PIC16F84A-04I/P - Microchip Technology

 2001 Microchip Technology Inc. DS35007B

PIC16F84A

Data Sheet

18-pin Enhanced FLASH/EEPROM

8-bit Microcontroller

DS35007B - page ii  2001 Microchip Technology Inc.

Information contained in this publication regarding device

applications and the like is intended through suggestion only

and may be superseded by updates. It is your responsibility to

ensure that your application meets with your specifications.

No representation or warranty is given and no liability is

assumed by Microc hip Technology Incorporated with respect

to the accuracy or use of such inform ation, or infringement of

patents or other intellectual property rights arising from such

use or otherwise. Use of Microchip’s products as critical com-

ponents in life support systems is not authorized except with

express written approval by Microchip. No licenses are con-

veyed, implicitly or otherwise, under any intellectual property

rights.

Trademarks

The Mi crochip name and logo, the Micr ochip lo go, PIC, PICm icro,

PICMASTER, PICSTART, PRO MATE, KEELOQ, SEEVAL,

MPLAB and The Embedded Control Solutions Company are reg-

istered trademarks of Microchip Te chnology In corporated in the

U.S.A. and other countries.

Total Endurance, ICSP, In-Circuit Serial Pro gramming, Filter-

Lab, MXDEV, microID,

Flex

ROM,

fuzzy

LAB, MPASM,

MPLINK, MPLIB, PICC, PICDEM, PICDEM.net, ICEPIC,

Migratable Memory, FanSense, ECONOMONITOR, Select

Mode and microPort are trademarks of Microchip Technology

Incorporated in the U.S.A.

Serialized Quick Term Programming (SQTP) is a service mark

of Microchip Technology Incorporated in the U.S.A.

All other trademarks mentioned herein are property of their

respective companies.

Printed on recycled paper.

Microchip received QS-9000 quality system

certific at ion for i ts worldwid e headquarters,

design and wafer fabrication facilities in

Chandler and Tempe, Arizona in July 1999. The

Company’s quality system processes and

procedures are QS-9000 compliant for its

PICmicro

8-bit MCUs, KEELOQ

cod e ho pp in g

devices, Serial EEPROMs and microperipheral

products. In addition, Microchip’s quality

system for the design and manufacture of

development systems is ISO 9001 certified.

Note the following details of the code protection feature on PICmicro® MCUs.

• The PICmicro family meets the specifications contained in the Microchip Data Sheet.

• Microchip believes that its family of PICmicro microcontrollers is one of the most secure products of its kind on the market today,

when used in the intended manner and under normal conditions.

• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowl-

edge, require using the PICmicro microcontroller in a manner outside the operating specifications contained in the data sheet.

The person doing so may be engaged in theft of intellectual property.

• Microchip is willing to work with the customer who is concerned about the integrity of their code.

• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not

mean that we are guaranteeing the product as “unbreakable”.

• Code protection is constant ly evolving. We at Microchip are committed to continuously i mproving the code protection features of

our product.

If you have any further questions about this matter , please contact the local sales off ice nearest to you.

 2001 Microchip Technology Inc. DS35007B-page 1

MPIC16F84A

High Performance RISC CPU Features:

• Only 35 single word instructions to learn

• All instructions single-cycle except for program

branches which are two-cycle

• Operating speed: DC - 20 MHz clock input

DC - 200 ns instruction cycle

• 1024 words of program memory

• 68 bytes of Data RAM

• 64 bytes of Data EEPROM

• 14-bit wide instruction words

• 8-bit wide data bytes

• 15 Special Function Hardware registers

• Eight-level deep hardware stack

• Direct, indirect and relative addressing modes

• Four interrupt sources:

- External RB0/INT pin

- TMR0 timer overflow

- PORTB<7:4> interrupt-on-change

- Data EEPROM write complete

Peripheral Features:

• 13 I/O pins with individual direction control

• High current sink/source for direct LED drive

- 25 mA sink max. per pin

- 25 mA source max. per pin

• TMR0: 8-bit timer/counter with 8-bit

progra mmable prescaler

Special Microcontroller Features:

• 10,000 erase/write cycles

Enhanced

FLASH

Program memory typical

• 10,000,0 00 typ ic al erase/wri te cy cle s EEPROM

Data memory typical

• EEPROM Data Retention > 40 years

• In-Circuit Serial Programming™ (ICSP™) - via

two pins

• Power-on Res et (POR), Power-up T imer (PWRT),

Oscillator Start-up Timer (OST)

• Watchdog Timer (WDT) with its own On-Chip RC

Osci llator for reliabl e oper ation

• Code protection

• Power saving SLEEP mode

• Selectable oscillator options

Pin Diagrams

CMOS Enhanced

FLASH/EEPROM

Technology:

• Low power, high speed technology

• Fully static design

• Wide operating voltage range:

- Commercial: 2.0V to 5.5V

- Industrial: 2.0V to 5.5V

• Low power consumption:

- < 2 mA typical @ 5V, 4 MHz

-15 µA typical @ 2V, 32 kHz

- < 0.5 µA typical standby cur r ent @ 2V

RA1

RA0

OSC1/CLKIN

OSC2/CLKOUT

VDD

RB7

RB6

RB5

RB4

RA2

RA3

RA4/T0CKI

MCLR

VSS

RB0/INT

RB1

RB2

RB3

•1

PDIP, SOIC

PIC16F84A

RA1

RA0

OSC1/CLKIN

OSC2/CLKOUT

VDD

RB7

RB6

RB5

RB4

RA2

RA3

RA4/T0CKI

MCLR

VSS

RB0/INT

RB1

RB2

RB3

•1

SSOP

PIC16F84A

10 11

VSS

VDD

18-pin Enhanced FLASH/EEPROM 8-Bit Microcontroller

PIC16F84A
DS35007B-page 2  2001 Microchip Technology Inc.
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 3
2.0 Memory Organization................................................................................................................................................................... 5
3.0 Data EEPROM Mem o ry........ ...... ....... ...... ...... ....... ...... ...... ...... ....... ...... ...... ....... ...... ...... ....... ........ ...... ....... ...... ...... ...... ....... ...... ..13
4.0 I/O Ports ......... ...... ....... ...... ...... ...... ....... ...... ...... ....... ...... ...... ....... ...... ...... ...... ....... ................... ...... ...... ....... ...... ...... ...... ....... ...... .. 15
5.0 Timer0 Module ........................................................................................................................................................................... 19
6.0 Special Features of the CPU...................................................................................................................................................... 21
7.0 Instruction Set Summary............................................................................................................................................................ 35
8.0 Development Support. ................................................................................................................................................................ 43
9.0 Electrical Characteristics............................................................................................................................................................ 49
10.0 DC/AC Characteristic Graphs .................................................................................................................................................... 61
11.0 Packaging Information...................................... ................... ............. ................... ............ ........................................................... 71
Appendix A: Revision History .............................................................................................................................................................. 75
Appendix B: Conversion Considerations............ ............. .................. ............. ................... ............. ...................................................... 76
Appendix C: Migration from Baseline to Mid-Range Devices .............................................................................................................. 78
Index .................................................................................................................................................................................................... 79
On-Line Support... ...... ................... ............. .................. ............. ................... ............. ........................................................................... 83
Reader Response................................................................................................................................................................................ 84
PIC16F84A Product Identification System........................................................................................................................................... 85
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 2001 Microchip Technology Inc. DS35007B-page 3

PIC16F84A

1.0 DEVICE OVERVIEW

This document contains device specific inf ormation for

the operation of the PIC16F84A device. Additional

information may be found in the PICmicro™ Mid-

Range Reference Manual, (DS33023), which may be

downloaded from the Microchip website. The Refer-

ence Manual should be considered a complementary

document to this data sheet, and is highly recom-

mended reading for a better understanding of the

device architecture and operation of the peripheral

modules.

The PIC 16 F84 A be lo ngs to t he mid-ra nge fa mi ly o f th e

PICmicro® microcontroller devices. A block diagram of

the device is shown in Figure 1-1.

The program memory contains 1K words, which trans-

lates to 1024 instructions, since each 14-bit program

memory word is the same width as each device instruc-

tion. The data memory (RAM) contains 68 bytes. Data

EEPROM is 64 bytes.

There are also 13 I/O pins that are user-configured on

a pin-to-pin basis. Some pins are multiplexed with other

device functions. These functions include:

• External inte rrup t

• Change on PORTB interrupt

• Timer0 clock input

Table 1-1 details the pinout of the device with descrip-

tions and details for each pin.

FIGURE 1-1: PIC16F84A BLOCK DIAGRAM

FLASH

Program

Memory

Program Counter

Program

Bus

Instruction Register

8 Level S tack

(13-bit)

Direct Addr

Instruction

Decode &

Control

Timing

Generation

OSC2/CLKOUT

OSC1/CLKIN

Power-up

Timer

Oscillator

Start-up Timer

Power-on

Reset

Watchdog

Timer

MCLR VDD, VSS

W reg

ALU

MUX I/O Ports

TMR0

STATUS reg

FSR reg

Indirect

Addr

RA3:RA0

RB7:RB1

RA4/T0CKI

EEADR

EEPROM

Data Memory

64 x 8

EEDATA

Addr Mux

RAM Addr

RAM

File Registers

EEPROM Data Memor y

Data Bus

RB0/INT

1K x 14 68 x 8

PIC16F84A

DS35007B-page 4  2001 Microchip Technology Inc.

TABLE 1-1: PIC16F84A PINOUT DESCRIPTION

Pin Name PDIP

No. SOIC

No. SSOP

No. I/O/P

Type Buffer

Type Description

OSC1/CLKIN 16 16 18 I ST/CMOS(3) Oscillat or cry s tal input /external clock source input .

OSC2/CLKOUT 15 15 19 O — Oscillator crystal output. Connects to crystal or

resonator in Crystal Oscillator mode. In RC mode,

OSC2 pin outputs CLKOUT, which has 1/4 the

frequency of OSC1 and denotes the instruction

cycle rate.

MCLR 4 4 4 I/P ST Master Clear (Reset) input/programming voltage

input. Thi s pin is an activ e low RESET to the de vice.

PORTA is a bi-directional I/O port.

RA0 17 17 19 I/O TTL

RA1 18 18 20 I/O TTL

RA2 1 1 1 I/O TTL

RA3 2 2 2 I/O TTL

RA4/T0CKI 3 3 3 I/O ST Can also be se lec ted to be the clo ck in put t o the

TMR0 timer/counter. Output is open drain type.

PORTB is a bi-directional I/O port. PORTB can be

software programmed for internal weak pull-up on

all inputs.

RB0/INT 6 6 7 I/O TTL/ST(1) RB0/INT ca n also be selected as an external

interrupt pin.

RB1 7 7 8 I/O TTL

RB2 8 8 9 I/O TTL

RB3 9 9 10 I/O TTL

RB4 10 10 11 I/O TTL Interrupt-on-change pin.

RB5 11 11 12 I/O TTL Interrupt-on-change pin.

RB6 12 12 13 I/O TTL/ST(2) Interrupt-on-change pin.

Serial program mi ng cloc k.

RB7 13 13 14 I/O TTL/ST(2) Interrupt-on-change pin.

Serial program mi ng dat a.

VSS 5 5 5,6 P — Ground reference for logic and I/O pins.

VDD 14 14 15,16 P — Positive supply for logic and I/O pins.

Legend: I= input O = Output I/O = Input/Output P = Power

— = Not used TTL = TTL input ST = Schmitt Trigger input

Note 1: T his buffer is a Schmitt Trigger input when configur ed as the externa l interrupt.

2: This buffer is a Schmitt Trigger input wh en used in Serial Prog ramming mode.

3: This buffer is a Schmitt Trigger input wh en configured in RC os cillator mode and a CMOS input otherwise.

 2001 Microchip Technology Inc. DS35007B-page 5

PIC16F84A

2.0 MEMORY ORGANIZATION

There are two memory blocks in the PIC16F84A.

These are the program memory and the data memory.

Each block has its own bus, so that access to each

block can occur during the same oscillator cycle.

The data memory can further be broken down into the

general purpose RAM and the Special Function

Registers (SFRs). The operation of the SFRs that

control the “core” are described here. The SFRs used

to control the peripheral modules are described in the

section discussing each individual peripheral module.

The data memory area also contains the data

EEPROM memory. This memory is not directly mapped

into th e data m emory, but is i ndi rec tly m ap ped . T hat is ,

an indir ect add ress p ointer s pecifies the ad dress of th e

data EEPROM memory to read/write. The 64 bytes of

data EEPROM memory have the address range

0h-3Fh. More details on the EEPROM memory can be

found in Section 3.0.

Addit ional informa tion on devi ce memory may be found

in the PICmicro™ Mid-Range Reference Manual,

(DS33023).

2.1 Program Memory Organization

The PIC16FXX has a 13-bit program counter capable

of addressing an 8K x 14 program memory space. For

the PIC16F84A, the first 1K x 14 (0000h-03FFh) are

physic ally im plemente d (Figure 2-1). Ac cessin g a loca-

tion above the physically implemented address will

cause a wraparound. For example, for locations 20h,

420h, 820h, C20h, 1020h, 1420h, 1820h, and 1C20h,

the instructi on wi ll be the sa me.

The RESET vector is at 0000h and the interrupt vector

is at 0004h.

FIGURE 2-1: PROGRAM MEMORY MAP

AND STACK - PIC16F84A

PC<12:0>

Stack Level 1

•

Stack Level 8

RESET Vector

Peripheral Interrupt Vector

•

User Memory

Space

CALL, RETURN

RETFIE, RETLW 13

0000h

0004h

1FFFh

3FFh

PIC16F84A

DS35007B-page 6  2001 Microchip Technology Inc.

2.2 Data Memory Organization

The dat a mem ory is p artitione d into tw o areas . The firs t

is the Speci al Fu nction R egis ters (SFR) a rea, wh ile th e

second is the General Purpose Registers (GPR) area.

The SFRs control the operation of the device.

Portions of data memory are banked. This is for both

the SFR area and the GPR area. The GPR area is

banked to allow greater than 116 bytes of general

purpose RAM. The banked areas of the SFR are for the

registers that control the peripheral functions. Banking

requires the use of control bits for bank selection.

These c ont rol b it s are loc at ed in the STATUS Registe r.

Figure 2-2 shows the data memory map organization.

Instructions MOVWF and MOVF can move values from

the W register to any location in the register file (“F”),

and vice-versa.

The entire data memory can be accessed either

directly us in g the abso lute ad dres s o f ea ch regi ste r fil e

or indirectly through the File Select Register (FSR)

(Section 2.5). Indirect addressing uses the present

value of the RP0 b it for access into the ba nked areas of

data memory.

Data memory is partitioned into two banks which

contain the general purpose registers and the special

function registers. Bank 0 is selected by clearing the

RP0 bit (ST A TUS<5>). Setting the RP0 bit selects Bank

1. Each Bank extends up to 7Fh (128 bytes). The first

twelve locations of each Bank are reserved for the

Special Function Registers. The remainder are Gen-

eral Purpose Registers, implemented as static RAM.

2.2.1 GENERAL PURPOSE REGISTER

FILE

Each General Purpose Register (GPR) is 8-bits wide

and is a cces sed ei ther directl y or ind ire ctl y throu gh the

FSR (Section 2.5).

The GPR addresses in Bank 1 are mapped to

address es in B ank 0. As an ex am ple , add res si ng l oc a-

tion 0Ch or 8Ch will access the same GPR.

FIGURE 2-2: REGISTER FILE MAP -

PIC16F84A

File Address

00h

01h

02h

03h

04h

05h

06h

07h

08h

09h

0Ah

0Bh

0Ch

7Fh

80h

81h

82h

83h

84h

85h

86h

87h

88h

89h

8Ah

8Bh

8Ch

FFh

Bank 0 Bank 1

Indirect addr.(1) Indirect addr.(1)

TMR0 OPTION_REG

PCL

STATUS

FSR

PORTA

PORTB

EEDATA

EEADR

PCLATH

INTCON

General

Purpose

Registers

(SRAM)

PCL

STATUS

FSR

TRISA

TRISB

EECON1

EECON2(1)

PCLATH

INTCON

Mapped

in Bank 0

Unimplemented data memory location, read as ’0’.

File Address

Note 1: Not a physical register.

CFh

D0h

4Fh

50h

(accesses)

——

 2001 Microchip Technology Inc. DS35007B-page 7
PIC16F84A
2.3 Special Function Registers
The Special Function Registers (Figure 2-2 and
Table 2-1) are used by the CPU and Peripheral
functions to control the device operation. These
registers are static RAM.
The spec ial function regi sters can be clas sified into two
sets, core and peripheral. Those associated with the
core functions are described in this section. Those
related to the operation of the peripheral features are
described in the section for that specific feature.
TABLE 2-1: SPECIAL FUNCTION REGISTER FILE SUMMARY    
Addr Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2  Bit 1 Bit 0 Value  on  
Power-on 
RESET
Details 
on pa ge
 Bank 0
00h INDF Uses contents of FSR to address Data Memory (not a physical register) ---- ---- 11
01h TMR0 8-bit Real-Time Clock/Counter xxxx xxxx 20
02h PCL Low Order 8 bits of the Program Counter (PC) 0000 0000 11
03h STATUS(2) IRP RP1 RP0 TO PD ZDCC
0001 1xxx 8
04h FSR Indirect Data Memory Add ress Pointer 0 xxxx xxxx 11
05h PORTA(4) — — — RA4/T0CKI RA3 RA2 RA1 RA0 ---x xxxx 16
06h PORTB(5) RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0/INT xxxx xxxx 18
07h —Unimplemented location, read as '0' — —
08h EEDATA EEP ROM Data Register xxxx xxxx 13,14
09h EEADR EEPROM Address Register xxxx xxxx 13,14
0Ah PCLATH — — — Write Buffer for upper 5 bits of the PC(1) ---0 0000 11
0Bh INTCON GIE EEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 10
Bank 1
80h INDF Uses Contents of FSR to address Data Memory (not a physical register) ---- ---- 11
81h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 9
82h PCL Low order 8 bits of Program Counter (PC) 0000 0000 11
83h STATUS (2) IRP RP1 RP0 TO PD ZDCC
0001 1xxx 8
84h FSR Indirect data memory address po inter 0 xxxx xxxx 11
85h TRISA — — — PORTA Data Direction Register ---1 1111 16
86h TRISB PORTB Data Direction Register 1111 1111 18
87h —Unimplemented location, read as '0' — —
88h EECON1 — — — EEIF WRERR WREN WR RD ---0 x000 13
89h EECON2 EEPROM Control Register 2 (not a physical register) ---- ---- 14
0Ah PCLATH — — — Write buf fer for upper 5 bits of the PC(1) ---0 0000 11
0Bh INTCON GIE EEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 10
Legend: x = unknown, u = unchanged. - = unimplemented, read as '0', q = value depends on condition
Note 1: The upper byte of the program counter is not directly accessible. PCLATH is a slave register for PC<12:8>. The contents 
of PCLATH can be transferred to the upper byte of the program counter, but the contents of PC<12:8> are never trans-
ferred to PCLATH.
2: The TO and PD status bits in the STATUS register are not affected by a MCLR Reset. 
3: Other (non power-up) RESETS include: external RESET through MCLR and the Watchdog Timer Reset.
4: On any device RESET, these pins are configured as inputs.
5: This is the value that will be in the port output latch.

PIC16F84A

DS35007B-page 8  2001 Microchip Technology Inc.

2.3.1 STATUS REGISTER

The STATUS register contains the arithmetic status of

the ALU, the RESET status and the bank select bit for

data memory.

As with any register, the STATUS register can be the

destina tion for any instruction. If the STA TUS regi ster is

the destination for an instruction that affects the Z, DC

or C bits, then the write to these three bits is disabled.

These b its ar e s et o r c lea red ac co rdin g to devi ce lo gic .

Furthermore, the TO and PD bits are not writable.

Therefore , the result of an ins truc ti on wi th the STATUS

For example, CLRF STATUS will clear the upper three

bits and set the Z bit. This leaves the STATUS register

as 000u u1uu (where u = unchanged).

Only the BCF, BSF, SWAPF and MOVWF instructions

should be used to alter the STATUS register (Table 7-2),

because these instructions do not affect any status bit.

Note 1: The IRP and RP1 bits (STATUS<7:6>)

are not used by the PIC16F84A and

should be progra mmed as cleared . Use of

these bits as general purpose R/W bits is

NOT recommended, since this may affect

upward compatibility with future products.

2: The C and DC bits operate as a borrow

and digit borrow out bit, respectively, in

subtraction. See the SUBLW and SUBWF

instructions for exampl es.

3: When the STATUS register is the

destination for an instruction that affects

the Z, DC or C bit s, then the write to th ese

three bits is disabled. The specified bit(s)

will be updated according to device logic

R/W-0 R/W-0 R/W-0 R-1 R-1 R/W-x R/W-x R/W-x

IRP RP1 RP0 TO PD ZDCC

bit 7 bit 0

bit 7-6 Unimplemented: Maintain as ‘0’

bit 5 RP0: Register Bank Select bits (used for direct addressing)

01 = Bank 1 (80h - FFh)

00 = Bank 0 (00h - 7Fh)

bit 4 TO: Time-out bit

1 = After power-up, CLRWDT inst ruct ion, or SLEEP instruction

0 = A WDT time-out occurred

bit 3 PD: Power-down bit

1 = After power-up or by the CLRWDT instruction

0 = By execution of the SLEEP instruction

bit 2 Z: Zero bit

1 = The result of an arithmetic or logic operation is zero

0 = The result of an arithmetic or logic operation is not zero

bit 1 DC: Digit carry/borrow bit (ADDWF, ADDLW,SUBLW,SUBWF instruc tions) (for borrow , the p olarit y

is reversed)

1 = A carry-out from the 4th low order bit of the result occurred

0 = No carry-out from the 4th low order bit of the result

bit 0 C: Carry/borrow bit (ADDWF, ADDLW,SUBLW,SUBWF instructions) (for borrow, the polarity is

reversed)

1 = A carry-out from the Most Significant bit of the result occurred

0 = No carry-out from the Most Significant bit of the result occurred

Note: A subtraction is executed by adding the two’s complement of the second operand.

For rotate (RRF, RLF) inst ruc tio ns, this bi t is l oad ed w ith ei the r th e h igh or low ord er

bit of the source register.

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

- n = Value at POR ’1’ = Bit is set ’0’ = Bit is cleared x = Bit is unknown

 2001 Microchip Technology Inc. DS35007B-page 9

PIC16F84A

2.3.2 OPTION REGISTER

The OPTION register is a readable and writable

the TMR0/WDT prescaler, the external INT interrupt,

TMR0, and the weak pull-u ps on PORTB.

Note: When the prescaler is assigned to

the WDT (PSA = ’1’), TMR0 has a 1:1

prescaler assignment.

