RB0 + Internal Pullup + Interrupt

[Archangel]

Sorry, it was stupid of me to forget the pic - it's a PIC16F628A

And no, I really have no room left for much more on that board, I can probably cram one more resistor in as a pulldown but that's about it.

Datasheet PP36 sec. 5.2 . . . "A single control bit can turn on ALL THE PULLUPS. . . . The weak pull up is automatically turned off when the port pin is configured as an output." I think you are stuck using the resistor unless you can flip the port's use in the software I E. instead of, if high then to if low then. I have a blinky running right now which toggles the tris on a port and as soon as it goes back to input the wpu is on.