Sysview log does not start if chip in low power state

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  • Sysview log does not start if chip in low power state

    Hi,
    I'm using Sysview with FreeRTOS, all is fine but I have to disable low power mode (ie remove WFI calls ), otherwise Sysview does not log anything. Is it the expected behaviour?
    Note I did the test using configUSE_IDLE_HOOK or configUSE_TICKLESS_IDLE but same result, the only workaround I found is to disable these 2 defines when using SysView
  • Hi,

    Yes.
    I don't know which device you are using, but in most cases, when a device is in low power mode some peripherals are disabled.
    When the debug unit is disabled or the RAM cannot be read in low power mode, debugging (and recording with SystemViewer) is not possible.

    In general it is recommended not to use low power modes for debugging.

    Best regards
    Johannes
  • It's a chip based on CortexM3.
    For information I'm able to use the Jlink (eg I use live watches which works fine), but when trying to connect via segger it's rejected.
    Below a log for your convenience. The first part (T3C7C) is linked with my live watches (you will recognize the RTT block header), the second part (T35FC) is linked with Sysview.
    Note that while doing further tests I succeeded once to get sysview running (probably the request was sent while my chip was not in sleep mode). As the live watches are working fine I guess Sysview could do the same (may be managing a time out?)
    Regards,
    Frederic

    T3C7C 364:497 JLINK_ReadMemU32(0x20000000, 0x0004 Items, ...) - Data: 0x47474553 0x52205245 ...
    T3C7C 364:502 JLINK_ReadMemU32(0x20000010, 0x0004 Items, ...) - Data: 0x00000002 0x00000002 ...
    T3C7C 364:504 JLINK_ReadMemU32(0x20000020, 0x0004 Items, ...) - Data: 0x00000400 0x000000F6 ...
    T3C7C 364:508 JLINK_ReadMemU32(0x20000030, 0x0004 Items, ...) - Data: 0x00041A50 0x20002001 ...
    T3C7C 364:512 JLINK_ReadMemU32(0x20000040, 0x0004 Items, ...) - Data: 0x0000007B 0x00000000 ...
    T3C7C 364:515 JLINK_ReadMemU32(0x20000050, 0x0004 Items, ...) - Data: 0x00000010 0x00000000 ...
    T3C7C 364:517 JLINK_ReadMemU32(0x20000060, 0x0004 Items, ...) - Data: 0x00041A50 0x20001FF9 ...
    T3C7C 364:522 JLINK_ReadMemU32(0x20000070, 0x0004 Items, ...) - Data: 0x00000002 0x00000000 ...

    T35FC 369:487 JLINK_RTTERMINAL_Control(Cmd = JLINKARM_RTTERMINAL_CMD_START)
    T35FC 369:489 JLINK_RTTERMINAL_Control(Cmd = ???)
    T35FC 369:493 JLINK_RTTERMINAL_Control(Cmd = ???)
    T35FC 369:497 JLINK_RTTERMINAL_Control(Cmd = ???)