> > Software USART did not work at all on the 12F629 and it
> > looks like will be very hard to make it work
> =

> It is not a difficult task for the micro. A common way is to sample
> three times in a bit time and use the majority bit value. However,
> if the line is noise-free then one sample, mid-bit, may be enough.
> ISTR that the PIC's hardware UART samples 16 times per bit
> =

> For example in s/w, in an ideal environment, you wait for the first
> high-low transition (if this is an inverted signal). This signals the
> begining of the Start bit. Start the timer and time the period until
> the low-high transition, which is the end of the Start bit. This is a
> bit length, which you keep for reference. To sample mid-bit, run
> the timer for a half-bit then sample. Thereafter reload the timer
> with the full bit length. Occassionally you can use bit edges to
> check that your timing is OK
> =


This will only work if the first bit after the startbit is of different =

polarity from the start bit (don't remember if it is a 1 or 0).

/Ruben
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124, 200 39 Malm=F6, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
ruben@pp.sbbs.se
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D

-- =

http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist