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Factory reset for GEN4-4DPI-50CT-CLB (due to inverted/negative colors)

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  • Factory reset for GEN4-4DPI-50CT-CLB (due to inverted/negative colors)

    Hi,

    I have recently purchased GEN4-4DPI-50CT-CLB display (https://4dsystems.com.au/gen4-4dpi-50ct-clb) and tried it out on a couple of older RaspberryPi boards. It worked fine while testing with python/pygame.
    However, at some point, after swapping the display (disconnect + connect, with power off) between two RaspberryPi boards, now the display shows inverted colors (what should be black is white, etc). This is visible already after boot when the screen displays the boot sequence (on tty1), and when my own python script has not been run yet.
    I have checked the connection of the 30pin cable on both ends and seems OK.
    What else could it be? Hardware error or software error?

    Is there maybe a way to factory reset the Xilinx processor on-board? If possible, I'd like to do this from C or Python while connected to the RaspberryPi.
    Thank you.

  • #2
    Hi IstvanZK,

    Good Day.

    Did you try the display module on the older Raspberry Pi that works fine, again? What is the version of the other Raspberry Pi where you put the display and cause this inverted colors. Please try to check the driver on this other RPi boards.

    With the way you swap the display with raspberry pi's has no reason that the xilinx processor will be affected.

    As to factory reset, xilinx processor is loaded with our firmware which we only programmed at our production facilities. Any attempt to access this may void the warranty of your display module.

    Thank you.

    BR,

    Comment


    • #3
      Hi Frsantiago,

      Thank you.
      The screen works now the same way, inverted colors, when connected to any of my RaspberryPi s, regardless of their model, Model B+ and Model A+.
      I was hoping that this is a software error, and can be corrected with a factory reset or similar procedure.
      What else can be the cause of this inverted colors?
      Are there any test points on the board where I could measure reference logic levels or power supply levels (with a multimeter or oscilloscope) just to test the correct functioning of the hardware?
      Does the warranty cover this defect?

      Kind regards
      IstvanZK

      Comment


      • #4
        Good Day.

        Thank you for your quick response. You can test power and logic levels but for now let's try on the software side first.

        Did you try to update your raspberry pi? What is the current Kernel version of the Raspberry Pi that you are using? Can you try to edit some lines on your on config.txt file to force the display to boot to gen4-4DPi-50CT try to uncomment line #dtoverlay=4dpi-50ct save and restart.

        Can you also send us image of the display screen and the back of the display module? This can be covered as long as within warranty period.

        Hope this helps.

        Best Regards,

        Comment


        • #5
          Hi Frsantiago,

          Thank you.
          I'm using the latest raspberry kernel and the 4dsystems patch: 4.14.34+ #2 Mon Apr 30 06:17:57 UTC 2018 armv6l, on both Raspberry Pi s
          I have tried with the line #dtoverlay=4dpi-50ct uncommented. The result is the same.
          I have attached below the two pictures: the back of the display and front of the display after boot.

          The back of the display
          Front of the display after boot
          Attached Files

          Comment


          • #6
            Hi Frsantiago,

            Please note that although on the back of the display the gen4-4DPi-43 is marked, the display is actually a gen4-4DPi-50 according to the emballage/box and the active screen size.
            Also, when the screen was working fine, the boot sequence was displayed on black background with white characters. Now is sort of 'reversed'.

            Kind regards
            IstvanZK

            Comment


            • #7
              Hi Frsantiago,

              I was looking at other TFT displays and their drivers (kernel modules and overlays). Does the 4dpi-50ct have an option like 'display_invert_colors' or 'bgr' or anything alike, which could be used in the boot/cmdline.txt or boo/config.txt?

              Comment


              • #8
                Dear IstvanZK,

                Good Day.

                Thank you for all the information and images that you give us. With that, can you raise a ticket on our CMC to proceed with this.

                https://4dsystems.com.au/support

                Thank you.

                Best Regards,


                Comment


                • #9
                  Hi Frsantiago,

                  Thank you. I have submitted the ticket and referred to this forum thread for details.

                  Kind regards
                  IstvanZK

                  Comment

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