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0

bit 7 bit 0

bit 7 RBPU: PORTB Pull-up Enable bit

1 = PORTB pull-ups are disabled

0 = PORTB pull-ups are enabled by individual port latch values

bit 6 INTEDG: Interrupt Edge Select bit

1 = Interrupt on rising edge of RB0/INT pin

0 = Interrupt on falling edge of RB0/INT pin

bit 5 T0CS: TMR0 Clock Source Select bit

1 = Transition on RA4/T0CKI pin

0 = Internal instruction cycle clock (CLKOUT)

bit 4 T0SE: TMR0 Source Edge Select bit

1 = Increment on high-to-low transition on RA4/T0CKI pin

0 = Increment on low-to-high transition on RA4/T0CKI pin

bit 3 PSA: Prescaler Assignment bit

1 = Prescaler is assigned to the WDT

0 = Prescaler is assigned to the Timer0 module

bit 2-0 PS2:PS0: Prescaler Rate Select bits

Legend:

R = Readable bit W = Wri t ab le bit U = Unimplemented bit , read as ‘0’

- n = Value at POR ’1’ = Bit is set ’ 0’ = Bit is cleared x = Bit is unknown

000

001

010

011

100

101

110

111

1 : 2

1 : 4

1 : 8

1 : 16

1 : 32

1 : 64

1 : 128

1 : 256

1 : 1

1 : 2

1 : 4

1 : 8

1 : 16

1 : 32

1 : 64

1 : 128

Bit Value TMR0 Rate WDT Rate

PIC16F84A

DS35007B-page 10  2001 Microchip Technology Inc.

2.3.3 INTCON REGISTER

The INTCON register is a readable and writable

interrupt sources.

Note: Interru pt fl ag bits are set w he n an in terru pt

conditi on occurs , regardle ss of the sta te of

its corresponding enable bit or the global

enable bit, GIE (INTCON<7>).

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-x

GIE EEIE T0IE INTE RBIE T0IF INTF RBIF

bit 7 bit 0

bit 7 G IE: Global Interrupt Enable bit

1 = Enables all unmasked interrupts

0 = Disables all interrupts

bit 6 EEIE: EE Write Complete Interrupt Enable bit

1 = Enables the EE Write Complete interrupts

0 = Disables the EE Write Complete interrupt

bit 5 T0IE: TMR0 Ov erflow Inter rupt Enable bit

1 = Enables the TMR0 interrupt

0 = Disables th e TM R0 interru pt

bit 4 INTE: RB0/INT External Interrupt Enable bit

1 = Enables the RB0/INT external interrupt

0 = Disables the RB0/INT external interrupt

bit 3 RBIE: RB Port Change Interrupt Enable bit

1 = Enables the RB port change interrupt

0 = Disables the RB port change interrupt

bit 2 T0IF: TMR0 Overflow Interrupt Flag bit

1 = TMR0 reg ister has overfl owed (must be cleared in software)

0 = TMR0 reg ister did not overflow

bit 1 INTF: RB0/INT External Interrupt Flag bit

1 = The RB0/ INT external inte rrupt occurred (must be cleared in software)

0 = The RB0/INT external interrupt did not occur

bit 0 RBIF: RB Port Change Interrupt Flag bit

1 = At least one of the RB7:RB4 pins changed state (must be cleared in software)

0 = None of the RB7:RB4 pins have changed state

Legend:

R = Readable bit W = Wri t ab le bit U = Unimplemented bit , read as ‘0’

- n = Value at POR ’1’ = Bit is set ’ 0’ = Bit is cleared x = Bit is unknown

 2001 Microchip Technology Inc. DS35007B-page 11

PIC16F84A

2.4 PCL and PCLATH

The program counter (PC ) sp eci fie s th e a ddre ss of th e

instruction to fetch for execution. The PC is 13 bits

wide. The low byte is called the PCL register . This reg-

ister is readable and writable. The high byte is called

the PCH register. This register contains the PC<12:8>

bits and is not directly readable or writable. If the pro-

gram counter (PC) is modified or a conditional test is

true, the instruction requires two cycles. The second

cycle is execu ted as a NOP. All u pdates to t he PCH reg-

ister go through the PCLATH register.

2.4.1 STACK

The stack allows a combination of up to 8 program calls

and interrupts to occur. The stack contains the return

address from thi s branch in program execution.

Mid-range devices have an 8 level deep x 13-bit wide

hardware stack. The stack space is not part of either

program or data space and the stack pointer is not

readable or writ able. The PC i s PUSHed on to the st ack

when a CALL instruction is executed or an interrupt

causes a bran ch . The stac k i s POPed in t he ev en t of a

RETURN, RETLW or a RETFIE instruction execution.

PCLATH is n o t mo di f ied w hen t h e s tack i s P US Hed o r

POPed.

After the stac k has been PUSHed ei ght times, the nin th

push ov erwrit es the v alue tha t was stored fro m the firs t

push. The tenth p us h ov erwr i tes the se cond push (and

so on).

2.5 Indirect Addressing; INDF and

FSR Registers

The INDF register is no t a physical reg ister . Address ing

INDF actu ally ad dresse s the regi ster w hose ad dress i s

cont ained in the FSR reg ister (FSR is a

pointer

). This is

indirect addressing.

EXAMPLE 2-1: INDIRECT ADDRESSING

Reading INDF itself indirectly (FSR = 0) will produce

00h. Writing to the INDF register indirectly results in a

no-operation (although STATUS bits may be affected).

A simple program to clear RAM locations 20h-2Fh

using indirect addressing is shown in Example 2-2.

EXAMPLE 2-2: HOW TO CLEAR RAM

USING INDIRECT

ADDRESSING

An ef fect ive 9-b it addre ss is obtained by conca tenatin g

the 8-bit FSR reg ister and the IRP bit (STA TUS<7>), a s

shown in Figure 2-3. However, IRP is not used in the

PIC16F84A.

• Register file 05 contains the value 10h

• Register file 06 contains the value 0Ah

• Load the value 05 into the FSR register

• A read of th e IND F r egi ste r will ret urn the value

of 10h

• Increment the value of the FSR register by one

(FSR = 06)

• A read of the INDF register now will return the

value of 0Ah.

movlw 0x20 ;initialize pointer

movwf FSR ;to RAM

NEXT clrf INDF ;clear INDF register

incf FSR ;inc pointer

btfss FSR,4 ;all done?

goto NEXT ;NO, clear next

CONTINUE

: ;YES, continue

PIC16F84A

DS35007B-page 12  2001 Microchip Technology Inc.

FIGURE 2-3: DIRECT/INDIRECT ADDRESSING

Direct Addressing

RP1 RP0 6 From Opcode 0IRP7

(FSR) 0

Indirect Addressing

Bank Select Location Select Bank Select Location Select

00 01 80h

FFh

00h

0Bh

0Ch

7Fh

Bank 0 Bank 1

Note 1: For memory map detail, see Figure 2-2.

2: Maintain as clear for upward compatibility with future products.

3: Not implemented.

4Fh

50h

Data

Memory(1)

(3) (3)

(2) (2)

Addresses

map back to

Bank 0

 2001 Microchip Technology Inc. DS35007B-page 13

PIC16F84A

3.0 DATA EEPROM MEMORY

The EEPROM data memory is readable and writable

during normal ope ration (full VDD range). Thi s me mo ry

is not directly mapped in the register file space. Instead

it is indirectly addressed through the Special Function

Registers. There are four SFRs used to read and write

this memory. These registers are:

• EECON1

• EECON2 (not a physically implemented register)

• EEDATA

• EEADR

EEDATA holds the 8-bit data for read/write, and

EEADR holds the address of the EEPROM location

being accessed. PIC16F84A devices have 64 bytes of

data EEPROM with an address range from 0h to 3Fh.

The EEPROM data memory allows byte read and write.

A byte write automatically erases the location and

writes the n ew data (erase be fore write). The EEPROM

data memory is rated for high erase/write cycles. The

write time is controlled by an on-chip timer. The write-

time will vary with voltage and temperature as well as

from chip to c hip. P lea se re fer to AC spe cif icati ons for

exact limits.

When the device is code protected, the CPU may

continu e to rea d and wr ite th e data EEPROM memory.

The device programmer can no longer access

this memory.

Additional information on the Data EEPROM is avail-

able in the PICmicro™ Mid-Range Reference Manual

(DS33023).

U-0 U-0 U-0 R/W-0 R/W-x R/W-0 R/S-0 R/S-0

— — — EEIF WRERR WREN WR RD

bit 7 bit 0

bit 7-5 Unimplemented: Read as '0'

bit 4 EEIF: EEPROM Write Operation Interrupt Flag bit

1 = The write operation completed (must be cleared in software)

0 = The write operation is not complete or has not been started

bit 3 WRERR: EEPROM Error Flag bit

1 = A write operation is prem at urel y term ina ted

(any MCLR Reset or any WDT Reset during normal operation)

0 = The write operation completed

bit 2 WREN: EEPROM Write Enable bit

1 = Allows write cycles

0 = Inhibits write to the EEPROM

bit 1 WR: Write Control bit

1 = Initiates a write cycle. The bit is cleared by hardware once write is complete. The WR bit

can only be set (not cleared) in software.

0 = Write cycle to the EEPROM is complete

bit 0 RD: Read Control bit

1 = Initiates an EEPROM read RD is cleared in hardware. The RD bit can only be set (not

cleared) in software.

0 = Does not initiate an EEPROM read

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

- n = Value at POR ’1’ = Bit is set ’ 0’ = Bit is cleared x = Bit is unknown

PIC16F84A

DS35007B-page 14  2001 Microchip Technology Inc.

3.1 Reading the EEPROM Data

Memory

To read a data memory location, the user must write the

address to the EEADR register and then set control bit

RD (EECON1<0>). The data is available, in the very

nex t cycle, in the EEDATA register; therefore, it can be

read in the next instructi on. EEDAT A will hold this valu e

until another read or until it is written to by the user

(during a write operation).

EXAMPLE 3-1: DATA EEPROM READ

3.2 Writing to the EEPROM Data

Memory

To write an EEPROM data location, the user must first

write the address to the EEADR register and the data

to the EEDATA register. Then the user must follow a

specific sequence to initiate the write for each byte.

EXAMPLE 3-2: DATA EEPROM WRITE

The write will not initiate if the above sequence is not

exactly followed (write 55h to EECON2, write AAh to

EECON2, then set WR bit) for each byte. We strongly

recommend that interrupts be disabled during this

code segment.

Additionally, the WREN bit in EECON1 must be set to

enable write. This mechanism prevents accidental writes

to data EEPROM due to errant (unexpected) code exe-

cution (i.e., lost programs). The user should keep the

WREN bit clear at all times, except when updating

EEPROM. The WREN bit is not cleared by hardware.

After a write sequence has been initiated, clearing the

WREN bit wil l not af fect this writ e cycle. T he WR bit will

be inhib ited from being s et unless the W REN b it is se t.

At the completion of the write cycle, the WR bit is

cleared in hardware and the EE Write Complete

Interrupt Flag bit (EEIF) is set. The user can either

enable this interrupt or poll this bit. EEIF must be

cleared by software.

3.3 Write Verify

Depending on the application, good programming

practice may dictate that the value written to the Data

EEPROM should be verified (Example 3-3) to the

desired value to be written. This should be used in

applications where an EEPROM bit will be stressed

near the spe cif ic ati on lim it .

Generally, the EEPROM write failure will be a bi t which

was written as a ’0’, but reads back as a ’1’ (due to

leakage off the bit).

EXAMPLE 3-3: WRITE VERIFY

TABLE 3-1: REGISTERS/BITS ASSOCIATED WITH DATA EEPROM

BCF STATUS, RP0 ; Bank 0

MOVLW CONFIG_ADDR ;

MOVWF EEADR ; Address to read

BSF STATUS, RP0 ; Bank 1

BSF EECON1, RD ; EE Read

BCF STATUS, RP0 ; Bank 0

MOVF EEDATA, W ; W = EEDATA

BSF STATUS, RP0 ; Bank 1

BCF INTCON, GIE ; Disable INTs.

BSF EECON1, WREN ; Enable Write

MOVLW 55h ;

MOVWF EECON2 ; Write 55h

MOVLW AAh ;

MOVWF EECON2 ; Write AAh

BSF EECON1,WR ; Set WR bit

; begin write

BSF INTCON, GIE ; Enable INTs.

Required

Sequence

BCF STATUS,RP0 ; Bank 0

: ; Any code

: ; can go here

MOVF EEDATA,W ; Must be in Bank 0

BSF STATUS,RP0 ; Bank 1

READ BSF EECON1, RD ; YES, Read the

; value written

BCF STATUS, RP0 ; Bank 0

;

; Is the value written

; (in W reg) and

; read (in EEDATA)

; the same?

;

SUBWF EEDATA, W ;

BTFSS STATUS, Z ; Is difference 0?

GOTO WRITE_ERR ; NO, Write error

Address Name Bi t 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

Power-on

Reset

Value on

all other

RESETS

08h EEDATA EEPROM Data Register xxxx xxxx uuuu uuuu

09h EEADR EEPROM Address Register xxxx xxxx uuuu uuuu

88h EECON1 — — — EEIF WRERR WREN WR RD ---0 x000 ---0 q000

89h EECON2 EEPROM Control Register 2 ---- ---- ---- ----

Legend: x = unknown, u = unchanged, - = unimplemented, read as '0', q = value depends upon condition.

Shaded cells are not used by data EEPROM.

 2001 Microchip Technology Inc. DS35007B-page 15

PIC16F84A

4.0 I/O P ORTS

Some pins for these I/O ports are multiplexed with an

alternate function for the peripheral features on the

device. In general, when a peripheral is enabled, that

pin may not be used as a general purpose I/O pin.

Addit ion al inf orm atio n on I/O por ts ma y b e f oun d i n the

PICmicro™ M id-Rang e Refer ence Manu al (DS33 023).

4.1 PORTA and TRISA Registers

PORTA is a 5-bit wide, bi-directional port. The corre-

sponding data direction register is TRISA. Setting a

TRISA bit (= 1) will m ake the correspon ding POR T A pin

an input (i.e., put the corresponding output driver in a

Hi-Impedance mode). Clearing a TRISA bit (= 0) will

make the correspon ding POR TA pin an output (i .e., put

the contents of the output latch on the selected pin).

Reading the PORTA register reads the status of the

pins, where as wri tin g to i t wi ll write to th e port latch. All

write operations are read-modify-write operations.

Therefore , a write to a port implies that the port pins are

read. Th is v alue is m odifie d and th en w ritten to the port

data l atch.

Pin RA4 is multiplexed with the Timer0 module clock

input to become the RA4/T0CKI pin. The RA4/T0CKI

pin is a Schmitt Tr igger input and an open drain output.

All other RA port pins have TTL input levels and full

CMOS output drivers.

EXAMPLE 4-1: INITIALIZING PORTA

FIGURE 4-1: BLOCK DIAGRAM OF

PINS RA3:RA0

FIGURE 4-2: BLOCK DIAGRAM OF PIN

RA4

Note: On a Pow er-on Reset, t hese pins ar e con-

figured as inputs and read as '0'.

BCF STATUS, RP0 ;

CLRF PORTA ; Initialize PORTA by

; clearing output

; data latches

BSF STATUS, RP0 ; Select Bank 1

MOVLW 0x0F ; Value used to

; initialize data

; direction

MOVWF TRISA ; Set RA<3:0> as inputs

; RA4 as output

; TRISA<7:5> are always

; read as ’0’.

Data

Bus

Port

TRIS

Data Latch

TRIS Latch

RD TRIS

RD Port

TTL

Input

Buffer

VSS

VDD

I/O pin

Note: I/O pins have protection diodes to VDD and VSS.

Data

Bus

Port

TRIS

RD Port

Data Latch

TRIS Latch

RD TRIS

Schmitt

Trigger

Input

Buffer

VSS

RA4 pin

TMR0 Clock Input

Note: I/O pins have protection diodes to VDD and VSS.

PIC16F84A

DS35007B-page 16  2001 Microchip Technology Inc.

TABLE 4-1: PORTA FUNCTIONS

TABLE 4-2: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA

Name Bit0 Buffer Type Function

RA0 bit0 TTL Input/output

RA1 bit1 TTL Input/output

RA2 bit2 TTL Input/output

RA3 bit3 TTL Input/output

RA4/T0CKI bit4 ST Input/output or external clock input for TMR0.

Output is open drain type.

Legend: TTL = TTL input, ST = Schmitt Trigger input

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

Power-on

Reset

V alue on al l

other

RESETS

05h PORTA ——— RA4/T0CKI RA3 RA2 RA1 RA0 ---x xxxx ---u uuuu

85h TRISA ——— TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 ---1 1111 ---1 1111

Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are unimplemented, read as '0'.

 2001 Microchip Technology Inc. DS35007B-page 17

PIC16F84A

4.2 PORTB and TRISB Registers

PORTB is an 8-bit wide, bi-directional port. The corre-

sponding data direction register is TRISB. Setting a

TRISB bit (= 1) will make the correspondi ng PORTB pin

an input (i.e., put the corresponding output driver in a

Hi-Impedance mode). Clearing a TRISB bit (= 0) will

make the correspo nding PO RTB pin an outp ut (i.e., p ut

the contents of the output latch on the selected pin).

EXAMPLE 4-2: INITIALIZING PORTB

Each of th e POR TB pins has a we ak inte rnal pul l-up. A

single control bit can turn on all the pull-ups. This is per-

formed by clearing bit RBPU (OPTION<7>). The weak

pull-up is automatically turned off when the port pin is

configu red as an outpu t. The pull- ups are di sabled on a

Power-on Reset.

Four of POR TB’s pi ns, RB7:RB4, hav e an interrupt-o n-

change feature. Only pins configured as inputs can

cause this interrupt to occur (i.e., any RB7:RB4 pin

configured as an output is excluded from the interrupt-

on-change comparison). The input pins (of RB7:RB4)

are compared with the old value latched on the last

read of PORTB. The “mismatch” outputs of RB7:RB4

are OR’ed together to generate the RB Port Change

Interrupt with flag bit RBIF (INTCON<0>).

This interrupt can wake the device from SLEEP. The

user, in the Interrupt Service Routine, can clear the

interrupt in the following manner:

a) Any read or write of PORTB. This will end the

mismatch condition.

b) Clear flag bit RBIF.

A mismatch condition will continue to set flag bit RBIF.

Reading PORTB will end the mismatch condition and

allow flag bit RBIF to be cleared.

The interrupt-on-change feature is recommended for

wake-up on key depression operation and operations

where PORTB is o nly us ed f or the int errup t-on -ch ang e

feature. Polling of PORTB is not recommended while

usin g the interrupt- on-change feature.

FIGURE 4-3: BLOCK DIAGRAM OF

PINS RB7:RB4

FIGURE 4-4: BLOCK DIAGRAM OF

PINS RB3:RB0

BCF STATUS, RP0 ;

CLRF PORTB ; Initialize PORTB by

; clearing output

; data latches

BSF STATUS, RP0 ; Select Bank 1

MOVLW 0xCF ; Value used to

; initialize data

; direction

MOVWF TRISB ; Set RB<3:0> as inputs

; RB<5:4> as outputs

; RB<7:6> as inputs

RBPU(1)

Data Latch

From other

VDD

Data Bus

WR Port

WR TRIS

Set RBIF

TRIS Latch

RD TRIS

RD Port

RB7:RB4 pins

Weak

Pull-up

RD Port

Latch

TTL

Input

Buffer

Note 1: TRISB = ’1’ enables weak pull-up

(if RBPU = ’0’ in the OPTION_REG register).

2: I/O pins have diode protection to VDD and VSS.

I/O pin(2)

RBPU(1)

I/O pin(2)

Data Latch P

VDD

Data Bus

WR Port

WR TRIS

RD TRIS

RD Port

Weak

Pull-up

RD Port

RB0/INT

TTL

Input

Buffer

Schmitt Trigger

Buffer

TRIS Latch

Note 1: TRISB = ’1’ enables weak pull-up

(if RBPU = ’0’ in the OPTION_REG register).

2: I/O pins have diode protection to VDD and VSS.

PIC16F84A

DS35007B-page 18  2001 Microchip Technology Inc.

TABLE 4-3: PORTB FUNCTIONS

TABLE 4-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB

Name Bit Buffer Type I/O Consistency Function

RB0/INT bit0 TTL/ST(1) Input/output pin or external interrupt input.

Internal software programmable weak pull-up.

RB1 bit1 TTL Input/output pin. Internal softwar e programma ble weak pull-up.

RB2 bit2 TTL Input/output pin. Internal softwar e programma ble weak pull-up.

RB3 bit3 TTL Input/output pin. Internal softwar e programma ble weak pull-up.

RB4 bit4 TTL Input/output pin (with interrupt-on-change) .

Internal software programmable weak pull-up.

RB5 bit5 TTL Input/output pin (with interrupt-on-change) .

Internal software programmable weak pull-up.

RB6 bit6 TTL/ST(2) Input/output pin (with interrupt-on-change).

Internal software programmable weak pull-up. Serial programming clock.

RB7 bit7 TTL/ST(2) Input/output pin (with interrupt-on-change).

Internal software programmable weak pull-up. Serial programming data.

Legend: TTL = TTL input, ST = Schmitt Trigger.

Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.

2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

Power-on

Reset

Value on

all other

RESETS

06h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0/INT xxxx xxxx uuuu uuuu

86h TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 1111 1111 1111 1111

81h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

0Bh,8Bh INTCON GIE EEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u

Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.

 2001 Microchip Technology Inc. DS35007B-page 19

PIC16F84A

5.0 TIMER0 MODULE

The Timer0 module timer/counter has the following

features:

• 8-bit timer/counter

• Readable and writable

• Internal or external clock select

• Edge select for external clock

• 8-bit software programmable prescaler

• Interrupt-on-overflow from FFh to 00h

Figure 5-1 is a simplified block diagram of the Timer0

module.

Additional information on timer modules is available in

the PICmicro™ Mid-Range Reference Manual

(DS33023).

5.1 Timer0 Operation

Timer0 can operate as a timer or as a counter.

Timer mode is selected by clearing bit T0CS

(OPTION_REG<5>). In Timer mode, the Timer0 mod-

ule will incremen t ev ery ins tru cti on c y cle (with ou t pre s-

caler). If the TMR0 register is written, the increment is

inhibited for the following two instruction cycles. The

user can work around this by writing an adjusted value

to the TMR0 register.

Counter mode is selected by setting bit T0CS

(OPTION_REG<5>). In Counter mode, Timer0 will

increment, either on every rising or falling edge of pin

RA4/T0CKI. The incrementing edge is determined by

the Timer0 Source Edge Select bit, T0SE

(OPTION_REG<4>). Clearing bit T0SE selects the ris-

ing edge. Restrictions on the external clock input are

disc ussed below.

When an external cl ock input i s used for T ime r0, it must

meet certain requirements. The requirements ensure

the external clock ca n be synchronized with the internal

phase clock (TOSC). Also, th ere is a delay in the actu al

incrementing of Timer0 after synchronization.

Additional information on external clock requirements

is available in the PICmicro™ Mid-Range Reference

Manual, (DS33023).

