> Steve Lawther wrote:
> >
> >      The I2C bus for the 24LCxx etc. covered this situation - It has a
> >      collision aviodanbce scheme built in, where when two  masters each try
> >      to use the bus, the first to issue a high bit loses, realises it has
> >      lost, and holds off comms until the other has finished.
> >
> >      For the full spec on I2C see the philips web-page app notes. (can't
> >      remember the URL)
> >
> >      As to how this is implements in a 16F84, without any hardware to log
> >      start/stop  bits etc - I'll leave to Andys (#s 1 to 64) and others
> >

Or see the I2C Zone by Vincent Himpe, maintainer of the I2C FAQ:

http://www.ping.be/~ping0751/i2c.htm

He's decided to convert it completely to html. I'm sure older versions
are still available though. The FAQ is very good, certainly enlightened
me!

Conor.