The PI4IOE5V9536 provides 4 bits of General Purpose parallel Input/Output (GPIO) expansion for I2Cbus/ SMBus applications. It includes features like higher driving capability, 5V tolerance, lower power supply, individual I/O configuration, and smaller packaging. It provides a simple solution when additional I/O is required for ACPI power switches, sensors, push buttons, LEDs, fans, etc. The PI4IOE5V9536 consists of 4-bit registers to configure the I/Os as either inputs or outputs, and 4-bit polarity registers to change the polarity of the input port register data The data for each input or output is kept in the corresponding Input port or Output port register. All registers can be read by the system master.