单片机与微机的远距离串行通信

为完成测控系统中主从计算机间的远距离通信，设计了一种基于RS－485总线的方法。采用RS－485总线进行远距离数据收发，在上位机一端用MAX232完成RS－232电平与TTL电平信号之间的转换。运用C语言编程实现远距离实时数据传输。简述了系统结构、通信原理和软件设计。该通信模块已应用于实际测控系统，较好地完成了远距离数据通信任务。稍做扩展，即可用于主机与多下位机的串行通信。

Long distance serial communication between SCM and computer

A long distance communication method based on RS?485 bus between SCM and computer is designed.An RS?485 transceiver is used to receive and send data in long distance,and a MAX232 chip is used at computer side to perform the level conversion between RS?232 and TTL. C language is employed to realize the long distance real time data transmission. The system structure,communication theory and software design are detailed. The communication module has been applied to a real measuring and control system,and it fulfills the task of long distance communication properly.It can be used in the communication among host computer and SCMs a little expansion.