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eeprom.c
executable file
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eeprom.c
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/*
* The software for the x0xb0x is available for use in accordance with the
* following open source license (MIT License). For more information about
* OS licensing, please visit -> http://www.opensource.org/
*
* For more information about the x0xb0x project, please visit
* -> http://www.ladyada.net/make/x0xb0x
*
* *****
* Copyright (c) 2005 Limor Fried
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
* *****
*
*/
#include <avr/io.h>
#include <avr/boot.h>
#include <avr/pgmspace.h>
#include <stdio.h>
#include <avr/interrupt.h>
#include "eeprom.h"
#include "main.h"
void spieeprom_write(uint8_t data, uint16_t addr) {
uint8_t status;
//printf("writing %x to 0x%x\n\r", data, addr);
/* check if there is a write in progress, wait */
cli();
do {
cbi(SPIEE_CS_PORT, SPIEE_CS_PIN); // pull CS low
NOP; NOP; NOP; NOP;
SPDR = SPI_EEPROM_RDSR;
while (!(SPSR & (1<<SPIF)));
NOP; NOP; NOP; NOP;
SPDR = 0;
while (!(SPSR & (1<<SPIF)));
status = SPDR;
sbi(SPIEE_CS_PORT, SPIEE_CS_PIN); // pull CS high
//printf("status = 0x%x\n\r", status);
NOP; NOP;NOP; NOP;
} while ((status & 0x1) != 0);
/* set the spi write enable latch */
cbi(SPIEE_CS_PORT, SPIEE_CS_PIN); // pull CS low
NOP; NOP;
SPDR = SPI_EEPROM_WREN; // send command
while (!(SPSR & (1<<SPIF)));
NOP; NOP;
sbi(SPIEE_CS_PORT, SPIEE_CS_PIN); // pull CS low
NOP; NOP; NOP; NOP; // wait for write enable latch
cbi(SPIEE_CS_PORT, SPIEE_CS_PIN); // pull CS low
NOP; NOP;
SPDR = SPI_EEPROM_WRITE; // send command
while (!(SPSR & (1<<SPIF)));
SPDR = addr >> 8; // send high addr
while (!(SPSR & (1<<SPIF)));
SPDR = addr & 0xFF; // send low addr
while (!(SPSR & (1<<SPIF)));
SPDR = data; // send data
while (!(SPSR & (1<<SPIF)));
NOP;
NOP;
sbi(SPIEE_CS_PORT, SPIEE_CS_PIN); // pull CS low
sei();
}
uint8_t spieeprom_read(uint16_t addr) {
uint8_t data;
cli();
cbi(SPIEE_CS_PORT, SPIEE_CS_PIN); // pull CS low
NOP; NOP;
SPDR = SPI_EEPROM_READ; // send command
while (!(SPSR & (1<<SPIF)));
SPDR = addr >> 8; // send high addr
while (!(SPSR & (1<<SPIF)));
SPDR = addr & 0xFF; // send low addr
while (!(SPSR & (1<<SPIF)));
NOP;
NOP;
SPDR = 0;
while (!(SPSR & (1<<SPIF)));
data = SPDR;
//printf("got %x\n\r", data);
sbi(SPIEE_CS_PORT, SPIEE_CS_PIN); // pull CS high
sei();
return data;
}