5.2 Prescaler

An 8- bit counter i s availa ble as a prescaler fo r the T imer 0

module, or as a postscaler for the Watchdog Timer,

respectively (Figure 5-2). For simplicity, this counter is

being referred to as “prescaler” throughout this data

sheet. Note that there is only one prescaler available

whic h is mutual ly exclusi vely shar ed between the T imer0

module and the Watchdog Timer. Thus, a prescaler

assignment for the T imer0 module means t hat there is no

prescaler for the W atchdog Timer , and vice-versa.

The prescaler is not readable or writable.

The PSA and PS2:PS0 bits (OPTION_REG<3:0>)

determine the presca ler assignment and prescale ratio.

Clearing b it PSA will assign the p rescaler to the T i mer0

module. When the prescaler is assigned to the Timer0

module, prescale values of 1:2, 1:4, ..., 1:256 are

selectable.

Setting bit PSA will assign the prescaler to the Watchdog

Timer (WDT). When the prescaler is assigned to the

WDT, prescale values of 1:1, 1:2, ..., 1:128 are selectable.

When assigned to the Timer0 module, all instructions

writing to the TMR0 registe r (e.g., CLRF 1, MOVWF 1,

BSF 1,etc.) will clear the presca ler. When assig ned to

WDT, a CLRWDT instruction will clear the prescaler

along with the WDT.

FIGURE 5-1: TIMER0 BLOCK DIAGRAM

Note: Writing to TMR0 when the prescaler is

assigned to Timer 0 wi ll clear the presca ler

count, but will not change the prescaler

assignment.

Note 1: T0CS, T0SE, PSA, PS2:PS0 (OPTION_REG<5:0>).

2: The prescaler is shared with Watchdog Timer (refer to Figure 5-2 for detailed block diagram).

RA4/T0CKI

T0SE

T0CS

FOSC/4

Programmable

Prescaler

Sync with

Internal

Clocks TMR0

PSOUT

(2 Cycle Delay)

PSOUT Data Bus

PSA

PS2, PS1, PS 0 Set Interrupt

Flag bit T0IF

on Overflow

PIC16F84A

DS35007B-page 20  2001 Microchip Technology Inc.

5.2.1 SWITCHING PRESCALER

ASSIGNMENT

The prescaler assignment is fully under software con-

trol (i.e., it can be changed “on the fly” during program

execution).

5.3 Timer0 Interrupt

The TMR0 interrupt is generated when the TMR0 reg-

ister overflows from FFh to 00h. This overflow sets bit

T0IF (INTCON<2>). The interrupt can be masked by

clearing bit T0IE (INTCON<5>). Bit T0IF must be

cleared in software by the T ime r0 module Interrupt Ser-

vice Routine before re-enabling this interrupt. The

TMR0 interrupt cannot awaken the processor from

SLEEP since the timer is shut-off during SLEEP.

FIGURE 5-2: BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER

TABLE 5-1: REGISTERS ASSOCIATED WITH TIMER0

Note: To avoid an unintended device RESET, a

specific instruction sequ ence (shown in the

PICmicro™ Mid-Range Reference Man-

ual, DS33023) must be executed when

changing the prescaler assignment from

Timer0 to the WDT. This sequence must

be followed even if the WDT is disabled.

RA4/T0CKI

T0SE

CLKOUT (= FOSC/4)

SYNC

Cycles TMR0 reg

8-bit Prescaler

8 - to - 1 MUX

M U X

Watchdog

Timer

PSA

WDT

Time-out

PS2:PS0

Note: T0CS, T0SE, PSA, PS2:PS0 are (OPTION_REG<5:0>).

PSA

WDT Enable bit

Data Bus

Set Flag bit T0IF

on Overflow

PSA

T0CS

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

POR,

BOR

Value on all

other

RESETS

01h TMR0 Timer0 Module Register xxxx xxxx uuuu uuuu

0Bh,8Bh INTCON GIE EEIE T0IE INTE RBIE T0IF INTF RBIF 0000 000x 0000 000u

81h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

85h TRISA — — — PORTA Data Direction Register ---1 1111 ---1 1111

Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'. Shaded cells are not used by Timer0.

 2001 Microchip Technology Inc. DS35007B-page 21

PIC16F84A

6.0 SPECIAL FEATURES OF THE

CPU

What sets a microcontroller apart from other

proc essors are spec ial circuit s to deal w ith the needs of

real time applications. The PIC16F84A has a host of

such features intended to maximize system reliability,

minimize cost through elimination of external

components, provide power saving operating modes

and offer code protection. These features are:

• OSC Selection

• RESET

- Power-on Reset (POR)

- Power-up Ti mer (PWRT)

- Oscillator Start-up Timer (OST)

• Interrupts

• Watchdog Timer (WDT)

• SLEEP

• Code Protection

• ID Locations

• In-Circuit Serial Programming™ (ICSP™)

The PIC16F84A has a Watchdog Timer which can be

shut-off only through configuration bits. It runs off its

own RC oscillator for added reliability. There are two

timers th at of fer nec essary de lays on power-u p. One i s

the Oscillator Start-up Timer (OST), intended to keep

the chip in RESET until the crystal oscillator is stable.

The other is the Power-up Timer (PWRT), which pro-

vides a fixed delay of 72 ms (nominal) on power-up

only. This design keeps the device in RESET while the

power s upply st abili zes. W ith the se two ti mers o n-chi p,

most applications need no external RESET circuitry.

SLEEP mode offers a very low current power-down

mode. The user can wake-up from SLEEP through

external RESET, Watchdog Timer Time-out or through

an interrupt. Several oscillator options are provided to

allow the part to fit the application. The RC oscillator

option saves system cost while the LP crystal option

saves power. A set of configuration bits are used to

select the various options.

Additional information on special features is available

in the PICmicro™ Mid-Range Reference Manual

(DS33023).

6.1 Configuration Bits

The configuration bits can be programmed (read as '0'),

or left unprogrammed (read as '1'), to select various

device configurations. These bits are mapped in

program memory location 2007h.

Address 2007h is beyond the user program memory

space and it belongs to the special test/configuration

memory space (2000h - 3FFFh). This space can only

be accessed during programming.

R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u

CP CP CP CP CP CP CP CP CP CP PWRTE WDTE F0SC1 F0SC0

bit13 bit0

bit 13-4 CP: Code Protection bit

1 = Code protection disabled

0 = All program memory is code prote ct ed

bit 3 PWRTE: Power-up Timer Enable bit

1 = Power-up Timer is disabled

0 = Power-up Timer is enabled

bit 2 WDTE: Watchdog Timer Enable bit

1 = WDT enabled

0 = WDT disabled

bit 1-0 FOSC1:FOSC0: Oscillator Selection bits

11 = RC oscillator

10 = HS oscillator

01 = XT oscillator

00 = LP oscillator

PIC16F84A

DS35007B-page 22  2001 Microchip Technology Inc.

6.2 Oscillator Configurations

6.2.1 OSCILLATOR TYPES

The PIC16F84A can be operated in four different

oscillator modes. The user can program two

configu ration bit s (FOSC1 and F OSC0) to sele ct one of

these four modes:

• LP Low Power Crystal

• XT Crystal/Resonator

• HS High Speed Crystal/Resonator

• RC Resistor/Capacitor

6.2.2 CRYSTAL OSCILLATOR/CERAMIC

RESONATORS

In XT, LP, or HS modes, a crystal or ceramic resonator

is connected to the OSC1/CLKIN and OSC2/CLKOUT

pins to establish oscillation (Figure 6-1).

FIGURE 6-1: CRYSTAL/CERAMIC

RESONATOR OPERATION

(HS, XT OR LP OSC

CONFIGURATION)

The PIC16F84A oscillator design requires the use of a

parallel cut crystal. Use of a series cut crystal may give

a frequency out of the crystal manufacturers

specifications. When in XT, LP, or HS modes, the

device can have an external clock source to drive the

OSC1/CLKIN pin (Figure 6-2).

FIGURE 6-2: EXTERNAL CLOCK INPUT

OPERATION (HS, XT OR

LP OSC

CONFIGURATION)

TABLE 6-1: CAPACITOR SELECTION FOR

CERAMIC RESONATORS

Note 1: See Table 6-1 for re commended values

of C1 and C2.

2: A series resistor (RS) may be required

for AT strip cut crystals.

C1(1)

C2(1)

XTALOSC2

OSC1

RF(3)

SLEEP

Logic

PIC16FXX

RS(2)

Internal

Ranges Tested:

Mode Freq OSC1/C1 OSC2/C2

XT 45 5 kHz

2.0 MHz

4.0 MHz

47 - 100 pF

15 - 33 pF

47 - 100 pF

15 - 33 pF

HS 8.0 MHz

10.0 MHz 15 - 33 pF

15 - 33 pF 15 - 33 pF

15 - 33 pF

Note: Recommended values of C1 and C2 are

identical to the ranges tested in this table.

Higher capacitance increases the stability

of the oscillator, but also increases the

start-up time. These values are for design

guidance only. Since each resonator has

its own characteristics, the user should

consult the resonator manufacturer for the

appropriate values of external compo-

nents.

Note: When using resonators with frequencies

above 3 .5 MHz, the use of HS mode rather

than XT m ode, is recommend ed. HS mod e

may be used at any VDD for which the

controller is rated.

OSC1

OSC2

Open

Clock from

Ext. Syst em PIC16FXX

 2001 Microchip Technology Inc. DS35007B-page 23

PIC16F84A

TABLE 6-2: CAPACITOR SELECTION

FOR CRYSTAL OSCILLATOR 6.2.3 RC OSCILLATOR

For timing insensitive applications, the RC device

option offers additional cost savings. The RC oscillator

frequency is a function of the supply voltage, the

resistor (REXT) values, capacitor (CEXT) values, and

the operati ng tempe rature. In ad dition to this, the osci l-

lator frequency will vary from unit to unit due to normal

process parameter variation. Furthermore, the

dif f eren ce in le ad frame capacitance be tw ee n package

types also affects the oscillation frequency, especially

for low CEXT values. The user needs to take into

account variation, due to tolerance of the external

R and C components. Figure 6-3 shows how an R/C

combination is connected to the PIC16F84A.

FIGURE 6-3: RC OSCILLATOR MODE

Mode Freq OSC1/C1 OSC2/C2

LP 32 kHz

200 kHz 68 - 100 pF

15 - 33 pF 68 - 100 pF

15 - 33 pF

XT 100 kHz

2 MHz

4 MHz

100 - 150 pF

15 - 33 pF

100 - 150 pF

15 - 33 pF

HS 4 MHz

20 MHz 15 - 33 pF

15 - 33 pF 15 - 33 pF

15 - 33 pF

Note: Higher capacitance increases the stability

of the oscillator, but also increases the

start-up time. These values are for design

guidance only. Rs may be required in HS

mode, as wel l as XT mode , to av oid ove r-

driving crystals with low drive level specifi-

cation. Since each crystal has its own

char acteristi cs, the u ser should c onsult th e

crystal manufacturer for appropriate

values of external components.

For VDD > 4.5V, C1 = C2 ≈ 30 pF is recom-

mended.

OSC2/CLKOUT

CEXT

REXT

PIC16FXX

OSC1

FOSC/4

Internal

Clock

VDD

VSS

Recommended values: 5 kΩ ≤ REXT ≤ 100 kΩ

CEXT > 20pF

PIC16F84A

DS35007B-page 24  2001 Microchip Technology Inc.

6.3 RESET

The PIC16F84A differentiates between various kinds

of RESET:

• Power-on Reset (POR)

•MCLR

during normal operation

•MCLR during SLEEP

• WDT Reset (during normal operation)

• WDT Wake-up (during SLEEP)

Figure 6-4 shows a simplified block diagram of the

On-Chip RESET Circuit. The MCLR Reset path has a

noise filter to ignore small pulses. The electrical speci-

fications state the pulse width requirements for the

MCLR pin.

Some re gisters are not af fected in any RE SET cond ition;

their s t atu s is unkn own on a POR an d un chan ge d in a ny

other RESET. Most other registers are reset to a “RESET

state” on POR, MCLR or WDT Reset during normal oper-

atio n and on MCLR d uring SLE EP. They are no t aff ected

by a WDT Reset during SLEEP, since this RESET is

viewed as the resumption of normal operation.

Table 6-3 gives a description of RESET conditions for

the program counter (PC) and the STATUS register.

Table 6-4 gives a full description of RESET states for all

registers.

The TO and PD bits are set or cleared differently in dif-

ferent RESET situations (Section 6.7). These bits are

used in software to determine the nature of the RESET.

FIGURE 6-4: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT

TABLE 6-3: RESET CONDITION FOR PROGRAM COUNTER AND THE STATUS REGISTER

External Reset

MCLR

VDD

OSC1/

WDT

Module

VDD Rise

Detect

OST/PWRT

On-Chip

RC Osc(1)

WDT

Time-out

Power-on Reset

OST

10-bit Ripple Counter

PWRT

Chip_Reset

10-bit Ripple Counter

Reset

Enable OST

Enable PWRT

SLEEP

CLKIN

Note 1: This is a sep arate oscillator from the RC oscillator of the CLKIN pin.

2: See Table 6-5.

See Table 6-5

Condition Program Counter STATUS Register

Power-on Reset 000h 0001 1xxx

MCLR during normal operation 000h 000u uuuu

MCLR during SLEEP 000h 0001 0uuu

WDT Reset (during normal operation) 000h 0000 1uuu

WDT Wake-up PC + 1 uuu0 0uuu

Interrupt wake-up from SLEEP PC + 1(1) uuu1 0uuu

Legend: u = unchanged, x = unknown

Note 1: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).

 2001 Microchip Technology Inc. DS35007B-page 25

PIC16F84A

TABLE 6-4: RESET CONDITIONS FOR ALL REGISTERS

MCLR during:

– normal operation

– SLEEP

WDT Reset during

normal operation

W ake -up fro m SLEEP:

– through interrupt

– through WDT Time-out

W—xxxx xxxx uuuu uuuu uuuu uuuu

INDF 00h ---- ---- ---- ---- ---- ----

TMR0 01h xxxx xxxx uuuu uuuu uuuu uuuu

PCL 02h 0000 0000 0000 0000 PC + 1(2)

STATUS 03h 0001 1xxx 000q quuu(3) uuuq quuu(3)

FSR 04h xxxx xxxx uuuu uuuu uuuu uuuu

PORTA(4) 05h ---x xxxx ---u uuuu ---u uuuu

PORTB(5) 06h xxxx xxxx uuuu uuuu uuuu uuuu

EEDATA 08h xxxx xxxx uuuu uuuu uuuu uuuu

EEADR 09h xxxx xxxx uuuu uuuu uuuu uuuu

PCLATH 0Ah ---0 0000 ---0 0000 ---u uuuu

INTCON 0Bh 0000 000x 0000 000u uuuu uuuu(1)

INDF 80h ---- ---- ---- ---- ---- ----

OPTION_REG 81h 1111 1111 1111 1111 uuuu uuuu

PCL 82h 0000 0000 0000 0000 PC + 1(2)

STATUS 83h 0001 1xxx 000q quuu(3) uuuq quuu(3)

FSR 84h xxxx xxxx uuuu uuuu uuuu uuuu

TRISA 85h ---1 1111 ---1 1111 ---u uuuu

TRISB 86h 1111 1111 1111 1111 uuuu uuuu

EECON1 88h ---0 x000 ---0 q000 ---0 uuuu

EECON2 89h ---- ---- ---- ---- ---- ----

PCLATH 8Ah ---0 0000 ---0 0000 ---u uuuu

INTCON 8Bh 0000 000x 0000 000u uuuu uuuu(1)

Legend: u = unchanged, x = unkno wn, - = unimplemented bit, read as '0', q = value depends on condition

Note 1: One or more bits in INTCON will be affected (to cause wake-up).

2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector

(0004h).

3: Table 6-3 lists the RESET value for each specific condition.

4: On any device RESET, these pins are configured as inputs.

5: This is the value that will be in the port output latch.

PIC16F84A
DS35007B-page 26  2001 Microchip Technology Inc.
6.4 Power-on Reset (POR)
A Power-on Reset pulse is generated on-chip when
VDD rise is detected (in the range of 1.2V - 1.7V). To
take advantage of the POR, just tie the MCLR pin
directly (or through a resistor) to VDD. This will
eliminate external RC components usually needed to
create Power-on Reset. A minimum rise time for VDD
must be met for this to operate properly. See Electrical
Specifications for details.
When the device starts normal operation (exits the
RESET condition), device operating parameters (volt-
age, frequency, temperature, etc.) must be met to
ensure operation. If these conditions are not met, the
device must be held in RESET until the operating con-
ditions are met.
For additional information, refer to Application Note
AN607, "
Power-up Trouble Shooting
."
The POR circuit does not produce an internal RESET
when VDD declines.
6.5  Power-up Timer (PWRT)
The Power-up Timer (PWRT) provides a fixed 72 ms
nominal time-out (TPWRT) from POR (Figures 6-6
through 6-9). The Power-up Timer operates on an
internal RC oscillator. The chip is kept in RESET as
long as the PWRT is active. The PWRT delay allows
the VDD to rise to an acceptable level (possible excep-
tion shown in Figure 6-9).
A configuration bit, PWRTE, can enable/disable the
PWRT. See Register 6-1 for the operation of the
PWRTE bit for a particu lar devi ce .
The power-up time delay TPWRT will  vary  from c hip to
chip due to VDD, temperature, and process variation.
See DC parameters for det a ils .
6.6  Oscillat or Start- up Timer (OST)
The Oscillator Start-up Timer (OST) provides a 1024
oscillator cycle delay (from OSC1 input) after the
PWRT delay ends (Figure 6-6, Figure 6-7, Figure 6-8
and Figure 6-9). This ensures the crystal oscillator or
resonator has started and stabilized.
The OST  time-ou t (TOST) is invoked only for XT, LP and
HS modes and only on Power-on Reset or wake-up
from SLEEP.
When VDD rises very slowly, it is possible that the
TPWRT time-out and TOST time-out will expire before
VDD has reached its final value. In this case
(Figure 6-9), an external Power-on Reset circuit may
be necessary (Figure 6-5).
FIGURE 6-5: EXTERNAL  POWER-ON 
RESET CIRCUIT (FOR 
SLOW VDD POWER-UP)   
Note 1: External Power-on Reset circuit is required
only if VDD power-up rate is too slow. The
diode D helps discharge the capacitor
quickly when VDD powers down.
2: R < 40 kΩ is recommended to make sure
that voltage drop across R does not exceed
0.2V (max leakage current spec on MCLR
pin is 5 µA). A larger voltage drop will
degrade VIH level on the MCLR pin.
3: R1 = 100Ω to 1 kΩ will limit any current flow-
ing into MCLR from external capacitor C, in
the event of a MCLR pin breakdown due  to
ESD or EOS.
C
R1
R
D
VDD
MCLR
PIC16FXX
VDD

 2001 Microchip Technology Inc. DS35007B-page 27

PIC16F84A

FIGURE 6-6: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1

FIGURE 6-7: TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2

FIGURE 6-8: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD): FAST VDD RISE

TIME

TPWRT

TOST

VDD

MCLR

INTERNAL POR

PWRT TIME-OUT

OST TIME-OUT

INTERNAL RESET

VDD

MCLR

INTERNAL POR

PWRT TIME -O UT

OST TIME-OUT

INTERNAL RESET

TPWRT

TOST

VDD

MCLR

INTERNAL POR

TPWRT

TOST

PWRT TIME-OUT

OST TIME-OUT

INTERNAL RESET

PIC16F84A

DS35007B-page 28  2001 Microchip Technology Inc.

FIGURE 6-9: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD):

SLOW VDD RISE TIME

6.7 Time-out Sequence and

Power-down Status Bits (TO/PD)

On power-up (Figures 6-6 through 6-9), the time-out

sequence is as follows:

1. PWRT time-out is invoked after a POR has

expired.

2. Then, the OST is activated.

The total time-out will vary based on oscillator configu-

ration and PWRTE configuration bit status. For exam-

ple, in RC mode with the PWRT disabled, there will be

no time-out a t all.

TABLE 6-5: TIME-OUT IN VARIOUS

SITUATIONS

Since the time-outs occur from the PO R pulse, if MCLR

is kept low long enough, the time-outs will expire. Then

bringing MCLR high, execution will begin immediately

(Figure 6-6). This is useful for testing purposes or to

synchronize more than one PIC16F84A device when

operating in parallel.

Table 6-6 shows the significance of the TO and PD bits.

Table 6-3 lists the RESET conditions for some special

registers, while Table 6-4 lists the RESET conditions

for all the registers.

TABLE 6-6: STATUS BITS AND THEIR

SIGNIFICANCE

VDD

MCLR

When VDD rises very slowly, it is possible that the TPWRT time-out and TOST time-out will expire before VDD

has reached its final value. In this example, the chip will reset properly if, and only if, V1 ≥ VDD min.

INTERNAL POR

TPWRT

TOST

PWRT TIME -O UT

OST TIME-OUT

INTERNAL RESET

Oscillator

Configuration

Power-up Wake-up

from

SLEEP

PWRT

Enabled PWRT

Disabled

XT, HS, LP 72 ms +

1024TOSC 1024TOSC 1024TOSC

RC 72 ms ——

TO PD Condition

Power-on Reset

Illegal, TO is set on POR

Illegal, PD is set on POR

WDT Reset (during normal operation)

WDT Wake-up

MCLR during normal operation

MCLR during SLEEP or interrupt

wake-up from SLEEP

 2001 Microchip Technology Inc. DS35007B-page 29

PIC16F84A

6.8 Interrupts

The P IC16F84A has 4 sources of interrupt:

• External interrupt RB0/INT pin

• TMR0 overflow interrupt

• PORTB change interrupts (pins RB7:RB4)

• Data EEPROM write complete interrupt

The interrupt control register (INTCON) records

individual int errup t requ es t s in flag b it s . It also c ontains

the individual and global interrupt enable bits.

The global interrupt enable bit, GIE (INTCON<7>),

enables (if set) all unmasked interrupts or disables (if

cleared) all interrupts. Individual interrupts can be

disabled through their corresponding enable bits in

INTCON register. Bit GIE is cleared on RESET.

The “return from interrupt” instruction, RETFIE, exits

interrupt routine as well as sets the GIE bit, which

re-enable s inte rrup t s.

The RB0/INT pin interrupt, the RB port change interrupt

and the TMR0 overflow interrupt flags are contained in

the INTCON register.

When an interrupt is responded to, the GIE bit is

cleared to disable any further interrupt, the return

address is pu sh ed onto th e s t ac k a nd the PC is lo ade d

with 0004h. For external interrupt events, such as the

RB0/INT pin or PORTB change interrupt, the interrupt

latency will be three to four instruction cycles. The

exact latency depends when the interru pt event occurs.

The latency is the same for both one and two cycle

instructions. Once in the Interrupt Service Routine, the

source(s) of the interrupt can be determined by polling

the interrupt flag bits. The interrupt flag bit(s) must be

cleared in software before re-enabling interrupts to

avoid infinite interrupt requests.

