I2C

The Inter-integrated Circuit (I2C) Protocol is a protocol intended to allow multiple
“slave”digital integrated circuits (“chips”) to communicate with one or more “master”
chips.

Like the Serial Peripheral Interface (SPI), it is only intended for short distance 
communications within a single device. Like Asynchronous Serial Interfaces (such as
RS-232 or UARTs), it only requires two signal wires to exchange information.

Learning resources:

• https://learn.sparkfun.com/tutorials/i2c
• http://www.i2c-bus.org/i2c-primer/