Based on for raspberry P40 pin GPIO interface, it is suitable for series motherboard. On board sc168752 can expand 2-channel serial port and 8 programmable IO through I2C without occupying additional pins. By changing the address jumper, up to 16 modules can be connected at the same time, that is, 32 serial ports can be expanded. There are multiple indicators on the board to facilitate viewing the working status of the extended serial port. I2C control interface is reserved to facilitate access to other main control boards. Working voltage: 3.3V Expansion chip: sc16is752 Control interface: I2C Product size: 65mmx30mm Via diameter: 3mm Colour: blue Material: PCB Package Contents: 1 * Expansion Board 1set * Screws 1 * Connecting Cable Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.