1、Compatibility Level: Changes in the state of an input port can generate an interrupt output (INT). On board level conversion circuit, compatible with 3.3V/5V working level. 2、Support 4 Expansion Modules: I2C communication address can be set, short circuit AO, A1 solder joint can modify the communication address, support the use of 4 expansion modules. 3、I2C Interface Control: I2C interface control, only 2 signal lines are needed to expand 16 I/O ports. 4、Current Controllable: The Extension module supports 16 channel common anode constant current ED drive, 256 step linear dimming, and current controllable. 5、Two Interface Types: The I2C interface expand board provides two interface types, PH2.0 terminal and pad, and supports parallel connection of multiple I2C modules. Item Type: IO Expansion Board Material: PCB Working Voltage: 2.4-5.5V Working Temperature: Minus40 to 80℃ Control Interface: I2C Number of Expansion I/O Ports: 16 VCC: Positive power supply, can be connected to 3.3V/5V power supply GND: Power Ground SDA: I2C Data Line SCL: I2C Clock Line INT: Interrupt Output RST: Hardware Reset Size: Approx. 38 x 23mm / 1.5 x 0.9in 1 x IO Expansion Board 1 x For Dupont Wire