该模块实现串口DMA发送中断接收，与系统或者外设通信，一发一答的方式，发送一帧数据，需等待对方应答，如果在规定时间内未等到ACK数据，发送端 会重发该数据，采用状态机制原理，对串口使用以及协议搭建很参考价值(The module DMA send serial interrupt receiving, and system or peripheral communication, one answer, send a frame of data, need to wait for the answer, if ACK did not wait until the data within the specified time, the sender will retransmit the data, using the state mechanism principle, build a reference value for the use of serial port and protocol)