Section 28.1 “Description”

Updated Section 28.2 “Embedded Characteristics”

Section 28.3.1 “General Purpose Backup Register x”: updated GPBR_VALUE field description

Section 29. “Flexible Seria l Communication Controller (FLEXCOM)”

Updated Table 29-1 “I/O Line Description”

Section 29.5.3 “Interrupt Sources”: changed title (was “Interrupt”)

Table 29-2 “FLEXCOM Configuration”: updated TWI function names

Section 29.7 “Flexible Seri al Communication Controller (FLEXCOM) User Interface” : modified title (was “Fle xible Serial

Communication Unit (FLEXCOM) User Interface”)

Section 29.7.1 “FLEXCOM Mode Register”: remo ved mention of “RS485” from OPMODE field description

Section 30. “Universal Synchronous Asynchronous Receiver Transceiver (USART)”

Section 30.5 “Product Dependencies”: instances of “FX_MR” corrected to “FLEX_MR”

Section 30.6.1.2 “Fractional Baud Rate in Asynchronous Mode”: deleted sentence “This feature is only available when

using USART normal mode.”

Section 30.6.3.8 “Receiver Timeout”: deleted redundant paragraphs on STTTO and RETTO.

Section 30.6.4 “ISO7816 Mode”: "...to the value 0x5 for protocol T = 1" changed to "...to the value 0x6 for protocol T = 1"

Section 31. “Serial Peripheral Interface (SPI)”

Section 31.6 “Product Dependencies”: instances of “FX_MR” corrected to “FLEX_MR”

Section 31.7.5 “SPI Comparison on Received Character”: “The comparison trigger event is restarted by writing a 1 to the

REQCLR bit in SPI_CR” changed to “The comparison trigger event is restarted by setting the REQCLR bit in SPI_CR if

SleepW alking mode is disabled”

Section 32. “Two-wire Interface (TWI)”

Change all instances of “TWIHS” to “TWI”

Deleted bullet on SMBALERT in Section 32.6.3.10 “SMBus Mode” and Section “SMBus Mode”

Section 33. “Inter-IC Sound Controller (I2SC)”

Section 33.6.3 “Master, Controll er and Slave Modes”: updated last sentence

Section 33.8.2 “Inter-IC Sound Controller Mode Register”: updated first sentence below bitmap

Section 34. “Pulse Density Modulation Interfa ce Controller (PDMIC)”

Section 34.6 “Functional Description”: removed section “Buffer Structure”

Section 34.6.2.6 “Gain and Offset Compensation”: updated “dgain” bullet

Section 34.7.3 “PDMIC Converted Data Regi ster” : updated DATA field description

Section 34.7.8 “PDMIC DSP Configuration Register 0”: updated OSR field description

Section 36. “USB Host Port (UHP)”

Section 36.1 “Description”: changed content of third paragraph

Added Section 36.2 “Embedded Characteristics”

Section 36.3 “Block Diagram”: deleted warning referencing connecting a pull-down to DP; deleted content about port

overcurrent protection

Updated Section 36.6 “Typi ca l Connection”

Added address for Section 36.7.22 “UHP HC Port 1 Status and Control Register” and Section 36.7.23 “UHP HC Port 2

Status and Control Register”

Table 44-1. SAM G55 Datasheet Rev. 11289F Revision History (Continued)

Issue Date Changes

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Section 37. “USB Device Port (UDP)”

Updated Section 37.4.1 “I/O Lines”

Section 37.5 “Typical Connection” : removed second figure “Board Schematic to Interface Device Peripheral”

Updated Section 37.5.2 “VBUS Monitoring”

Section 38. “Analog-to-Digital Converter (ADC)”

Section 38.1 “Description”: at end of section, deleted paragraphs referencing digital error correction circuit and ADC

timings

Updated Section 38.2 “Embedded Characteristics”

Figure 38-1 “Analog-to-Digital Converter Block Diagram”: added captions “all channels trigger” and “last channel trigger”

Section 38.5 “Product Dependen cies”:

- in Section 38.5 .3 “I/O Lines”, “ADC_ADTRG” corrected to “ADTRG”

- deleted sections “Timer Triggers” and “Conversion Performances”

- added Section 38.5.4 “Hardware Triggers”

Updated Section 38.6.1 “An alog-to-Digital Conversion”

Updated Section 38.6.4 “Conversio n Resolution”

Updated Section 38.6.6 “Conversion Triggers”

