Arduino code to initialize eMac IVAD board via i2c.
When starting the eMac, the logic board or mother board initializes the IVAD board via an i2c interface so that the CRT can be used. This arduino sketch sends the commands to the IVAD board in order to initialize it. The logic board can now be removed and replaced with almost anything that can output a VGA signal.
These commands were captured with a logic analyzer during the booting process and implemented here.
This program waits for a button press and turns on/off relays that turn the CRT on and off.