I am having problems making 2 arduino pro mini boards communicate. I connected A4 to A4 and A5 to A5 on the boards. I also connected the ground from the 2 boards together.
5V from power supply is connected to the master VCC and from there to the slave VCC. GND from power supply is connected to the master GND and from there to the slave VCC.
I am using this code http://www.instructables.com/id/I2C-between-Arduinos/?ALLSTEPS
What am I doing wrong? I found some info saying that I should connect the A4 and A5 pins to 4.7K resistors and VCC. Also I read that the slave 5V should be connected to RAW, not VCC.
Any help would be appreciated.