Section 38.6.8 “Comparison Window”: instance of ADC_SR corrected to ADC_ISR

Replaced section “Differential Inputs” with Section 38.6.9 “Differential and Single-ended Input Modes”

Removed section “Input Offset”

Updated Section 38.6.10 “ADC Timings”

Updated Section 38.6.11 “Last Channel Specifi c Measurement Trigger”

Revised Section 38.6.12 “Enhanced Resolution Mode and Digital Averaging Function”

Updated Section 38.6.13 “Asyn c hronous and Partial Wakeup (SleepWalking)”

Table 38-7 “Register Mapping”: renamed “Channel Offset Register” to “Channel Differential Input Register”

Section 38.7.2 “ADC Mode Register”: updated TRACKTIM field description.

Section 38.7.12 “ADC Last Channel Trigge r Mode Register”: updated CMPMOD field description

Section 38.7.15 “ADC Extended Mode Regi ster”: updated CMPMODE field description

Section 38.7.17 “ADC Channel Differential Input Register”: changed title (was “ADC Channel Offset Register”) removed

OFFx bits; updated DIFFx bit description

Section 38.7.19 “ADC Analog Control Register” : added address; updated AUTOTEST field description

Section 39. “Electrical Characteristics”

Table 39-3 “DC Characteristics”: updated note on using PA21–PA22 (USB pads)

Updated Figure 39-4 “Backup Mode Measurement Setup”

Updated Figure 39-6 “Wait Mode Measurement Setup (Dual Supply)”

Removed column “FS (kSps)” from Table 39-31 “ADC Resolution Following Digital Averagi ng (Typical Value) at 1.8V”,

Table 39-32 “ADC Resolution Following Digital Averaging (Typical Value) at 3.0V”, Table 39-33 “ADC Resolution

Following Digital Averaging (Typical Value) at 1.8V” and Ta ble 39-34 “AD C Resolution Following Digital Averagi ng

(Typical Value) at 3.0V”

Added Section 39.8.6 “Auto test Values”

Added Section 39.9.1 “External Reset”

Updated Table 39-43 “I/O Characteristics”

Section 42. “Ordering Information”

Table 42-1 “SAM G55 Ordering Information”: added MRL B ordering codes

Table 44-1. SAM G55 Datasheet Rev. 11289F Revision History (Continued)

Issue Date Changes

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27-May-16 Section 43. “Errata”

Added Section 43.2 “Revision B Parts”

Table 44-2. SAM G55 Datasheet Rev. 11289E Revision History

Issue Date Changes

30-Nov-15

Updated ”Description”.

Modified ”Features” (Note in “Core” section & “Up to 48 I/O lines” instead of “Up to 32 I/O lines” in “I/O “section)

Updated Figure 2-1 SAM G5 5 Block Diagram

Modified comments on VDDCORE, DM and DP in Table 3-1 “Signal Description List”.

Replaced PDMCLK0 with PDMIC_CLK and PDMDAT0 with PDMIC_DAT in Figure 2-1 SAM G55 Block Diagram, Table

3-1 “Signal Description List” and Table 9-3 “Multi plexing on PIO Controller A (PIOA)”

Modified note 3 in Table 9-3 “Multiplexing on PIO Controller A (PIOA)” and note 2 in Table 9-4 “Multiplexing on PIO

Controller B (PIOB)”.

Modified Section 5.1 “Power Supplies”

Added Section 5.2.1 “VDDIO Versus VDDCORE”

Modified Section 5.3 “Voltage Regulator” and Section 5.4 “Typical Powering Schematics”

Updated Section 5.5.2 “Backup Mo de”, Section 5. 5. 3 “Wa i t Mo de” and Section 5.5.5 “Low-power Mode Configuration

Summary”

Removed row for chip name “SAM G55N19” in Table 12-1 “SAM G55 Chip ID Registers”

Removed 100-lead version in ARCH description (Section 12.3.1 “Chip ID Register”)

Modified Section 7. “Bootloader”

Modified Section 8.1 “Internal SRAM”, Section 8. 3.1.5 “Uniqu e Identifier” and Section 8.3.1.8 “Calibration Bits”

Added DM and DP in Table 9-6 “System I/O Configuration Pin List”

Section 15. ”Bus Matrix (MATRIX)”

Section 15.3 ”Master/Slave Management”: in tables, harmonized naming for masters

Section 15.8 ”Register Write Protection”: updated text about clearing the WPVS flag

