I2C interface control, only 2 signal lines, can expand 16 I/O ports; The I2C communication address can be set, and the communication address can be modified by shorting A0/A1/A2 solder joints; PH 2.0 terminal and pad are available to support parallel connection of multiple I2C modules; On-board level shifting circuitry is compatible with 3.3V /5V operating levels