说明：  51单片机的I2C通信程序包，采样IO口模拟I2C，程序简洁支持基本的I2C协议，经过测试运行非常稳定可靠，稍加改动可满足其他需要。
(51 SCM I2C communications package, sampling analog IO mouth I2C, simple procedures to support the basic I2C agreement, after the test run is very stable and reliable and can be modified to meet other needs.)