Troubleshooting
QT
RACE
-
U
SER
M
ANUAL
© 2018 PDQLogic Ltd.
QTrace User Manual Rev 1.01
Page 47
11.
Troubleshooting
There are a number of potential reasons why tracing does not work or is erratic. The table below shows
a number of problem scenarios and suggestions to try to resolve them.
No
.
Symptom
Category
Possible remedy(s)
1
Can't re-enumerate
into Super Speed mode
USB3
communications
issue
• Check the trace probe is connected to a USB3 port
• Verify that a different USB 3.0 device runs at Super Speed in
the same port
• Try unplugging the trace probe from the USB port and re-
connecting
• Try a different USB3 hub
• If the PC was in sleep mode then try rebooting
2
Trace probe not found
USB3
communications
issue
Try a different USB3 port and USB3 hub, check 'QTrace' found
in device manager
3
No visible trace activity
but H/W buffer
overflows*
USB3
communications
issue
Power cycle USB3 hub or reboot PC if trace probe is connected
directly
4
'Target reset detected'
pop-up window
persists
Target trace
configuration
Check that:
• IDE is configured to run user script** after target FLASHing /
reset
• Target has stopped after being reprogrammed
• Target watchdog isn't repeatedly firing (excessive reset
count indicates this)
5
Unable to synchronise
to trace
Trace
configuration
Check that:
• The IDE is configured to run user script** after target
FLASHing / reset
• IDE options to enable ETM / ITM are deselected
• The correct TCF & ELF files are loaded
• The firmware is not modifying the trace I/O pin configuration
(including I/O directions)
• The firmware is not configuring Single Wire Output (SWO)
debug mode
6
Trace synchronisation
lost
Excessive
synchronisation
errors
Verify that:
• Target firmware does not overwrite trace I/O settings e.g.
for STM32 part, trace = PE2-PE6
• The firmware is not configuring Single Wire Output (SWO)
debug mode
• Any code ranges outside of the main code are defined in the
trace configuration window
• The appropriate Windows USB drivers are up to date
• The USB lead directly to the PC rather than via a hub
• Note: Persistent sync loss can indicate sub-optimal trace
signal PCB layout (try a slower clock speed)
7
Execution counts in
random places
Wrong ELF file /
out of date or
compiler
optimisations
Verify ELF is correct and/or turn off compiler optimisation