MCP23017 16-pin I2C IO-expander library for Arduino

This is a MCP23017 16-pin I2C IO-expander library for Arduino with interrupt change/edge support and extensive examples.

Library features

• I2C interface
• Input/output/read/write/toggle/mask control per pin or per 16-pins
• Configurable pullup per pin
• Interrupt change/falling/rising per pin
• Interrupt edge handled by the library, because the chip supports pin change / level only.
• Low-power support
• Generic examples / AVR / ESP8266 / ESP32 support

Hardware

The following targets are supported:

• AVR: UNO, MINI, Pro Mini 8/16 MHz, ATMega2560, Leonardo
• ARM: DUE
• ESP8266: Mini D1 & D2, NodeMCU
• ESP32: Lolin D32

Examples

Extensive examples are located here.

Documentation

• Online HTML
• Download PDF

Getting started LED blink

#include <Arduino.h>
#include <Wire.h>
#include <ErriezMCP23017.h>

// PORTA: pins 0..7
// PORTB: pins 8..15
#define LED_PIN                 8 // Pin B0

// Default I2C Address 0x20
#define MCP23017_I2C_ADDRESS    0x20

// Create MCP23017 object
ErriezMCP23017 mcp = ErriezMCP23017(MCP23017_I2C_ADDRESS);

void setup()
{
    // Initialize Wire
    Wire.begin();
    Wire.setClock(400000);

    // Initialize MCP23017
    while (!mcp.begin()) {
        // MCP23017 not detected
        delay(3000);
    }

    // LED pin output
    mcp.pinMode(LED_PIN, OUTPUT);
}

void loop()
{
    mcp.digitalWrite(LED_PIN, HIGH);
    delay(1000);
    mcp.digitalWrite(LED_PIN, LOW);
    delay(1000);
}

Library installation

Please refer to the Wiki page.

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