[SOLVED] Again - or still: Failed to start recording. RTT Control Block not found.

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  • [SOLVED] Again - or still: Failed to start recording. RTT Control Block not found.

    Hi,
    I read through many posts but still I do not get it working. The control block address is
    0x200021e8 (retrieved via _SEGGER_RTT in Keil command window).

    However, I do not receive RTT with SystemView.

    J-Link commander does not give an output when I type, e.g.:
    J-Link> exec SetRTTSearchRanges 0x20002000 0x1000

    J-Link RTT Client shows:
    ###RTT Client: Connecting to J-Link RTT Server via localhost:19021 Connected.
    SEGGER J-Link V6.20d - Real time terminal output
    J-Trace PRO V1 Cortex-M compiled Sep 26 2017 17:01:49 V1.0, SN=751000184
    Process: UV4.exe


    This is my environment:
    STM32F411VHx, SWD
    Firmware: J-Trace PRO V1 Cortex-M compiled Sep 26 2017 17:01:49 Hardware: V1.00
    Keil µVision 5.22 and Segger SystemView V2.52a


    Thanks for any help -

    Marcus
  • Hi Marcus,

    In general there should not be a problem, as with STM32F4 devices even auto detection should work.
    So if the control block cannot be found there seems to be an issue with your setup.

    It is correct that J-Link Commander does not give an output, neither will RTT Client if you do not do any prontf output viar RTT.

    Do you run SystemView stand-alone or is there any other connection to J-Link, e.g. a debug session, open?
    Did you select the device in the SystemView configuration dialog?
    Does your system use any low-power mode, i.e. call WFI?

    Regards
    Johannes
  • Hi Johannes,

    thanks for the hint with the printf output:


    SEGGER_RTT_WriteString(0, "Hello
    World!\n");




    is working correctly. Then I re-examined my code and found that the initialization block

    SEGGER_SYSVIEW_Conf();
    SEGGER_SYSVIEW_EnableEvents(....)


    was beyond a break statement - sorry, dumb fault. After correction everything is fine...

    Thanks again,

    Marcus