The MCP23X08 family, which consist of the MCP23008 and MCP23S08, provides 8-bit I/O expansion. The MCP23X17 family, which consists of the MCP23017 and MCP23S17 provides 16-bit I/O expansion. The I²C version (MCP23008 and MCP23017) is specified for 1.7MHz max. The SPI version (MCP23S08 and MCP23S17) is specified for 10MHz max. The voltage range is from 1.8V to 5.5V covering the vast majority of applications. It is well known that I²C slave devices often have hardware address pins which allow for multiple devices with the same opcode to share the bus. The SPI versions also have address pins to allow multiple devices to share the bus using only one chip select pin. Each I/O pin, when configures as an input, can be individually enabled and configured to interrupt either when the pin changes state from a previous value or when the state of the pin does not match a pre configured value in a register (DEFVAL). The polarity of the INT pin is configurable for push-pull active high or low, as open drain (active low).