Hello,

I had an application where I had a motion detector that outputted a 12vdc signal to a 16f84a and I passed the 12vdc signal through a 22k resistor to the pic input pin. I also tied a 10k resistor from the pic pin to -5 v (ground) along with a 10uf capacitor to -5 v (ground) the two resistors formed a voltage divider. That was years ago and it still works great.

Here is a great Potential Divider Calculator that's real easy to use and according to the calculator my voltage to the pic input pin would be 3.75vdc.
http://www.electronics2000.co.uk/calc/calcdiv.htm

It was on another list years ago that, that was recommended and like I said, its still working good.

Good Luck
jessey