I plan on using the SCI modules of two PIC16c74 for full duplex
asychronous communication. I plan to run them at 1200 baud with a 4mhz clock.
There are no specs for error rates in the PIC manuals. I plan
on linking them with twisted pair wire, maximimum 15ft in length, in an
automobile. I was wondering if the 9th bit parity option is adequate for
error detection. Just to be safe, I designed my software to send a 32 bit
packet and then resend an identical
copy. If they both matched, the receiver will assume all bits are correct.
That would achieve excellent error detection yet eat up quite a bit of
transmission time, but still could be practical.
The only reason I want to keep transmission speed as low as
1200 baud and so concerned about error detection, is that I may want
to link these these PICs using Ming RF digital modules, which add
considerable to error rates and allow maximum speeds of 1200 baud. I
am much more conerned with detecting errors than correcting or eliminating
them. I would also appreciate any programming and implementation advice,
from people who have used the SCI successfully. I can't believe this
thing looks so easy to use, I wish I read about it earlier.

                Neil Gandler