FIGURE 6-10: INTERRUPT LOGIC

6.8.1 INT INTERRUPT

External interrupt on RB0/INT pin is edge triggered:

either rising if INTEDG bit (OPTION_REG<6>) is set,

or falling if INTEDG bit is clear. When a valid edge

appears on the RB0/INT pin, the INTF bit

(INTCON<1>) is set. This interrupt can be disabled by

clearing control bit INTE (INTCON<4>). Flag bit INTF

must be cleared in software via the Interrupt Service

Routine before re-enabling this interrupt. The INT

interrupt can wake the processor from SLEEP

(Section 6.1 1) o nly if the INTE bit was s et prior to going

into SLEEP. The status of the GIE bit decides whether

the processor branches to the interrupt vector

following wake-up.

6.8.2 TMR0 INTERRUPT

An overflow (FFh → 00h) in TMR0 will set flag bit T0IF

(INTCON<2>). The interrupt can be enabled/disabled

by setting/clearing enable bit T0IE (INTCON<5>)

(Section 5.0).

6.8.3 PORTB INTERRUPT

An input change on PORTB<7:4> sets flag bit RBIF

(INTCON<0>). The interrupt can be enabled/disabled

by setting/clearing enable bit RBIE (INTCON<3>)

(Section 4.2).

6.8.4 DAT A EEPROM INTERRUPT

At the completion of a data EEPROM write cycle, flag

bit EEIF (EECON1<4 >) will be set. The interrupt can be

enabled/disabled by setting/clearing enable bit EEIE

(INTCON<6>) (Section 3 .0).

Note: Individual interrupt flag bits are set

regardless of the status of their

corresponding mask bit or the GIE bit.

RBIF

RBIE

T0IF

T0IE

INTF

INTE

GIE

EEIE

Wake-up

(If in SLEEP mode)

Interrupt to CPU

EEIF

Note: For a change on the I/O pin to be

recognized, the pulse width must be at

least TCY wide.

PIC16F84A

DS35007B-page 30  2001 Microchip Technology Inc.

6.9 Context Saving During Interrupts

During an interrupt, only the return PC value is saved

on the sta ck. Typicall y, users wi sh to save ke y r egi st e r

values during an interrupt (e.g., W register and

STATUS regi ster). This is implem ented in software.

The code in Example 6-1 stores and restores the

STATUS and W register’s values. The user defined

registers, W_TEMP and STATUS_TEMP are the tem-

porary storage locations for the W and STATUS

registers values.

Example 6-1 does the following:

a) Stores the W register.

b) Stores the STATUS register in STATUS_TEMP.

c) Executes the Interrupt Service Routine code.

d) Restores the STATUS (and bank select bit)

e) Restores the W register.

EXAMPLE 6-1: SAVING STATUS AND W REGISTERS IN RAM

6.10 Watchdog Timer (WDT)

The Watchdog Timer is a free running On-Chip RC

Oscillator which does not require any external

components. This RC oscillator is separate from the

RC oscillator of the OSC1/CLKIN pin. That means that

the WDT will run even if the clock on the OSC1/CLKIN

and OSC2/CLKOUT pins of the device has been

stopped, for example, by execution of a SLEEP

instruction. During normal operation, a WDT time-out

generates a device RESET. If the device is in SLEEP

mode, a WDT wake-up causes the device to wake-up

and continue with normal operation. The WDT can be

permanently disabled by prog ramming configuration bit

WDTE as a '0' (S ect ion 6.1).

6.10.1 WDT PERIOD

The WDT ha s a nominal time-o ut period of 18 ms, (wi th

no prescaler). The time-out periods vary with

temperature, VDD and process variations from part to

part (see DC specs). If longer time-out periods are

desired, a prescaler with a division ratio of up to 1:128

can be as si gned to the W DT under softwa re c ontrol by

writing to the OPTION_REG register. Thus, time-out

periods up to 2.3 seconds can be realized.

The CLRWDT and SLEEP instructions clear the WDT

and the postscaler (if assigned to the WDT) and pre-

vent it from timing out and generating a device

RESETcondition.

The TO bit in the ST ATUS register will be cleared upon

a WDT time-out.

PUSH MOVWF W_TEMP ; Copy W to TEMP register,

SWAPF STATUS, W ; Swap status to be saved into W

MOVWF STATUS_TEMP ; Save status to STATUS_TEMP register

ISR : :

: ; Interrupt Service Routine

: ; should configure Bank as required

POP SWAPF STATUS_TEMP,W ; Swap nibbles in STATUS_TEMP register

; and place result into W

MOVWF STATUS ; Move W into STATUS register

; (sets bank to original state)

SWAPF W_TEMP, F ; Swap nibbles in W_TEMP and place result in W_TEMP

SWAPF W_TEMP, W ; Swap nibbles in W_TEMP and place result into W

 2001 Microchip Technology Inc. DS35007B-page 31

PIC16F84A

6.10.2 WDT PROGRA MMI NG

CONSIDERATIONS

It should also be taken into account that under worst

case conditions (VDD = Min., T emperature = Max., Max.

WDT Pr e sca ler ), it ma y take sev e r al se co nd s b efo r e a

WDT time-out occurs.

FIGURE 6-11: WATCHDOG TIMER BLOCK DIAGRAM

TABLE 6-7: SUMMARY OF REGISTERS ASSOCIATED WITH THE WATCHDOG TIMER

From TMR0 Clock Source

(Figure 5-2)

To TMR0 (Figure 5-2)

Postscaler

WDT Timer

PSA

8 - to -1 MUX

PSA

WDT

Time-out

WDT

Enable Bit

PS2:PS0

•

MUX

Note: PSA and PS2:PS0 are bits in the OPTION_REG register.

Addr Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

Power-on

Reset

V alue on all

other

RESETS

2007h Config. bits (2) (2) (2) (2) PWRTE(1) WDTE FOSC1 FOSC0 (2)

81h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

Legend: x = unknown. Shaded cells are not used by the WDT.

Note 1: S ee Register 6-1 for operation of the PWRTE bit.

2: See Register 6-1 and Section 6.12 for operation of the code and data protection bits.

PIC16F84A

DS35007B-page 32  2001 Microchip Technology Inc.

6.11 Power-down Mode (SLEEP)

A device may be powered down (SLEEP) and later

powered up (wake-up from SLEEP).

6.11.1 SLEEP

The Power-down mode is entered by executing the

SLEEP instruction.

If enabled, the Watchdog Timer is cleared (but keeps

running) , the PD bit (STA TUS<3>) is cleared, the TO bit

(STATUS<4>) is set, and the oscillator driver is turned

off. The I/O ports maintain the status they had before

the SLEEP instruction was executed (driving high, low,

or hi-impedance).

For the lowest current consumption in SLEEP mode,

place al l I/O pin s at either V DD or VSS, with no externa l

circuitry drawing current from the I/O pins, and disable

external clocks. I/O pins that are hi-impedance inputs

should be pulled h igh or lo w externally to a void s w itc h-

ing curre nts cause d by floatin g input s. The T0CKI inp ut

should also be at VDD or VSS. The contribution from

on-chip pull-ups on PORTB should be considered.

The MCLR pin must be at a logic high level (VIHMC).

It should be noted that a RESET generated by a WDT

time-out does not drive the MCLR pin low.

6.11.2 W AKE-UP FRO M SLEEP

The device can wake-up from SLEEP through one of

the following events:

1. External RESET input on MCLR pin.

2. WDT wake-up (if WDT was enabled).

3. Interrupt from RB0/INT pin, RB port change, or

data EEPROM write complete.

Peripherals cannot generate interrupts during SLEEP,

since no on-chip Q clocks are present.

The first event (MCLR Reset) will cause a device

RESET. The two latte r ev en t s are c ons id ered a co nti n-

uation of program execution. The TO and PD bits can

be used to determine the cause of a device RESET.

The PD bit, wh ich i s set on pow er-u p, is clear ed wh en

SLEEP is invoked. The TO bit is cleared if a WDT

time-out occurred (and caused wake-up).

While th e SLEEP instruction is being executed, the next

instruction (PC + 1) is pre-fetched. For the device to

wake-up through an interrupt event, the corresponding

interrupt enable bit must be set (enabled). Wake-up

occurs regardless of the state of the GIE bit. If the GIE

bit is clear (disabled), the device continues execution at

the ins truction a fter the SLEEP instruction. If the GIE bit

is set (enabled), the device executes the instruction

after the SLEEP instruction and then branches to the

interrupt address (0004h). In cases where the

execution of the instruction following SLEEP is not

desirable, the user should have a NOP after the

SLEEP instruction.

FIGURE 6-12: WAKE-UP FROM SLEEP THROUGH INTERRUPT

Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

OSC1

CLKOUT(4)

INT pin

INTF Flag

(INTCON<1>)

GIE bit

(INTCON<7>)

INSTRUCTION FLOW

Instruction

Fetched

Instruction

Executed

PC PC+1 PC+2

Inst(PC) = SLEEP

Inst(PC - 1)

Inst(PC + 1)

SLEEP

Processor in

SLEEP

Interrupt Latency

(Note 2)

Inst(PC + 2)

Inst(PC + 1)

Inst(0004h) Inst(0005h)

Inst(0004h)

Dummy cycle

PC + 2 0004h 0005h

Dummy cycle

TOST(2)

PC+2

Note 1: XT, HS, or LP oscillator mode assumed.

2: TOST = 1024TOSC (drawing not to scale). This delay will not be there for RC osc mode.

3: GIE = ’1’ assumed. In this case after wake-up, the processor jumps to the interrupt routine. If GIE = ’0’, execution will continue in-line.

4: CLKOUT is not available in these osc modes, but shown here for timing reference.

 2001 Microchip Technology Inc. DS35007B-page 33

PIC16F84A

6.11 .3 WAKE-UP USING INTERRUPTS

When global interrupts are disabled (GIE cleared) and

any interrupt source has both its interrupt enable bit

and inte rrupt fla g bit s et, one of the fo llowin g will oc cur:

• If the interrupt occurs before the execution of a

SLEEP instruction, the SLEEP instruction will com-

plete as a NOP. Therefore, the WDT and WDT

pos tsc aler will not be clear ed, the TO bit will not

be set and PD bits will not be cleared.

• If the interrupt occurs during or after the execu-

tion of a SLEEP instruction, the device will imme-

diately wake-up from SLEEP. The SLEEP

instruction will be completely executed before the

wake-up. Therefore, the WDT and WDT

pos tsc aler will be cleared, the TO bit will be set

and the PD bit will be cleared.

Even if the flag bits were checked before executing a

SLEEP instruction, it may be possible for flag bits to

become set before the SLEEP instruction completes. To

determine whether a SLEEP instruction executed, test

the PD bit. If the PD bit is set, the SLEEP instruction

was executed as a NOP.

To ensure that the WDT is cleared, a CLRWDT instruc-

tion should be executed before a SLEEP instru ction.

6.12 Program Verification/Code

Protection

If the code protection bit(s) have not been pro-

grammed, the on-chip program memory can be read

out for verification purposes.

6.13 ID Locations

Four memo ry locations (2000h - 2004h) are designated

as ID locations to store checksum or other code

identification numbers. These locations are not

accessible during normal execution but are readable

and writable only during program/verify. Only the

four Least Significant bits of ID location are usable.

6.14 In -Circuit Serial Programmi ng

PIC16F84A microcontrollers can be serially

progra mmed w hile in t he end appl icati on ci rcuit. This is

simply done with two line s for clock and dat a, and three

other lines for power, ground, and the programming

voltage. Customers can manufacture boards with

unprogrammed devices, and then program the

microcontroller just before shipping the product,

allowing the most recent firmware or custom firmware

to be programmed.

For complete details of Serial Programming, please

refer to the In-Circuit Serial Programming™ (ICSP™)

Guide, (DS302 77).

PIC16F84A

DS35007B-page 34  2001 Microchip Technology Inc.

NOTES:

 2000 Microchip Technology Inc. DS35007B-page 35

PIC16F84A

7.0 INSTRUCTION SET SUMMARY

Each PIC16CXX instruction is a 14-bit word, divided

into an OPCODE which specifies the instruction type

and one or more operands which further specify the

operation o f the instru ction. The PIC16CXX instruction

set summary in Table 7-2 lists byte-oriented, bit-ori-

ented, and literal and control operations. Table 7-1

shows the opcode field descriptions.

For byte-oriented instructio ns, ’f’ repr es ents a file reg-

ister designator and ’d’ represents a destination desig-

nator. The file register designator specifies which file

The desti nation designator specifies where the result of

the operation is to be placed. If ’d’ is zero, the result is

placed in the W reg ister . If ’ d’ is one, the resu lt is placed

in the file register specified in the instruction.

For bit-oriented instructions, ’b’ represents a bit field

designator whic h selec t s the nu mber of th e bi t a ffecte d

by the oper ation, whi le ’ f’ represen ts the address of the

file in which the bit is located.

For literal and control operations, ’k’ represents an

eight or eleven bit constant or literal value.

TABLE 7-1: OPCODE FIELD

DESCRIPTIONS

The instruction set is highly orthogonal and is grouped

into three basic categories:

•Byte-oriented operations

•Bit-oriented operations

•Literal and cont rol operations

All instructions are executed within one single instruc-

tion cycle, unless a conditional test is true or the pro-

gram counter is changed as a result of an instruction.

In this case, the execution takes two instruction cycles

with the second cycle executed as a NOP. One instruc-

tion cycle consists of four oscillator periods. Thus, for

an osc illator frequency of 4 M Hz, th e normal instruct ion

executi on ti me is 1 µs. If a condit ion al test is true o r the

program counter is changed as a result of an instruc-

tion, the instruction execution time is 2 µs.

Table 7-2 lists the instructions recognized by the

MPASM™ Assembler.

Figure 7-1 shows the general formats that the instruc-

tions can have.

All examples use the following format to represent a

hexadecimal number:

0xhh

where h signifies a hexadecimal digit.

FIGURE 7-1: GENERAL FORMAT FOR

INSTRUCTIONS

A description of each instruction is available in the

PICmicro™ M id-Range Referenc e Manu al (DS33023 ).

Field Description

fRegister file address (0x00 to 0x 7F)

WWorking register (accumulator)

bBit address within an 8-bit file register

kLiteral field, constant data or label

xDon't care location (= 0 or 1)

The assembler will generate code with x = 0.

It is the rec om me nde d form o f u se for compat-

ibility with all Microchip software tools.

dDestinatio n select; d = 0: store result in W,

d = 1: store result in file register f.

Default is d = 1

PC Program Counter

TO Time-out bit

PD Power-down bit

Note: To maintain upward compatibility with

future PIC16CXX products, do not use the

OPTION and TRIS instr uctions.

Byte-oriented file register operations

13 8 7 6 0

d = 0 for destination W

OPCODE d f (FILE #)

d = 1 for destination f

f = 7-bit file register address

Bit-oriented file register operations

13 10 9 7 6 0

OPCODE b (BIT #) f (FILE #)

b = 3-bit bit address

f = 7-bit file register address

Literal and control operations

13 8 7 0

OPCODE k (literal)

k = 8-bit immediate value

13 11 10 0

OPCODE k (literal)

k = 11-bit immediate value

General

CALL and GOTO instructions only

PIC16F84A

DS35007B-page 36  2000 Microchip Technology Inc.

TABLE 7-2: PIC16CXXX INSTRUCTION SET

Mnemonic,

Operands Description Cycles 14-Bit Opcode Status

Affected Notes

MSb LSb

BYTE-ORIENTED FILE REGISTER OPERATIONS

ADDWF

ANDWF

CLRF

CLRW

COMF

DECF

DECFSZ

INCF

INCFSZ

IORWF

MOVF

MOVWF

NOP

RLF

RRF

SUBWF

SWAPF

XORWF

f, d

Add W and f

AND W with f

Clear f

Clear W

Complement f

Decrement f

Decrement f, Skip if 0

Increment f

Increment f, Skip if 0

Inclusive OR W with f

Move f

Move W to f

No Operation

Rotate Left f through Carry

Rotate Right f through Carry

Subtract W from f

Swap nibbles in f

Exclusive OR W with f

1 (2)

0111

0101

0001

1001

0011

1011

1010

1111

0100

1000

0000

1101

1100

0010

1110

0110

dfff

lfff

0xxx

dfff

lfff

0xx0

dfff

ffff

xxxx

ffff

0000

ffff

C,DC,Z

1,2

1,2,3

1,2

1,2,3

1,2

BIT-ORIENTED FILE REGISTER OPERATIONS

BCF

BSF

BTFSC

BTFSS

f, b

Bit Clear f

Bit Set f

Bit Test f, Skip if Clear

Bit Test f, Skip if Set

1 (2)

00bb

01bb

10bb

11bb

bfff

ffff

1,2

LITERAL AND CONTROL OPERATIONS

ADDLW

ANDLW

CALL

CLRWDT

GOTO

IORLW

MOVLW

RETFIE

RETLW

RETURN

SLEEP

SUBLW

XORLW

Add literal and W

AND literal with W

Call subroutine

Clear Watchdog Timer

Go to address

Inclusive OR literal with W

Move literal to W

Return from interrupt

Return with literal in W

Return from Subroutine

Go into standby mode

Subtract W from literal

Exclusive OR literal with W

111x

1001

0kkk

0000

1kkk

1000

00xx

0000

01xx

0000

110x

1010

kkkk

0110

kkkk

0000

kkkk

0000

0110

kkkk

0100

kkkk

1001

kkkk

1000

0011

kkkk

C,DC,Z

TO,PD

C,DC,Z

Note 1: When an I/O register is modified as a function of itself ( e.g., MOVF PORTB, 1), the value used will be that value present

on the pins themselves. For example, if the data latch is ’1 ’ for a pin configured as input and is driven low by an external

device, the data will be written back with a ’0’.

2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if

assigned to the Timer0 Module.

3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is

executed as a NOP.

Note: Additional information on the mid-range instruction set is available in the PICmicro™ Mid-Range MCU

Family Reference Manual (DS33023).

 2000 Microchip Technology Inc. DS35007B-page 37

PIC16F84A

7.1 Instruction Descriptions

ADDLW Add Literal and W

Syntax: [

label

] ADDLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) + k → (W)

Status Affected: C, DC, Z

Desc ript ion : The conten t s of the W regis ter

are adde d to the eight-bi t literal ’ k’

and the result is placed in the W

ADDWF Add W and f

Syntax: [

label

] ADDWF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (W) + (f) → (destination)

Status Affected: C, DC, Z

Descript ion: Add the con tents of the W re gister

with register ’f’. If ’d’ is 0, the result

is stored in the W register. If ’d’ is

1, the result is stored back in

ANDLW AND Literal with W

Syntax: [

label

] ANDLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) .AND. (k) → (W)

Status Affected: Z

Desc ript ion : The conten t s of W regist er ar e

AND’ed with the eight-bit literal

'k'. The result is placed in the W

ANDWF AND W with f

Syntax: [

label

] ANDWF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (W) .AND. (f) → (destination)

Status Affected: Z

Description: AND the W register with register

'f'. If 'd' is 0, the result is stored in

the W regist er. If 'd' is 1, the re sult

is stored back in register 'f'.

BCF Bit Clear f

Syntax: [

label

] BCF f,b

Operands: 0 ≤ f ≤ 127

0 ≤ b ≤ 7

Operation: 0 → (f<b>)

Status Affe cte d: No ne

Descrip tion: Bit 'b' in re gister 'f' is cleared.

BSF Bit Set f

Syntax: [

label

] BSF f,b

Operands: 0 ≤ f ≤ 127

0 ≤ b ≤ 7

Operation: 1 → (f<b>)

Status Affe cte d: No ne

Descrip tion: Bit 'b' in re gister 'f' is set.

BTFSS Bit Test f, Skip if Set

Syntax: [

label

] BTFSS f,b

Operands: 0 ≤ f ≤ 127

0 ≤ b < 7

Operation: skip if (f<b>) = 1

Status Affe cte d: None

Desc ripti on : If bit 'b' in regi st er ' f' is '0 ', the next

instruction is execu ted .

If bit 'b' is '1', then the next instruc-

tion is discarded and a NOP is exe-

cuted instead, making this a 2TCY

instruction.

PIC16F84A

DS35007B-page 38  2000 Microchip Technology Inc.

BTFSC Bit Test, Skip if Clear

Syntax: [

label

] BTFSC f,b

Operands: 0 ≤ f ≤ 127

0 ≤ b ≤ 7

Operation: skip if ( f<b> ) = 0

Status Affected: None

Description: If bit ’b’ in register ’f’ is ’1’, the next

instruction is executed.

If bit ’b’ in register ’f’ is ’0’, the next

instruction is discarded, and a NOP

is exec ute d ins tead, makin g this a

2TCY instruction.

CALL Call Subroutine

Syntax: [

label

] CALL k

Operands: 0 ≤ k ≤ 204 7

Operation: (PC)+ 1→ TOS,

k → PC<10:0>,

(PCLATH<4:3>) → PC<12:11>

Status Affected: None

Description: Call Subroutine. First, return

address (PC+1) is pushed onto

the stack. The eleven-bit immedi-

ate a ddress is loade d into P C bit s

<10:0>. The upper bits of the PC

are load ed from PCLA TH. CALL is

a two -cycle instruction.

CLRF Clear f

Syntax: [

label

] CLRF f

Operands: 0 ≤ f ≤ 127

Operation: 00h → (f)

1 → Z

Status Affected: Z

Desc ript ion : The content s of regi ste r ’f’ are

cleared and the Z bit is set.

CLRW Clear W

Syntax: [

label

] CLRW

Operands: None

Operation: 00h → (W)

1 → Z

Status Affected: Z

Description: W register is cleared. Zero bit (Z)

is set.

CLRWDT Clear Watchdog Timer

Syntax: [

label

] CLRWDT

Operands: None

Operation: 00h → WDT

0 → WDT prescaler,

1 → TO

1 → PD

Status Affe cte d: TO, PD

Description: CLRWDT instruction resets the

W atchdog T imer . It also reset s the

prescaler of the WDT. Status bits

TO and PD are set.

COMF Complement f

Syntax: [

label

] COMF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) → (destination)

Status Affe cte d: Z

Description: The contents of register ’f’ are

complemented. If ’d’ is 0, the

result is st ored in W. If ’d’ is 1, t he

result is stored back in register ’f’.

DECF Decrement f

Syntax: [

label

] DECF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) - 1 → (destination)

Status Affe cte d: Z

Description: Decrement register ’f’. If ’d’ is 0,

the result is stored in the W regis-

ter. If ’d’ is 1, the result is stored

back in register ’f’.

 2000 Microchip Technology Inc. DS35007B-page 39

PIC16F84A

DECFSZ Decrement f, Skip if 0

Syntax: [

label

] DECFSZ f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) - 1 → (destination);

skip if result = 0

Status Affected: None

Description: The contents of register ’f’ are

decremented. If ’d’ is 0, the result

is placed in the W register. If ’d’ is

1, the result is place d back in

If the result is 1, the next instruc-

tion is executed. If the result is 0,

then a NOP is executed instead,

making it a 2TCY in stru ction.

GOTO Unconditional Branch

Syntax: [

label

] GOTO k

Operands: 0 ≤ k ≤ 2047

Operation: k → PC<10:0>

PCLATH<4:3> → PC<12:11>

Status Affected: None

Description: GOTO is an unconditional branch.