Section 15.9.9 ”Bus Matrix Write Protection Status Register”: updated description of bit WPVS

Section 17. ”Clock Generator”

Modified Figure 17.2 “Embedded Characteristics”

Figure 17-1 “Clock Generator Block Diagram”: updated Clock Genera tor circuitry

Updated Section 17.5.7 ”Switching Main Clock between the RC Oscillator and the Crystal Oscillator”

Updated Section 17.5.6 ”Main Clock Frequency Counter”

Section 18. ”Power Management Controlle r (PMC)”

Figure 18-1 “General Clock Block Diagram”: updated Clock Generator circuitry

Added information on 32768Hz crystal oscillator frequency monitor: updated Section 18.2 ”Embedded Characteristics”,

added Section 18.16 ”32768 Hz Crystal Oscillator Frequency Monitor”, added XT32KFME bit in Section 18.20.7 ”PMC

Clock Generator Main Oscillator Register”, added XT32KERR in Section 18.20.14 ”PMC Interrupt Enable Register”,

Section 18.19 ”Register Write Protection”: added “PMC Clock Generator Main Clock Frequency Register” to list of

protectable registers

Section 18.20.15 ”PMC Interrupt Disable Register” and Section 18.20.16 ”PMC Status Register”.

Section 18.20.7 ”PMC Clock Generator Main Oscillator Regi ster”: updated notes in CFDEN bit description.

Section 18.20.8 ”PMC Clock Generator Main Clock Frequency Register”: updated MAINF bit description

Section 18.13 ”Fast Startup” : added one step and inserted warning

Table 44-1. SAM G55 Datasheet Rev. 11289F Revision History (Continued)

Issue Date Changes

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Section 20. ”Watchdog Timer (WDT)”

Updated Section 20.5.3 ”Watchdog Timer Status Register”

Section 20.5.2 ”Watchdog Timer Mode Register”: updated note on modification of WDT_MR values.

Added “When the WDDIS bit is set, the fields WDV and WDD must not be modified.” in Se ction 20.4 ”Functional

Description” and Section 20.5.2 ”Watchdog Timer Mode Register” (WDDIS bit description)

Replaced “Idle mode” with “Sleep mode (Idle mode)” in Section 20.1 ”Description”and with “Sleep mode” in Section 20.4

”Functional Description”

Section 23. ”Enhanced Emb edded Flash Controller (EEFC)”

Section 23.5.1 ”EEFC Flash Mode Register”: added missing cross-reference to Section 6.5 ”EEFC Write Protection Mode

Modified Section 23.2 ”Embedded Characteristics”

Added Figure 23-1 Flash Memory Areas

Section 24. ”Timer Counter (TC)”

Section 24.1 ”Description”: modified first paragraph

Section 24.7.3 ”TC Channel Mode Regi ster: Waveform Mode”: in ‘Name’ line, repl aced “(WAVE = 1)” with

“(WAVEFORM_MODE)

Moved Table 24-1 “Timer Counter Clock Assignment” from Section 24.1 ”Description” to Section 24.3 ”Block Diagram”

Section 24.5.2 ”Power Management” added “of each channel” after "to enable the Timer Counter clock"

Section 24.5.3 ”Interrupt Sources”: added “per channel” after "The TC has an interrupt line"

Section 24.6.16 ”Register Write Protection”: added "The Timer Counter clock of the first channel must be enabled to

access TC_WPMR."

Section 24.7.16 ”TC Write Protection Mode Register” updated WPEN bit description

Section 26. ”Supply Controller (SUPC)”

Table 26-2 “Register Mapping”: Modified SUPC_PWMR reset value (0x00FF_180A instead of 0x0000_0000)

Added VDDSEL and VRVDD in Section 26.5.5 ”Supply Controller Mode Register”

Modified Section 26.5.9 ”Supply Controller Power Mode Register”

Section 26. ”Real-time Clock (RTC)”

Updated Section 26.1 ”Description”“ and Section 26.5 ”Functional Description ” (removed references to the 20th century)

Updated Section 26.5.7 ”RTC Accurate Clock Calibration”

Updated Section 26.2 ”Embedded Characteristics”.

