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pixxiLCD-13P2-CTP-CLB refresh rate using USART

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  • pixxiLCD-13P2-CTP-CLB refresh rate using USART

    Hi,

    I recently bought a pixxiLCD-13P2-CTP-CLB. My goal was to draw any kind of shapes in serial slave mode and refresh continuously the screen, like gauge, bargraph etc.
    But, I can only put 9600 bauds and the refresh is too slow (shape are redrawing slowly) and if I try higher baudrate it crashes.
    In my application, when I refresh the screen, I redraw all shapes. I use a STM32H7 to control the screen via USART.

    Have you any idea to improve this process ?

    Hope you can help me.
    Thank you.

    Thomas

  • #2
    Hi Thomas,

    It is strange to hear that you can only set the baud rate to 9600. You say if you try and increase the speed it crashes. What exactly is crashing (display, your MCU) and what do you mean by crash. Could you send a photo of the display after a crash?

    Also, you say you are using the 'serial slave mode' but also make references to widgets like bargraph, are you using the Serial Environment, or are you perhaps using the ViSi-Genie environment? Either way, would you be able to test a higher baud rate communication with either the Serial Commander for Serial, and the GTX tool on ViSi-Genie. These can be found in the Tools tab on Workshop4.

    Thanks,
    Adem

    Comment


    • #3
      Hi Thomas,

      A common reason for this occurring is due to a baud rate miss-match, which prevents communication from occurring. What you might need to do is find the baud rate error table (or actual baud rate table) for the STM32H7 and compare it to the same thing on the Pixxi and find two high baud rates that are within 2% of each other.

      Regards,
      Adem

      Comment


      • #4
        Originally posted by ademdeojee View Post
        Hi Thomas,

        It is strange to hear that you can only set the baud rate to 9600. You say if you try and increase the speed it crashes. What exactly is crashing (display, your MCU) and what do you mean by crash. Could you send a photo of the display after a crash?

        Also, you say you are using the 'serial slave mode' but also make references to widgets like bargraph, are you using the Serial Environment, or are you perhaps using the ViSi-Genie environment? Either way, would you be able to test a higher baud rate communication with either the Serial Commander for Serial, and the GTX tool on ViSi-Genie. These can be found in the Tools tab on Workshop4.

        Thanks,
        Adem
        Hi,
        Thanks for your answer.
        The display crashes and here is a picture of the display, I see a black screen with some green writings.
        ‚Äč
        I am currently using the Serial environnement. When I talked about bargraph, I was not talking about bargraph of 4D workshop IDE. All the shapes, including bargraph, are drawn by my MCU.
        I implemented all the functions given in some documents on your website to be able to draw my own shapes.
        With the serial commander, I can put a baudrate of 115200 or 200000 and the display never crashes.

        So, I think there is something wrong with my MCU. I will check the baud rate error table of my MCU.
        Thanks you

        Thomas

        Comment


        • #5
          Hi Thomas,

          Just following up to see how you are going with your serial communication. Was there a baudrate that was effective?

          Regards,
          Adem

          Comment


          • #6
            Originally posted by ademdeojee View Post
            Hi Thomas,

            Just following up to see how you are going with your serial communication. Was there a baudrate that was effective?

            Regards,
            Adem
            Hi Adem,

            I kept 9600 as baudrate and I improve a bit all my functions to display shapes faster and it seems to be ok, far from perfect but ok.

            Regards,
            Thomas

            Comment


            • #7
              Hi Thomas,

              We're you able to find a higher baudrate on the MCU side that was within a 2% range of a baudrate on the display side? I am assuming you either did find one but there were still issues, or you did not find one. If it's the first case, let me know and we can perhaps solve the issue.

              Regards,
              Adem

              Comment

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