The I2C Bus is a bidirectional 2-line bus for the transfer of data between various integrated circuits. It consists of a serial data line SDA and a serial clock line SCL. The data line requires an external pull-up resistor to VCC (open drain output stage). The possible operational states of the I2C Bus are shown in figure 1. In the quiescent state, both lines SDA and SCL are high, i.e. the output stage of the data line is disabled. As long a SCL remains "1", information changes on the data bus indicate the start or the end of data transfer between two components.