Deleted “All non-significant bits read zero.” from the following registers:

- Section 26.6.3 ”RTC Time Register”

- Section 26.6.4 ”RTC Calendar Register”

Figure 26-4 “Calibration Circuitry Waveforms”: corrected two instances of “3,906 ms” to “3.906 ms”

Section 26-2 ”Register Mapping ”: added offset 0xCC as reserved

Section 26.6.1 ”RTC Control Register”: updated descriptions of value ‘0’ for bits UPDTIM and UPDCA

Section 28. ”General Purpose Backup Regi sters (GPBR)”

Rephrased partly Section 2. ”Description” and Section 3. ”Embedded Characteristics”

Section 30. ”Flexible Seria l Communication Controller (FLEXCOM)”

Added Table 30-2 “FLEXCOM configuration”

Table 44-2. SAM G55 Datasheet Rev. 11289E Revision History (Continued)

Issue Date Changes

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Section 30. “Universal Synchronous Asynchronous Receiver Transceiver (USART)”

Removed references to RS485 mode

Section 30.5.1 “I/O Lines”: removed second paragraph (“To prevent the TXD line from falling... must also be enabled

Section 30.7.17 ”USART Channel Status Register”, Section 30.7.18 ”USART Channel Status Register (SPI_MODE)”,

Section 30.7.19 ”USART Channel Status Register (LIN_MODE)”: corrected description of bit “ENDRX: End of RX Buffer”

(“has not reached” replaced with “has reached” for 1:)

Section 30.6.10.5 ”Character Transmission”: after first paragraph, inserted new paragraph “The chip select line is de-

asserted for a period equivalent to three bits between the transmission of two data.”

Section 30.6.8 ”USART Comparison Function on Received Character”: corrected instance of “US_RDR” to “US_RHR”

Figure 30-39 Receive Holding Register Management: updated to add RHR details

Section 30.7.1 “USART Control Register”: updated RTSEN and RTSDIS bit descriptions

Section 30.7.23 ”USART Baud Rate Generator Register”: restructured equations in CD field description

Section 30.7.25 ”USART Transmitter Timeguard Register”: restructured equations in TG field description

Added NSSE bit in Section 30.7.6 “USART Interrupt Enable Register (SPI_MODE)”, Section 30.7.10 ”USART Interrupt

Disable Register (SPI_MODE)”, Section 30.7.14 ”USART Interrupt Mask Register (SPI_MODE)” and

Section 30.7.18 ”USART Channel Status Register (SPI_MODE)”

Added NSS bit in Section 30.7.18 ”USART Channel Status Register (SPI_MODE)”

Added Warning in Section 30.6.1.2 ”Fractional Baud Rate in Asynchronous Mode” and Section 30.7.23 ”USART Baud

Rate Generator Register”

Added Figure 30-28 RT S line software control when US_MR.USART_MODE = 2”

Updated USART_MODE desciption in Section 30.7.3 “USART Mode Register”

Added CLKO bit in Section 30.7.4 “USART Mode Register (SPI_MODE)”

Updated RTSDIS description in Section 30.7.1 “USART Control Register”

Updated Section 30.6.11.8 ”Slave Nod e Synchronization” (modified Oversampling paramete r:

“OVER = 0 => 16X or OVER = 1 => 8X” instead of “Over=0 => 16X or Over=0 => 8X”)

Table 44-2. SAM G55 Datasheet Rev. 11289E Revision History (Continued)

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Section 32. ”Two-wire Interface (TWI)”

Between Section 32.3 ”Block Diagram”and Section 32.4 ”I/O Lines Description”, removed section “Appli cation Block

Diagram”

Section 32.6.3 ”Master Mode” and Section 32.6.5 ”Slave Modes”: removed subsection “Application Block Diagram”

Section 32.7.6 ”TWI Status Register”: in TXRDY bit description, added links to figures for “TXRDY behavior in Master

mode”

Updated Section 32.6.5.6 ”Alte rnative Command”

Section 32.2 ”Embedded Characteristics”: added note “See Table 2-1 for details on compatibility with I²C Standard.”

