Arduino Master to 2 rainbowduino slaves(v3)

I have done some extensive searching to find a basic description and example code to drive 2 rainbowduinos via an arduino mega and have not found anything complete. I am attempting to use inputs on the arduino to drive changes in the images on the rainbowduino. I assume i will use i2c to do this, but have not found any concrete information for arduino to v3 rainbowduino master/slave setup.

Any help someone could provide would be greatly appreciated.

note, i can connect and program both the arduino and rainbowduino v3 fine, so first step complete.

hey, now we don’t have any code for control rainbowduino via Arduino,but the rainbowduino has two digital pins pointed out(D2 and D3),maybe you can use that for your project.