Re: 9 bit communication on RS 232

"moocowmoo" <[EMAIL PROTECTED]> wrote in
news:[EMAIL PROTECTED]: 

>> I wanted to know how can we configure com port for 9 bit
>> communication.

You can't.

>> I intend to use the 9th bit as Address/data bit..since i want to
>> communicate with more than one devices.
> 
> I'm pretty sure that the acceptable values for serial data bit count are
> 5,6,7 or 8. 

True but the 8051's have a 9-bit mode where the extra bit means "this is
an address byte, wake up and see if it's for you". 

> You might be able to fake the extra bit by sending character by
> character switching between odd and even parity as required but it's not
> going to be very quick.

That's how most do it with a PC or normal UART.
 
> The real solution is to send the extra bit in an extra byte.

I agree, dump the odd 9-bit mode and use a protocol that does not depend
on hardware specific features. 

-- 
- Mark ->
--