Section 32.5.2 ”Power Management”: changed “FX_MR” to “ FLEXCOM Mode Regiser (FLEX_MR)”

Section 32.5.3 ”Interrupt Sources”: corrected “SPI interrupt line” to “TWI interrupt line”; corrected “FX_MR” to “FLEX_MR”

Table 32-5 “Register Mapping”: removed reset value for TWI_THR (register is write-only); added reset value for

TWI_ACR

Section 32.6.3.4 ”Master Transmitter Mode”: added note describing how TXRDY flag can be cleared

Section ”Read Sequence”: added note describing how TXRDY flag can be cleared

Section 32.6.3.2 ”Programming Master Mode”: added register names

Section 32.6.3.10 ”SMBus Mode”: replaced instance of “will send/check the PEC field” with “will send/check the PEC field

of the TWI frame”

Updated Table 32-2, “I/O Lines Description”

Section 32.7.5 ”TWI Clock Waveform Generator Register”: renamed SCL to TWCK in descriptions of fields CLDIV,

CHDIV, and CKDIV

Section 32.7.6 ”TWI Status Register”: updated descriptions of bits SCL and SDA

Updated Section 32.6.5.5 ”H igh-Speed Slave Mode”

Removed CKSRC bit description in Section 32.7.5 ”TWI Clock Waveform Generator Register”

Section 33. ”Inter-IC Sound Controller (I2SC)”

Updated explanations regarding calculation of the master clock frequency in Section 33.6.5 ”Serial Clock and Word

Select Generation” and in IMCKDIV and IMCKFS field descriptions in Section 33.8.2 ”Inter-IC Sound Controller Mode

Section 33.8.2 ”Inter-IC Sound Controller Mode Register”: Modified IWS descriptio n and FORMAT field descriptio n and

added note 2 to MCKDIV field description

Section 34. ”Pulse Density Modulation Interfa ce Controller (PDMIC)”

Section 34.7.7 ”PDMIC Interrupt Status Register”: added “(cleared by writing PDMIC_RCR or PDMIC_RNCR)” to

descriptions of bits ENDRX and RXBUF

Table 34-4 “Register Mapping”: adde d row for reserved offset range 0x08–0x10

Updated Section 34.7.7 ”PDMIC Interrupt Status Register”

PDMDAT’ renamed to ‘PDMIC_DAT’ and ‘PDMCLK’ renamed to ‘PDMIC_CLK’ in Section 34.3 “Block Diagram” , Table

34-1 “PDMIC Pin Description”, Section 34.1 ”Descr ip ti o n ”, Section 34.6.1.3 ”Restrictions” and Section 34.7.2 ”PDMIC

Mode Register”

Table 44-2. SAM G55 Datasheet Rev. 11289E Revision History (Continued)

Issue Date Changes

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1098

30-Nov-15

Section 37. ”USB Device Port (UDP)”

Section ”Using Endpoints With Ping-pong Attribute”: Replaced Bank 0 with Bank 1 in step 12

Section 37.7.10 ”UDP Endpoint Control and Status Register (CONTROL_ BULK)”: below warning, inserted code

Section 37.7.7 ”UDP Interrupt Status Register”: in EPxINT bit description, corrected two instances of “Endpoint0

Interrupt” to “Endpointx Interrupt”

Section 37.7.10 ”UDP Endpoint Control and Status Register (CONTROL_ BULK)”: reorganized order of EPTYPE field

configuration values and add ed value ‘4’ (reserved)

Section 37.7.11 ”UDP Endpoint Control and Status Register (ISOCHRONOUS)”: reorganized order of EPTYPE field

configuration values and add ed value ‘4’ (reserved)

Modified Section 37.4.1 ”I/O Lines”

Section 39. ”Analog-to-Digital Converter (ADC)”

Renamed “Hold time” to “Transfer time”

Section 39.2 ”Embedded Characteristics”: replaced “Hz” with “sps” in Conversion Rate Characteristics: replaced “Hz”

with “sps” in Conversion Rate Characteristics

In text below Section 39-8 ”Independent Trigge r Measurement for Last Channel (ADC_CHSR[LCI] = 0 and

ADC_MR.TRGEN = 1)”, replaced “rate defined by the RTC OUT1 field” with “rate defined by the RTCOUT1”

Figure 39-9 Only Last Channel Measurement Triggered at Low Speed (ADC_CHSR[LCI] = 0 and ADC_MR.TRGEN = 0):

replaced “RTCOUT1 field” with “RTCOUT

Revised Section 39.6 .1 ”Ana l o g-to-Digital Conversion”

Added Section 39.6.2 ”ADC Clock”

Updated Section 39.6.3 ”AD C Reference Voltage” and changed title (was “Conversion Reference”)

Section 39.7.2 ”ADC Mode Register”: updated description of ‘TRANSFER’’ field

Section 39.7.4 ”ADC Channel Enable Registe r ”: upd ated CHx field description

Removed Section “Analog Inputs”

Modified Section 39.5.3 ”I/O Lines”