The e le ven -bi t im me dia te v alue is

loaded into PC bits <10:0>. The

upper bits of PC are loaded from

PCLATH<4:3>. GOTO is a two-

cycle instruction.

INCF Increment f

Syntax: [

label

] INCF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) + 1 → (destination)

Status Affected: Z

Description: The contents of register ’f’ are

incremented. If ’d’ is 0, the result

is placed in the W register. If ’d’ is

1, the result is placed back in

INCFSZ Increment f, Skip if 0

Syntax: [

label

] INCFSZ f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) + 1 → (destination),

skip if result = 0

Status Affe cte d: None

Description: The contents of register ’f’ are

incremen ted. If ’ d’ is 0, th e result is

placed in the W re gister. If ’d’ is 1,

the result is placed back in

If the result is 1, the next instruc-

tion is executed. If the result is 0,

a NOP is executed instead, making

it a 2TCY instruction.

IORLW Inclusive OR Literal with W

Syntax: [

label

] IORLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) .OR. k → (W)

Status Affe cte d: Z

Descripti on: The conten ts of the W register are

OR’ed with the eight-bit literal 'k'.

The result is placed in the W

IORWF Inclusive OR W with f

Syntax: [

label

] IORWF f,d

Operands: 0 ≤ f ≤ 12 7

d ∈ [0,1]

Operation: (W) .OR. (f) → (destination)

Status Affe cte d: Z

Description: Inclusive OR the W register with

regi ster 'f'. If 'd' is 0, the result is

placed in the W re gis ter. If 'd' is 1,

the result is placed back in

PIC16F84A

DS35007B-page 40  2000 Microchip Technology Inc.

MOVF Move f

Syntax: [

label

] MOVF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) → (destination)

Status Affected: Z

Description: The contents of register f are

moved t o a destination dependant

upon the status of d. If d = 0, des-

tination is W register. If d = 1, the

destination is file register f itself.

d = 1 is useful to test a file register ,

since status flag Z is affected.

MOVLW Move Literal to W

Syntax: [

label

] MOVLW k

Operands: 0 ≤ k ≤ 255

Operation: k → (W)

Status Affected: None

Description: The eight-bit literal ’k’ is loaded

into W register. The don’t cares

will asse mble as 0’s.

MOVWF Move W to f

Syntax: [

label

] MOVWF f

Operands: 0 ≤ f ≤ 127

Operation: (W) → (f)

Status Affected: None

Description: Move data from W register to

NOP No Operation

Syntax: [

label

] NOP

Operands: None

Operation: No operation

Status Affected: None

Description: No operation.

RETFIE Return from Interrupt

Syntax: [

label

] RETFIE

Operands: None

Operation: TOS → PC,

1 → GIE

Status Affe cte d: None

RETLW Return with Literal in W

Syntax: [

label

] RETLW k

Operands: 0 ≤ k ≤ 255

Operation: k → (W);

TOS → PC

Status Affe cte d: None

Description: The W register is loaded with the

eight-bit literal 'k'. The program

counter is loaded from the top of

the stack (the return address).

This is a two-cycle instruction.

RETURN Return from Subroutine

Syntax: [

label

] RETURN

Operands: None

Operation: TOS → PC

Status Affe cte d: None

Description: Return from subroutine. The stack

is POPed an d the top of th e s t a ck

(TOS) is loaded into the program

counter. This is a two-cycle

instruction.

 2000 Microchip Technology Inc. DS35007B-page 41

PIC16F84A

RLF Rotate Left f through Carry

Syntax: [

label

] RLF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: See description below

Status Affected: C

Description: The contents of register ’f’ are

rotated one bit to the left through

the Carry Flag. If ’d’ is 0, the

result is placed in the W regis ter.

If ’d’ is 1, the result is stored back

in register ’f’.

RRF Rotate Right f through Carry

Syntax: [

label

] RRF f,d

Operands: 0 ≤ f ≤ 12 7

d ∈ [0,1]

Operation: See description below

Status Affected: C

Desc ript ion : The conten t s of regis te r ’ f ’ are

rotat ed one bit to the r ight throug h

the C arry Flag. If ’ d’ is 0, t he resul t

is placed in the W register. If ’d’ is

1, the result is pl aced bac k in

SLEEP

Syntax: [

label

]SLEEP

Operands: None

Operation: 00h → WDT,

0 → WDT presca ler,

1 → TO,

0 → PD

Status Affected: TO, PD

Desc ription : The power-do wn sta tus b it, PD is

cleared. Time-out status bit, TO

is set. Watchdog Timer and it s

pres ca ler are cl eare d.

The processor is put into SLEEP

mode w ith the osci llator st opp ed.

SUBLW Subtract W from Literal

Syntax: [

label

] SUBLW k

Operands: 0 ≤ k ≤ 255

Operation: k - (W) → (W)

Status Affected: C, DC, Z

Description: The W regist er is subtra cted (2’s

complement method) from the

eight-bit literal 'k'. The result is

placed in the W register.

SUBWF Subtract W from f

Syntax: [

label

] SUBWF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) - (W) → (destination)

Status Affected: C, DC, Z

Description: Subtract (2’s complement method)

W register from registe r 'f'. If 'd' is 0,

the result is stored in the W regis-

ter. If 'd' is 1, the result is stored

back in registe r 'f'.

SWAPF Swap Nibbles in f

Syntax: [

label

] SWAPF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f<3:0>) → (destination<7:4>),

(f<7:4>) → (destination<3:0>)

Status Affe cte d: None

Description: The upper and lower nibbles of

0, the re sult is placed in W regis-

ter. If 'd' i s 1, the result is plac ed in

PIC16F84A

DS35007B-page 42  2000 Microchip Technology Inc.

XORLW Exclusive OR Literal with W

Syntax: [

label

] XORLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) .XOR. k → (W)

Status Affected: Z

Description: The contents of the W register

are XOR’ed with the eight-bit lit-

eral 'k'. The result is placed in

the W register.

XORWF Exclusive OR W with f

Syntax: [

label

] XORWF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (W) .XOR. (f) → (destination)

Status Affe cte d: Z

Description: Exclusive OR the contents of the

W register with register 'f'. If 'd' is

0, the result is stored in the W

stored back in register 'f'.

 2001 Microchip Technology Inc. DS35007B-page 43

PIC16F84A

8.0 DEVELOP ME NT SUPPO RT

The PICmicro® microcontrollers are supported with a

full ran ge of hardware a nd softw are dev elopment tools:

• Integrated Development Environment

- MPLAB® IDE Software

• Assemblers/Compilers/Linkers

- MPASMTM Assembler

- MPLAB C17 and MPLAB C18 C Compilers

- MPLINKTM Object Linker/

MPLIBTM Object Librarian

• Simulators

- MPLAB SIM Software Simulator

•Emulators

- MPLAB ICE 2000 In-Circuit Emulator

- ICEPIC™ In-Circuit Emulator

• In-Circuit Debugger

- MPLAB ICD

• Device Progra mm ers

-PRO MATE

® II Universa l D evi ce Pro gra mm er

- PICSTART® Plu s Entr y-Level Develo pmen t

Programmer

• Low Cost Demonstration Boards

- PICDEMTM 1 Demonstration Board

- PICDEM 2 Demonstration Board

- PICDEM 3 Demonstration Board

- PICDEM 17 Demonstration Board

-K

EELOQ® Demonstration Board

8.1 MPLAB Integrated Development

Environment Software

The MPLAB IDE software brings an ease of software

development previously unseen in the 8-bit microcon-

troller market. The MPLAB IDE is a Windows®-based

applic ation that cont ai ns :

• An interface to debugging tools

- simulator

- programmer (sold separately)

- emulator (sold separately)

- in-circuit debugger (sold separately)

• A full-featured editor

• A project manager

• Customizable toolbar and key mapping

• A status bar

• On-line help

The MPLAB IDE allows you to:

• Edit your source files (either assembly or ‘C’)

• One touch assemble (or compile) and download

to PICmicro emulator and simulator tools (auto-

matically updates all project information)

• Debug us ing :

- source files

- absolu te listing file

- machine code

The ability to use MPLAB IDE with multiple debugging

tools allows users to easily switch from the cost-

effective simulator to a full-featured emulator with

minimal retraining.

8.2 MPASM Assembler

The MPASM assembler is a full-featured universal

macro assembler for all PICmicro MCU’s.

The MPASM assembler has a command line interface

and a Windows shell. It can be used as a stand-alone

application on a Windows 3.x or greater system, or it

can be us ed through MPL AB IDE. The MP ASM assem-

bler generates relocatable object files for the MPLINK

object linker, Intel® standard HEX files, MAP files to

detail memory usage and symbol reference, an abso-

lute LST file that contains source lines and generated

machine code, and a COD file for debugging.

The MPASM assembler features include:

• Integration into MPLAB IDE projects.

• User-defined macros to streamline assembly

code.

• Condit ion al as sem bl y for mul ti-p urpose source

files.

• Directives that allow complete control over the

assembly proc ess.

8.3 MPLAB C17 and MPLAB C18

C Compilers

The MPLAB C17 and MPLAB C18 Code Development

Systems are complete ANSI ‘C’ compilers for

Microchip’s PIC17CXXX and PIC18CXXX family of

microc ontrollers, re spectively. Thes e compile rs provide

powerful integration capabilities and ease of use not

found with other compilers.

For easier source level debugging, the compilers pro-

vide symbol information that is compatible with the

MPLAB IDE memory display.

PIC16F84A

DS35007B-page 44  2001 Microchip Technology Inc.

8.4 MPLINK Object Linker/

MPLIB Object Librarian

The MPLINK object linker combines relocatable

objects created by the MPASM assembler and the

MPLAB C17 and MPLAB C18 C compilers. It can also

link relocatable objects from pre-compiled libraries,

usin g directives fro m a li nker script.

The MPLIB object librarian is a librarian for pre-

compiled code to be used with the MPLINK object

linker. When a routine from a library is called from

another source file, only the modules that contain that

routine w ill be link ed in with the ap plicatio n. This allo ws

large libraries to be used efficiently in many different

applications. The MPLIB object librarian manages the

creation and modification of library files.

The MPLINK object linker features include:

• Integration with MPASM assembler and MPLAB

C17 and MPLAB C18 C compilers.

• Allows all m emory areas t o be d efined as se ctio ns

to provide l ink -time flexibility.

The MPLIB object librarian features include:

• Easier linking because single libraries can be

included instead of many smaller files.

• Helps keep code maintainable by grouping

related modules together.

• Allows libraries to be created and modules to be

added, listed, replaced, deleted or extracted.

8.5 MPLAB SIM Software Simulator

The MPL AB SIM softwar e simulator all ows code deve l-

opment in a PC-hosted environment by simulating the

PICmicro series microcontrollers on an instruction

level. On any given instruction, the data areas can be

examined or modified and stimuli can be applied from

a file, or user-defin ed key press, to any of the pin s. The

execution can be performed in single step, execute

until break, or trace mode.

The MPLAB SIM simulator fully supports symbolic debug-

ging using the MPLAB C17 and the MPLAB C18 C com-

pilers and the MP ASM assembler . The software simulator

offers the flexibility to develop and debug code outside of

the labo ratory envir onment, making it an excelle nt multi-

project software development tool.

8.6 MPLAB ICE High Performance

Universal In-C ircuit Emulator with

MPLAB IDE

The MPLAB ICE universal in-circuit emulator is intended

to provide the product development engineer with a

complete microcontroller design tool set for PICmicro

microcontrollers (MCUs). Software control of the

MPLAB ICE in-circuit emulator is provided by the

MPLAB Integrated Development Environment (IDE),

which allows editi ng, buildin g, downlo ading and so urce

debugging from a single environment.

The MPLAB ICE 2000 is a full-featured emulator sys-

tem with enhanced trace, trigger and data monitoring

featur es. Interchang eable processo r modules al low the

system to be easily reconfigured for emulation of differ-

ent processors. The universal architecture of the

MPLAB ICE in-circuit emulator allows expansion to

support new PICmicro microcontrollers.

The MPLAB ICE in-circuit emulator system has been

designed as a real-time emulation system, with

advanced features that are generally found on more

expensive development tools. The PC platform and

Microsoft® Windows® environment were chosen to best

make these features available to you, the end user.

8.7 ICEPIC In-Circuit Emulator

The ICEPIC low cost, in-circuit emulator is a solution

for the Microchip Technology PIC16C5X, PIC16C6X,

PIC16C7X and PIC16CXXX families of 8-bit One-

T ime-Programmable (OTP) microcontrollers. The mod-

ular sy stem can support d ifferen t subset s of PIC 16C5X

or PIC16CXXX products through the use of inter-

changeable personality modules, or daughter boards.

The emulator is capable of emulating without target

application circuitry being present.

 2001 Microchip Technology Inc. DS35007B-page 45

PIC16F84A

8.8 MPLAB ICD In-Circuit Debugger

Microc hip’ s In-Circuit Deb ugger , MPLAB IC D, is a pow-

erful, low cost, run-time development tool. This tool is

based o n the F LASH PICmic ro MCUs an d can be used

to devel op for this and other PICmicro mic rocontrollers .

The MPLAB IC D u tili ze s th e in-circu it d ebugging capa-

bility built into the FLASH devices. This feature, along

with Microchip’s In-Circuit Serial ProgrammingTM proto-

col, offers cost-effective in-circuit FLASH debugging

from the graphical user interface of the MPLAB

Integrated Development Environment. This enables a

designer to develop and debug source code by watch-

ing variables, si ngl e-s tep pin g and setting brea k poi nt s .

Runni ng at full sp eed enab les tes ting hardwa re in real-

time.

8.9 PRO MATE II Universal Device

Programmer

The PRO MATE II universal device programmer is a

full-featured programmer, capable of operating in

stand-alone mode, as well as PC-hosted mode. The

PRO MATE II device programm er is CE compliant.

The PRO MATE II device programmer has program-

mable VDD and VPP supplies, which allow it to verify

programmed memory at VDD min and VDD max for max-

imum reliability. It has an LCD display for instructions

and error messages, keys to enter commands and a

modular detachable socket assembly to support various

package types. In stand-alone mode, the PRO MATE II

device programmer can read, verify, or program

PICmicro devices. It can also set code protection in this

mode.

8.10 PICSTART Plus Entry Level

Development Programmer

The PICSTART Plus development programmer is an

easy-to-use, low cost, prototype programmer. It con-

nects to the PC via a COM (RS-232) port. MPLAB

Inte grated Devel opmen t Envi ronmen t soft ware m akes

using the programmer simple and efficient.

The PICSTART Plus development programmer sup-

ports all PICmicro devices with up to 40 pins. Larger pin

count devices, such as the PIC16C92X and

PIC17C76 X, may be suppor ted with an a dapter socket.

The PICSTART Plus development programmer is CE

compliant.

8.11 PICDEM 1 Low Cost PICmicro

Demonstration Board

The PICDEM 1 demonstration board is a simple board

which demonstrates the capabilities of several of

Microc hip’ s m icroc ontrol lers. T he mi croco ntrolle rs su p-

ported are: PIC16C5X (PIC16C54 to PIC16C58A),

PIC16C61, PIC16C62X, PIC16C71, PIC16C8X,

PIC17C42, PIC17C43 and PIC17C44. All necessary

hardware and software is included to run basic demo

programs. The user can program the sample microcon-

trollers provided with the PICDEM 1 demonstration

board on a PRO MATE II device programmer, or a

PICSTART Plus development programmer, and easily

test firmware. The user can also connect the

PICDEM 1 demonstration board to the MPLAB ICE in-

circuit emulato r and downlo ad the firmware to the em u-

lator for testing. A prototype area is available for the

user to build some additional hardware and connect it

to the microcontroller socket(s). Some of the features

include an RS-232 interface, a potentiometer for simu-

lated analog input, push button switches and eight

LEDs connected to PORTB.

8.12 PICDEM 2 Low Cost PIC16CXX

Demonstration Board

The PICDEM 2 demonstration board is a simple dem-

onstration board that supports the PIC16C62,

PIC16C64, PIC16C65, PIC16C73 and PIC16C74

microcontrollers. All the necessary hardware and soft-

ware is included to run the basic demonstration pro-

grams. The user can program the sample

microcontrollers provided with the PICDEM 2 demon-

stration board on a PRO MATE II device programmer,

or a PICSTART Plus development programmer, and

easily test firmware. The MPLAB ICE in-circuit emula-

tor may also be used with the PI CDEM 2 demonstration

board to test firmware. A prototype area has been pro-

vided to the user for adding additional hardware and

connecting it to the microcontroller socket(s). Some of

the features include a RS-232 interface, push button

switches , a poten tiomet er for simula ted anal og inpu t, a

serial EEPROM to demonstrate usage of the I2CTM

bus and separate headers for connection to an LCD

module and a keypad.

PIC16F84A

DS35007B-page 46  2001 Microchip Technology Inc.

8.13 PICDEM 3 Low Cost PIC16CXXX

Demonstration Board

The PICDEM 3 demonstration board is a simple dem-

onstration board that supports the PIC16C923 and

PIC16C924 in the PLCC package. It will also support

future 44-p in PLCC microcontro llers with an LCD Mo d-

ule. All the necessary hardware and software is

includ ed to r un the basic demons tration progra ms. The

user can program the sample microcontrollers pro-

vided with the PICDEM 3 demonstration board on a

PRO MATE II device programmer , o r a PICST AR T Plus

development programmer with an adapter socket, and

easily test firmware. The MPLAB ICE in-circuit emula-

tor may a lso be used with the PICDEM 3 demon stration

board to test firmware. A prototype area has been pro-

vided t o the use r for ad ding hardwa re and con necting it

to the microcontroller socket(s). Some of the features

include a RS-232 interface, push button switches, a

potentiometer for simulated analog input, a thermistor

and separate headers for connection to an external

LCD module and a keypad. Also provided on the

PICDEM 3 demonstration board is a LCD panel, with 4

commo ns a nd 1 2 se gm ents, tha t is capable of displa y-

ing time, temperature and day of the week. The

PICDEM 3 d emons tration board pr ovi des an additi onal

RS-232 interface and Windows software for showing

the demultiplexed LCD signals on a PC. A simple serial

interface allows the user to construct a hardware

demultiplex er for the L CD signals.

8.14 PICDEM 17 Demonstration Board

The P IC D EM 17 de mo ns t r at i on bo a rd is an ev al u at i on

board that demonstrates the capabilities of several

Microchip microcontrollers, including PIC17C752,

PIC17C756A, PIC17C762 and PIC17C766. All neces-

sary hard ware is inc luded to run b asic dem o programs,

which are supplied on a 3.5-inch disk. A programmed

sample is included and the user may erase it and

program it with the other sample programs using the

PRO MATE II device programmer, or the PICSTART

Plus development programmer, and easily debug and

test the sample code. In addition, the PICDEM 17 dem-

onstratio n board supports download ing of programs to

and executing out of external FLASH memory on board.

The PICDEM 17 demonstration board is also usable

with the MPLAB ICE in-circuit emulator, or the

PICMAST ER emulat or and al l of the samp le progr ams

can be run and modified using either emulator . Addition-

ally, a generous prototype area is available for user

hardware.

8.15 KEELOQ Evaluation and

Programming Tools

KEELOQ evaluation and programming tools support

Microchip’s HCS Secure Data Products. The HCS eval-

uation kit includes a LCD display to show changing

codes, a decoder to decode transmissions and a pro-

gramming interface to program test transmitters.

 2001 Microchip Technology Inc. DS35007B-page 47

PIC16F84A

TABLE 8-1: DEVELOPMENT TOOLS FROM MICROCHIP

PIC12CXXX

PIC14000

PIC16C5X

PIC16C6X

PIC16CXXX

PIC16F62X

PIC16C7X

PIC16C7XX

PIC16C8X

PIC16F8XX

PIC16C9XX

PIC17C4X

PIC17C7XX

PIC18CXX2

PIC18FXXX

24CXX/

25CXX/

93CXX

HCSXXX

MCRFXXX

MCP2510

Soft war e To ol s

MPLAB® Integrated

Developm ent En vironment

MPLAB® C17 C Compiler

MPLAB® C18 C Compiler

MPASMTM Assembler/

MPLINKTM Obje ct Lin ke r

Emulators

MPLAB® ICE In-Circuit Emulator

ICEPICTM In-Circuit Emulator

Debugger

MPLAB® ICD In-Circuit

Debugger

Programmers

PICSTART® Plus En try Level

Deve lopment Programmer

PRO MATE® II

Universal Device Programmer

Demo Boards and Eval Kits

PICDEMTM 1 Demonstration

Board

†

PICDEMTM 2 Demonstration

Board

†

PICDEMTM 3 Demonstration

Board

PICDEMTM 14A Demonstration

Board

PICDEMTM 17 Demonstration

Board

KEELOQ® Evaluation Kit

KEELOQ® Transp on d er Kit

microIDTM Programmer’s Kit

125 kHz microIDTM

Developer’s Kit

125 kHz Anticollision microIDTM

Developer’s Kit

13.56 MHz Anticollision

microIDTM Developer’s Kit

MCP2510 CAN Developer’s Kit

* Contact the Microchip Technology Inc. web site at www.microchip.com for information on how to use the MPLAB® ICD In-Circuit Debugger (DV164001) with PIC16C62, 63, 64, 65, 72, 73, 74, 76, 77.

** Contact Microchip Technology Inc. for availability date.

†Development tool is available on select devices.

PIC16F84A

DS35007B-page 48  2001 Microchip Technology Inc.

NOTES:

 2001 Microchip Technology Inc. DS35007B-page 49

PIC16F84A

9.0 ELECTRICAL CHARACTERISTICS

Absolute Maximum Ratings †

Ambient temperature under bias.............................................................................................................-55°C to +125°C

Storage temperature .............................................................................................................................. -65°C to +150°C

Voltage on any pin with respect to VSS (except VDD, MCLR, and RA4) .........................................-0.3V to (VDD + 0.3V)

Voltage on VDD with respect to VSS ........................................................................................................... -0.3 to +7.5V

Voltage on MCLR with respect to VSS(1).......................................................................................................-0.3 to +14V

Voltage on RA4 with respect to VSS ........................................................................................................... -0.3 to +8.5V

Total power dissipation(2) .....................................................................................................................................800 mW

Maximum current out of VSS pin ...........................................................................................................................150 mA

Maximum current into VDD pin..............................................................................................................................100 mA

Input clamp current, IIK (VI < 0 or VI > VDD).....................................................................................................................± 20 mA

Output clamp cu rrent, I OK (VO < 0 or VO > VDD).............................................................................................................± 20 mA

Maximum output current sunk by any I/O pin..........................................................................................................25 mA

Maximum output current sourced by any I/O pin ....................................................................................................25 mA

Maximum current sunk b y PORTA..........................................................................................................................80 mA

Maximum current sourced by PORTA.....................................................................................................................50 mA

Maximum current sunk by PORTB........................................................................................................................150 mA

Maximum current sourced by PORTB ..................................................................................................................100 mA

Note 1: Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up.

