用485实现单片机之间的串行通信。 主机部分发送从机地址，等待从机响应，从机准备好就发数据,发完就接收从机的响应，接受成功就跳出循环，否则重发-Serial communication between MCU with 485. Host part of the Slave Address, waiting for the slave response from the machine ready to send data, finished his receiving slave response, underwent successful out of the loop, otherwise re-issued