Modified information about USCHx fields in:

- Section 39.6.7 ”Sleep Mode and Conve rsion Sequencer”

- Section 39.7.3 ”ADC Channel Se quence 1 Register”

Updated Section 39.6.12 ”Last Channel Specifi c Measurement Trigger”

Updated Section 39-7 ”Same Trig ger for All Channels (ADC_CHSR[LCI] = 1 and ADC_MR.TRGEN = 1)”, Section 39-8

”Independent Trigger Measurement for Last Channel (ADC_CH SR[LCI] = 0 and ADC_MR.TRGEN = 1)” and Section 39-

9 ”Only Last Channel Measurement Triggered at Low Speed (ADC_CHSR[LC I] = 0 and ADC_MR.TRGEN = 0)”

Section 39. “Electrical Characteristics”

Updated Table 39-2 “Recommen ded Operating Conditions”, Table 39-3 “DC Characteristics” , Table 39-4 “VDDCORE

Voltage Regulator Ch aracteristics”

Modified Section 39.4.1 “Backup Mode Current Consumption”, Section 39.4.2 “Wait Mode Power Consumption”, Section

39.4.2.2 “Wait Mode Dual Supply”, Section 39.4.4 “Active Mode Power Consumption”, Section 39.6 “PLLA

Characteristics”, Section 39.7 “PLLB Characteristics”, Section 39.5.2 “8/16/24 MHz RC Oscillators Characteristics”,

Section 39.5.6 “3 to 20 MHz Crystal Oscillator Characteristics”, Table 39-29 “Analog Power Supply Characteristics” ,

Section 39.8.4 “External Reference Volta ge”, Table 39-44 “PDM Characteristics”, Section 39.9.4 “SPI Characteristics”,

Section 39.9.4.1 “Maximum SPI Frequency”, Section 39.9.4.2 “SPI Timings”, Section 39.9.5.1 “USART SPI TImings”

(Table 39-44 title)

Added Section 39.5.5 “32.768 kHz XIN32 Clock Input Characteristics in Bypass Mode”

Section 43. “Errata”

Added Section Issue: “No Write Protection On SUPC_WUIR”, Section Issue: “PMC Asynchronous Wakeup”, Section

43.1.5 “TWI/TWIHS” and Section 43.1.6 “CMC C”

Table 44-2. SAM G55 Datasheet Rev. 11289E Revision History (Continued)

Issue Date Changes

1099

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

Table 44-3. SAM G55 Datasheet Rev. 11289D Revision History

Issue Date Changes

15-Jun-15

Removed “Preliminary” marking.

Modified Section ”Description”

Updated Figure 2-1 “SAM G55 Block Diagram”(GPBR)

Added note to PB0/PB15 in Table 3-1 “Signal Description List”

Added note to Section 4.2.1 “64-lead QFN / LQFP Pinout”

Modified “Flash Wait States” information in Section 5.5.3 “Wa i t Mo de ”

Replaced “Processor and architecture ” section with Section 6. “Product Mapping” (removed redundant information)

Modified Figure 6-1 SAM G55 Product Mapping (information added in “Boot Memory”)

Section 7. “Bootloader”

Updated section

Section 8. “Memories”

Modified Section 8.3.1.5 “Unique Identifier”

Section 9. “Peripherals”

Added notes to Extra functions in Table 9-3 “Multiplexing on PIO Controller A (PIOA)” and Table 9-4 “Multiplexing on PIO

Controller B (PIOB)”

Added Section 9.3 ”System I/O Lines”

Section 10. “Real-time Event Management”

Replaced AFEC with ADC in Table 10-1, “Real-ti me Even t Mapping List”

Section 11. “Debug and Test Features”

Added Section 11.6.2 “NRST Pin” and Section 11.6.3 “ERASE Pin”

Section 38. “Analog-to-Digital Converter (ADC)”

Modified conversion rate in Section 38.2 “Embedded Characteristics”

Section 39. “Electrical Characteristics”

Updated Table 39-20, “8/16/24 MHz RC Oscillator Characteristics” and Section 39.4. 2 “Wa i t Mo de Power Consumptio n”

Section 39.4.4 “Active Mode Power Consumption”: removed table “Typi cal Current Consu mpti on Running at VVDDIO =

1.8V and VVDDCORE = default settings” and text.

Table 39-3, “DC Characteristics”: added reference to REXT in note 1.

