一种用于51单片的扩展串口的多机通信模式 使用这种方式可以支持电脑和主机通信，主机也可以和从机通信其中含主机，从机。中转机代码-A serial extension for 51 single multi-machine communication mode in this way can support computers and host communication, the host can also containing the host and slave communicatio