说明：  I2C总线是一种非常常用的串行总线，它操作简便，占用接口少。本程序介绍操作一个I2C总线接口的EEPROM AT24C02 的方法，使用户了解I2C总线协议和读写方法。
(I2C bus is a very common serial bus, it is simple to operate, take up less interface. This procedure describes the method of operation of an EEPROM AT24C02 I2C bus interface, allowing users to learn to read and write I2C bus protocol and methods.)