Hi,

	Using and edge interrupt is a great option if you need to make just
one soft uart and the best part is that you can use 1x sampling. If you need
to make 4 uart, for example, the slower you can get "safely" to work is 3x.
4x does not improve things much because you do not have enough data to use a
"majority vote" to decide if you are getting noise or not. To really improve
it significantly you need 16x sampling as the hardware uarts usually do..

	I had a project quite a while ago that made 8 full duplex uarts with
3x sampling and it worked fine. 
 
Best regards,
Alexandre Guimaraes


-----Mensagem original-----
De: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] Em nome de
Dario Greggio
Enviada em: quinta-feira, 12 de junho de 2008 16:26
Para: Microcontroller discussion list - Public.
Assunto: Re: [PIC]: Multiple serial (RS232) interfaces on a PIC18Fxxxx

Enki wrote:

> 	I have done soft-uarts using just 1x sampling.
> 	Detected the start-bit with an edge interrupt, set the next timer 
> interrupt for 1.5 bit-time and the other interrupts for one bit-time.
> 
> 	Never had a single problem but never used on noisy signals.

yep, same here.
I understand oversampling is better, but I believe a trade-off is reachable.

--
Ciao, Dario
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