说明：  单片机C51串口中断接收和发送测试例程（含通信协议的实现），这是我自己写的一个程序，觉得挺好用，发出来大家参考一下
(C51 single-chip serial port receive and transmit interrupt routine test (including the Communication Protocol), which I wrote it myself a process, feel good, and sent to U.S. reference)