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voxl-uart-loopback problems

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  • R Offline
    R Offline
    relevinsky
    Contributor
    wrote on last edited by
    #1

    Hi,

    I run into the problem with voxl-uart-loopback on baud rate (921600) and buffer size >= 500 bytes. many times the loopback returns 0 bytes (on reading part). If i set low baud rate 9600 and 200 bytes of data, its FAIL always on reading.![alt text](b74ee7f1-d647-4e37-9af9-56c26427fb8f-image.png image url) . Please help me . It's not a regular serial,it works with DSP via RPC. So i need to be sure that will not be a problem with data integrity.Thanks.

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    • Alex KushleyevA Offline
      Alex KushleyevA Offline
      Alex Kushleyev
      ModalAI Team
      wrote on last edited by Alex Kushleyev
      #2

      Hello,

      There were a few issues with the uart loopback example:

      • the test buffer size was not handled properly (if test size is larger than HelloWorld strin
      • the sleep time was not enough to allow the transfer to happen (the write function is non-blocking, it seems)

      I have made some fixes here:
      https://gitlab.com/voxl-public/core-libs/libvoxl_io/-/blob/dev/lib/apps/voxl-uart-loopback.c

      Now the behavior is as shown below.. please try it.

      ./voxl-uart-loopback -d 7 -b 9600 -s 20
      INITIALIZING
      Sending 20 bytes:
      0123456789:;<=>?@ABC
      Transfer should take ~20833us, sleeping for 25833us (+5000us overhead)
      Reading back data...
      Received 20 bytes:
      0123456789:;<=>?@ABC
      closing uart bus
      PASS


      ./voxl-uart-loopback -d 7 -b 9600 -s 500
      INITIALIZING
      Sending 500 bytes:
      0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJ
      Transfer should take ~520833us, sleeping for 525833us (+5000us overhead)
      Reading back data...
      Received 500 bytes:
      0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789:;<=>?@ABCDEFGHIJ
      closing uart bus
      PASS

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