用ATmega48单片机的IIC通讯对大容量的eeprom AT24C512进行读写操作，简单，方便，好用

IIC读写程序， 时序非常重要，如果时序出了问题就会造成无法写入EEPROM，或是无法从EEPROM里面读出数据-IIC read and write procedures, timing is very important, if the timing is a problem it will cause can not be written to the EEPROM, or can not read data from the EEPROM inside