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/**************************************************************************//**
 * \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 <stdint.h>

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


/**************************************************************************//**
 * \def     MCP23008__ADDRESS
 * \brief   MCP23008 address on TWI bus.
 * This value is given by the datasheet.
 ******************************************************************************/

#define MCP23008__ADDRESS       0x20

/**************************************************************************//**
 * \def     MCP23008__REG_IODIR
 * \brief   I/O direction register.
 ******************************************************************************/

#define MCP23008__REG_IODIR     0x00

/**************************************************************************//**
 * \def     MCP23008__REG_IPOL
 * \brief   Input polarity register.
 ******************************************************************************/

#define MCP23008__REG_IPOL      0x01

/**************************************************************************//**
 * \def     MCP23008__REG_GPINTEN
 * \brief   Interrupt on change control register.
 ******************************************************************************/

#define MCP23008__REG_GPINTEN   0x02

/**************************************************************************//**
 * \def     MCP23008__REG_DEFVAL
 * \brief   Default compare register for interrupt on change.
 ******************************************************************************/

#define MCP23008__REG_DEFVAL    0x03

/**************************************************************************//**
 * \def     MCP23008__REG_INTCON
 * \brief   Interrupt control register.
 ******************************************************************************/

#define MCP23008__REG_INTCON    0x04

/**************************************************************************//**
 * \def     MCP23008__REG_IOCON
 * \brief   Configuration register.
 ******************************************************************************/

#define MCP23008__REG_IOCON     0x05

/**************************************************************************//**
 * \def     MCP23008__REG_GPPU
 * \brief   Pull-up resistor configuration register.
 ******************************************************************************/

#define MCP23008__REG_GPPU      0x06

/**************************************************************************//**
 * \def     MCP23008__REG_INTF
 * \brief   Interrupt flag register.
 ******************************************************************************/

#define MCP23008__REG_INTF      0x07

/**************************************************************************//**
 * \def     MCP23008__REG_INTCAP
 * \brief   Interrupt capture register.
 ******************************************************************************/

#define MCP23008__REG_INTCAP    0x08

/**************************************************************************//**
 * \def     MCP23008__REG_GPIO
 * \brief   Port register.
 ******************************************************************************/

#define MCP23008__REG_GPIO      0x09

/**************************************************************************//**
 * \def     MCP23008__REG_OLAT
 * \brief   Output latch register.
 ******************************************************************************/

#define MCP23008__REG_OLAT      0x0A

/**************************************************************************//**
 * \def     MCP23008__CLOCK_RATE
 * \brief   MCP23008 frequency in Hertz.
 * On ATmega, can be 100 kHz or 400 Khz.
 ******************************************************************************/

#define MCP23008__CLOCK_RATE    400000

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


/**************************************************************************//**
 * \fn static uint8_t mcp23008__read_register(uint8_t address)
 *
 * \brief Read MCP23008 register value.
 *
 * \param   address Address of the register to read value.
 ******************************************************************************/

static
uint8_t
mcp23008__read_register
(
    uint8_t address
);

/**************************************************************************//**
 * \fn static void mcp23008__write_register(uint8_t address, uint8_t value)
 *
 * \brief Write MCP23008 register value.
 *
 * \param address   Address of the register to write value.
 * \param value     Value to write.
 ******************************************************************************/

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();
}

/**************************************************************************//**
 * \fn void mcp23008__configure pin(
 * mcp23008__gpio_t         pin,
 * mcp23008__direction_t    direction)
 *
 * \brief Configure pin direction.
 *
 * \param pin       Pin to configure.
 * \param direction Pin direction.
 ******************************************************************************/

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);
}

/**************************************************************************//**
 * \fn void mcp23008__configure_port(mcp23008__direction_t direction)
 *
 * \brief Configure port direction.
 *
 * \param direction Port direction.
 ******************************************************************************/

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

/**************************************************************************//**
 * \fn mcp23008__level_t mcp23008__get_pin_level(mcp23008__gpio_t pin)
 *
 * \brief Get pin level.
 *
 * \param pin   Pin to get level.
 *
 * \return Pin level.
 ******************************************************************************/

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;
}

/**************************************************************************//**
 * \fn void mcp23008__set_pin_level(
 * mcp23008__gpio_t     pin,
 * mcp23008__level_t    level)
 *
 * \brief Set pin level.
 *
 * \param pin   Pin to set level.
 * \param level Level to set.
 ******************************************************************************/

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);
}

/**************************************************************************//**
 * \fn uin8_t mcp23008__get_port_value(void)
 *
 * \brief Get port value.
 *
 * \return Port value.
 ******************************************************************************/

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

    return value;
}

/**************************************************************************//**
 * \fn void mcp23008__set_port_value(uint8_t value)
 *
 * \brief Set port value.
 *
 * \param value Value to set.
 ******************************************************************************/

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

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


/**************************************************************************//**
 * \fn static uint8_t mcp23008__read_register(uint8_t address)
 *
 * \brief Read MCP23008 register value.
 *
 * \param   address Address of the register to read value.
 ******************************************************************************/

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;
}

/**************************************************************************//**
 * \fn static void mcp23008__write_register(uint8_t address, uint8_t value)
 *
 * \brief Write MCP23008 register value.
 *
 * \param address   Address of the register to write value.
 * \param value     Value to write.
 ******************************************************************************/

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();
}