Datasheet
Frequently Asked Questions (FAQ)
2013 Microchip Technology Inc. DS52085A-page 85
Q: To debug a dsPIC® DSC running at 30 MIPS, is high-speed communications
necessary to do even basic debugging?
A: Basic debugging at any device frequency can be accomplished with either
standard or high-speed (Performance Pak) communications.
Q: My target board connector is for standard communications but I want to use
high-speed communications. Can I use the high-speed/LVDS communications
(Performance Pak) cables, high-speed-to-standard converter board, and standard
communication (ICSP) cable?
A: No. You cannot use the standard/ICSP cable for high-speed communications,
i.e., high device operational frequencies. This introduces signal integrity issues,
due to the lower quality of cable transmission, when using the RJ-11 converter
board.
Q: If the high-speed receiver board is used, do pins 7-8 have to be connected, or can
they just be left open?
A: They can be left open. The high-speed receiver board weakly pulls them
down.
Q: What is the function of pin 6, the auxiliary pin?
A: There is no function on pin 6. It is a legacy connection, compatible with the
typical ICSP 6-pin header definition.
9.3 HOW TRACE WORKS – 8 AND 16 BIT DEVICES
Q: When using trace, is this connection electrically isolated in any way, i.e., do the
triggers have any isolation?
A: They are buffered and DC adjusted to whatever V
DD level you are running.
The buffers tristate when off. This minimal isolation makes the system fast and
opens the door to adapt to new and faster technologies. However, you may
implement more RS-232 isolation (4-6 lines) if desired, but this may impact your
speed.
Q: Can we do trace by using the 5 or 6 ICSP pins only?
A: Tracing is possible using the standard ICSP interface.
Q: Does inputting execution speed in the Project Properties dialog (File>Project
Properties, REAL ICE category, Clock option) actually set communication clock?
A: No. The input box in this tab merely reports the speed to the emulator so that
it can accurately control timing. The actual communication speed is based on the
target system clock. Reporting the clock is needed only for Native trace, data
capture, and runtime watches.
Q: When would SPI trace be used? What extra advantage does this have?
A: SPI trace is faster than Native trace and impacts code size less. It can also be
used on many devices that do not have Native trace. See the online help, “Device
and Feature Support”.
Q: In order to use the SPI trace, what is the hardware connection?
A: For serial SPI port trace, the device SPI SDO (serial data output) and SCK
(serial clock) are required. These pins must be connected, respectively, to the
DAT and CLK pin interface on the Performance Pak receiver board. See
Section 3.6.2 “SPI Trace Connections (High-Speed/LVDS Connection)” for
more information.