Nun lese ich aber etwas von eeprom_read_byte auf microcontroller.net.
Das bezieht sich auf den EEPROM im Kontroller.
Die Device-Adresse sollte A8 sein?
Vielleicht kannst du mit dem hier was anfangen:
Code:
/****************************************************************************
Title: Access serial EEPROM 24C02 using I2C interace
Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
Date: 9-Mar-2003
Software: AVR-GCC 3.3
Hardware: AT90S8515 at 4 Mhz, any AVR device can be used
Description:
This example shows how the I2C library i2cmaster.S can be used to
access a serial eeprom.
Based on Atmel Application Note AVR300, adapted to AVR-GCC C interface
*****************************************************************************/
#include <avr/io.h>
#include "i2cmaster.h"
#define Dev24C02 0xA2 // device address of EEPROM 24C02, see datasheet
int main(void)
{
unsigned char ret;
DDRB = 0xff; // use all pins on port B for output
PORTB = 0xff; // (active low LED's )
i2c_init(); // init I2C interface
/* write 0x75 to eeprom address 0x05 (Byte Write) */
ret = i2c_start(Dev24C02+I2C_WRITE); // set device address and write mode
if ( ret ) {
/* failed to issue start condition, possibly no device found */
i2c_stop();
PORTB=0x00; // activate all 8 LED to show error */
}else {
/* issuing start condition ok, device accessible */
i2c_write(0x05); // write address = 5
i2c_write(0x75); // ret=0 -> Ok, ret=1 -> no ACK
i2c_stop(); // set stop conditon = release bus
/* write ok, read value back from eeprom address 0x05, wait until
the device is no longer busy from the previous write operation */
i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode
i2c_write(0x05); // write address = 5
i2c_rep_start(Dev24C02+I2C_READ); // set device address and read mode
ret = i2c_readNak(); // read one byte
i2c_stop();
PORTB = ~ret; // output byte on the LED's
/* write 0x70,0x71,072,073 to eeprom address 0x00..0x03 (Page Write),
wait until the device is no longer busy from the previous write operation */
i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode
i2c_write(0x00); // write start address = 0
i2c_write(0x70); // write data to address 0
i2c_write(0x71); // " " " " 1
i2c_write(0x72); // " " " " 2
i2c_write(0x74); // " " " " 3
i2c_stop(); // set stop conditon = release bus
/* write ok, read value back from eeprom address 0..3 (Sequencial Read),
wait until the device is no longer busy from the previous write operation */
i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode
i2c_write(0x00); // write address = 0
i2c_rep_start(Dev24C02+I2C_READ); // set device address and read mode
ret = i2c_readAck(); // read one byte form address 0
ret = i2c_readAck(); // " " " " " 1
ret = i2c_readAck(); // " " " " " 2
ret = i2c_readNak(); // " " " " " 3
i2c_stop(); // set stop condition = release bus
PORTB = ~ret; // output byte on the LED's
}
for(;;);
}
Bezieht sich zwar auf einen 24C02 sollte aber sonst passen.
Lesezeichen