One minute self introduction:I am an I/O expansion module based on I2C interface control, which can expand up to 16 V/O ports and support the simultaneous use of up to 8 expansion modules, up to 128 I/O ports. It is compatible with 3.3V and 5V levels 12C interface control, only 2 signal lines are needed to expand 16 I/O ports The I2C communication address can be set, and the communication address can be modified by short circuiting A0/A1/A2 solder joints. It provides two interface types: PH2.0 terminal and solder pad, and supports parallel connection of multiple I2C modules. Onboard level conversion circuit, compatible with operating levels of 3.3V/5V Working voltage: 5V/3.3V Control interface: 12C Product size: 38mm x 23mm Via diameter: 2.0mm Colour:As Shown Material:PC Due to different product batches, the appearance , which does not affect the use Package Contents: 1 * expansion module 1 * cable Only the above package content, other products are not included. Note: Light reflection 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.