Home › Forums › Hardware › Strange GPIO voltage issue

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
    Posts
  • December 30, 2016 at 10:43 pm #1980
    Aaron, N3MBH
    Forum Administrator

    A few thoughts. One are you trying to check this with circuitry attached? If so I would remove your interface and use a basic LED and resistor between your gpio and ground pin. Also, verify that the gpio pins are properly registered and showing up under /sys/gpio. I would also recommend toggling the high/low values outside of ORP from just the command line to make sure the low level functionality is working. To me it sound like you might have a short in your circuit that is. I would check that first.

    73,
    Aaron – N3MBH / WRFV871

    OpenRepeater is offered free of charge. Find out how you can support us.

    December 30, 2016 at 11:03 pm #1982
    Aaron, N3MBH
    Forum Administrator

    Check out this link for instructions on controlling the GPIO pins from command line:
    https://sites.google.com/site/semilleroadt/raspberry-pi-tutorials/gpio

    73,
    Aaron – N3MBH / WRFV871

    OpenRepeater is offered free of charge. Find out how you can support us.

    December 31, 2016 at 12:05 pm #1989
    Leo, KK6OCI
    User

    All those measurements were taken with the circuitry not connected – just the oscilloscope probe straight to the GPIO pins. Though the behavior is the same when it is connected. Not enough voltage is produced to activate the optocoupler, which is how I noticed the problem originally.

    I’ll give manually setting the pins a try. Could you point me to where in the code the PTT pin gets set in case I need to tinker with it?

    Thanks!

    December 31, 2016 at 9:10 pm #1990
    Aaron, N3MBH
    Forum Administrator

    SSH into the board and shut down the SVXLink Core (services svxlink stop). If you don’t know how to SSH into the board, see this: https://openrepeater.com/knowledgebase/topic/connecting-via-ssh

    Once you do that use the tutorial above (just the top portion of the page) to register pins and manually toggle the values. You can cat the values on both in and out pins to see what their current state is and you can echo out a new value to output pins.

    Also, make sure that you are specifying that GPIO pin numbers and not the actual header pin numbers. If the RPI seems to function already, try another GPIO pin. Maybe try the inputs you know are good.

    73,
    Aaron – N3MBH / WRFV871

    OpenRepeater is offered free of charge. Find out how you can support us.

  • Author
    Posts
Viewing 4 posts - 1 through 4 (of 4 total)
  • The forum ‘Hardware’ is closed to new topics and replies.