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INPUT_PULLUP on pin 17?

Posted: 08 May 2021 01:21
by randallman
Hello,

Does anyone know what, if anything, could be causing INPUT_PULLUP to not actually pullup on pin 17 (INT0)? It works on pin 18 (INT1) and furthermore it used to work on pin 17. Is it possible I did something or that something happened to kill this 20k internal resistor?

Re: INPUT_PULLUP on pin 17?

Posted: 08 May 2021 02:36
by randallman
Oh boy, so yeah... I switched pin 17 from INPUT_PULLUP to INPUT and then used a 10k resistor off of 3.3V that is also powering the Zuno (from a buck conv) and I have a really nice square wave now. Unfortunately, it's still not triggering inputs. Do I have a dead a** pin? Is that what's going on? Prior to this, my input looked like rf noise on the scope with periodic pulses, but not high enough to call it a pulse due to the pullup not working. I guess my last test would be to try to use it as an output, but it really doesn't matter since INT0 *must* be pin 17 right?

70 bucks, down the shatter on account of entropy.., IDK even if it was my fault or if it was random nonsense. Nothing changed on my end. Any other forensics I could do? Pin 18 is fine and accepting interrupts (INT1) and the pullup works fine.

Re: INPUT_PULLUP on pin 17?

Posted: 13 May 2021 02:14
by PoltoS
How do you set up INT0 ? does digitalRead get correct values on that pon?