说明：  atmega128控制IIC程序，调用前先初始化，然后发送START信号，接着向IIC总线上写一个字节数据即可控制一个IIC的外围器件。
(Atmega128 IIC control procedures, initialization, call the front and then send the START signal, and then to write a byte data on the IIC bus can control a IIC peripheral devices.)