51单片机的多机串口互连 通信函数，提供缓冲区，通过P2口的输入决定从机号。在STC89C52，AT89S52上通过。-51 Single-chip interconnection of multi-machine serial communications function, providing a buffer, through the input port P2 from the machine its decision. In STC89C52, AT89S52 adopted.