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RE: I need to configure serial port to send 5 bit characters




OK, this trick worked for sending characters, however I have another 
problem which
is that the B75 baud rate (75 baud) does not seem to work.

I am using cfsetospeed with B75 but the baud still seems to be 9600 coming 
out of
the serial port.

Is 75 baud not supported by the UART? Is there a way to manually set the 
baud rate
divisor from a user program?

Thanks,
         Henry




At 09:27 AM 10/4/2002 +0200, gerhard@xxxxxxx.at wrote:

>Hello,
>
>even when the hardware does not support 5 bits (and that's a fact) you can 
>send
>5 bit characters using a simple trick:
>
>1. Configure the serial port for 8 data bits
>2. Take your character and shift it left by 3
>3. Set the 3 lowest bits to 1
>4. Send it out
>
>This should basically work, but you have o live with some limitations.
>
>- Between two characters you have now 3 more stop bits, this means that you
>cannot send at the full data rate
>- This works only on transmitting. When you want that receiving works the 
>same
>way you must ensure that the opposite system inserts also some pause time
>between two characters, and you have to mask off the "unused stop bits".
>
>Hope this may work for you,
>Gerhard