Since it's hard to debug an onReceive/onRequest handler via a Serial console (merely because doing Serial operations in an interrupt handler is impossible), I had to look through the Arduino libraries code trying to guess what's going on.Īfter a while I found a set of instructions that looked suspicious. It was bothering me for a while until I decided to figure it out yesterday.

In practice it is seen as if an Arduino gets stuck sending -1 to whatever request it receives. All Arduinoes are operating in slave mode, the bus master is a Raspberry Pi board.įor this apparently you have to install both onReceive and onRequest handlers the 'write' operation is simply handled by onReceive by receiving the register and immediately after that a new value the 'read' is a bit more complicated, as onReceive receives the register from the wire, and then onRequest that follows needs to send the data.Īll that works quite fine until the speed at which Raspberry Pi queries the Arduinoes is skyrocketing to where Wire library apparently gets confused. So I was implementing an i2c slave on the Rover's Arduinoes the one that could be read from and written to.

Arduino better wire library