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YASP (Yet another sync problem)

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  • #16
    Originally posted by DLC View Post

    It is difficult to get async serial to work at high speeds with a single ended channel, using RS485/differential is way easier. I'm finding that I don't get any speed over 230400 to work even on 10cm wiring. I'll try shielding next - Then maybe a half-duplex 485 transmission setup to get the speeds up.

    DLC
    Shielding didn't help. 230400 worked, 460800 didn't, 921600 worked, but the data is corrupted, giving a terrible image. What is weird on 921600 is that this sequence:
    <code>
    // Talk to the camera, this is the max auto-baud detect that will work.
    Serial1.begin(921600);
    Serial1.write(SYNC,6);

    Serial1.begin(899500);
    [sync code]
    </code>
    worked and gave a MUCH better image. I am not sure what this means...

    DLC

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    • #17
      Hmm, well that's making it sound like a baud rate error, do you have a table of requested vs actual for your controller, or can you generate one?
      Mark

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      • #18
        Let me catch up.

        The 4D cable is USB with virtually zero logic level serial length.

        Resets happen. A user zaps the enclosure, some code glitch, or code development when there is a new program downloaded.

        Yes, it is looking like a serial data problem. I have used boards with this processor on a variety of projects using logic level serial at speeds up to 1Mbps, so I am confident of the processors USART divider accuracy. Shortening my wires helped a little. I need to put a scope on the lines. It seems the data coming back from the camera is corrupted since data speed affects the image quality. Now I need to quantify that.

        Would you like me to send my uecide source for the Picadillo and camera so you can examine it? I'd love to find out what I am doing wrong!

        Thanks,
        DLC

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        • #19
          Hi DLC,

          If you can send your source code for the Picadillo and the uCAM-II, I will test it here and will give you a feedback.

          Regards.
          Doff

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