Adafruit_MCP23017.h library

/***************************************************

This is a library for the MCP23017 i2c port expander

These displays use I2C to communicate, 2 pins are required to

interface

Adafruit invests time and resources providing this open source code,

please support Adafruit and open-source hardware by purchasing

products from Adafruit!

Written by Limor Fried/Ladyada for Adafruit Industries.

BSD license, all text above must be included in any redistribution

****************************************************/

#ifndef _Adafruit_MCP23017_H_

#define _Adafruit_MCP23017_H_

// Don't forget the Wire library

#ifndef ARDUINO_AVR_GEMMA

//TinyWireM is now part of

// Adafruit version of Wire Library, so this

// will work with Adafruit ATtiny85's

//But Arduino Gemma doesn't use that library

// We do NOT want to include Wire if it's an arduino Gemma

#include <Wire.h>

#else

#include <TinyWireM.h>

#define Wire TinyWireM

#endif

class Adafruit_MCP23017 {

public:

void begin(uint8_t addr);

void begin(void);

void pinMode(uint8_t p, uint8_t d);

void digitalWrite(uint8_t p, uint8_t d);

void pullUp(uint8_t p, uint8_t d);

uint8_t digitalRead(uint8_t p);

void writeGPIOAB(uint16_t);

uint16_t readGPIOAB();

uint8_t readGPIO(uint8_t b);

void setupInterrupts(uint8_t mirroring, uint8_t open, uint8_t polarity);

void setupInterruptPin(uint8_t p, uint8_t mode);

uint8_t getLastInterruptPin();

uint8_t getLastInterruptPinValue();

private:

uint8_t i2caddr;

uint8_t bitForPin(uint8_t pin);

uint8_t regForPin(uint8_t pin, uint8_t portAaddr, uint8_t portBaddr);

uint8_t readRegister(uint8_t addr);

void writeRegister(uint8_t addr, uint8_t value);

/**

* Utility private method to update a register associated with a pin (whether port A/B)

* reads its value, updates the particular bit, and writes its value.

*/

void updateRegisterBit(uint8_t p, uint8_t pValue, uint8_t portAaddr, uint8_t portBaddr);

};

#define MCP23017_ADDRESS 0x20

// registers

#define MCP23017_IODIRA 0x00

#define MCP23017_IPOLA 0x02

#define MCP23017_GPINTENA 0x04

#define MCP23017_DEFVALA 0x06

#define MCP23017_INTCONA 0x08

#define MCP23017_IOCONA 0x0A

#define MCP23017_GPPUA 0x0C

#define MCP23017_INTFA 0x0E

#define MCP23017_INTCAPA 0x10

#define MCP23017_GPIOA 0x12

#define MCP23017_OLATA 0x14

#define MCP23017_IODIRB 0x01

#define MCP23017_IPOLB 0x03

#define MCP23017_GPINTENB 0x05

#define MCP23017_DEFVALB 0x07

#define MCP23017_INTCONB 0x09

#define MCP23017_IOCONB 0x0B

#define MCP23017_GPPUB 0x0D

#define MCP23017_INTFB 0x0F

#define MCP23017_INTCAPB 0x11

#define MCP23017_GPIOB 0x13

#define MCP23017_OLATB 0x15

#define MCP23017_INT_ERR 255

#endif