Datasheet

Emulator User’s Guide for MPLAB X IDE
DS52085A-page 84  2013 Microchip Technology Inc.
Q: On traditional emulators, 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 REAL ICE
in-circuit emulator? For example, could I halt based on a flag going high?
A: Traditional emulators use a special emulator chip (-ME) for monitoring. There
is no -ME with the MPLAB REAL ICE in-circuit emulator so there are no busses
to monitor externally. With the MPLAB REAL ICE in-circuit emulator, 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.
Q: Does the MPLAB REAL ICE in-circuit emulator have complex breakpoints?
A: Yes. You can break based on pass counts, program memory execution at a
specific address or data memory reads/writes at a specific address. You can also
do event breakpoints (break on an event) sequenced breakpoints (break after
events occur in a specific order), or ANDed breakpoint (break when events occur
all together).
Q: One of the probe pins is labeled 5V. How much drive capability does this probe
have?
A: This is a monitoring function (allows you to see what V
DD is actually being
applied and used on the driver buffers). The MPLAB REAL ICE in-circuit
emulator cannot provide power to the target.
Q: Are any of the driver boards optoisolated or electrically isolated?
A: They are DC optoisolated, but not AC optoisolated. To apply high voltage
(120V) to the current system, see Section 13.4 “MPLAB REAL ICE Isolator
Unit (Opto-Isolator)”.
Q: What limitations are there with the 4 (PGC) or 5 (PGD) pins only?
A: There are several limiations on these pins:
- The standard ICSP RJ-11 cable does not allow for clock speeds greater than
about 15 Mb/sec. For these high-speed applications, the Performance Pak
(high-speed/LVDS) cable interface is required.
- Some circuitry should not be used on these pins. See Section 3.5.4 “Circuits
That Will Prevent the Emulator From Functioning”. Also refer to “Develop-
ment Tools Design Advisory” (DS51764).
Q: Will this slow down the running of the program?
A: There is no cycle stealing with the MPLAB REAL ICE in-circuit emulator. The
output of data is performed by the state machine in the silicon.
Q: How do I connect CLK and DAT when using high-speed communications?
A: These connections are optional and used for SPI trace. For more information,
see Section 3.6.2 “SPI Trace Connections (High-Speed/LVDS
Connection)”.
Q: What is meant by the data rate is limited to 15 MIPS, when using the standard
board? Is this caused by the core processor or transfer rate?
A: The standard board uses the RJ-11 cable and has a limitation on how fast data
can reliably be transmitted when using trace, runtime watches, and data capture.
The top end is when the processor has an operational speed of 15 MIPS. The
trace clock is derived from the main system clock of the device.
The 15 MIPS limit is a worst case limit. For well designed boards with less signal
integrity problems, the limit may be higher.
Q: Does the 15 MIPS limit apply to PIC32 devices?
A: No. The PIC32 MCU uses a fixed rate clock that doesn't derive from the target
system clock. It also uses a more robust communication protocol.