FAQs for ARM/Cortex Trace (parallel)
|What are FIFOFULLs in the trace?|
A FIFOFULL happens when the trace sources are producing more information than the trace infrastructure of the chip could handle. As a consequence, trace packets are lost.
There are two solutions to avoid FIFOFULLs
1. The trace infrastructure needs to run faster to increase the bandwidth. Check that the trace clock is running a the fastest supported rate and use the maximum port speed and width.
2. The trace sources need to send less trace information.
|What can be the reason of "BAD TRACE PACKET" in the trace?|
"BAD TRACE PACKET" generally means that invalid trace data was recorded. Invalid trace data appears due to wrong sampling points, voltage threshold, too high trace clock, electrical issues on the board (e.g. crosstalk) or a broken ETM implementation on the chip.
Please refer for more information to the "Diagnosis" chapter from the "AutoFocus User's Guide"
|What does HARDERROR or FLOWERROR mean?|
HARDERRORS means that the trace data is not valid. Possible reasons are:
|What is different between pin 14 (VTref(JTAG)) and pin 12 (VTref(ETM)) on ETM MICTOR connector?|
On the ETM MICTOR connector are both ETM trace and JTAG signals available, but VTref (pin12) is not splitted into JTAG and ETM by the ARM specification. Lauterbach has defined:
On the TRACE32 preprocessor the VTref is routed to the ETM buffers and VCC is routed to JTAG buffers. Herewith it is possible to use different voltage levels on ETM and JTAG pins.
|Which function does the EXTRIG on the ETM MICTOR connector have?|
The function of EXTRIG is not exactly defined by ARM, it can be input or output. On TRACE32 side it can be used to trigger the TRACE32 hardware (input with 10 kOhm pull-down) on some trace hardware.
|Which trace port bandwidth is supported with the different TRACE32 modules and ETM preprocessors?|
Please refer to the "Diagnosis" chapter from the "AutoFocus User's Guide"
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Last generated/modified: 10-Jan-2020