[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
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • 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