基于freeModbus架构，加入事件驱动机制，用于51单片机的485通信协议框架-Based architecture of freeModbus to join the event-driven mechanism for the 51 single-chip 485 communications protocol framework

通过消息队列为任务调度的程序框架,根据实际工程应用,封装了消息结构体,任何开发板demo中都没有的经典工程软件架构.本工程的单片机平台为STM32F103.(Through the message queue for the task scheduling process framework, according to actual engineering applications, encapsulates the message structure, any development boar