Modified fIN min value in Table 39-27, “PLLA Characteristics” and Table 39-28, “PLLB Characteristics”

Updated Section 39.5.2 “8/1 6/24 MHz RC Oscillators Characteristic s”

Removed note on bi t LO WR ES in Table 39-31, “ADC Resolution Following Digital Averaging (Typical Value) at 1.8V”,

Table 39-32, “ADC Resolution Following Digital Averaging (Typical Value) at 3.0V”, Table 39-33, “ADC Resol ution

Following Digital Averaging (Typical Value) at 1.8V”, Table 39-34, “ADC Resolution Following Digital Averaging (Typical

Value) at 3.0V”

Section 40. “Mechanical Characteristics”

Updated Table 40-6 “64-lead QFN Package Characteristics”

Section 42. “Orderi ng In forma tion”

Replaced ATSAMG55J19-A-AUT with ATSAMG55J19A-AUT in Table 42-1 “SAM G55 Orderi ng Information”.

Section 43. “Errata”

Modified Section Issue: “INL and DNL values at 25°C”: added temperature of 25°C.

Added new Section Issue: “INL and DNL values from 40°C to 85°C”.

SAM G55 [DATASHEET]

Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16

1100

Table 44-4. SAM G55 Datasheet Rev. 11289C Revision History

Issue Date Changes

14-Jan-15 Added “Preliminary Status” marking.

Table 44-5. SAM G55 Datasheet Rev. 11289B Revision History

Issue Date Changes

13-Jan-15

Section 5. “Power Considerations”

Added Section 5.2 “Powerup Considerations”

Section 18. “Power Management Controlle r (PMC)”

Section 18.19.18 “PMC Fast Startup Mode Register”: added bit FFLPM (Force Flash Low-power Mode)

Section 39. “Electrical Characteristics”

Updated and restructured Section 39.4.4 “Active Mode Power Consumption”.

Updated Table 39-20 “8/16/2 4 MHz RC Oscillator Characteristics”.

Table 44-6. SAM G55 Datasheet Rev. 11289A Revision History

Issue Date Changes

19-Dec-14 First issue.

i
SAM G55 [DATASHEET]
Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16
Table of Contents
Configuration Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
Block Diagram  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Signal Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Package and Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1 49-ball WLCSP Pinout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2 64-lead QFN/LQFP Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Power Considerations  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1 Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2 Powerup Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3 Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4 Typical Powering Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5 Functional Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6 Fast Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  17
Product Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Bootloader  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Memories  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1 Internal SRAM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2 Internal ROM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3 Embedded Flash. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1 Peripheral Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2 Peripheral Signal Multiplexing on I/O Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3 System I/O Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Real-time Event Management  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
1 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
2 Real-time Event Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Debug and Test Features  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3 Debug and Test Block Diagram  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4 Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5 Debug and Test Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Chip Identifier (CHIPID)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3 Chip Identifier (CHIPID) User Interface  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
ARM Cortex-M4 Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

SAM G55 [DATASHEET]
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ii
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4 Cortex-M4 Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5 Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6 Cortex-M4 Instruction Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
7 Cortex-M4 Core Peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
8 Nested Vectored Interrupt Controller (NVIC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
9 System Control Block (SCB). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234
10 System Timer (SysTick) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
11 Memory Protection Unit (MPU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
12 Floating Point Unit (FPU)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
13 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
Cortex-M Cache Controller (CMCC)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
5 Cortex-M Cache Controller (CMCC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
Bus Matrix (MATRIX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 320
3 Master/Slave Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
4 Memory Mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
5 Special Bus Granting Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
6 Arbitration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
7 System Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324
8 Register Write Protection  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  324
9 Bus Matrix (MATRIX) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Parallel Input/Output Controller (PIO)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336
5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
6 Parallel Input/Output Controller (PIO) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
Clock Generator   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
4 Slow Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
5 Main Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
6 Divider and PLL Block. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405
 Power Management Controller (PMC)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408
4 Master Clock Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409
5 Processor Clock Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409

