Uses a Serial Data Line ( SDA ) and a Serial Clock Line ( SCL ).
Each slave device has a unique 7-bit (or 10-bit) address, eliminating the need for complex Chip Select (CS) lines used in SPI. I2C Overview
The slave device with the matching address responds with an Acknowledge (ACK) bit (low), signaling it is ready, or a Not Acknowledge (NACK) bit (high). Uses a Serial Data Line ( SDA )
The master releases the SDA line to high while SCL is high, signaling the end of transmission. Advantages and Limitations Understanding I2C signaling it is ready