RECORD_START when SEGGER_SYSVIEW_USE_STATIC_BUFFER is set to 0 (and other general questions)

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    • RECORD_START when SEGGER_SYSVIEW_USE_STATIC_BUFFER is set to 0 (and other general questions)

      Hi all,
      a question from my side:
      Why there is no lock mechanism in record start and record end when buffer on the stack is used?

      Bonus questions:
      The usage of SEGGER_SYSVIEW_RTT_BUFFER_SIZE is not really clear to me.
      1. What's the relation between SEGGER_SYSVIEW_RTT_BUFFER_SIZE and the interface speed that shall be used to retrieve data without losing packets or having transmission errors?
      2. Are there any (appreciable) differences in performances between selecting JTAG and SWD debugger interfaces?
      3. Jlink plus has a max 15MHz of interface speed and 30MHz of SWO sampling frequency. The maximum target interface speed shall then be 15000KHz in sysview? If the debugger is connected (e.g. IAR in debug mode + SystemView) the maximum speed availlable for the interface shall be divided by a 2 factor?
      Thansk and kind regards,

      Catosh
    • Hello Catosh,

      Thank you for your inquiry.

      catosh wrote:

      Why there is no lock mechanism in record start and record end when buffer on the stack is used?
      Can you elaborate which API function you mean exactly? Also which SystemView source version are you using?

      1: See here: segger.com/products/debug-prob…about-real-time-transfer/

      2: No

      3: SWO is simply an input and thus be much higher than the max debug interface speed as a debug interface must apply that speed for both I/O. The more expensive probes J-Link Ultra and higher come with a FPGA for this reason so they can reach that speeds on I/O and not only on the I side.

      Best regards,
      Nino
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