OK, I'm looking for ideas for a protocol for bi-directional comms between 2
pic's on a single wire. Master can control when slave transmits, but master
is asynchronous to slave so slave doesn't know when Master will transmit.

Both devices are running on RC so there could be a 10% error between clocks.

I've figured a suitable protocol, but its custom and I just wondered if
anyone out there has doen this or can recommend a standard ?

Just for the record my protocol is based on sending a 100uS low start bit,
then 100uS high, then 8 bits one at a time, 25uS low for a 0, 75uS low for a
1 and then make the time for each bit up to 100uS. 770 bytes per second
which is fine for my app. Every byte from master followed immediately by a
byte from the slave back to the master.


Robin Abbott
Forest Electronics - Home of WIZ-C ANSI C Compiler for PIC's with RAD Front
end
robin.abbott@fored.co.uk
www.fored.co.uk 
 

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