PJON is more an abstraction over a bunch of different protocols. CAN is for off board comms. I2C should really never leave the board. I've actually seen a bl

PJON is more an abstraction over a bunch of different protocols. CAN is for off board comms. I2C should really never leave the board. I've actually seen a blend though, where someone hooked a couple CAN transceivers to bridge an I2C bus off board (a simple LED board had to be 3 meters away from the micro controller). At the end of the day they should have just put a micro controller on the other end and ran CAN over it, as they still had a bunch of glitches anyway.