Features: I2C control, based on the I2C, expands 2 signal pins to 16I/O pins, supports 8 expansion boards, and can be expanded to 128I/O ports The I2C address can be configured withonboard voltage converters by shortening theA0/1/2 Compatible with3.3V/5V levels, providing two connector options: PH2.0 terminals and/or solder pads, allowing for stackingmultiple Suitable for electronics enthusiasts, engineers, students, and project developers who need to expand I/O ports. It can be widely used in various electronic projects, such as robot control, home automation, and other fields. I2C module Specifications: Working voltage: 5V/3.3V Interfaces: I2C Interruptpins: forNTA INTB Extended I/O: 16 Size:approx38mmx23mm/1.5x0.91in Installation hole size: 2.0mm Interfaces Definition PIN I2C VCC power supply, 3.3V/5V Grounding - Grounding SDAI2C Data cable SCLI2C Clock line IntaPA Groupinterrupt output INTBPB forRaspberryPi /forSTM32 Note: Please allow 1-2cm errors due to manual measurement,please make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1Set MCP23017 I/O Expansion Board