This is I2C serial interface 16 bit I/O Expander Serial Module. MCP23017 can convert 16-bit parallel data into serial data of IIC interface and convert each other. Internal integrated power-on reset (POR) circuit reset to device default state. Two opposite programmable interrupt source outputs. Polarity flip register configures GPIO input polarity. Feature: 16-Bit Remote Bidirectional I/O Port: -I/O pins default to input High-Speed I2C Interface (MCP23017): -100kHz -400kHz -1.7MHz High-Speed SPI Interface (MCP23S17): -10 MHz (maximum) Three Hardware Address Pins to Allow Up to Eight Devices On the Bus Configurable Interrupt Output Pins: -Configurable as active-high, active-low or open-drain INTA and INTB Can Be Configured to Operate Independently or Together Configurable Interrupt Source: -Interrupt-on-change from configured register defaults or pin changes Polarity Inversion Register to Configure the Polarity of the Input Port Data External Reset Input Low Standby Current: 1 μA (max.) Operating Voltage: -1.8V to 5.5V @ -40°C to +85°C -2.7V to 5.5V @ -40°C to +85°C -4.5V to 5.5V @ -40°C to +125°C Module Size: 26.5 x 21mm Weight: 3.5g