Okay. But I'm still curious to know if this was why Martina changed from P3 to P2. If she wrote a zero to a pin and then used a switch to tie it to Vcc without limiting the current, I'm doubtful that that bit (at a very minimum) would continue to function properly. (And yes, in case you're wondering. I've had a great deal of experience leting the smoke out of a myriad components).

As for the internal pull-ups, do you know if it's standard architecture to have only P1 - P3 with internals, and P0 as open drain? Or does this change from one variant to another?