Again the response is:

Read the manual. (I myself have made the same mistake once. :-) ). Unfortunately, EEPROM handling for atmega48 does not work. Solution is to take the original assembler files from the avr-libc sources and compile them with the correct compile switches for your processor. Avr-libc is compiled for all controllers and assume that the eeprom registers are at another location than they are in fact for atmega48.

Yours,

Björn

Excerpt from the manual:

EEPROM handling

Detailed Description

 #include <avr/eeprom.h>

This header file declares the interface to some simple library routines suitable for handling the data EEPROM contained in the AVR microcontrollers. The implementation uses a simple polled mode interface. Applications that require interrupt-controlled EEPROM access to ensure that no time will be wasted in spinloops will have to deploy their own implementation.

Note:: All of the read/write functions first make sure the EEPROM is ready to be accessed. Since this may cause long delays if a write operation is still pending, time-critical applications should first poll the EEPROM e. g. using eeprom_is_ready() before attempting any actual I/O.
This library will not work with the following devices since these devices have the EEPROM IO ports at different locations:

AT90CAN128
ATmega48
ATmega88
ATmega165
ATmega168
ATmega169
ATmega325
ATmega3250
ATmega645
ATmega6450

Dear All,

I used the ATmega48 EEPROM stored my parameter.

But I can't read back right data before in my program

I have defined it.Please see the below part,give me some advice!

Thanks!

Laser

#include <inttypes.h>
#include <avr/io.h>
#include <avr/eeprom.h>

unsigned char EMy_addr __attribute__((section(".eeprom"))) =5;

unsigned char my_addr;

int main(void)

{

eeprom_busy_wait();
my_addr=eeprom_read_byte(&EMy_addr);

}

__________________________________________________
赶快注册雅虎超大容量免费邮箱?
http://cn.mail.yahoo.com