Can't make RA1 a digital Input on (10 out of 20) 16F887.

[paulgrut]

Yes. I have 20 boards with the PIC soldered in. And on half the RA1 input does not work.

I am able to make the RA1 act as an output and it works correctly on all of them.

I am seeing 2 different silicon date codes on the chips, but the problem is with some of each.

The circuit boards are all from the same batch.

The RA1 input is held high with 10K pullup resistor to 5V. The switch pulls this to ground. I have verified the voltage on the chip pin
and it changes from 5V to 0V with the switch. I am going to look over all the ground traces and make sure there isn't (as Henrik asked)
a seperated ground. Although the boards all look to be in good shape.

Thanks for any other ideas. I might order some new 887's and see what happens. And some sockets also...

Paul