The TCA9555 is a 16-bit I/O expander for the I2C bus, designed for voltage operation from 1.65 V to 5.5 V. It provides general-purpose remote I/O expansion for most microcontroller families through the I2C interface. This device features low standby- current consumption, 5-V tolerant I/O ports, and an open-drain active-low interrupt output. It is commonly used for controlling LEDs, controlling enable or reset signals of other devices, and reading the outputs of other devices or buttons.