ErriezMCP23017.h

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/*
 * MIT License
 *
 * Copyright (c) 2020 Erriez
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef ERRIEZ_MCP23017_H_
#define ERRIEZ_MCP23017_H_

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

// Default configuration macro's
#define MCP23017_I2C_ADDRESS    0x20    

// Register defines
#define MCP23017_REG_IODIR      0x00    
#define MCP23017_REG_IPOL       0x02    
#define MCP23017_REG_GPINTEN    0x04    
#define MCP23017_REG_DEFVAL     0x06    
#define MCP23017_REG_INTCON     0x08    
#define MCP23017_REG_IOCON      0x0A    
#define MCP23017_REG_GPPU       0x0C    
#define MCP23017_REG_INTF       0x0E    
#define MCP23017_REG_INTCAP     0x10    
#define MCP23017_REG_GPIO       0x12    
#define MCP23017_REG_OLAT       0x14    

#define MCP23017_NUM_REGS       0x16    
#define MCP23017_NUM_PINS       16      

// Bit masks
#define MCP23017_MASK_ALL_PINS  0xFFFF  
#define MCP23017_MASK_REG_A     0x1E    

// Bit defines IOCON register
#define IOCON_BANK              7       
#define IOCON_MIRROR            6       
#define IOCON_SEQOP             5       
#define IOCON_DISSLW            4       
#define IOCON_ODR               2       
#define IOCON_INTPOL            1       

#define REG_IOCON_VALUE \
    ((0<<IOCON_BANK) |      /* 1 = The registers associated with each port are separated into different banks. */ \
     (1<<IOCON_MIRROR) |    /* 1 = INTA and INTB pins are OR'ed to INTA (INTB disabled) */ \
     (0<<IOCON_SEQOP) |     /* 1 = Sequential operation disabled, address  pointer does not increment. */ \
     (0<<IOCON_DISSLW) |    /* 1 = Slew rate disabled */ \
     (0<<IOCON_ODR) |       /* 1 = Open-drain output (overrides the INTPOL bit.) */ \
     (0<<IOCON_INTPOL))     /* 1 = Active-high */

class ErriezMCP23017
{
public:
    ErriezMCP23017(uint8_t i2cAddress=MCP23017_I2C_ADDRESS,
                   TwoWire *twoWire = &Wire);

    // Initialization
    bool begin(bool reset=true);

    // Single pin control
    void pinMode(uint8_t pin, uint8_t mode);
    void digitalWrite(uint8_t pin, uint8_t level);
    int digitalRead(uint8_t pin);

    // Set/get port direction input/output
    void setPortDirection(uint16_t outputPins);
    uint16_t getPortDirection();

    // Set/get port pull-up
    void setPortPullup(uint16_t pullupPins);
    uint16_t getPortPullup();

    // Pin read/write/toggle
    void pinWrite(uint8_t pin, bool level);
    void pinToggle(uint8_t pin);
    bool pinRead(uint8_t pin);

    // Port read/write/toggle/mask
    void portWrite(uint16_t value);
    void portToggle(uint16_t value);
    void portMask(uint16_t maskSet, uint16_t maskClear);
    uint16_t portRead();

    // Set/get interrupt mask/status
    void setInterruptPolarityINTA(bool activeHigh);
    uint16_t getPortInterruptMask();
    void setPortInterruptEnable(uint16_t pins);
    void setPortInterruptDisable(uint16_t pins);
    // Registers INTF and INTCAP can hold only one pin interrupt. A second
    // incoming pin interrupt is not updated in these registers and will be
    // lost. For this reason, reading these registers is useless and therefore
    // not implemented.

    // Interrupt generated by INTA pin
    bool interruptINTA();

    // Register access
    uint16_t registerRead(uint8_t reg);
    void registerWrite(uint8_t reg, uint16_t value);

    // I2C transfer status
    uint8_t getI2CStatus();

    // Debug function
    void dumpRegisters(HardwareSerial *serial);

    uint16_t portState;

    uint16_t pinsChanged;

    uint16_t pinsFalling;

    uint16_t pinsRising;

private:
    TwoWire *_wire;             
    uint8_t _i2cAddress;        
    uint8_t _i2cStatus;         

    // Cached variables to speed-up I2C bus access without I2C reads
    uint16_t _gpioPort;         
    uint16_t _gpioDir;          
    uint16_t _gpioPullup;       
    uint16_t _portStateLast;    
};

#endif // ERRIEZ_MCP23017_H_