Re: [avr-gcc-list] Small program for UART not working

[Vincent Trouilliez]

> >Send 0xAA continiously. That way you get a nice
> >square wave at the baud rate frequency. If you drop
> 
> I thought it was 0x55 (or ASCII 'U') that you wanted, rather than 0xAA.
> 
> An idle RS-232 line is in the "Mark" state.  Start bit is "Mark" to "Space" 
> transition.  Data bits are then sent LSB first, with "Mark" == 1, "Space" == 
> 0, so the LSB has to be a '1'.  After the last databit (bit 7 is zero, or 
> "Space"), the stop bit puts the line back into idle ("Mark") for 1 bit time.
> 
> This should work for 8N1.
> 
> Regards,
>    -=Dave

Indeed, when I started playing with my AVR's UART a few days ago and
sent an 0xAA, the frame looked weird on the scope, at first I thought I
got the frame format wrong, 5 data bit instead of 8 or something ! ;-)
0x55 would probably have looked much better indeed...


--
Vince