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ARM ETM/ITM Tracing
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This is an example capture from ARM Cortex-M3 ETM/ITM trace stream.

The trace was captured from STM32F105 microcontroller while running
this software (revision 5a1553c):
https://github.com/PetteriAimonen/STM32_Trace_Example

The example software outputs both ITM and ETM trace as follows:

1) The main loop blinks PC8 approx every 10 ms.
   On every blink it prints "On" and "Off" to ITM port 0.

2) TIM2 interrupt blinks PC9 approx every 6 ms.
   It is kept on for the duration of a bubble_sort() call.
   ETM tracing is enabled for the duration of that subroutine.
   Sort results are printed to ITM port 1.

3) DWT is continuously reporting exception status and periodically
   reporting PC values (these go to the ITM stream).

Both ITM and ETM are mixed into the same stream by TPIU module
ITM is configured as stream 1 and ETM as stream 2.

Trace output is configured as 8 MHz UART protocol from TRACESWO pin.


Logic analyzer setup
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The logic analyzer used was an FX2 based device (at 24MHz):

  Probe       STM32F105
  ---------------------
  3           PC9
  5           SWO
  7           PC8


Data
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Capture command:

  sigrok-cli -d fx2lafw -c samplerate=24MHz -C 4=SWO,2=PC9,6=PC8 -o trace_example.sr --time 50

Decoding command for ITM output:

  sigrok-cli -i trace_example.sr -P \
    uart:rx=SWO:baudrate=8000000,arm_tpiu:stream=1,arm_itm:elffile=trace_example.elf

Decoding command for ETM output:

  sigrok-cli -i trace_example.sr -P \
    uart:rx=SWO:baudrate=8000000,arm_tpiu:stream=2,arm_etmv3:elffile=trace_example.elf