contiki/platform/mbxxx/dev/eeprom.c

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/*
* Copyright (c) 2013, IDentification Automation Laboratory
* IDALab (http://www.idalab.unisalento.it)
* Department of Innovation Engineering - University of Salento
*
* All rights reserved.
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*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/**
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* \file platform/mbxxx/dev/eeprom.c
* \brief ST M24C64W EEPROM driver.
* \author Maria Laura Stefanizzi <laura28582@gmail.com>
* \date 2013-11-20
*/
#include PLATFORM_HEADER
#include <dev/eeprom.h>
#include <dev/i2c.h>
#define EE_HW_ADDRESS 0xA0
#define EE_PAGESIZE 32
#define EE_PAGEMASK 0x1F
#define EE_MAX_TRIALS 300
/* Write Cycle polling
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*
* During the internal Write cycle, the device disconnects itself from the bus,
* and writes a copy of the data from its internal latches to the memory cells.
*/
static inline void
eeprom_wait(void)
{
uint32_t trials = 0;
/* Keep looping till the slave acknowledge his address or maximum number of
trials is reached */
do {
/* Generate start */
i2c_start();
/* Device select in in write mode */
i2c_write(EE_HW_ADDRESS | 0x0);
/* Check if the maximum allowed number of trials has been reached */
if(trials++ == EE_MAX_TRIALS) {
/* If the maximum number of trials has been reached, exit the function */
break;
}
} while((SC2_STAT(SC_TWIRXNAK)) == SC_TWIRXNAK);
/* eeprom reply with an ACK then it has terminated the internal Write cycle */
i2c_stop();
}
/**
* eeprom initializzation function
*/
void
eeprom_init(void)
{
/* Nothing must be done here */
}
/**
* Write data to eeprom
* @param addr The eeprom memory address
* @param buf It is the buffer of bytes that will be written to the eeprom
* @param size It is the number of byte to write
*/
void
eeprom_write(eeprom_addr_t addr, unsigned char *buf, int size)
{
unsigned int i = 0;
unsigned int curaddr;
curaddr = addr;
for(i = 0; i < size; i++) {
/* If we are writing the first byte or are on a EE_PAGEMASK page boundary
we have to start a new write. */
if(i == 0 || (curaddr & EE_PAGEMASK) == 0) {
i2c_start();
i2c_write(EE_HW_ADDRESS | 0x0);
/* Write the new address to the bus. */
i2c_write((curaddr & 0xFF00) >> 8);
i2c_write(curaddr & 0xFF);
}
/* Write byte. */
i2c_write(buf[i] & 0xFF);
/* If we are writing the last byte totally or of a 32b page
generate a stop condition */
if(i == size - 1 || (curaddr & EE_PAGEMASK) == EE_PAGEMASK) {
i2c_stop();
eeprom_wait();
}
curaddr++;
}
}
/**
* Read data from eeprom
* @param addr The eeprom memory address
* @param buf It is the destination buffer in witch the bytes will be written
* @param size It is the number of byte to read
*/
void
eeprom_read(eeprom_addr_t addr, unsigned char *buf, int size)
{
uint8_t i;
i2c_start();
/* Select eeprom with write mode bit enabled */
i2c_write(EE_HW_ADDRESS | 0x0);
/* Send address */
i2c_write((addr & 0xFF00) >> 8);
i2c_write(addr & 0xFF);
i2c_start();
/* Select eeprom with write mode bit disabled */
i2c_write(EE_HW_ADDRESS | 0x1);
for(i = 0; i < size; i++) {
if(i < (size - 1)) {
/* Read data and send ACK */
*(buf + i) = i2c_read(1);
} else {
/* Last data, don't send ACK */
*(buf + i) = i2c_read(0);
}
}
i2c_stop();
}
/** @} */