ETM TRACE on STM32446E-EVAL​ board not working between 168MHz-180MHz CPU clock (84-90MHz trace clock)

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    • ETM TRACE on STM32446E-EVAL​ board not working between 168MHz-180MHz CPU clock (84-90MHz trace clock)

      Try as I might - and even with the exceptionally good support received from SEGGER, I'm unable to get my STM32446E-EVAL board to give reliable trace connection at the upper clock ranges.
      I have two J-Trace debuggers (HW V1.0) and even designed my own PCB board as a public domain project board to be 'The model of perfect ETM trace connector layout'. It was to overcome the 'issues' that were present on the EVAL board. (routing, track splits, no series termination). After all that, Same problem.
      Test carried out on an 'out the box' STM32CubeMX example with STM32F446VE micro

      <code>
      LTRACE (Time since start: 0.352 152, Thread=ETM4): Unknown trace data packet detected (Offset = 0x5D2, Data = 0x22)
      LTRACE (Time since start: 0.000 109, Thread=RX :( Unknown packet received from J-Trace.
      </code>

      I'm not looking for tips of suggestions - all has been tried. I've settled on 160MHz which works fine.
      If you have any comments on your own experiences for this micro / platform then please share your experience - this is mine..
      Thanks..

      The post was edited 1 time, last by jnewcomb: Micro not appearing when searching forum - even though its a tagged ().

    • I had similar problems with a STM32H743.

      See: [SOLVED] STM32H7 ETM Trace

      "The pins that the STM32H7 uses for tracing are specified for maximum 133 MHz. However even under lab conditions we could get stable trace up until ~118 MHz trace clock. Higher than that and the STM32H7 could not fulfil the trace signal specifications anymore and trace got unstable. For this reason are examples are capped at 100 MHz even though CPU is running on 400 Mhz"

      The STM32F446 likely has the same limitations.

      I reduced my trace clock to 66 MHz (even at 400 MHz CPU clock), and it still works just fine without loosing trace data.