16F877 is the device. I found the problem, but still is a little perplexing. The wire for the pup voltage had popped loose, so the port pin (happened to be A4) was floating. That explains why the output wasn't going high, but the register wasn't holding the bit set, but now that it is pulled up, the PORTA register shows it set. I would have expected the bit to show high, even if the output was floating. Strange. >From: Jan-Erik Soderholm >Reply-To: pic microcontroller discussion list >To: PICLIST@MITVMA.MIT.EDU >Subject: Re: [PIC:] PORTA digital/analog issues >Date: Tue, 30 Mar 2004 21:58:07 +0200 > >al smith wrote : > > > Subject: [PIC:] PORTA digital/analog issues > >What PIC ?? > >Jan-Erik. > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! >email listserv@mitvma.mit.edu with SET PICList DIGEST in the body _________________________________________________________________ Get rid of annoying pop-up ads with the new MSN Toolbar FREE! http://toolbar.msn.com/go/onm00200414ave/direct/01/ -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu