INPUT_PULLUP not supported?

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Danny
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Joined: Tue Mar 19, 2019 10:49 pm

INPUT_PULLUP not supported?

Post by Danny » Tue Mar 19, 2019 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?

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Mr. CONTROLLINO
Posts: 18
Joined: Thu Dec 13, 2018 3:07 pm

Re: INPUT_PULLUP not supported?

Post by Mr. CONTROLLINO » Wed Mar 20, 2019 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

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