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Gen4-4dpi-50CT-CLB touchscreen and GPIO

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  • Gen4-4dpi-50CT-CLB touchscreen and GPIO

    I have a Gen4-4dpi-50CT-CLB connected to a Raspberry Pi 3B+ running the X11 graphical interface.
    I'm using the latest version of kernel:
    [email protected]:/ $ uname -a
    Linux raspberrypi 5.4.68-v7_4DPi+ #1 SMP Fri Oct 2 14:48:37 BST 2020 armv7l GNU/Linux

    All is working fine until I'm using any of GPIO commands, after that the touchscreen isn't responding.
    For instance, after an ordinary:
    [email protected]:/ $ gpio export 17 high
    the touchscreen isn't responsive at all until I reboot the machine.

    What should I do to have both touchscreen and GPIO lines?

  • #2
    Good day!

    I noticed you also sent this inquiry in our ticketing system. I've already responded to your ticket and I'll send here my response as well.

    On that note, we would appreciate it if inquiries are kept in one place rather than creating duplicates. Rest assured that we will respond as soon as possible regardless of whether your inquiry is in forum or our ticket system. This is simply to avoid multiple people responding to the same inquiry. Thank you for your kind understanding.

    Regarding your inquiry, there shouldn't be any issue as long as you are using a GPIO pin that is not being used by the display.

    GPIO17, which you are currently using seems to be used by the gen4-4DPi as the interrupt pin for the touchscreen controller. See images below:

    Click image for larger version

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    Click image for larger version

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    Note that the H1 Pinout is the connector in the gen4-4DPi-Adaptor board. Notice that the pin numbering represents the header of the Raspberry Pi and that the pin numbering is swapped between even and odd numbered pins. I highlighted in RED the Supply Pins as a reference of the swapped numbering.

    As you might have noticed, Pin 12 of H1 (gen4-4DPi Adaptor header) connects to Pin11 of Raspberry Pi header, this is GPIO17.

    You can find some unused pins that you can use by referring to this table which you can find in the product datasheet. As always, the product datasheet can be found in the download section of the product page.

    I hope this helps.

    Best Regards
    Juniel Cruz