[SOLVED] Weird tasks appears

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  • [SOLVED] Weird tasks appears


    I'm currently porting a non-OS firmware to FreeRTOS 10.2.1.
    I re-used a previous FreeRTOS /systemview setup that was working fine on an other project / mcu (but still cortex-M).

    Program has 3 tasks + 2 timers.

    My firmware seems to work as expected but when I enabled SystemView I saw that new tasks appeared out of the blue (task 0x1C06, 0XFCO, ...)
    This seems to happens only after some IRQ

    I think there is a "leak" somewhere but I don't know how to look for it. Any advice ?

    I used SystemView 3.12

  • After some investigations, I found that
    • SystemView timing is completely off (~250ms between 2 logs send by a timer triggered every 1.5s) but "real" timing is ok (check with an oscillo)
    • All the previous issues are not present if I disable the tickless mode.
    I use a custom tickless mode where I go in stop mode 2 and I'm wake up either by an interrupt or a RTC timer.

    It seems "normal" that timing is off in tickless because system timestamp (Cortex-M cycle counter.) is stop while I'm in tickless.
    I'm suppose I will need to redefine SEGGER_SYSVIEW_GET_TIMESTAMP in order to get correct timing in tickless mode ?

    Is it possible that the weird task problem is also linked to my tickless mode ?
  • Hello,

    Thank you for your inquiry.
    The issues you are seeing are definitely related to the tickless mode and the used sleep modes.
    SystemView operation requires RAM and debug access to the target device at all times.

    Depending on your setup it might work if you set up the SEGGER_SYSVIEW_GET_TIMESTAMP to fit your exact setup.
    Please understand that we can't provide support in such endeavor though as this is not the intended use for SystemView.

    Best regards,
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