Thus, a series re si sto r of 50-100Ω sho uld be us ed w hen ap ply in g a “low” le vel to the M CLR pin ra the r tha n

pulling this pin directly to VSS.

2: Power di ssip atio n is ca lcula ted as follow s: Pdis = V DD x {IDD - ∑ IOH} + ∑ {(VDD-VOH) x IOH} + ∑(VOl x IOL).

† NOTICE: Stresses above 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 those or any other conditions above

those ind icated in the ope ration listi ngs of this spe cificati on is not impli ed. Exposure to ma ximum ratin g conditio ns for

extended periods may affect device reliability.

PIC16F84A

DS35007B-page 50  2001 Microchip Technology Inc.

FIGURE 9-1: PIC16F84A-20 VOLTAGE-FREQUENCY GRAPH

FIGURE 9-2: PIC16LF84A- 04 VOLTAGE-

FREQUENCY GRAPH FIGURE 9-3: PIC16F84A-04 VOLTAGE-

FREQUENCY GRAPH

Frequency

Voltage

6.0V

5.5V

4.5V

4.0V

2.0V

20 MHz

5.0V

3.5V

3.0V

2.5V

Frequency

Voltage

6.0V

5.5V

4.5V

4.0V

2.0V

5.0V

3.5V

3.0V

2.5V

FMAX = (6.0 MHz/V) (VDDAPPMIN - 2.0V) + 4 MHz

4 MHz 10 MHz

Note 1: VDDAPPMIN is the minimum voltage of the

PICmicro®

device in the application.

2: FMAX has a maximum frequency of 10 MHz.

Frequency

Voltage

6.0V

5.5V

4.5V

4.0V

2.0V

5.0V

3.5V

3.0V

2.5V

4 MHz

 2001 Microchip Technology Inc. DS35007B-page 51

PIC16F84A

9.1 DC Characteristics

PIC16LF84A-04

(Commercial, Industrial)

Standard Operating Conditions (unless otherwise stated)

Operating temperature 0°C ≤ TA ≤ +70°C (commercial)

-40°C≤ TA ≤ +85°C (industrial)

-40°C≤ TA ≤ +125°C (extend ed)

PIC16F84A-04

(Commercial, Industrial, Extended)

PIC16F84A-20

(Commercial, Industrial, Extended)

Standard Operating Conditions (unless otherwise stated)

Operating temperature 0°C ≤ TA ≤ +70°C (commercial)

-40°C≤ TA ≤ +85°C (industrial)

-40°C≤ TA ≤ +125°C (extend ed)

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

VDD Supply Voltage

D001 16LF84A 2.0 — 5.5 V XT, RC, and LP osc configuration

D001

D001A 16F84A 4.0

4.5 —

—5.5

5.5 V

VXT, RC and LP osc configuration

HS osc configuration

D002 VDR RAM Data Retention

Voltage (Note 1) 1.5 — — V Device in SLEEP mode

D003 VPOR VDD Start Voltage to ensure

internal Power-on Reset

signal

— Vss — V See se ctio n on Pow er-on Rese t for de ta ils

D004 SVDD VDD Rise Rate to ensure

internal Power-on Reset

signal

0.05 — — V/ms

IDD Supply Current (Note 2)

D010 16LF84A — 1 4 mA RC and XT osc configuration (Note 4)

FOSC = 2.0 MHz, VDD = 5.5V

D010

D010A

D013

16F84A —

—

1.8

4.5

RC and XT osc configuration (Note 4)

FOSC = 4.0 MHz, VDD = 5.5V

RC and XT osc configuration (Note 4)

FOSC = 4.0 MHz, VDD = 5.5V

(During FLASH programming)

HS osc configuration (PIC16F84A-20)

FOSC = 20 MHz, VDD = 5.5V

D014 16LF84A — 15 45 µA LP osc configu rati on

FOSC = 32 kHz, VDD = 2.0V, WDT disabled

Legend: Rows with standard voltage device data only are shaded for improved readability.

† Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested.

NR Not rated for operation.

Note 1: T his is th e limit to which VDD can be lowered without losing RAM data.

2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O

pin loading and switching rate, oscillator type, internal code execution pattern, and temperature also have

an impact on the current consumption.

The test conditions for all IDD measurements in active operation mode are:

OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD,

T0CKI = VDD, MCLR = VDD; WDT enabled/disabled as specified.

3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is

measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD and VSS.

4: For RC osc configuration, current through REXT is not included. The current through the resistor can be

estimated by the formula IR = VDD/2REXT (mA) with REXT in kOhm.

5: The ∆ current is the additional current consumed when this peripheral is enabled. This current should be

added to the base IDD measurement.

PIC16F84A

DS35007B-page 52  2001 Microchip Technology Inc.

IPD Power-down Current (Note 3)

D020 16LF84A

D020 16F84A-20

16F84A-04

D021A 16LF84A —0.41.0µAVDD = 2.0V, WDT disabled, industrial

D021A 16F84A-20

16F84A-04 —

—1.5

1.0 3.5

3.0 µA

µAVDD = 4.5V, WDT disabled, industrial

VDD = 4.0V, WDT disabled, industrial

D021B 16F84A-20

16F84A-04 —

—1.5

1.0 5.5

5.0 µA

µAVDD = 4.5V, WDT disabled, extended

VDD = 4.0V, WDT disabled, extended

D022 ∆IWDT

Module Differential Current

(Note 5)

Watchdog Timer —

—

.20

3.5

4.8

µA

VDD = 2.0V, Industrial, Commercial

VDD = 4.0V, Commercial

VDD = 4.0V, Industrial, Extended

VDD = 4.5V, Commercial

VDD = 4.5V, Industrial, Extended

9.1 DC Characteristics (Continued)

PIC16LF84A-04

(Commercial, Industrial)

Standard Operating Conditions (unless otherwise stated)

Operating temperature 0°C ≤ TA ≤ +70°C (commercial)

-40°C≤ TA ≤ +85°C (industrial)

-40°C≤ TA ≤ +125°C (extend ed)

PIC16F84A-04

(Commercial, Industrial, Extended)

PIC16F84A-20

(Commercial, Industrial, Extended)

Standard Operating Conditions (unless otherwise stated)

Operating temperature 0°C ≤ TA ≤ +70°C (commercial)

-40°C≤ TA ≤ +85°C (industrial)

-40°C≤ TA ≤ +125°C (extend ed)

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

Legend: Rows with standard voltage device data only are shaded for improved readability.

† Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested.

NR Not rated for operation.

Note 1: T his is th e limit to which VDD can be lowered without losing RAM data.

2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O

pin loading and switching rate, oscillator type, internal code execution pattern, and temperature also have

an impact on the current consumption.

The test conditions for all IDD measurements in active operation mode are:

OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD,

T0CKI = VDD, MCLR = VDD; WDT enabled/disabled as specified.

3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is

measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD and VSS.

4: For RC osc configuration, current through REXT is not included. The current through the resistor can be

estimated by the formula IR = VDD/2REXT (mA) with REXT in kOhm.

5: The ∆ current is the additional current consumed when this peripheral is enabled. This current should be

added to the base IDD measurement.

 2001 Microchip Technology Inc. DS35007B-page 53

PIC16F84A

9.2 DC Characteristics: PIC16F84A-04 (Commercial, Industrial)

PIC16F84A-20 (Commercial, Industrial)

PIC16LF84A-04 (Commercial, Industrial)

DC Characteristics

All Pins Except Power Supply Pins

Standard Operating Conditions (unless otherwise stated)

Operati ng tem per ature 0°C ≤ TA ≤ +70°C (commercial)

-40°C≤ TA ≤ +85°C (industrial)

Operating volt ag e VDD range as described in DC specifications

(Section 9.1)

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

VIL Input Low Voltage

I/O ports:

D030 with TTL buf fer VSS —0.8 V4.5V ≤ VDD ≤ 5.5V (Note 4)

D030A VSS —0.16VDD V Entire range (Note 4)

D031 with Schmitt Trigger buffer VSS —0.2VDD V Entire range

D032 MCLR, RA4/T0CKI V SS —0.2VDD V

D033 OSC1 (XT, HS and LP modes) VSS —0.3VDD V(Note 1)

D034 OSC1 (RC mode) VSS —0.1VDD V

VIH Input Hi gh Voltage

I/O ports: —

D040

D040A with TTL buffer 2.0

0.25VDD+0.8 —

—VDD

VDD V

V4.5V ≤ VDD ≤ 5.5V (Note 4)

Entire range (Note 4)

D041 with Schmitt Trigger buffer 0.8 VDD —VDD Entire range

D042 MCLR, 0.8 VDD —VDD V

D042A RA4/T0CKI 0.8 VDD —8.5 V

D043 OSC1 (XT, HS and LP modes) 0.8 VDD —VDD V(Note 1)

D043A OSC1 (RC mode) 0.9 VDD VDD V

D050 VHYS Hysteresis of Schmitt Trigger

Inputs —0.1—V

D070 IPURB PORTB Weak Pull-up Current 50 250 400 µAVDD = 5.0V, VPIN = VSS

IIL Input Leakage Current

(Notes 2, 3)

D060 I/O ports — — ±1µAVss ≤ VPIN ≤ VDD,

Pin at hi-impedance

D061 MCLR, RA4/T0CKI — — ±5µAVss ≤ VPIN ≤ VDD

D063 OSC1 — — ±5µAVss ≤ VPIN ≤ VDD, XT, HS

and LP osc configuration

† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested.

Note 1: I n RC os cillator conf iguration, the OSC1 pin is a Schmitt Trigger input. Do not drive th e PIC16F84A with an

external cl ock while the device is in RC mode, or chip damage may result.

2: The leakage current on the MCL R pin is strongly dependent on the applied voltage level. The specified

levels represent normal operating conditions. Higher leakage current may be measured at different input

voltages.

3: Negative current is defined as coming out of the pin.

4: The user may choose the better of the two specs.

PIC16F84A

DS35007B-page 54  2001 Microchip Technology Inc.

VOL Output Low Voltage

D080 I/O ports ——0.6VI

OL = 8.5 mA, VDD = 4.5V

D083 OSC2/CLKOUT — — 0.6 V IOL = 1.6 mA, VDD = 4.5V,

(RC mode only)

VOH Output High Voltage

D090 I/O ports (Note 3) VDD-0.7 — — V IOH = -3.0 mA, VDD = 4.5V

D092 OSC2/CLKOUT (Note 3) VDD-0.7 — — V IOH = -1.3 mA, VDD = 4.5V

(RC mode only)

VOD Open Drain High Voltage

D150 RA4 pin — — 8.5 V

Capacitive Loading Specs on

Output Pins

D100 COSC2 OSC2 pin — — 15 pF In XT, HS and LP modes

when external clock is used

to drive OSC1

D101 CIO All I/O pins and OSC2

(RC mode) ——50pF

Data EEPROM Memory

D120 EDEndurance 1M 10M — E/W 25°C at 5V

D121 VDRW VDD for read/write VMIN —5.5 VVMIN = Minimum operating

voltage

D122 TDEW Erase/Write cycle time — 4 8 ms

Program FLASH Memory

D130 EPEndurance 1000 10K — E/W

D131 VPR VDD for read VMIN —5.5 VVMIN = Minimum operating

voltage

D132 VPEW VDD for erase/write 4.5 — 5.5 V

D133 TPEW Erase/Write cycle time — 4 8 ms

9.2 DC Characteristics: PIC16F84A-04 (Commercial, Industrial)

PIC16F84A-20 (Commercial, Industrial)

PIC16LF84A-04 (Commercial, Industrial) (Continued)

DC Characteristics

All Pins Except Power Supply Pins

Standard Operating Conditions (unless otherwise stated)

Operati ng tem per ature 0°C ≤ TA ≤ +70°C (commercial)

-40°C≤ TA ≤ +85°C (industrial)

Operating volt ag e VDD range as described in DC specifications

(Section 9.1)

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested.

Note 1: I n RC os cillator conf iguration, the OSC1 pin is a Schmitt Trigger input. Do not drive th e PIC16F84A with an

external clock while the device is in RC mode, or chip damage may result.

2: The leakage current on the MCL R pin is strongly dependent on the applied voltage level. The specified

levels represent normal operating conditions. Higher leakage current may be measured at different input

voltages.

3: Negative current is defined as coming out of the pin.

4: The user may choose the better of the two specs.

 2001 Microchip Technology Inc. DS35007B-page 55

PIC16F84A

9.3 AC (Timing) Characteristics

9.3.1 TIMING PARAME TER SYMBOLOGY

The timing parameter symbols have been created fol-

lowing one of the following formats:

1. TppS2ppS

2. TppS

TF Frequency T Time

Lowercase letters (pp) and their meanings:

pp 2 to os, osc OSC1

ck CLKOUT ost oscillator start-up tim er

cy cycle time pwrt power-up timer

io I/O port rbt RBx pins

inp INT pin t0 T0CKI

mp MCLR wdt watchdog timer

Uppe rcase letters and their meanings:

SF Fall P Period

HHigh RRise

I Invalid (high impedance) V Valid

L Low Z High Impedance

PIC16F84A

DS35007B-page 56  2001 Microchip Technology Inc.

9.3.2 TIMING CONDITIONS

The temperature and voltages specified in Table 9-1

apply to all timing specifications unless otherwise

noted. All timing s are measured between high and low

measurement points as indicated in Figure 9-4.

Figure 9-5 specifies the load conditions for the timing

specifications.

TABLE 9-1: TEMPERATURE AND VOLTAGE SPECIFICATIONS - AC

FIGURE 9-4: PARAMETER MEASUREMENT INFORMATION

FIGURE 9-5: LOAD CONDITIONS

AC CHARACTERISTICS

S tandard Operat ing Conditi ons (unle ss otherw is e stated)

Operating temperature 0°C ≤ TA ≤ +70°C for commercial

-40°C ≤ TA ≤ +85°C for indu strial

Operating voltage VDD range as described in DC specifications (Section 9.1)

0.9 VDD (High)

0.1 VDD (Low)

0.8 VDD RC

0.3 VDD XTAL

OSC1 Measurement Points I/O Port Measurement Points

0.15 VDD RC

0.7 VDD XTAL (High)

(Low)

Load Condition 1 Lo ad Conditio n 2

VSS

VDD/2

VSS

RL = 464Ω

CL = 50 pF for all pins except OSC2

15 pF for OSC2 output

 2001 Microchip Technology Inc. DS35007B-page 57

PIC16F84A

9.3.3 TIMING DIAGRAMS AND SPECIFICATIONS

FIGURE 9-6: EXTERNAL CLOCK TIMING

OSC1

CLKOUT

Q4 Q1 Q2 Q3 Q4 Q1

13344

TABLE 9-2: EXTERNAL CLOCK TIMING REQUIREMENTS

Param No. Sym Characteristic Min Typ† Max Units Conditions

FOSC External CLKIN Frequency(1) DC — 2 MHz XT, RC osc (-04, LF)

DC — 4 MHz XT, RC osc (-04)

DC — 20 MHz HS osc (-20)

DC — 200 kHz LP osc (-04, LF)

Oscillator Frequency(1) DC — 2 MHz RC osc (-04, LF)

DC — 4 MHz RC osc (-04)

0.1 — 2 MHz XT osc (-04, LF)

0.1 — 4 MHz XT osc (-04)

1.0 — 20 MHz HS osc (-20)

DC — 200 kHz LP osc (-04, LF)

OSC External CLKIN Period(1) 500 — — ns XT, RC osc (-04, LF)

250 — — ns XT, RC osc (-04)

50 — — ns HS osc (-20)

5.0 — — µs LP osc (-04, LF)

Oscillator Period(1) 500 — — ns RC osc (-04, LF)

250 — — ns RC osc (-04)

500 — 10,000 ns XT osc (-04, LF)

250 — 10,000 ns XT osc (-04)

50 — 1,000 ns HS osc (-20)

5.0 — — µs LP osc (-04, LF)

CY Instruction Cycle Time(1) 0.2 4/FOSC DC µs

3 TosL,

TosH Clock in (OSC1) High or Low

Time 60 — — ns XT osc (-04, LF)

50 — — ns XT osc (-04)

2.0 — — µs LP osc (-04, LF)

17.5 — — ns HS osc (-20)

4TosR,

TosF Clock in (OSC1) Rise or Fall

Time 25 — — ns XT osc (-04)

50 — — ns LP osc (-04, LF)

7.5 — — ns HS osc (-20)

† Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested.

Note 1: Instr uction cycle p eriod (TCY) equals four times the input oscillator time-base period. All specified values

are based on characterization data for that particular oscillator type under standard operating conditions

with the dev ic e exe cu tin g cod e. Exc eed ing these sp ec ifi ed li mi ts may resul t in an unst abl e osc il la t or ope ra-

tion and/or higher than expected current consumption. All devices are tested to operate at "Min." values

with an external clock applied to the OSC1 pin.

When an external clock input is used, the "Max." cycle time limit is "DC" (no clock) for all devices.

PIC16F84A

DS35007B-page 58  2001 Microchip Technology Inc.

FIGURE 9-7: CLKOUT AND I/O TIMING

TABLE 9-3: CLKOUT AND I/O TIMING REQUIREMENTS

OSC1

CLKOUT

I/O Pin

(Input)

I/O Pin

(Output)

Q4 Q1 Q2 Q3

20, 21

19 18

old value new value

Note: All tests must be done with specified capacitive loads (Figure 9-5) 50 pF on I/O pins and CLKOUT.

Param

No. Sym Characteristic Min Typ† Max Units Conditions

10 TosH2ckL OSC1↑ to CLKOUT↓ Standard —1530ns(Note 1)

10A Extended (LF) — 15 120 ns (Note 1)

11 TosH2ckH OSC1↑ to CLKOUT↑ Standard — 15 30 ns (Note 1)

11A Extended (LF) — 15 120 ns (Note 1)

12 TckR CLKOUT rise time Standard — 15 30 ns (Note 1)

12A Extended (LF) — 15 100 ns (Note 1)

13 TckF CLKOUT fall time Standard — 15 30 ns (Note 1)

13A Extended (LF) — 15 100 ns (Note 1)

14 TckL2ioV CLKOUT ↓ to Port out valid — — 0.5TCY +20 ns (Note 1)

15 TioV2ckH Port in valid before

CLKOUT ↑ Standard 0.30TCY + 30 — — ns (Note 1)

Extended (LF) 0.30TCY + 80 — — ns (Note 1)

16 TckH2ioI Por t in hold after CLKOUT ↑ 0——ns(Note 1)

17 TosH2ioV OSC1↑ (Q1 cycle) to

Port out valid Standard — — 125 ns

Extended (LF) — — 250 ns

18 TosH2ioI OSC1↑ (Q2 cycle) to Port

input invalid (I/O in hold time) Standard 10 — — ns

Extended (LF) 10 — — ns

19 TioV2osH Port input valid to OSC1↑

(I/O in setup time) Standard -75 — — ns

Extended (LF) -175 — — ns

20 TioR Port output rise time Standard — 10 35 ns

20A Extended (LF) — 10 70 ns

21 TioF Port output fall time Standard — 10 35 ns

21A Extended (LF) — 10 70 ns

22 TINP INT pin high

or low time Standard 20 — — ns

22A Extended (LF) 55 — — ns

23 TRBP RB7:RB4 change INT

high or low time Standard TOSC§— — ns

23A Extended (LF) TOSC§— — ns

† Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested.

§ By design.

Note 1: Measurements are taken in RC mode where CLKOUT output is 4 x TOSC.

 2001 Microchip Technology Inc. DS35007B-page 59

PIC16F84A

FIGURE 9-8: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP

TIMER TIMING

TABLE 9-4: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND

POWER-UP TIMER REQUIREMENTS

VDD

MCLR

Internal

POR

PWRT

Time-out

OSC

Time-out

Internal

Reset

Watchdog

Timer

Reset

I/O Pi ns

Parameter

No. Sym Characteristic Min Typ† Max Units Conditions

30 TmcL MCLR Pulse Width (low) 2 ——µsVDD = 5.0V

31 TWDT Watchdog Timer Time-out

Period (No Prescaler) 71833msV

DD = 5.0V

32 TOST Oscillation Start-up Timer

Period 1024TOSC ms TOSC = OSC1 period

33 TPWRT Power-up Timer Period 28 72 132 ms VDD = 5.0V

34 TIOZ I/O hi-impedance from MCLR

Low or RESET ——100ns

† Data in "Typ" column is at 5V, 25°C, unless otherwise stated. These parameters are for design guidance

only and are not tested.

PIC16F84A

DS35007B-page 60  2001 Microchip Technology Inc.

FIGURE 9-9: TIMER0 CLOCK TIMINGS

TABLE 9-5: TIMER0 CLOCK REQUIREMENTS

RA4/T0CKI

40 41

Parameter

No. Sym Characteristic Min Typ† Max Units Conditions

40 Tt0H T0CKI High Pulse

Width No Prescaler 0.5TCY + 20 ——ns

With Prescaler 50

30 —

——

—ns

ns 2.0V ≤ VDD ≤ 3.0V

3.0V ≤ VDD ≤ 6.0V

41 Tt0L T0CKI Low Pulse

Width No Prescaler 0.5TCY + 20 — — ns

With Prescaler 50

20 —

——

—ns

ns 2.0V ≤ VDD ≤ 3.0V

3.0V ≤ VDD ≤ 6.0V

42 Tt0P T0CKI Period TCY + 40

N— — ns N = prescale value

(2, 4, ..., 256)

† Data in "Typ" column is at 5.0V, 25°C, unless otherwise stated. These parameters are for design guidance

only and are not tested.

 2001 Microchip Technology Inc. DS35007B-page 61

PIC16F84A

10.0 DC/AC CHARACTERISTIC GRAPHS

The graphs provided in this section are for design guidance and are not tested.

In som e grap hs , th e data pres ent ed are outside s pec ified op eratin g ran ge (i.e ., out side sp eci fied VDD ran ge) . Th is i s

for information only and devices are ensured to operate properly only within the specified range.

The data pr esented in this section is a statistical summary of data collected on units from different lots over a period

of time and matrix samples. ‘Typical’ represents the mean of the distribution at 25°C. ‘Max’ or ‘Min’ represents

(mean + 3σ) or (mean - 3σ), respectively, where σ is a standard deviation over the whole temperature range.

