04-12-2018, 08:08 AM
Internal SoC PullUps are usually between 20K to 100K.
So, using a external PullDown to put it low is like creating a voltage divider with the internal pullup, therefore with a external 20K, you get a voltage that is neither a LOW or a HIGH, explaining why you get interrupts triggered repeatedly.
If you use a external 1K as a pulldown instead, you will see that will be close to 0V ...
So, using a external PullDown to put it low is like creating a voltage divider with the internal pullup, therefore with a external 20K, you get a voltage that is neither a LOW or a HIGH, explaining why you get interrupts triggered repeatedly.
If you use a external 1K as a pulldown instead, you will see that will be close to 0V ...