Lpc2000

--- In lpc2000@yahoogroups.com, "hansklos2003" <hansklos2003@y...> wrote:
> Hi!
> 
> I set LPC2106 UART to work with 2 stop bits. After this I try to 
> recieve few bytes transmitted with one stop bit, from PC computer to 
> LPC2106. And, what is strange for me, LPC2106 UART returns only one, 
> last byte from transmitted frame. I think, it is an error, becouse 
> all chips compatible with 16c550, in this case return all bytes with 
> no error indication (when second stop bit is missing). 
> Am I right or not ?
> 
> Regards
> Robert

Who said the LPC2106 was 16c550 compatible?

A stop bit is the same as an idle line. Using 2 stop bits increases
the idle time between characters. Many UARTS, when set for 2 stop bits
put them on the transmission but do not bother to implement them on
the reception (2 stop bits is always recievable by a UART set to 1
stop bit). If framing checks are fully implemented then a UART should
not receive when there is only 1 stop bit.

Having said that the UART in the LPC will always try and use a new
edge as a start bit and so should recieve a successive character even
if it causes a frame error in the previous character. Have you
investigated frame errors? Are they being generated?