PIC16F84A

FIGURE 10-1: TYPICAL IDD vs. FOSC OVER VDD (HS MODE, 25°C)

FIGURE 10-2: MAX IMU M IDD vs. FOSC OVER VDD (HS MODE, -40° TO +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4 6 8 10 12 14 16 18 20

FOSC (MHz)

IDD (mA)

2.5 V

3.0 V

3.5 V

4.0 V

4.5 V

5.0 V

5.5 V

2.0 V

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

4 6 8 10 12 14 16 18 20

FOSC (MHz)

IDD (mA)

2.5 V

3.0 V

3.5 V

4.0 V

4.5 V

5.0 V

5.5 V

2.0 V

 2001 Microchip Technology Inc. DS35007B-page 63

PIC16F84A

FIGURE 10-3: TYPICAL IDD vs. FOSC OVER VDD (XT MODE, 25°C)

FIGURE 10-4: MAX IMU M IDD vs. FOSC OVER VDD (XT MODE, -40° TO +125°C)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

FOSC (MHz)

IDD (mA)

2.0 V

2.5 V

3.0 V

3.5 V

4.0 V

4.5 V

5.0 V

5.5 V

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

FOSC (MHz)

IDD (mA)

2.0 V

2.5 V

3.0 V

3.5 V

4.0 V

4.5 V

5.0 V

5.5 V

PIC16F84A

FIGURE 10-5: TYPICAL IDD vs. FOSC OVER VDD (LP MODE, 25°C)

FIGURE 10-6: MAX IMU M IDD vs. FOSC OVER VDD (LP MODE, -40° TO +125°C)

25 50 75 100 125 150 175 200

FOSC (kHz)

IDD (µA)

5.0 V

5.5 V

4.0 V

3.5 V

4.5 V

3.0 V

2.5 V

2.0 V

100

150

200

250

25 50 75 100 125 150 175 200

FOSC (kHz)

IDD (µA)

5.0 V

5.5 V

4.0 V

3.5 V

4.5 V

3.0 V

2.5 V

2.0 V

 2001 Microchip Technology Inc. DS35007B-page 65

PIC16F84A

FIGURE 10-7: AVERAGE FOSC vs. VDD FOR R (RC MODE, C = 22 pF, 25°C)

FIGURE 10-8: AVERAGE FOSC vs. VDD FOR R (RC MODE, C = 100 pF, 25°C)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

Freq ( M Hz)

5.1 kΩ

3.3 kΩ

10 kΩ

100 kΩ

200

400

600

800

1000

1200

1400

1600

1800

2000

2.02.53.03.54.04.55.05.5

VDD (V)

Freq (KHz)

100 kΩ

10 kΩ

5.1 kΩ

3.3 kΩ

PIC16F84A

FIGURE 10-9: AVERAGE FOSC vs. VDD FOR R (RC MODE, C = 300 pF, 25°C)

FIGURE 10-10: IPD vs. VDD (SLEEP MODE, ALL PERIPHERALS DISABLED)

100

200

300

400

500

600

700

800

900

2.02.53.03.54.04.55.05.5

VDD (V )

Freq (KHz)

3.3 kΩ

5.1 kΩ

10 kΩ

100 kΩ

0.0

0.1

1.0

10.0

2.02.53.03.54.04.55.05.5

VDD (V)

IPD (µA)

Max

Typ

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

 2001 Microchip Technology Inc. DS35007B-page 67

PIC16F84A

FIGURE 10-11: IPD vs. VDD (WDT MODE)

FIGURE 10-12: TYPICAL, MINIMUM, AND MAXIMUM WDT PERIOD vs. VDD OVER TEMP

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

IPD (µA)

Max

Typ

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

WDT Period (ms)

Min

Typ

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

PIC16F84A

FIGURE 10-13: TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 5V, -40°C TO +125°C)

FIGURE 10-14: TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 3V, -40°C TO +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0

IOH (mA)

VOH (V)

Typ

Min

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20 25

IOH (mA)

VOH (V)

Max

Typ

Min

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

 2001 Microchip Technology Inc. DS35007B-page 69

PIC16F84A

FIGURE 10-15: TYPICAL, MINIMUM AND MAXIMUM VOL vs. IOL (VDD = 5V, -40°C TO +125°C)

FIGURE 10-16: TYPICAL, MINIMUM AND MAXIMUM VOL vs. IOL (VDD = 3V, -40°C TO +125°C)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 5 10 15 20 25

IOL (mA)

VOL (V)

Max

Typ

Min

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0

IOL (mA)

VOL (V)

Max

Typ

Min

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

PIC16F84A

FIGURE 10-17: MINIMUM AND MAXIMUM VIN vs. VDD, (TTL INPUT, -40°C TO +125°C)

FIGURE 10-18: MINIMUM AND MAXIMUM VIN vs. VDD (ST INPUT, -40°C TO +125°C)

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

VIN (V)

VTH

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

3.25

3.50

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

VIN (V)

VIH Max VIH Typ

VIH Min

VIL Max VIL Typ

VIL Min

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

 2001 Microchip Technology Inc. DS35007B-page 71

PIC16F84A

11.0 PACKAGING INFORMATION

11.1 Package Marking Information

18-Lead PDIP

XXXXXXXXXXXXXXXXX

YYWWNNN

XXXXXXXXXXXX

18-Lead SOIC

Example

XXXXXXXXXXXX

Example

YYWWNNN

XXXXXXXXXXX

20-Lead SSOP Example

Legend: XX...X Customer specific information*

Y Year code (last digit of calendar year)

YY Year code (last 2 digits of calendar year)

WW Week code (week of January 1 is week ‘01’)

NNN Alphanumeric traceability code

Note: In the event the full Mi crochip p art nu mb er canno t be marked on one line , it will

be carried o ver to the next line thus lim it ing the numb er of a vai la ble cha r ac ters

for customer specific information.

*Standard PICmicro device marking consists of Microchip part number, year code, week code, and

traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check

with your Microchip sales office. For QTP devices, any special marking adders are included in QTP

price.

PIC16F84A-04I/P

0110017

/SO

PIC16F84A-04

0110017

20/SS

PIC16F84A-

PIC16F84A

DS35007B-page 72  2001 Microchip Technology Inc.

18-Lead Plastic Dual In-line (P) – 300 mil (PDIP)

1510515105

Mold Draft Angle Bottom 1510515105

Mold Draft Angle Top 10.929.407.87.430.370.310eBOverall Row Spacing § 0.560.460.36.022.018.014BLower Lead Width 1.781.461.14.070.058.045B1Upper Lead Width 0.380.290.20.015.012.008

Lead Thick ness 3.433.303.18.135.130.125LTip to Seating Plane 22.9922.8022.61.905.898.890DOverall Length 6.606.356.10.260.250.240E1Molded Package Width 8.267.947.62.325.313.300EShoulder to Shoulder Width 0.38.015A1Base to Seating Plane 3.683.302.92.145.130.115A2Molded Package Thickness 4.323.943.56.170.155.140ATop to Seating Plane 2.54.100

Pitch 1818

Number of Pins MAXNOMMINMAXNOMMINDimension Limits MILLIMETERSINCHES*Units

* Controlling Parameter

Notes:

Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed

.010” (0.254mm) per side.

JEDEC Equivalent: MS-001

Drawing No. C04-007

§ Significant Characteristic

 2001 Microchip Technology Inc. DS35007B-page 73

PIC16F84A

18-Lead Plastic Small Outline (SO) – Wide, 300 mil (SOIC)

Foot A ngle φ048048

1512015120

Mold Draft Angle Bottom 1512015120

Mold Draft Angle Top 0.510.420.36.020.017.014BLead Widt h 0.300.270.23.012.011.009

Lead Thick ness

1.270.840.41.050.033.016LFoot Length 0.740.500.25.029.020.010hChamfer Distance 11.7311.5311.33.462.454.446DOverall Length 7.597.497.39.299.295.291E1Molded Package Width 10.6710.3410.01.420.407.394EOverall Width 0.300.200.10.012.008.004A1Standoff § 2.392.312.24.094.091.088A2Molded Package Thickness 2.642.502.36.104.099.093AOverall Height 1.27.050

Pitch 1818

Number of Pins MAXNOMMINMAXNOMMINDimension Limits MILLIMETERSINCHES*Units

45°

* Controlling Parameter

Notes:

Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed

.010” (0.254mm) per side.

JEDEC Equivalent: MS-013

Drawing No. C04-051

§ Significant Characteristic

PIC16F84A

DS35007B-page 74  2001 Microchip Technology Inc.

20-Lead Plastic Shrink Small Outline (SS) – 209 mil, 5.30 mm (SSOP)

10501050

Mold Draft Angle Bottom 10501050

Mold Draft Angle Top 0.380.320.25.015.013.010BLead Width 203.20101.600.00840

Foot Angle 0.250.180.10.010.007.004

Lead Thickness 0.940.750.56.037.030.022LFoot Length 7.347.207.06.289.284.278DOverall Length 5.385.255.11.212.207.201E1Molded Package Width 8.187.857.59.322.309.299EOverall Width 0.250.150.05.010.006.002A1Standoff § 1.831.731.63.072.068.064A2Molded Package Thickness 1.981.851.73.078.073.068AOverall Height 0.65.026

Pitch 2020

Number of Pins MAXNOMMINMAXNOMMINDimension Limits MILLIMETERSINCHES*Units

* Controlling Parameter

Notes:

Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed

.010” (0.254mm) per side.

JEDEC Equivalent: MO-150

Drawing No. C04-072

§ Significant Characteristic

 2001 Microchip Technology Inc. DS35007B-page 75

PIC16F84A

APPENDIX A: REVISION HISTORY

Version Date Revision Description

A 9/98 This is a new data sheet. However, the devices described in this data sheet are

the upgrades to the devices found in the

PIC16F8X Dat a Sheet

, DS30430.

B 8/01 Added DC and AC Characteristics Graphs and Tables to Section 10.

PIC16F84A

DS35007B-page 76  2001 Microchip Technology Inc.

APPENDIX B: CONVERSION CONSIDERATIONS

Considerations for converting from one PIC16X8X

dev ice to another are listed in Table 1.

TABLE 1: CONVERSION CONSIDERATIONS - PIC16C84, PIC16F83/F84, PIC16CR83/CR84,

PIC16F84A

Difference PIC16C84 PIC16F83/F84 PIC16CR83/

CR84 PIC16F84A

Program Memory Size 1K x 14 512 x 14 / 1K x 14 512 x 14 / 1K x 14 1K x 14

Data Memory Size 36 x 8 36 x 8 / 68 x 8 36 x 8 / 68 x 8 68 x 8

Voltage Range 2.0V - 6.0V

(-40°C to +85°C) 2.0V - 6.0V

(-40°C to +85°C) 2.0V - 5.5V

(-40°C to +125°C)

Maximum Operating Fre-

quency 10 MHz 10 MHz 10 MHz 20 MHz

Supply Current (IDD).

See parameter # D014 in

the electrical specs for

more detail.

IDD (typ) = 60 µA

IDD (max) = 400 µA

(LP osc, FOSC = 32 kHz,

VDD = 2.0V,

WDT disabled)

IDD (typ) = 15 µA

IDD (m ax) = 45 µA

(LP osc, FOSC = 32 kHz,

VDD = 2.0V,

WDT disabled)

IDD (typ) = 15 µA

IDD (max) = 45 µA

(LP osc, FOSC = 32 kHz,

VDD = 2.0V,

WDT disabled)

IDD (typ) = 15 µA

IDD (max) = 45 µA

(LP osc, FOSC = 32 kHz ,

VDD = 2.0V,

WDT disabled)

Power-down Current

(IPD). See parameters #

D020, D021, and D021A

in the electrical specs for

more detail.

IPD (typ) = 26 µA

IPD (max) = 100 µA

(VDD = 2.0V,

WDT disabled, industrial)

IPD (typ) = 0.4 µA

IPD (max) = 9 µA

(VDD = 2.0V,

WDT disabled, industrial)

IPD (typ) = 0.4 µA

IPD (max) = 6 µA

(VDD = 2.0V,

WDT disabled, industrial)

IPD (typ) = 0.4 µA

IPD (max) = 1 µA

(VDD = 2.0V,

WDT disabled, industrial)

Input Low Voltage (VIL).

See parameters # D032

and D034 in the electrical

specs for more detail.

VIL (max) = 0.2VDD

(OSC1, RC mode) VIL (max) = 0.1VDD

(OSC1, RC mode)

Input High Voltage (VIH).

See parameter # D040 in

the electrical specs for

more detail.

VIH (min) = 0.36VDD

(I/O Por ts with TTL,

4.5V ≤ VDD ≤ 5.5V)

VIH (min) = 2.4V

(I/O Ports with TTL,

4.5V ≤ VDD ≤ 5.5V)

VIH (min) = 2.4V

(I/O Ports with TTL,

4.5V ≤ VDD ≤ 5.5V)

VIH (min) = 2.4V

(I/O Ports with TTL,

4.5V ≤ VDD ≤ 5.5V)

Data EEPROM Memory

Erase/Write cycle time

(TDEW). See parameter #

D122 in the electrical

specs for more detail.

TDEW (typ) = 10 ms

TDEW (max) = 20 ms TDEW (typ) = 10 ms

TDEW (max) = 20 ms TDEW (typ) = 4 ms

TDEW (max) = 8 ms

Port Output Rise/Fall

time (TioR, TioF). See

parameters #20, 20A,

21, and 21A in the elec-

trical specs for more

detail.

TioR, TioF (max) = 25 ns

(C84)

TioR, TioF (max) = 60 ns

(LC84)

Ti oR, T i oF (max) = 35 ns

(C84)

Ti oR, T i oF (max) = 70 ns

(LC84)

T ioR, T ioF (max) = 35 ns

(C84)

T ioR, T ioF (max) = 70 ns

(LC84)

Ti oR, Ti oF (max) = 35 ns

(C84)

Ti oR, Ti oF (max) = 70 ns

(LC84)

MCLR on-chip filter. See

parameter #30 in the

electrical specs for more

detail.

No Yes Yes Yes

PORTA and crystal oscil-

lator values less than

500 kHz

For crystal oscillator con-

figurations operating

below 500 kHz, the device

may generate a spurious

internal Q-clock when

PORTA<0> switches

state.

N/A N/A N/A

RB0/INT pin TTL TTL/ST*

(*Schmitt Trigger) TTL/ST*

(*Schmitt Trigger)

 2001 Microchip Technology Inc. DS35007B-page 77

PIC16F84A

EEADR<7:6> and IDD It is recommended that

the EEADR<7:6> bits be

cleared. When either of

these bits is set, the maxi-

mum IDD for the device is

higher than when both are

cleared.

N/A N/A N/A

The polarity of the

PWRTE bit PWRTE PWRTE PWRTE PWRTE

Recommended value of

REXT for RC oscillator

circuits

REXT = 3kΩ - 100kΩREXT = 5kΩ - 100kΩREXT = 5kΩ - 100kΩREXT = 3kΩ - 100kΩ

GIE bit unintentional

enable If an interrupt occurs while

the Global Interrupt

Enable (GIE) bit is being

cleared, the GIE bit may

unintentionally be re-

enabled by the user’s

Interrupt Service Routine

(the RETFIE instruction).

N/A N/A N/A

Packages PDIP, SOIC PDIP, SOIC PDIP, SOIC PDIP, SOIC, SSOP

Open Drain High

Voltage (VOD)14V 12V 12V 8.5V

TABLE 1: CONVERSION CONSIDERATIONS - PIC16C84, PIC16F83/F84, PIC16CR83/CR84,

PIC16F84A (CONTINUED)

Difference PIC16C84 PIC16F83/F84 PIC16CR83/

CR84 PIC16F84A

PIC16F84A

DS35007B-page 78  2001 Microchip Technology Inc.

APPENDIX C: MIGRATION FROM

BASELINE TO

MID-RANGE DEVICES

This section discusses how to migrate from a baseline

device (i.e., PIC16C5X) to a mid-range device (i.e.,

PIC16CXXX).

The following is the list of feature improvements over

the PIC16C5X microcontroller family:

1. Instruction word length is increased to 14-bits.

This allows larger page sizes, both in program

memory (2K now as opposed to 512K before)

and the register file (128 bytes now versus

32 bytes before).

2. A PC latch register (PCLATH) is added to han-

dle progra m memory p aging. PA2, P A 1 and PA0

bits are removed from the STATUS register and

placed in the OPTION register.

3. Data memory paging is redefined slightly. The

STATUS register is modified.

4. Four new instructions have been added:

RETURN, RETFIE, ADDLW, and SUBLW. Two

instructions, TRIS and OPTION, are being

phased out, although they are kept for

compatibility with PIC16C5X.

5. OPTION and TRIS registers are made

addressable.

6. Inte rrupt capabili ty is ad ded. Int errup t vect or is

at 0004h.

7. Stack size is increased to eight-deep.

8. RESET vector is changed to 0000h.

9. RESET of all registers is revisited. Five dif ferent

RESET (and wake-up) types are recognized.

Registers are reset differently.

10. Wake-up from SLEEP through interrupt is

added.

11. Two separate timers, the Oscillator Start-up

Timer (OST) and Power-up Timer (PWRT), are

included for more reliable power-up. These

timers are invoked selectively to avoid

unnecessary delays on power-up and wake-up.

12. PORTB has weak pull-ups and interrupt-on-

change features.

13. T0CKI pin is also a port pin (RA4/T0CKI).

14. FSR is a full 8-bit register.

15. "In system programming" is made possible. The

user can program PIC16CXX devi ces using only

five pins: VDD, VSS, VPP, RB6 (clock) and RB7

(data in/out).

To convert code written for PIC16C5X to PIC16F84A,

the user should take the following steps:

1. Remove any program memory page select

operatio ns (P A2, PA1, P A0 bit s) for CALL, GOTO.

2. Revisit any computed jump operations (write to

PC or add to PC, etc.) to make sure page bits

are set properly under the new scheme.

3. Eliminate any data memory page switching.

Redefine data variables for reallocation.

4. Verify all writes to STATUS, OPTION, and FSR

registers since these have changed.

5. Change RESET vector to 0000h.

 2001 Microchip Technology Inc. DS35007B-page 79
PIC16F84A
INDEX
A
Absolute Maximum Ratings................................................49
AC (Timing) Characteristics................................................55
Architecture, Block Diagram ... ........ ......................................3
Assembler
MPASM Assembler.....................................................43
B
Banking, Data Memory .........................................................6
Block Diagrams
Crystal/Ceramic Resonator Operation....... .................22
External Clock Input Operation...................................22
External Power-on Reset Circuit.................................26
Interr upt Logic................. ................... ............. ............29
On-Chip Reset............ ............ ................... ............. ....24
PIC16F84A ...................................................................3
PORTA
RA3:RA0 Pins..... ............................... ............. ....15
RA4 Pins.............................................................15
PORTB
RB3:RB0 Pins..... ............................... ............. ....17
RB7:RB4 Pins..... ............................... ............. ....17
RC Oscillator Mode.....................................................23
Timer0.........................................................................19
Timer0/WDT Prescaler ...............................................20
Watchdog Timer (WDT).... ......... .................................31
C
C (Carry) bit ..........................................................................8
CLKIN Pin.............................................................................4
CLKOUT Pin.........................................................................4
Code Examples
Clearing RAM Using Indirect Addressing....................11
Data EEPOM Write Ver ify.......................... .................14
Indirect Addressing.....................................................11
Initializing PORTA.......................................................15
Initializing PORTB.......................................................17
Reading Data EEPROM ..... ......... ...............................14
Saving STATUS and W Registers in RAM .................30
Writing to Data EEPROM............................................14
Code Protection........................................................... 21, 33
Configuration Bits................................................................21
Configuration Word.............................................................21
Conversion Considerations......... ......... ...............................76
D
Data EEPROM Mem o ry............ ...... ....... ...... ...... ....... ...... ....13
Associated Registers...... ............................................14
EEADR Register..............................................7, 13, 25
EECON1 Register................... ............. ............7, 13, 25
EECON2 Register................... ............. ............7, 13, 25
EEDATA Register............................................7, 13, 25
Write Complete Enable (EEIE Bit)........... .. .. ......... ......29
Write Complete Flag (EEIF Bit)...................................29
Data EEPROM Write Complete.................................... ......29
Data Memory ............. ....... ...... ...... ....... ...... ...... ....... ...... ...... ..6
Bank Select (RP0 Bit)...................................................6
Banking.........................................................................6
DC Bit....................................................................................8
DC Characteristics....................................................... 51, 53
Development Support.........................................................43
Device Overview...................................................................3
E
EECON1 Register
EEIF Bit ...................................................................... 29
Electrical Characteristics .................................................... 49
Load Conditions.......................................................... 56
Parameter  Measurement Inform ation................. ........ 56
PIC16F84A-04 Voltage-Frequency Graph ................. 50
PIC16F84A-20 Voltage-Frequency Graph ................. 50
PIC16LF84A-04 Voltage-Frequency Graph ......... .. .. .. 50
Temperature and Voltage Specifications - AC ........... 56
Endurance ............................................................................ 1
Errata.................................................................................... 2
External Clock Input (RA4/T0CKI). 
See
 Timer0
External Interrupt Input (RB0/INT). 
See
 Interrupt Sources
External Power-on Reset Circuit......................................... 26
F
Firmware Instructions ......................................................... 35
I
I/O Ports ............ ....... ...... ...... ....... ...... ...... ....... ...... ...... ...... .. 15
ICEPIC In-Circuit Emulator................................................. 44
ID Locations ..................................................................21, 33
In-Circuit Serial Programming (ICSP) ...........................21, 33
INDF Register....................................................................... 7
Indirect Addressing............................................................. 11
FSR Register.............................................. 6, 7, 11, 25
INDF Register..................................................7, 11, 25
Instruction Format............................................................... 35
Instruction Set ..................................................................... 35
ADDLW....................................................................... 37
ADDWF ...................................................................... 37
ANDLW....................................................................... 37
ANDWF ...................................................................... 37
BCF ............................................................................ 37
BSF............................................................................. 37
BTFSC........................................................................ 38
BTFSS........................................................................ 37
CALL........................................................................... 38
CLRF.......................................................................... 38
CLRW......................................................................... 38
CLRWDT.................................................................... 38
COMF......................................................................... 38
DECF.......................................................................... 38
DECFSZ..................................................................... 39
GOTO......................................................................... 39
INCF........................................................................... 39
INCFSZ....................................................................... 39
IORLW........................................................................ 39
IORWF........................................................................ 39
MOVF......................................................................... 40
MOVLW...................................................................... 40
MOVWF...................................................................... 40
NOP............................................................................ 40
RETFIE....................................................................... 40
RETLW....................................................................... 40
RETURN..................................................................... 40
RLF............................................................................. 41
RRF............................................................................ 41
SLEEP........................................................................ 41
SUBLW....................................................................... 41
SUBWF....................................................................... 41
SWAPF....................................................................... 41
XORLW ...................................................................... 42

