单片机与单片机通信实例（主机） 功能：通过串口与从机与主机的通信，对从机1发出问询帧，然后接收从机1 的脉冲数，通过简单计算得出电压控制值，通过串口发给从机2-Examples of single-chip MCU and Communication (host) function: through the serial port and from the machine with the host communications, on information sent fro