Activity Forums Questions & Troubleshooting Software & Firmware INPUT_PULLUP not supported?

  • INPUT_PULLUP not supported?

     Robb updated 1 month ago 4 Members · 4 Posts
  • danny

    Member
    March 19, 2019 at 10:52 pm

    I posted on the GitHub site but I realize it should have probably gone here:

    I have a prototype that I built with a standard Arduino and I’m trying to adapt it to Controllino. The devices I am interfacing with signal LOW, so unifying the supply ground for my Arduino and the device allows me to use INPUT_PULLUP on the input pins to use Arduino’s internal pullup resistors. Then I simply read the LOW signal directly. If what I see is correct the Controllino has an internal PULLDOWN resistor, that prevents the use of INPUT_PULLUP which is unfortunate because that would then require an additional external relay to basically change the LOW signals into HIGH signals. Am I missing something or is there another way to gather LOW signals directly?

  • mr-controllino

    Administrator
    March 20, 2019 at 7:56 am

    Hello Danny,

    Yes the screw terminal Inputs are all forced to ground by the voltage divider.

    If you need a screw terminal input to be pulled up … you can us an external pullup resistor … 10k for example.

    If you need a 5V pin … I would recommend to use one of the not used communication pins like I2C, RX/TX 2, /SS, … or also the digital outputs D0, D1, Dx (of course the screw output will then switch accordingly, but if you don’t use it, it does not matter) … these pins are not tied to GND and you can use the internal Pullup.

    regards

    Marco

  • aua90

    Member
    May 23, 2019 at 10:03 am

    Do guys have video off ow hit work?

  • Robb

    Member
    May 20, 2024 at 10:11 pm

    Just in case anyone ends up here 4 years later:

    Just wire the button with one wire to +12VDC(or +24dc) and the other wire to the input, such as A0. It will be low when the button is open, and high when the button is closed.

    It only seems to support pulldown, or active high buttons unless you want to mess with an external resistor. This is not the common way to wire a button to an Arduino, but it seems to work great!

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