PIC16F84A
DS35007B-page 80  2001 Microchip Technology Inc.
XORWF.......................................................................42
Summary Table............. .................. ............. ...............36
INT Interrupt (RB0/INT) .......................................................29
INTCON Register.......................................7, 10, 20, 25, 29
EEIE Bi t............ ...... ....... ...... ...... ...... ....... ...... ...... ....... ..29
GIE Bi t............ ...... ...... ....... ...... ...... ....... ...... ...... .... 10, 29
INTE Bit...... ...... ...... ....... ...... ...... ...... ....... ...... ...... ..10, 29
INTF Bit. ....... ...... ...... ....... ...... ...... ....... ...... ...... ......10, 29
PEIE Bi t............ ...... ....... ...... ...... ...... ....... ...... ...... ....... ..10
RBIE Bit ...............................................................10, 29
RBIF Bit............ ...... ....... ...... ...... ...... ....... ...... ..10, 17, 29
T0IE Bit.......... ...... ...... ....... ...... ...... ....... ...... ...... .... 10, 29
T0IF Bit .................. ....... ...... ...... ...... ....... ...... ..10, 20, 29
Interrupt Sources.............. ....... ...... ...... ....... ...... ...... ......21, 29
Block Diagram............... .................. ............. ...............29
Data EEPROM Write Complete............. ..............29, 32
Interrupt-on-Change (RB7:RB4) .......... .. ...4, 17, 29, 32
RB0/INT Pin, External...............................4, 18, 29, 32
TMR0 Overflow.................................................... 20, 29
Interrupts, Context Saving During..... ....................... ......... ..30
Interrupts, Enable Bits
Data EEPROM Write Complete Enable 
(EEIE Bit)................ ...... ...... ....... ...... ...... ...... .......29
Global Interrupt Enable (GIE Bit)................................10
Interrupt-on-Change (RB7:RB4) Enable 
(RBIE Bit)............................................................10
Peripheral Interrupt Enable (PEIE Bit)........................10
RB0/INT Enable (INTE Bit) .........................................10
TMR0 Overflow Enable (T0IE Bit)...............................10
Interrupts, Flag Bits...... ...... ................... ............. .................29
Data EEPROM Write Complete Flag 
(EEIF Bit) ............................................................29
Interrupt-on-Change (RB7:RB4) Flag 
(RBIF Bit)......... ....... ...... ...... ....... ...... ...... ...... .......10
RB0/INT Flag (INTF Bit) ..............................................10
TMR0 Overflow Flag (T0IF Bit)...................................10
IRP bit ................ ...... ...... ....... ...... ...... ...... ....... ...... ...... ....... ....8
K
KEELOQ Evaluation and Programming Tools ......................46
M
Master Clear (MCLR)
MCLR Pin........... ...... ....... ...... ...... ....... ...... ...... ...... ....... ..4
MCLR Reset, Normal Operation... ................... ...........24
MCLR Reset, SLEEP.......... ...... ...... ....... ...... ...... ..24, 32
Memory Organization............................................................5
Data EEPROM Mem o ry............ ...... ....... ...... ...... ....... ..13
Data Memory ............. ....... ...... ...... ....... ...... ...... ....... ......6
Program Memory..........................................................5
Migration from Baseline to Mid-Range Devices..................78
MPLAB C17 and MPLAB C18 C Compilers........................43
MPLAB ICD In-Circuit Debugger......... ....................... .........45
MPLAB ICE High Performance Universal In-Circuit 
Emulator with MPLAB IDE..........................................44
MPLAB Integrated Development Environment 
Software......................................................................43
MPLINK Object Linker/MPLIB Object Librarian ........... .......44
O
OPCODE Field Descriptions... ........ ........ ............................35
OPTION Register..................................................................9
INTEDG Bi t.......... ...... ....... ...... ...... ....... ...... ...... ....... ......9
PS2:PS0 Bits ................................................................9
PSA Bit..........................................................................9
RBPU Bit............ ...... ....... ...... ...... ....... ...... ...... ...... ....... ..9
T0CS Bit....................................................................... 9
T0SE Bit ............... ...... ...... ...... ....... ...... ...... ....... ...... ...... 9
OPTION_REG Register.. ........ .......................... 7, 18, 20, 25
INTEDG Bit............. ...... ...... ....... ...... ...... ...... ....... ...... .. 29
PS2:PS0 Bits.............................................................. 19
PSA Bit....................................................................... 19
OSC1 Pin.............................................................................. 4
OSC2 Pin.............................................................................. 4
Oscillator Configuration ........ ........................................21, 22
Block Diagram ........ ...... ............. .................. .........22, 23
Capacitor Selection for Ceramic Resonators.......... .... 22
Capacitor Selection for Crystal Oscillator............. ...... 23
Crystal Oscillator/Ceramic Resonators....................... 22
HS.........................................................................22, 28
LP .........................................................................22, 28
Oscillator Types.................. ................... ............. ........ 22
RC .................................................................22, 23, 28
XT.........................................................................22, 28
P
Packaging Information........ ............ ................... ............. .... 71
Marking....................................................................... 71
PD Bit.................................................................................... 8
PICDEM 1 Low Cost PICmicro 
Demonstration Board.................................................. 45
PICDEM 17 Demonstration Board......................................46
PICDEM 2 Low Cost PIC16CXX 
Demonstration Board.................................................. 45
PICDEM 3 Low Cost PIC16CXXX 
Demonstration Board.................................................. 46
PICSTART Plus Entry Level Development 
Programmer................................................................ 45
Pinout Descriptions............... ................... ............ ................. 4
Pointer, FSR....................................................................... 11
POR. 
See
 Power-on Reset
PORTA ...........................................................................4, 15
Associated Registers.................................................. 16
Functions.................................................................... 16
Initializing.................................................................... 15
PORTA Register.......................................7, 15, 16, 25
RA3:RA0 Block Diagram ............................................ 15
RA4 Block Diagram.................................................... 15
RA4/T0CKI Pin......... ............ ................... ........4, 15, 19
TRISA Register . ..................................7, 15, 16, 20, 25
PORTB ...........................................................................4, 17
Associated Registers.................................................. 18
Functions.................................................................... 18
Initializing.................................................................... 17
PORTB Register.......................................7, 17, 18, 25
Pull-up Enable Bit (RBPU Bit)....................................... 9
RB0/INT Edge Select (INTEDG Bit)............................. 9
RB0/INT Pin, External......................................4, 18, 29
RB3:RB0 Block Diagram ............................................ 17
RB7:RB4 Block Diagram ............................................ 17
RB7:RB4 Interrupt-on-Change ...... ........ ..........4, 17, 29
RB7:RB4 Interrupt-on-Change 
Enable (RBIE Bit) ............................................... 10
RB7:RB4 Interrupt-on-Change 
Flag (RBIF Bit).............................................. 10, 17
TRISB Register . ........................................7, 17, 18, 25
Postscaler, WDT
Assignment (PSA Bit)............................................. ...... 9
Rate Select (PS2:PS0 Bits)..........................................9
Postscaler. 
See
 Prescaler
Power-down (PD) Bit. 
See
 Power-on Reset (POR)
Power-down Mode. 
See
 SLEEP

 2001 Microchip Technology Inc. DS35007B-page 81
PIC16F84A
Power-on Reset (POR)........................ ..................21, 24, 26
Oscillator Start-up Timer (OST)........................... 21, 26
PD Bit................................................. 8, 24, 28, 32, 33
Power-up Timer (PWRT) .... ............................ ..... 21, 26
Time-out Sequence........................ ................... ..........28
Time-out Sequence on Power-up ............ .. .......... 27, 28
TO Bit........................................... 8, 24, 28, 30, 32, 33
Prescaler.............................................................................19
Assignment (PSA Bit) ..... ........ ....................................19
Block Diagram............. ............ ................... ............. ....20
Rate Select (PS2:PS0 Bits) ........................................19
Switching Prescaler Assignment.............. ......... ..........20
Prescaler, Timer0
Assignment (PSA Bit) ..... ........ ......................................9
Rate Select (PS2:PS0 Bits) ..........................................9
PRO MATE II Universal Device Programmer ............. ........45
Program Counter ................................................................11
PCL Register....................................................7, 11, 25
PCLATH Register ... ...... ................... ............ ....7, 11, 25
Reset Conditions................... ............. ................... ......24
Program Memory..................................................................5
General Purpose Registers.......................... .................6
Interrupt Vector............... ...... ....... ...... ...... ....... ...... . 5, 29
RESET Vector............... ...... ....... ...... ...... ...... ....... ...... ....5
Special Function Registers...................................... 6, 7
Programming, Device Instructions......................................35
R
RAM. 
See
 Data Memory
Register File.................................... ............. ................... ......6
Register File Map.................. ................... ............ .................6
Registers
Configuration Word.....................................................21
EECON1 (EEPROM Control)....................... ...............13
INTCON......................................................................10
OPTION........................................................................9
STATUS........................................................................8
Reset............................................................................ 21, 24
Block Diagram............. ............ ................... .......... 24, 26
MCLR Reset. 
See
 MCLR
Power-on Reset (POR). 
See
 Power-on Reset (POR)
Reset Conditions for All Registers..............................25
Reset Conditions for Program Counter.......................24
Reset Conditions for STATUS Register......................24
WDT Reset. 
See
 Watchdog Timer (WDT)
Revision History..................................................................75
RP1:RP0 (Bank Select) bits...... ............................................8
S
Saving W Register and STATUS in RAM ...........................30
SLEEP ............................................................21, 24, 29, 32
Software Simulator (MPLAB SIM)................ .......................44
Special Features of the CPU ..............................................21
Special Function Registers.............................................. 6, 7
Speed, Operating..... ....... ................... ............ ...1 , 22, 23, 57
Stack...................................................................................11
STATUS Register ............. ............ ................... ...7, 8, 25, 30
C Bit......... ...... ....... ...... ...... ...... ....... ...... ...... ....... ...... ......8
DC Bit............................................................................8
PD Bit................................................. 8, 24, 28, 32, 33
RESET Conditions................................. ............. ........24
RP0 Bit..........................................................................6
TO Bit........................................... 8, 24, 28, 30, 32, 33
Z Bit...............................................................................8
T
Time-out (TO) Bit. 
See
 Power-on Reset (POR)
Timer0 ................................................................................ 19
Associated Registers.... .............................................. 20
Block Diagram........ ............. ............ ................... ........ 19
Clock Source Edge Select (T0SE Bit).......................... 9
Clock Source Select (T0CS Bit) ................................... 9
Overflow Enable (T0IE Bit)...... ........................... ..10, 29
Overflow Flag (T0IF Bit) ............ ............. .......10, 20, 29
Overflow Interrupt................................ ............. ....20, 29
Prescaler. 
See
 Prescaler
RA4/T0CKI Pin, External Clock.................................. 19
TMR0 Register ................................................7, 20, 25
Timing Conditions................. ....... ................... ............ ........ 56
Timing Diagrams
CLKOUT and I/O........................................................ 58
Diagrams and Specifications......... .. ......... ........ .......... 57
CLKOUT and I/O Requirements......................... 58
External Clock Requirements............................. 57
RESET, Watchdog Timer, Oscillator Start-up 
Timer and Power-up 
Timer Requirements................................... 59
Timer0 Clock Requirements............................... 60
External Clock ............................................................ 57
RESET, Watchdog Timer, Oscillator Start-up 
Timer and Power-up Timer................................. 59
Time-out Sequence on Power-up.... .....................27, 28
Timer0 Clock .............................................................. 60
Wake-up From SLEEP Through Interrupt .................. 32
Timing Parameter Symbology ......... ........................... ........ 55
TO bit.................................................................................... 8
W
W Register................ ...... ...... ....... ...... ...... ....... ...... ...... ..25, 30
Wake-up from SLEEP...............................21, 26, 28, 29, 32
Interrupts ..............................................................32, 33
MCLR Reset..... ...... ...... ....... ...... ...... ....... ...... ...... ...... .. 32
WDT Reset............... ...... ....... ...... ...... ....... ...... ...... ...... 32
Watchdog Timer (WDT)................................................21 , 30
Block Diagram........ ............. ............ ................... ........ 31
Postscaler. 
See
 Prescaler
Programming Considerations...... ............................... 31
RC Oscillator .............................................................. 30
Time-out Period........ ...... ....... ...... ...... ....... ...... ...... ...... 30
WDT Reset, Normal Operation........................... ........ 24
WDT Reset, SLEEP ..... ....... ...... ...... ....... ...... ...... ..24, 32
WWW, On-Line Support....................................................... 2
Z
Z (Zero) bit............................................................................ 8

PIC16F84A

DS35007B-page 82  2001 Microchip Technology Inc.

NOTES:

 2001 Microchip Technology Inc. DS35007B-page 83

PIC16F84A

ON-LINE SUPPORT

Microchip provides on-line support on the Microchip

World Wide Web (WWW) site.

The web site is used b y Microc hip as a means to mak e

files and information easily available to customers. To

view t he site, the user must have acce ss to the In ternet

and a web browser, such as Netscape® or Microsoft®

Explorer. Files are also available for FTP download

from our FTP site.

Connecting to the Microchip Internet Web Site

The Microchip web site is available by using your

fa vorite Internet browser to attach to:

www.microchip.com

The file transfer site is available by using an FTP ser-

vice to connect to:

ftp://ftp.microchip.com

The web site and file transfer site provide a variety of

services. Users may download files for the latest

Development Tools, Data Sheets, Application Notes,

User’s Guides, Articles and Sample Programs. A vari-

ety of Microchip specific business information is also

available, including listings of Microchip sales offices,

distributors and factory representatives. Other data

available for consideration is:

• Latest Microchip Press Releases

• Technical Support Section with Frequently Asked

Questions

• Design Tips

• Device Errata

• Job Postin gs

• Microchip Consultant Program Member List ing

• Links to other useful web sites related to

Microchip Products

• Confere nces for prod ucts, Dev elopment Systems,

technical information and more

• List ing of semi nars and eve nt s

Systems Information and Upgrade Hot Line

The Systems Information and Upgrade Line provides

system users a listing of the latest versions of all of

Microchip's development systems software products.

Plus, this line provides information on how customers

can receive any currently available upgrade kits.The

Hot Line Numbers are:

1-800-755-2345 for U.S. and most of Canada, and

1-480-792-7302 for the rest of the world.

013001

PIC16F84A

DS35007B-page 84  2001 Microchip Technology Inc.

READER RESPONSE

It is our inten tio n to pro vi de you wit h the bes t do cu me ntation po ss ib le to ens ure suc c es sfu l u se of y ou r Mic r oc hip pro d-

uct. If you wi sh to prov ide you r comment s on org anizatio n, clar ity, subj ect matte r , a nd ways i n which o ur docum entatio n

can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150.

Please list the following information, and use this outline to provide us with your comments about this Data Sheet.

1. What are the best features of this document?

2. How does this document meet your hardware and software development needs?

3. Do you find the organization of this data sheet easy to follow? If not, why?

4. What additions to the data sheet do you think would enhance the structure and subject?

5. What deletions from the data sheet could be made without affecting the overall usefulness?

6. Is there any incorrect or misleading information (what and where)?

7. How would you improve this document?

8. How would you improve our software, systems, and silicon products?

To: Techni ca l Publi cations Ma nag er

RE: Reader Response Tota l Pages Se nt

From: Name

Company

Address

City / State / ZIP / Country

Telephone: (_______) _________ - _________

Application (optional):

Would you like a reply? Y N

Device: Literature Num ber:

Questions:

FAX: (______) _________ - _________

DS35007B

PIC16F84A

 2001 Microchip Technology Inc. DS35007B-page85

PIC16F84A

PIC16F84A PRODUCT IDENTIFICATION SYSTEM

To order or obtain information (e.g., on pricing or delivery) refer to the factory or the listed sales office.

Sales and Support

Data Sheets

Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recom-

mended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:

1. Your local Microchip sales office

2. The Microchip Corporate Literature Center U.S. F AX: (480) 792-7277

3. The Microchip Worldwide Site (www.microchip.com)

Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.

New Customer Notification System

Device PIC16F84A(1), PIC16F84AT(2)

PIC16LF84A(1), PI C16LF84AT(2)

Frequency Range 04 = 4 MHz

20 = 20 MHz

Temperature

Range -= 0°C to +70°C

I = -40°C to +85°C

Package P = PDIP

SO = SOIC (Gull Wing, 300 mil body)

SS = SSOP

Pattern QTP, SQTP, ROM Code (factory specified) or

Special Requirements . Blank for OTP and

Windowed devices.

Examples:

a) PIC16F84A -04/P 301 = Commercial

temp., PDIP package, 4 MHz, normal VDD

limits, QTP pattern #301.

b) PIC16LF84A - 04I/SO = Industrial temp.,

SOIC package, 200 kHz, Extended VDD

limits.

c) PIC16F84A - 20I/P = Industrial temp.,

PDIP package, 20 MHz, normal VDD limits.

Note 1: F = Standard VDD range

LF = Extended VDD range

2: T = in tape and reel - SOIC and

SSOP packages only.

PART NO. -XX X/XX XXX

PatternPackageTemperature

Range

Frequency

Range

Device

DS35007B-page 86  2001 Microchip Technology Inc.

AMERICAS

Corporate Office

2355 West Chandler Blvd.

Chandler, AZ 85224-6199

Tel: 480-792-7200 Fax: 480-792-7277

Technical Support: 480-792-7627

Web Address: http://ww w.microchip .com

Rocky Mountain

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Chandler, AZ 85224-6199

Tel: 480-792-7966 Fax: 480-792-7456

Atlanta

500 Sugar Mill Road, Suite 200B

Atlanta, GA 30350

Tel : 770 -6 40- 003 4 Fax: 770- 640 -0307

Austin - Analog

13740 North Highway 183

Building J, Suite 4

Austin, TX 78750

Tel : 512 -2 57- 337 0 Fax: 512- 257 -8526

Boston

2 Lan Drive, Suite 120

Westford, MA 01886

Tel : 978 -6 92- 384 8 Fax: 978- 692 -3821

Boston - Analog

Unit A-8-1 Millbrook Tarry Condominium

97 Lowell Road

Concord, MA 01742

Tel : 978 -3 71- 640 0 Fax: 978- 371 -0050

Chicago

333 Pierce Road, Suite 180

Itasca, IL 60143

Tel: 630-285-0071 Fax: 630-285-0075

Dallas

4570 Westgrove Drive, Suite 160

Addison, TX 7500 1

Tel : 972 -8 18- 742 3 Fax: 972- 818 -2924

Dayton

Two Prestige Pla ce, Su it e 130

Miamisburg, OH 45342

Tel : 937 -2 91- 165 4 Fax: 937- 291 -9175

Detroit

Tri-Atria Office Building

32255 Northwestern Highway, Suite 190

Farmington Hills, MI 48334

Tel: 248-538-2250 Fax: 248-538-2260

Los Angeles

18201 Von Karman, Suite 1090

Irvine, CA 92612

Tel : 949 -2 63- 188 8 Fax: 949- 263 -1338

New York

150 Motor Parkway, Suite 202

Hauppauge, NY 11788

Tel : 631 -2 73- 530 5 Fax: 631- 273 -5335

San Jose

Microchip Technology Inc.

2107 North First Street, Suite 590

San Jose, CA 95131

Tel : 408 -4 36- 795 0 Fax: 408- 436 -7955

Toronto

6285 Northam Drive, Suite 108

Mississauga, Ontario L4V 1X5, Canada

Tel: 905-673-0699 Fax: 905-673-6509

ASIA/PACIFIC

Australia

Microchip Technology Australia Pty Ltd

Suite 22, 41 Rawson Street

Epping 2121, NSW

Australia

Tel: 61-2-9868-6733 Fax: 61-2-9868-6755

China - Beijing

Microchip Technology Consulting (Shanghai)

Co., Ltd., Beijing Liaison Office

Unit 915

Bei Hai Wa n Tai Bldg.

No. 6 Chaoyangmen Beidajie

Beijing, 100027, No. China

Tel: 86-10-85282100 Fax: 86-10-85282104

China - Chengdu

Microchip Technology Consulting (Shanghai)

Co., Ltd., Chengdu Liaison Office

Rm. 2401, 24th Floor,

Ming Xing Financial Tower

No. 88 TIDU Street

Chengdu 610016, China

Tel: 86-28-6766200 Fax: 86-28-6766599

China - Fuzhou

Microchip Technology Consulting (Shanghai)

Co., Ltd., Fuzhou Liaison Office

Rm. 531, North Building

Fujian Foreign Trade Center Hotel

73 Wusi Road

Fuzhou 350001, China

Tel: 86-591-7557563 Fax: 86-591-7557572

China - Shanghai

Microchip Technology Consulting (Shanghai)

Co., Ltd.

Room 701, Bldg. B

Far East International Plaza

No. 317 Xian Xia Road

Shanghai, 200051

Tel: 86-21-6275-5700 Fax: 86-21-6275-5060

China - Shenzhen

Microchip Technology Consulting (Shanghai)

Co., Ltd., Shenzhen Liaison Office

Rm. 1315, 13/F, Shenzhen Kerry Centre,

Renminnan Lu

Shenzhen 518001, China

Tel: 86-755-2350361 Fax: 86-755-2366086

Hong Kong

Microchip Technology Hongkong Ltd.

Unit 901-6, Tower 2, Metroplaza

223 Hing Fong Road

Kwai Fong, N.T., Hong Kong

Tel: 852-2401-1200 Fax: 852-2401-3431

India

Microchip Technology Inc.

India Liaison Office

Divyasree Chambers

1 Floor, Wing A (A3/A 4)

No. 11, O’Shaugnessey Road

Bangalore, 560 025, India

Tel: 91-80-2290061 Fax: 91-80-2290062

Japan

Microchip Technology Japan K.K.

Benex S-1 6F

3-18-20, Shinyokohama

Kohoku-Ku, Yokohama-shi

Kanagawa, 222-0033, Japan

Tel: 81-45-471- 6166 Fax: 81-45-471-6122

Korea

Micro chip Technol o gy Korea

168-1, Youngbo Bldg. 3 Fl oor

Samsung-Dong, Kangnam-Ku

Seoul, Korea 135-882

Tel: 82-2-554-7200 Fax: 82-2-558-5934

Singapore

Microchip Technology Singapore Pte Ltd.

200 Middle Road

#07-02 Prime Centre

Singapore, 188980

Tel: 65-334-8870 Fax: 65-334-8850

Taiwan

Micro chip Technol o gy Taiwan

11F-3, No. 207

Tung Hua North Road

Taipei, 105, Taiwan

Tel: 886-2-2717-7175 Fax: 886-2-2545-0139

EUROPE

Denmark

Microchip Technology Denmark ApS

Regus Business Centre

Lautrup hoj 1-3

Ballerup DK-2750 Denmark

Tel: 45 4420 9895 Fax: 45 4420 9910

France

Arizona Microchip Technology SARL

Parc d’Activite du Moulin de Massy

43 Rue du Saule Trapu

Batiment A - ler Eta ge

91300 Massy, France

Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90 - 79

Germany

Arizona Microchip Technology GmbH

Gustav-Heinemann Ring 125

D-81739 Munich, Germany

Tel: 49-89-627-144 0 Fax: 49-89-627-144-44

Germany - Analog

Lochhamer Strasse 13

D-82152 Martinsried, Germany

Tel: 49-89-895650-0 Fax: 49-89-895650-22

Italy

Arizona Microchip Technology SRL

Centro Direzionale Colleoni

Palazzo Taurus 1 V. Le Colleoni 1

20041 Agrate Brianza

Milan, Italy

Tel: 39-039-65791-1 Fax: 39-039-6899883

United Kingdom

Arizona Microchip Technology Ltd.

505 Eskdale Road

Winnersh Triangle

Wokingham

Berksh ire, E ngla nd RG41 5TU

Tel: 44 118 921 5869 Fax: 44-118 921-5820

08/01/01

WORLDWIDE SALES AND SERVICE