On Sat, 1 Dec 2001 09:53:07 -0500, you wrote:

>If you are driving the pin high, then you have a start bit and you'll
>get a framing error until you drive it low.  If you clear the framing
>error, it will come right back unless you drive the pin low.
>
>If you need to drive the pin high for some reason, either turn off the
>rx interrupt, or turn off the uart rx.
>
>Remember that in 0-5v logic, rs-232 is not inverted, so a 1 is +5v.  A
>start bit is +5v, stop bit is 0v.
>

Are you sure about that? I think you have it backwards.

All of the UART timing diagrams that I've seen in Microchip docs show
the idle RS-232 input as a high on the Rx pin. (See PIC16F87X,
DS30292B, page 101, figure 10-5) The start bit is detected when the RX
pin goes low. The stop bit is shown as a high.

Regards, Bob

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body