Microchip Technology MPLAB ICE, User Manual

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MPLAB
®
ICE User’s Guide
DS51159B-page 110

2001 Microchip Technology Inc.
2. Use “Reload Data” as you are filtering events to get a trace display of the
current trace buffer. Continue to select “Reload Data” to upload another
capture of the current data being filtered. This is useful if you are moni-
toring a system in real time and just want to see what’s going on without
halting the system.
3. Sometimes a system misbehaves after a long period of time. Infinite
events will continue collecting the data in your critical routine until the
application is halted. Often the misbehaving state will get into a place in
the program where no events will be collected. The trace buffer will then
be a record of the data of interest before the “glitch.”
4. Filtered traces can output a series of triggers on the TRGOUT connector.
If you wanted to trigger an external logic analyzer every time a particular
routine is executed, this can be achieved by filtering on that address and
setting the appropriate triggering in the Trigger In/Out Dialog. Infinite
Events, in this case, will allow continuous triggers to be generated on the
TRGOUT connector.
Trigger Position is inapplicable when filtering, as is Halt on Trigger and Halt on
Trace Buffer Full.
Ignore FNOP Cycles should not be specified when performing a Filter Trace;
otherwise, the trace buffer will capture the cycle that executes after the cycle
that caused the trigger.
Also, performing a Filter Trace on Data Memory access is not recommended,
since the traced data will be one cycle after the trigger specification.
Note: Since Ignore FNOP Cycles should not be specified with a Filter
Trace, prefetches will cause the trigger to fire.
Note: When triggering on multiple events, keep in mind that triggers on
data memory accesses are skewed two cycles from the instruc-
tions that caused them.