On Wed, Oct 03, 2001 at 09:18:30AM -0400, Byron A Jeff wrote:
> On Wed, Oct 03, 2001 at 01:13:13PM +0200, Wojciech Zabolotny wrote:
> > Hi All,
> >
> > I have to use PC to communicate with RS-485 bus. I'd like to use the 9-bit
> > addressing codes available for PICs/8051s and other uCons. Unfortunately
> > The PC's UART is 8-bit, but I can manually control the parity bit.
>
> Woj,
>
> You need to read a bit more! ;-) PIC's do nine bits. Take a look at page 103
> in section 10.2.3 in the 16F877 manual. It describes not only the ninth bit
> but more importantly how to configure the USART interrupt so that it'll only
> interrupt when the 9th bit is set.
>

Well, but my problem is not with PIC but with PC (probably the
misunderstanding was caused by my poor english).
I have to force the standard (16450 or 16550A based) PC UART (AKA com port)
to drive the RS485 bus (maybe with PICs and 8051s connected to it).
I know I have to use the level shifter (MAX232) and RS485 transceiver
(SN75176). But the main problem is how to emulate the 9-bit mode in the PC.
--
                              Wojciech M. Zabolotny
        http://www.ise.pw.edu.pl/~wzab  <--> wzab@ise.pw.edu.pl

http://www.ise.pw.edu.pl/~wzab/picadc/picadc.html - Build your FREE Data
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