The TCA6418E is a 18 channel GPIO expansion device with integrated ESD protection. It can operate from 1.65 V to 3.6 V and has 18 general purpose inputs/outputs (GPIO) that can be used via the I2C interface [serial clock (SCL), serial data (SDA)].
The major benefit of this device is it frees up the processor from having to individually monitor changes in multiple inputs and also frees up the GPIOs on the processor to drive other outputs.. This provides power and bandwidth savings. The TCA6418E is also ideal for usage with processors that have limited GPIOs.