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10c7066035
This patch adds the eeprom driver needed to access M24C64 eeprom which is on some mbxxx boards. Signed-off-by: Maria Laura Stefanizzi <laura28582@gmail.com>
169 lines
4.7 KiB
C
169 lines
4.7 KiB
C
/*
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* Copyright (c) 2013, IDentification Automation Laboratory
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* IDALab (http://www.idalab.unisalento.it)
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* Department of Innovation Engineering - University of Salento
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the Institute nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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/**
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* \file eeprom.c
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* \brief ST M24C64W EEPROM driver.
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* \author Maria Laura Stefanizzi <laura28582@gmail.com>
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* \date 2013-11-20
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*/
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#include PLATFORM_HEADER
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#include <dev/eeprom.h>
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#include <dev/i2c.h>
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#define EE_HW_ADDRESS 0xA0
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#define EE_PAGESIZE 32
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#define EE_PAGEMASK 0x1F
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#define EE_MAX_TRIALS 300
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/* Write Cycle polling
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*
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* During the internal Write cycle, the device disconnects itself from the bus,
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* and writes a copy of the data from its internal latches to the memory cells.
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*/
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static inline void
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eeprom_wait(void)
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{
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uint32_t trials = 0;
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/* Keep looping till the slave acknowledge his address or maximum number of
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trials is reached */
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do {
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/* Generate start */
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i2c_start();
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/* Device select in in write mode */
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i2c_write(EE_HW_ADDRESS | 0x0);
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/* Check if the maximum allowed number of trials has been reached */
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if(trials++ == EE_MAX_TRIALS) {
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/* If the maximum number of trials has been reached, exit the function */
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break;
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}
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} while((SC2_STAT(SC_TWIRXNAK)) == SC_TWIRXNAK);
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/* eeprom reply with an ACK then it has terminated the internal Write cycle */
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i2c_stop();
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}
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/**
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* eeprom initializzation function
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*/
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void
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eeprom_init(void)
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{
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/* Nothing must be done here */
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}
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/**
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* Write data to eeprom
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* @param addr The eeprom memory address
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* @param buf It is the buffer of bytes that will be written to the eeprom
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* @param size It is the number of byte to write
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*/
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void
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eeprom_write(eeprom_addr_t addr, unsigned char *buf, int size)
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{
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unsigned int i = 0;
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unsigned int curaddr;
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curaddr = addr;
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for(i = 0; i < size; i++) {
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/* If we are writing the first byte or are on a EE_PAGEMASK page boundary
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we have to start a new write. */
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if(i == 0 || (curaddr & EE_PAGEMASK) == 0) {
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i2c_start();
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i2c_write(EE_HW_ADDRESS | 0x0);
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/* Write the new address to the bus. */
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i2c_write((curaddr & 0xFF00) >> 8);
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i2c_write(curaddr & 0xFF);
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}
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/* Write byte. */
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i2c_write(buf[i] & 0xFF);
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/* If we are writing the last byte totally or of a 32b page
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generate a stop condition */
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if(i == size - 1 || (curaddr & EE_PAGEMASK) == EE_PAGEMASK) {
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i2c_stop();
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eeprom_wait();
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}
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curaddr++;
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}
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}
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/**
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* Read data from eeprom
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* @param addr The eeprom memory address
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* @param buf It is the destination buffer in witch the bytes will be written
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* @param size It is the number of byte to read
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*/
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void
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eeprom_read(eeprom_addr_t addr, unsigned char *buf, int size)
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{
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uint8_t i;
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i2c_start();
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/* Select eeprom with write mode bit enabled */
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i2c_write(EE_HW_ADDRESS | 0x0);
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/* Send address */
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i2c_write((addr & 0xFF00) >> 8);
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i2c_write(addr & 0xFF);
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i2c_start();
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/* Select eeprom with write mode bit disabled */
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i2c_write(EE_HW_ADDRESS | 0x1);
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for(i = 0; i < size; i++) {
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if(i < (size - 1)) {
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/* Read data and send ACK */
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*(buf + i) = i2c_read(1);
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} else {
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/* Last data, don't send ACK */
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*(buf + i) = i2c_read(0);
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}
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}
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i2c_stop();
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}
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/** @} */
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