Introduce easy I/O port expansion using a standard serial interface using the Port Expander Board. The board features an MCP23S17 16-bit I/O expander with serial interface. The SPI clock has a speed up to 10 MHz, which makes it highly suitable for higher throughput applications. The Interrupt-on-change feature can be considered as 8 separate external interrupts mapped on to the same interrupt vector. The Port Expander Board features jumpers that enable the user to determine the port expander.