Harold wrote:
>         I'm considering using the UART in a PIC for a simple master/slave
>network between two PICs. I'm hoping to send data half-duplex on one
>wire. I'm thinking of just tying the Tx and Rx pins together. Normally
>the TRIS bit on the transmit line would be high. When a PIC needs to
>transmit, I'd set the TRIS low, send the data, then put TRIS high again.
>Will that work? Does a high TRIS float the USART transmit pin?
>
>         Thanks!

AFAIK, the TRIS has no effect on the UART pins while the UART is
active. You would have to turn the UART off but that would mean that
the receiver is also turned off - probably not what you want! You could
however put a 1N914 in series with the TX line (cathode to TX pin) before
it joins the RX line and use a pullup to +5 from there. That would make
it effectively a WIRED-OR type of comms line.
Regards...

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