MCP23017 IIC to 16CH GPIO Expander

This module adds 16 digital input/output (GPIO) pins to your microcontroller using only two I2C wires (SDA and SCL). It is built around the MCP23017 integrated circuit, providing a reliable solution for expanding digital interfaces without consuming additional MCU pins.

Each pin can be independently configured as an input or output. Internal pull-up resistors are programmable via the I2C bus, simplifying wiring for sensors and switches. The module also supports interrupt generation to notify the microcontroller of state changes on inputs.

Specifications

• IC: MCP23017 (original)
• Interface: I2C (SDA, SCL)
• GPIO count: 16 (A0-A7, B0-B7)
• Operating voltage: 2.3 V to 5.5 V
• Output current per pin: up to 25 mA
• I2C speed: 100 kHz (standard), 400 kHz (fast), up to 1.7 MHz (high-speed)
• Addressing: 3 address bits (A0-A2) allowing up to 8 modules on the same bus
• Features: programmable internal pull-ups, interrupt capability (INTA/INTB)
• Compatibility: Arduino, Raspberry Pi, ESP32, and any controller supporting I2C

Note: A software library is required to control the MCP23017 under Arduino (e.g., MCP23017.h). On Raspberry Pi, the kernel driver or command-line tools like i2cget/i2cset can be used.