DSPIC30F4013-20I/PT - MICROCHIP

GS003

INTRODUCTION

This document describes useful options that facilitate

in-circuit debugging of dsPIC30F embedded

application programs.

MULTIPLE DEBUGGING CHANNELS

dsPIC30F Digital Signal Controllers use Microchip's

low-cost development tool, MPLAB® ICD 2 In-Circuit

Debugger for both programming and in-circuit debug-

ging. MPLAB ICD 2 provides a 5-pin interface to the

dsPIC30F device. These pins are: VDD, VSS, MCLR,

PGC/EMUC and PGD/EMUD. The PGC/EMUC and

PGD/EMUD pins are used to communicate clock and

data signals, respectively, between the MPLAB ICD 2

unit and t he dsPIC3 0F device during progr ammin g and

debuggi ng operations .

To give you flexibility in board layout, dsPIC30F DSC

devices provide multiple options for connecting the

MPLAB ICD 2 to your target board for in-circuit debug-

ging. dsPIC30F devices are available in packages

ranging from 18 to 80 pins. Devices in small packages

ofte n hav e seve ral pe rip hera l fu ncti ons mult ipl exed on

each pin (see Figure 1). In certain cases, the default

programming and debugging pin functions, PGC/

EMUC and PGD/EMUD, are multiplexed on pins that

may be us ed by other peripheral s like the I2C™, SPI™,

or UART modules. In such cases, the application is

able to use these pins for programming, however they

cannot be used for in-circuit debugging. In-circuit

debugging should then be performed using alternate

debugging channels, as listed in Table 1. You should

note that the device programming and connect opera-

tions using MPLAB ICD 2 will continue to require the

use of the PGC and PGD pins.

TABLE 1: DEBUGGING CHANNELS

FIGURE 1: TYPICAL ALTERNATE

DEBUGGING CHANNEL

Author: Hrushikesh (Rishi) Vasuki

Microchip Technology Pin Name Pin Function

EMUD

EMUC Default Debug Data pin

Default Debug Clock pin

EMUD1

EMUC1 Alternate Debug Channel #1 Data pin

Alternate Debug Channel #1 Clock pin

EMUD2

EMUC2 Alternate Debug Channel #2 Data pin

Alternate Debug Channel #2 Clock pin

EMUD3

EMUC3 Alternate Debug Channel #3 Data pin

Alternate Debug Channel #3 Clock pin

PGC/EMUC/SDA

PGD/EMUD/SCL

PGC

PGD

VDD

VPP

VDD

VSS

MCLR

Program

Debug

ICD 2 Header dsPIC30F3012

EMUD3*

EMUC3*

To I2C™ Device

Switch

* Pin Multiplexing on dsPIC30F3012 (PDIP Package):

Pin Mult ipl exed Func tio ns

2EMUD3/AN0/VREF+/CN2/RB0

3EMUC3/AN1/VREF-/CN3/RB1

11 PGD/EMUD/AN6/U1TX/SDO1/SCL/CN6/RB4

12 PGC/EMUC/AN5/U1RX/SDI1/SDA/CN7/RB5

In-Circuit Debugging Interface Options with dsPIC DSC

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DESIGN PROCEDURE

To make use of these alternate debugging channels, a

few steps need to be taken:

1. Before you lay out your circuit board, decide

whether you will need to use alternate

debugging channels .

For instance, assume that an application run-

ning on a dsPIC30F3012 requires the SDA and

SCL pin functions to communicate via the I2C

protocol with other components on the board.

On the dsPIC30F3012 device, the SCL and

SDA pins (11 and 12) are multiplexed with the

default in-circuit debugging pins, EMUD and

EMUC, respectively. So, this application

requires an alternate in-circuit debugging

channel.

2. Select the alternate debugging channel to use

from EMUC1/EMUD1, EMUC2/EMUD2 or

EMUC3/EMUD3.

For the hypothetical application, assume that

pins 2 and 3 on the dsPIC30F3 012 a re avail able

for use during in-circuit debugging operations.

Thus, you would use EMUC3 and EMUD3 as

the alternate in-circuit debugging channel for

this application.

3. While designing your board, provide a connec-

tion between the PGC and PGD pins on the

MPLAB ICD 2 unit and the selected alternate

debugging channel, EMUC3 and EMUD3, as

shown by the switch in Figure 1.

4. Before downloading code (programming) into

the target device, you’ll need to set the configu-

ration bits dialog in MPLAB IDE to accurately

reflect the selected in-circuit debugging chan-

nel. MPLAB IDE, by default, uses the PGC/

EMUC and PGD/EMUD pins for programming

and debugging. For the hypothetical application

you’ll set the “COMM CHANNEL SELECT”

opti on t o “Us e EMU C3 a nd E MUD3 ”, as show n

in Figure 2. The configuration bits dialog is

invoked by selecting the Configure>Configura-

tion Bits menu in MPLAB IDE.

5. During a programming or connect operation

(with MPLAB ICD 2 selected as a Debugger),

the switch (or jumper) should be positioned so

that the MPLAB ICD 2 unit communicates with

the target dsPIC30F device via PGC and PGD

(pins 12 and 11, respectively).

6. When programming is complete, the switch (or

jumper) should be positioned so that the MPLAB

ICD 2 unit communicates with the target

dsPIC30F d ev ic e v ia EMU C3 an d EM U D3 (p in s

3 and 2, respectiv el y).

7. You are now ready to perform in-circuit debug-

ging operations using such functions as Reset,

Run, Single-step, Halt, Set Breakpoint, etc.

FIGURE 2: EXAMPLE MPLAB® IDE CONFIGURATION BITS DIALOG

GS003

MPLAB ICD 2 ERROR HANDLING

If any of the steps detailed in this document were not

performed, MPLAB IDE may display an error message

such as shown in Figure 3.

This error message is displayed because MPLAB ICD

2 is no t able to commun icate with the D ebug Execu tive

running on the dsPIC® DSC. This communication fail-

ure occurs because the Debug Executive expects to

communicate with MPLAB ICD 2 on a channel (for

exampl e EMUC3 and EMU D3) differ ent from the boa rd

configuration (for example EMUC and EMUD).

FIGURE 3: EXAMPLE DEBUGGING ERROR ON INCORRECT CONFIGURATION

Programming Target...

...Validating configuration fields

...Erasing Pa rt

...Programming Programming Executive

...Verifying Programming Executive

...Programming Program Memory (0x0 - 0x53F)

Verifying...

...Program Memo ry

...Verify Succeeded

...Loading DebugExecutive

...Programming DebugExecutive

...Debug Executive

...Programming Debug Vector

...Debug Vector

...Programming Configuration Bits

.. Config Memory

Verifying configuration memory...

Connecting to debug executive

ICD0083: Target not in debug mode, unable to perform operation

MPLAB ICD 2 Ready

Error message displays if the

dsPIC30F device is not properly

configured for debugging.

GS003

SUMMARY

This document described how alternate debugging

channels (EMUCx & EMUDx pins) can be used for in-

circuit debugging when the default debugging channel

(EMUC & EMUD pi ns) i s in use by the ap pl ication an d,

hence, rendered unavailable for use by MPLAB ICD 2.

Several dsPIC30F Development Boards, including

dsPICDEM™ MC1 and dsPICDEM 2, include jumpers

or switches that all ow you to select alt ernate debugging

channels.

For circuit details, see the schematics included in the

User’s Guides for these Development Boards

(dsPICDEM™ 1.1 Development Board User’s Guide

(DS70099) and dsPICDEM™ 2 Development Board

User’s Guide (DS51558)).