internal pullup resistors & digitalWrite

Forum 2005-2010 (read only) General Uno Punto Zero
20

If INPUT turns off the internal pullup, the risk is that existing code will break.

I believe there are two cases that would fail if INPUT disables the pullup...

  1. The user assumed pinMode would not alter the pullup.

  2. The user first called digitalWrite( pin, HIGH ) to enable the pullup then called pinMode( pin, INPUT ) to ensure the pin is configured as an input.

I've searched and searched the web site and the forum and I cannot find a single instance of either of these cases. I cannot find any existing code that would break.

I agree with the two above. INPUT should disable the internal pullup. That appears to be consistent with what users currently expect.