I2C Invalid reads

[ScruffR]

It would be good to see your codes (master/slave).

Or you could try this sample implementation

Casting Variables for I2C

I fear I have to rebuild your setup to see what’s happening first hand BTW, why are you calling requestEvent() form loop(). This function is supposed to be triggered by the master. The slave has no business just chatting away without being asked. I’ve tested communication between two Photons with this code and it works both directions //#define MASTER #define SLAVE const byte addr = 4; SerialLogHandler Logger(LOG_LEVEL_ALL); char msg[32] = "dummy"; #ifdef MASTER void setup() { W…