The STMPE1801 is a GPIO port expander capable of interfacing a main digital ASIC via the two-line bidirectional bus (I2C). It offers high flexibility, as each I/O can be configured as input, output, special key, keypad matrix, or dedicated key function. This device is designed to include very low quiescent current and a wakeup feature for each I/O to optimize power consumption. Potential applications include portable media players, game consoles, mobile phones, and smart phones.