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6 SysTick Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410
7 USB Clock Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410
8 Peripheral Clock Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  410
9 Asynchronous Partial Wakeup (SleepWalking). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
10 Free-Running Processor Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
11 Programmable Clock Outpu t Controller  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
12 Core and Bus Independent Clocks for Peripherals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
13 Fast Startup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  414
14 Startup from Embedded Flash  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
15 Main Clock Failure Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416
16 32768 Hz Crystal Oscillator Frequency Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
17 Programming Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
18 Clock Switching Details. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
19 Register Write Protection  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
20 Power Management Controller (PMC) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
Reset Controller (RSTC)   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
5 Reset Controller (RSTC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
Watchdog Timer (WDT)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
5 Watchdog Timer (WDT) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
Peripheral DMA Controller (PDC)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
3 Peripheral DMA Controller Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
4 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485
5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
6 Peripheral DMA Controller (PDC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
Memory to Memory (MEM2MEM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
6 Memory to Memory (MEM2MEM) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
Enhanced Embedded Flash Controller (EEFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
3 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511
5 Enhanced Embedded Flash Controller (EEF C) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . .  528

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Timer Counter (TC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
4 Pin List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537
5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537
6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538
7 Timer Counter (TC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552
Supply Controller (SUPC)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
4 Supply Controller Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580
5 Supply Controller (SUPC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588
Real-time Clock (RTC)   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 601
4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602
6 Real-time Clock (RTC) User Interface  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
Real-time Timer (RTT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 628
4 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 629
5 Real-time Timer (RTT) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 632
General Purpose Backup Registers (GPBR)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639
3 General Purpose Backup Registers (GPBR) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 640
Flexible Serial Communication Controller (FLEXCOM) . . . . . . . . . . . . . . . . . . . . . . . . . .  642
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 642
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 642
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 642
4 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643
5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643
6 FL EXC OM Fu nctional Descri pt ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644
7 Flexible Serial Communi cation Controller (FLEXCOM) User Interface. . . . . . . . . . . . . . . . . . . . . . 645
Universal Synchronous Asynchronous Receiver Transceiver (USART) . . . . . . . . . 649
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 649
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651
4 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652
5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 652
6 USART Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655

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7 Universal Synchronous Asynchronous Receiver Transmitter (USART) User Interface . . . . . . . . . 696
Serial Peripheral Interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745
4 Application Block Diagram  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 745
5 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 746
6 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 746
7 SPI Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 749
8 Serial Peripheral Interface (SPI) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 764
Two-wire Interface (TWI)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
4 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 783
5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784
6 TWI Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786
7 Two-wire Interface (TWI) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 826
Inter-IC Sound Controller (I2SC)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 855
4 I/O Lines Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 855
5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 855
6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 857
7 I2SC Application Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 862
8 Inter-IC Sound Controller (I2SC) User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 864
Pulse Density Modulation Interface Controller (PDMIC) . . . . . . . . . . . . . . . . . . . . . . . . . 878
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 878
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 878
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 878
4 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 879
5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 879
6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 880
7 Pulse Density Modulation Interface Controller (PDMIC) User Interface . . . . . . . . . . . . . . . . . . . . . 887
Cyclic Redundancy Check Calculation Unit (CRCCU) . . . . . . . . . . . . . . . . . . . . . . . . . . . 899
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 899
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 899
3 CRCCU Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900
4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900
5 CRCCU Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 901
6 Transfer Control Registers Memory Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 902
7 Cyclic Redundancy Check Calculation Unit (CRCCU) User Interface . . . . . . . . . . . . . . . . . . . . . . 906
USB Host Port (UHP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 922
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 922
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 922

SAM G55 [DATASHEET]
Atmel-11289F-ATARM-SAM-G55G-SAM-G55J-Datasheet_27-May-16
vi
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 922
4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 923
5 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 924
6 Typical Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 925
7 USB Host Port (UHP) User Interface  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 926
USB Device Port (UDP)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 960
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 960
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 960
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 961
4 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 962
5 Typical Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 962
6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 964
7 USB Device Port (UDP) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 977
Analog-to-Digital Converter (ADC)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000
1 Description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1000
2 Embedded Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1001
3 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1002
4 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1002
5 Product Dependencies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1003
6 Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1004
7 Analog-to-Digital (ADC) User Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1019
Electrical Characteristics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1044
1 Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1044
2 Recommended Operating Conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 44
3 DC Characteristics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1045
4 Power Consumption . . . . . . . . . . .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1050
5 Oscillator Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1058
6 PLLA Characteristics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1064
7 PLLB Characteristics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1064
8 12-bit ADC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1064
9 AC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1069
Mechanical Characteristics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1081
1 49-lead WLCSP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1081
2 64-lead QFN Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1082
3 64-lead LQFP Mechanical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1083
4 Soldering Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1084
5 Packaging Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1084
Marking  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1085
Ordering Information   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1086
Errata  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1087
1 Revision A Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1087
2 Revision B Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1089
Revision History  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1090

XXX

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