I have used Wire library (I2C) successfully (but not 0012) and reliably in a Master>Slave environment with my MRMP. http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1232140631
However, I am not satisfied with the Master (Bridge MRMP) and Slave (Controller MRMP) protocol.
Why? A slave cannot 'send', it must instead buffer a message (MRMP packet) and wait for the Master to poll the slave. In that case there is, or could be, a lot of chatter on the I2C bus just routing MRMP packets via the Bridge. There are occasions when it would make more sense to send a message directly to another Controller (Slave) or to the Bridge (in Slave mode). Such events I call alerts.
I2C specification states that it is multi-master capable. From my experimentation, multi-master is just not practical(possible) with Wire.
Perhaps bypass Wire and use twi ?
Has anyone tried/experimented/has thoughts about multi-master I2C bus? :-?