I²C (Inter Integrated Circuit) is a bi-directional two wires and serial data transmission communication protocol developed by Philips (Now NXP Semiconductor) at 1982. I2C is a Half-duplex communication protocol – (I2c can’t send and receive same time in bus-Data line). Multi master can communicate with multi salve. (Note : Can’t Communicate one master to another master, One master can communicate with single slave or multi slave). I2C is a Level Triggering. A device that sends data onto the bus is defined as transmitter, and a device receiving data is defined as receiver. The bus has to be controlled by a master device which generates the Start and Stop conditions, while the Some devices like LCD, EEPROM, RTC are works as slave. Both master and slave can operate as transmitter or receiver, but the master device determines which mode is activated.