Quote Originally Posted by jellis00 View Post
However, my 16F690 is running off 5.0 volts, so I would have expected the voltage at RA2 to be near 5.0 volts when the switch is open (not grounded). Yet what I see is 1.8 volts, which is obviously not enough for Vih. This doesn't make sense to me, but explains why the TMR0 value is not incrementing. Any ideas why the RA2 port voltage would be at 1.8 vdc rather than 5.0 vdc when it is unloaded?
RA2 is set as an input by the tris register, so the impeadence is relativly high, your meter MAY be enough load to reduce the voltage read, install a pull up resistor from RA2 to VDD to bring it up to the 5v level or enable WPUA (sect 4.3) data sheet.