说明：  i2c协议实现，对i2c的各个处理处过程，都用子程序实现，能认你灵活方面调用，用时钟芯片做例子，此芯片调好晶体精度可以保证一月不差一秒。
(i2c agreement achieved, all right i2c Department handling process, using subroutine realized, You will have a flexible connection call, with the clock chip as an example, this chip set our crystal precision can guarantee a second, in January is not bad.)