The TWI / I2C (I-two-C) protocol was invented by Philips. In TWI the serial data transmission is done in asynchronous mode. This protocol uses only two wires for communicating between two or more ICs. The two bidirectional open drain lines named SDA (Serial Data) and SCL (Serial Clock) with pull up resistors are used for data transfer between devices.
One of the two devices, which controls the whole process, is known as Master and the other which responds to the queries of master is known as Slave device. The ACK (acknowledgement) signal is sent/received from both the sides after every transfer and hence reduces the error. SCL is the clock line bus used for synchronization and is controlled by the master. SDA is known as the data transfer bus.
I2C/TWI is a half duplex serial transmission and hence the data flow can be in a direction at a time. The data transfer rate depends on crystal frequency of slave controller. The rate of data transfer refers to clock frequency on SCL bus which must be 1/16th
Filed Under: What Is