Chapter 6. Frequently Asked Questions (Faqs); Introduction; How Does It Work - Microchip Technology MPLAB ICD 3 User Manual

Chapter 6. Frequently Asked Questions (FAQs)

6.1

INTRODUCTION

Look here for answers to frequently asked questions about the MPLAB ICD 3 in-circuit
debugger system.

• How Does It Work

• What's Wrong
6.2 HOW DOES IT WORK
• What's in the silicon that allows it to communicate with the MPLAB ICD 3
in-circuit debugger?
MPLAB ICD 3 in-circuit debugger can communicate with Flash silicon via the
ICSP interface. It uses the debug executive located in test memory.
• How is the throughput of the processor affected by having to run the debug
executive?
• The debug executive doesn't run while in Run mode, so there is no throughput
reduction when running your code, i.e., the debugger doesn't 'steal' any cycles
from the target device. How does the MPLAB ICD 3 in-circuit debugger
compare with other in-circuit emulators/debuggers?
Please refer to Section 2.2 "MPLAB ICD 3 In-Circuit Debugger vs. MPLAB ICE
2000/4000 In-Circuit Emulators" and Section 2.3 "MPLAB ICD 3 In-Circuit
Debugger vs. MPLAB ICD 2 Debugger".
• How does MPLAB IDE interface with the MPLAB ICD 3 in-circuit debugger to
allow more features than MPLAB ICD 2?
MPLAB ICD 3 in-circuit debugger communicates using the debug executive
located in the test area. The debug exec is streamlined for more efficient commu-
nication. The debugger contains an FPGA, large SRAM Buffers (1Mx8) and a
High Speed USB interface. Program memory image is downloaded and is con-
tained in the SRAM to allow faster programming. The FPGA in the debugger
serves as an accelerator for interfacing with the device in-circuit debugger
modules.
• On the MPLAB ICE 2000/4000 debuggers, the data must come out on the
bus in order to perform a complex trigger on that data. Is this also required
on the MPLAB ICD 3 in-circuit debugger? For example, could I halt based on
a flag going high?
The MPLAB ICE 2000/4000 debuggers use a special debugger chip (-ME) for
monitoring. There is no -ME with the MPLAB ICD 3 in-circuit debugger so there
are no busses to monitor externally. With the MPLAB ICD 3 in-circuit debugger,
rather than using external breakpoints, the built-in breakpoint circuitry of the
debug engine is used – the busses and breakpoint logic are monitored inside the
part.
© 2008 Microchip Technology Inc.
®
MPLAB ICD 3 IN-CIRCUIT
DEBUGGER USER'S GUIDE
DS51766A-page 49