I haven't tried this yet, but it looks like, from the 16C76 data sheet, that you meant that TXEN (not SPEN) should be cleared to tristate the TX pin. I think clearing SPEN would disable both sections of the UART. Mitch Berkson ----- Original Message ----- From: "Kelly Kohls" To: Sent: Saturday, June 09, 2001 1:21 PM Subject: Re: [PIC]:Possible to use USART for RX and have TX as general purpose I/O? > One possible solution: Tie a pull down resistor to the transmit pin. When > you want the line to go low, clear the SPEN bit. This disables the > transmitter portion of the UART and places the transmit pin into a high > impedence state. When you want the line to go high, set the SPEN bit. > Since the idle state of the transmitter is high, the TX pin will be high. > This is the technique that I used in my DMX-512 transmitter to generate the > "break". Note: I used a 16C76 and 16F876 for my transmitters. The > information about the TX pin going to a high impedence state when the > transmitter is disabled is only in the datasheet for the 16C76 part. I > don't know why it was left out of the 16F876 datasheet, but it appears to > function just like the 16C76. Hope this helps. > > Kelly Kohls, N5TLE > Dallas, Texas > Homepage: http://www.qsl.net/n5tle/ > There's never enough time to do it right, but plenty of time to do it over. > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body