07-02-2021, 03:20 PM
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 ...
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First Motion Products
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 ...
__________________________
First Motion Products