Connect to existing debug session not available

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  • Connect to existing debug session not available

    Hello All,

    i am currently evaluating SystemView and found something strange.

    I am using J-Link Pro and the device is a STM32F071CB.
    When I have an active debug session via Ozone, then "Target | Start Recording" in SystemViewer 2.34 does not enable the button "Existing session", instead it is greyed out. Connection to J-Link is via TCP/IP.

    As far as I read in the SystemView documentation, using an existing Debug session should be possible.

    Am I mising something?

    Edit:
    I found another issue: The time scale is wrong (at least for the ISRs). The period of the SysTick is in reality 1ms, nut is shown in SystemViewer witth 1m29s (in words, 1minute 29seconds)!
    The duration of the SysTick ISR is also to high. It is shown as 1.0172ms, while it really is only a few microseconds.

    Best regards,
    Martin

    The post was edited 1 time, last by enz ().

  • Hi Martin,

    Existing session is not available, yet. It will be enabled in a future version of SystemViewer.

    If the time scale is wrong,
    either the configured system and timestamp frequency is incorrect,
    or if you see jumps in the SysTick interrupt, the GetTimestamp function is incorrect.

    Which OS are you using?

    Best regards
    Johannes
  • Hi Johannes,

    thanks for the response.

    With regard to the SystemViewer manual (UM8027; Rev.0 from 1. April 2016) I got the impression that Existing session is already available, Quote from the manual page 38:
    "Note: SystemViewer can be used parallel to a debugger. In this case recording can be done
    while the debugger is running. Make sure all required configuration is done in the debugger."

    Is there a schedule, when this feature will be enabled?


    I solved the issue with the timestamp. The RTOS used is FreeRTOS and the SystemViewer manual says that: "the SysTick handler
    should increment SEGGER_SYSVIEW_TickCnt" so I incremented it in "vApplicationTickHook". After examining the code (which would be much easier if a parallel debug connection could be used ;) ) I realized that it must be incremented at the beginning of the Systick handler, before any trace macro is called. If SEGGER_SYSVIEW_TickCnt is incemented in "vApplicationTickHook", then the "traceISR_ENTER" is already called and the time calculation is wrong.

    Maybe the manual could be improved be pointing this out more explicitly.

    Best regards,
    Martin
  • Hi Martin,

    SystemViewer in genral can already be used in parallel to a debugger without the existing session option,
    it will do this implicitly then.

    The sample code for SEGGER_SYSVIEW_TickCnt describes,
    that the increment needs to be done at the very first beginning of the tick interrupt, before creating any SystemView event.

    Best regards
    Johannes
  • Hi Johannes,

    this

    SEGGER - Johannes wrote:

    SystemViewer in genral can already be used in parallel to a debugger without the existing session option,
    it will do this implicitly then.
    works only if the J-Link is connected via USB.

    But I often use (and have to use) the Ethernet connection of my J-Link Pro. With this I get an error message "Max. number of connections exceeded" when I try to start recording.
    Anything I can do about this, or is this behaviour intentional?

    Best regards,
    Martin