Datasheet
MPLAB
®
REAL ICE
™
IN-CIRCUIT
EMULATOR USER’S GUIDE FOR
MPLAB X IDE
2013 Microchip Technology Inc. DS52085A-page 83
Chapter 9. Frequently Asked Questions (FAQ)
9.1 INTRODUCTION
Look here for answers (A) to frequently asked questions (Q) about the MPLAB REAL
ICE in-circuit emulator system.
• How The Emulator Works
• How Trace Works – 8 and 16 Bit Devices
• General Issues
9.2 HOW THE EMULATOR WORKS
Q: What's in the silicon that allows it to communicate with the MPLAB REAL ICE
in-circuit emulator?
A: Most silicon contains a debug module that can communicate with the REAL
ICE. A small debug executive program is also needed to be programmed in the
high area of memory (sometimes in a separate area of memory called test mem-
ory). On some small devices without on-chip debugging capability, an emulation
header may be purchased to allow debugging.
Q: How is the throughput of the processor affected by having to run the debug
executive?
A: The debug executive doesn't run while in Run mode, so there is no throughput
reduction when running your code, i.e., the emulator doesn’t ‘steal’ any cycles
from the target device. However, when you are doing Native trace, each macro
inserted takes about 200 instructions. Therefore, this will affect timing.
For more information, see Section 6.3.8 “Resource Usage Examples”.
Q: How does the MPLAB REAL ICE in-circuit emulator compare with other in-circuit
emulators/debuggers?
A: Please refer to Section 3.2 “Tools Comparison”.
Q: How does MPLAB IDE interface with the MPLAB REAL ICE in-circuit emulator to
allow more features than in-circuit debuggers?
A: For some devices, the MPLAB REAL ICE in-circuit emulator communicates
using the debug executive located in a special area of memory that does not use
application program memory. Also, the debug exec is streamlined for more effi-
cient communication. The emulator contains an FPGA, large SRAM Buffers
(1Mx8), and a high speed USB interface. The program memory image is down-
loaded and is contained in the SRAM to allow faster programming. The FPGA in
the emulator serves as an accelerator for interfacing with the device in-circuit
debugger modules.