Kenny Baby wrote: >On the pic71 I want to use an external clock to increment the RTCC. >Logic says that you set the RTCC pin as an input, tell the pic that >the RTCC signal source is on RA4 and hey presto it's supposed to work. >Well this had me baffeled for around two weeks because it did'nt work. >.... >I set the pin as an output and then sent a '1' to that pin, guess >what, that led started flashing. >.... >IS THERE ANOTHER WAY OF DOING IT.......? Kenny: The problem you're seeing is the result of a bug in the "rev A" 16C71's. The simulator models the parts as they should have been produced; that's why it behaves differently than your PIC. The problem's been fixed in the "rev B" parts. You can tell what rev you have by looking at the face of the 16C71; it'll say something like: PIC16C71 /JW-S1 9352 CAT or PIC16C71-04/P 9404 CAA TAIWAN The middle letter of that three-letter "CAT" or "CAA" designation is the chip's revision letter. -Andy -- Andrew Warren - fastfwd@ix.netcom.com Fast Forward Engineering, Vista, California