Subversion Repositories idreammicro-avr

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

 * \brief EEPROM 24C04/24C08/24C16 library.

 * \author Copyright (C) 2012  Julien Le Sech - www.idreammicro.com

 * \version 1.0

 * \date 20121102

 *

 * 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 eeprom_24c04_24c16.c

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

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

 * Header file inclusions.

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

#include "../eeprom_24c04_24c16.h"

#include <twi/twi.h>

#include <util/delay.h>

#include <assert.h>

#include <stdint.h>

#include <stdlib.h>

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

 * Private macro definitions.

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

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

 * \def     EEPROM_24C04_24C16__ADDRESS

 * \brief   EEPROM 24C04/24C08/24C16 address. Given by datasheet.

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

#define EEPROM_24C04_24C16__ADDRESS      0xA0

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

 * \def     EEPROM_24C04_24C16__PAGE_SIZE

 * \brief   Size of a page in EEPROM memory.

 * This size is given by EEPROM memory datasheet.

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

#define EEPROM_24C04_24C16__PAGE_SIZE    16

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

 * Private function prototypes.

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

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

 * \fn static void eeprom_24c04_24c16__write_page(

 * uint16_t address,

 * uint8_t  length,

 * uint8_t* p_data)

 *

 * \brief Write a page in memory.

 *

 * \param       address Start address of data to write.

 * \param       length  Number of bytes to write.

 * \param[in]   p_data  Bytes to write.

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

static

void

eeprom_24c04_24c16__write_page

(

    uint16_t    address,

    uint8_t     length,

    uint8_t*    p_data

);

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

 * Private variable declarations.

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

static uint8_t device_address = 0;

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

 * Public function definitions.

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

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

 * \fn void eeprom_24c04_24c16__initialize(uint8_t hardware_address)

 *

 * \brief Initialize EEPROM 24C04/24C08/24C16.

 *

 * \param hardware_address Hardware address. Pins A1 to A2.

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

void

eeprom_24c04_24c16__initialize

(

    uint8_t hardware_address

){

    // Compute device address.

    device_address = EEPROM_24C04_24C16__ADDRESS | ((hardware_address & 0x06) << 1);

    // We don't initialize TWI here: we may have several devices on the bus.

    // Initialize TWI.

    //twi__initialize(EEPROM_24C04_24C16__CLOCK_RATE);

}

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

 * \fn void eeprom_24c04_24c16__write_byte(uint16_t address, uint8_t data)

 *

 * \brief Write a byte into memory.

 *

 * \param   address Address in memory.

 * \param   data    Byte to write.

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

void

eeprom_24c04_24c16__write_byte

(

    uint16_t    address,

    uint8_t     data

){

    twi__start();

    twi__send_slaw(device_address | ((address & 0x30) >> 7));

    twi__send_data(address & 0xFF);

    twi__send_data(data);

    twi__stop();

}

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

 * \fn void eeprom_24c04_24c16__write_bytes(

 * uint16_t address,

 * uint16_t length,

 * uint8_t* p_data)

 *

 * \brief Write bytes into memory.

 *

 * \param       address Start address.

 * \param       length  Number of bytes to write.

 * \param[in]   p_data  Bytes to write.

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

void

eeprom_24c04_24c16__write_bytes

(

    uint16_t    address,

    uint16_t    length,

    uint8_t*    p_data

){

    // Check the preconditions.

    assert(NULL != p_data);

    // Write first page if not aligned.

    uint8_t not_aligned_length = 0;

    uint8_t page_offset = address % EEPROM_24C04_24C16__PAGE_SIZE;

    if (page_offset > 0)

    {

        not_aligned_length = EEPROM_24C04_24C16__PAGE_SIZE - page_offset;

        eeprom_24c04_24c16__write_page(address, not_aligned_length, p_data);

        length -= not_aligned_length;

    }

    if (length > 0)

    {

        address += not_aligned_length;

        p_data += not_aligned_length;

        // Write complete and aligned pages.

        uint16_t page_count = length / EEPROM_24C04_24C16__PAGE_SIZE;

        for (uint16_t i = 0; i < page_count; i++)

        {

            eeprom_24c04_24c16__write_page(address, EEPROM_24C04_24C16__PAGE_SIZE, p_data);

            address += EEPROM_24C04_24C16__PAGE_SIZE;

            p_data += EEPROM_24C04_24C16__PAGE_SIZE;

            length -= EEPROM_24C04_24C16__PAGE_SIZE;

        }

        if (length > 0)

        {

            // Write remaining uncomplete page.

            eeprom_24c04_24c16__write_page(address, length, p_data);

        }

    }

}

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

 * \fn uint8_t eeprom_24c04_24c16__read_byte(uint16_t address)

 *

 * \brief Read a byte in memory.

 *

 * \param address   Address to read.

 *

 * \return Read byte.

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

uint8_t

eeprom_24c04_24c16__read_byte

(

    uint16_t address

){

    uint8_t data = 0;

    twi__start();

    twi__send_slaw(device_address | ((address & 0x30) >> 7));

    twi__send_data(address & 0xFF);

    twi__repeat_start();

    twi__send_slar(device_address);

    twi__receive_data_nack(&data);

    twi__stop();

    return data;

}

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

 * \fn void eeprom_24c04_24c16__read_bytes(

 * uint16_t address,

 * uint16_t length,

 * uint8_t* p_data)

 *

 * \brief Read bytes in memory.

 *

 * \param       address Start address of data to read.

 * \param       length  Number of bytes to read.

 * \param[in]   p_data  Buffer to fill with read bytes.

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

void

eeprom_24c04_24c16__read_bytes

(

    uint16_t    address,

    uint16_t    length,

    uint8_t*    p_data

){

    // Check the preconditions.

    assert(NULL != p_data);

    twi__start();

    twi__send_slaw(device_address | ((address & 0x30) >> 7));

    twi__send_data(address & 0xFF);

    twi__repeat_start();

    twi__send_slar(device_address);

    for (uint16_t i = 0; i < length - 1; i++)

    {

        twi__receive_data_ack(p_data + i);

    }

    twi__receive_data_nack(p_data + length - 1);

    twi__stop();

}

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

 * Private function definitions.

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

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

 * \fn static void eeprom_24c04_24c16__write_page(

 * uint16_t address,

 * uint8_t  length,

 * uint8_t* p_data)

 *

 * \brief Write a page in memory.

 *

 * \param       address Start address of data to write.

 * \param       length  Number of bytes to write.

 * \param[in]   p_data  Bytes to write.

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

static

void

eeprom_24c04_24c16__write_page

(

    uint16_t    address,

    uint8_t     length,

    uint8_t*    p_data

){

    // Check the preconditions.

    assert(NULL != p_data);

    twi__start();

    twi__send_slaw(device_address | ((address & 0x30) >> 7));

    twi__send_data(address & 0xFF);

    for (uint8_t i = 0; i < length; i++)

    {

        twi__send_data(p_data[i]);

    }

    twi__stop();

    // Write cycle time (tWR). See EEPROM memory datasheet for more details.

    _delay_ms(10);

}