Subversion Repositories idreammicro-avr

/**************************************************************************//**
 * \brief MCP23008 library
 * \author Copyright (C) 2012  Julien Le Sech - www.idreammicro.com
 * \version 1.0
 * \date 201201025
 *
 * This file is part of the iDreamMicro library.
 *
 * This library is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option) any
 * later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see http://www.gnu.org/licenses/
 ******************************************************************************/

/**************************************************************************//**
 * \file mcp23008.c
 ******************************************************************************/

/******************************************************************************
 * Header file inclusions.
 ******************************************************************************/

#include <mcp23008/mcp23008.h>

#include <twi/twi.h>
#include <useful/bits.h>

#include <assert.h>
#include <stdint.h>
#include <stdlib.h>

/******************************************************************************
 * Private macros.
 ******************************************************************************/

#define MCP23008__ADDRESS               0x20

#define MCP23008__REG_IODIR             0x00
#define MCP23008__REG_IPOL              0x01
#define MCP23008__REG_GPINTEN   0x02
#define MCP23008__REG_DEFVAL    0x03
#define MCP23008__REG_INTCON    0x04
#define MCP23008__REG_IOCON             0x05
#define MCP23008__REG_GPPU              0x06
#define MCP23008__REG_INTF              0x07
#define MCP23008__REG_INTCAP    0x08
#define MCP23008__REG_GPIO              0x09
#define MCP23008__REG_OLAT              0x0A

#define MCP23008__CLOCK_RATE    400000

/******************************************************************************
 * Private function prototypes.
 ******************************************************************************/

/**************************************************************************//**
 *
 ******************************************************************************/
static
uint8_t
mcp23008__read_register
(
    uint8_t address
);

/**************************************************************************//**
 *
 ******************************************************************************/
static
void
mcp23008__write_register
(
    uint8_t     address,
    uint8_t     value
);

/******************************************************************************
 * Private variable declarations.
 ******************************************************************************/

static uint8_t mcp23008__twi_address = 0;

/******************************************************************************
 * Public function definitions.
 ******************************************************************************/

/**************************************************************************//**
 * \fn void mcp23008__initialize(uint8_t hardware_address)
 *
 * \brief Initialize MCP23008.
 *
 * \param hardware_address      Hardware address defined by pins A0 to A2.
 ******************************************************************************/
void
mcp23008__initialize
(
    uint8_t hardware_address
){
    // Initialize TWI.
    twi__initialize(MCP23008__CLOCK_RATE);

    // Compute MCP23008 TWI address.
    mcp23008__twi_address = (MCP23008__ADDRESS | hardware_address) << 1;

    twi__start();
    twi__send_slaw(mcp23008__twi_address);
    twi__send_data(MCP23008__REG_IODIR);
    twi__send_data(0xFF);
    twi__send_data(0x00);
    twi__send_data(0x00);
    twi__send_data(0x00);
    twi__send_data(0x00);
    twi__send_data(0x00);
    twi__send_data(0x00);
    twi__send_data(0x00);
    twi__send_data(0x00);
    twi__send_data(0x00);
    twi__stop();
}

/**************************************************************************//**
 *
 ******************************************************************************/
void
mcp23008__configure_pin
(

    mcp23008__gpio_t            pin,
    mcp23008__direction_t       direction
){
    uint8_t port_configuration = mcp23008__read_register(MCP23008__REG_IODIR);

    if (MCP23008__DIRECTION__INPUT == direction)
    {
        BIT__SET(port_configuration, pin);
    }
    else
    {
        BIT__RST(port_configuration, pin);
    }

    mcp23008__write_register(MCP23008__REG_IODIR, port_configuration);
}

/**************************************************************************//**
 *
 ******************************************************************************/
void
mcp23008__configure_port
(
    mcp23008__direction_t direction
){
    mcp23008__write_register(MCP23008__REG_IODIR, direction);
}

/**************************************************************************//**
 *
 ******************************************************************************/
mcp23008__level_t
mcp23008__get_pin_level
(
    mcp23008__gpio_t pin
){
    uint8_t port_value = mcp23008__read_register(MCP23008__REG_GPIO);

    mcp23008__level_t level = BIT__TST(port_value, pin);

    return level;
}

/**************************************************************************//**
 *
 ******************************************************************************/
void
mcp23008__set_pin_level
(
    mcp23008__gpio_t    pin,
    mcp23008__level_t   level
){
    uint8_t port_value = mcp23008__read_register(MCP23008__REG_GPIO);

    if (MCP23008__LEVEL__HIGH == level)
    {
        BIT__SET(port_value, pin);
    }
    else
    {
        BIT__RST(port_value, pin);
    }

    mcp23008__write_register(MCP23008__REG_GPIO, port_value);
}

/**************************************************************************//**
 *
 ******************************************************************************/
uint8_t
mcp23008__get_port_value
(
    void
){
    uint8_t value = mcp23008__read_register(MCP23008__REG_GPIO);

    return value;
}

/**************************************************************************//**
 *
 ******************************************************************************/
void
mcp23008__set_port_value
(
    uint8_t value
){
    mcp23008__write_register(MCP23008__REG_GPIO, value);
}

/******************************************************************************
 * Private function definitions.
 ******************************************************************************/

/**************************************************************************//**
 *
 ******************************************************************************/
static
uint8_t
mcp23008__read_register
(
    uint8_t address
){
    uint8_t value = 0;

    twi__start();
    twi__send_slaw(mcp23008__twi_address);
    twi__send_data(address);
    twi__stop();

    twi__start();
    twi__send_slar(mcp23008__twi_address);
    twi__receive_data_nack(&value);
    twi__stop();

    return value;
}

/**************************************************************************//**
 *
 ******************************************************************************/
static
void
mcp23008__write_register
(
    uint8_t     address,
    uint8_t     value
){
    twi__start();
    twi__send_slaw(mcp23008__twi_address);
    twi__send_data(address);
    twi__send_data(value);
    twi__stop();
}