EMAC I²C Programming
Background Information
I²C is a low-speed two wire serial interface used to connect to a variety of sensor and I/O devices. The interface uses bi-directional open-drain I/Os, SDA and SCL, to communicate to devices based on an address encoded in the data transmission. SDA is a data signal which sends and receives information using a protocol to address the appropriate device. SCL is a clock signal which is used to determine when to latch data from the SDA line.
For more information about the protocol see the following page: http://en.wikipedia.org/wiki/I%C2%B2C