Interfase trouble with the raspberry pi 3 (Digital inputs)



  • I am currently trying to find the technical specifications of the UniPi 1.1. in order to see how the digital input works. Because I already have the relays working however the digital inputs are still a problem. I can see that a optocoupler is used however I can not find the corresponding datasheet (Could you provide that for me?) and I am not sure if I need to do something with a pull up/down resistance on the Raspberry side because I can not find the circuit design of the digital input (Could somebody provide that for me? I can already see that there is a led, resistance, optocoupler, Something..... ,Raspberry Pi 3 input, but I simply do not know the exact layout which makes it difficult to trouble shoot using a oscilloscope). Currently I can read 3 of the 12 inputs (I1, I8 and I9) and it seems that a active input voltage gives a low input on the raspberry pi (is this correct?). This would be strange because all the other inputs (the ones that are not working) are low even trough I connected them to ground (So then I would expect them to be high).

    With kind regards,
    Jelle


  • administrators

    @jelle You have to enable internal pull-up resistor for the GPIOs and set them as inputs