基于RS485总线的多机通信系统设计摘要

本文介绍了一种基于RS485总线的多机通信系统设计方法。由于单片机具有高效的多机通信功能和价格优势，在多机通信领域中应用越来越广泛。然而，单片机的收发信号是TTI电平，驱动能力和抗干扰性有限，因此通常需要配合其他总线实现互联，RS485总线就是其中之一。RS485总线采用平衡差分传输，抗干扰性好，并且最远可传输4000m，可互联多达128个单片机，非常适合构建多机通信系统。 在多机通信中，保证通信有条不紊地进行是至关重要的，因此需要严格的通信协议和完善的通信软件。本文重点介绍了应用于某大型工程的单片机多机通信协议和通信软件的设计方法。通过利用单片机本身提供的串行通讯口，采用自定义串行通信协议，并结合总线驱动器如MAX481、MAX483、MAX485、MAX487等，组合成简单的RS485通讯网络，实现了单片机之间的多机通讯。 关键词：单片机；串行通信；RS485总线；多机通信协议 Abstract: This paper introduces a method for designing a multi-machine communication system based on the RS485 bus. Due to the efficient multi-machine communication function and price advantage of single-chip microcontrollers, their applications in the field of multi-machine communication are becoming more and more extensive. However, the single-chip microcontroller's receiving and transmitting signals are TTI levels, with limited driving capability and anti-interference performance, so it usually needs to be combined with other buses to achieve interconnection, and RS485 bus is one of them. The RS485 bus uses balanced differential transmission, with good anti-interference performance, and can transmit up to 4000m, and can interconnect up to 128 single-chip microcontrollers, making it very suitable for building a multi-machine communication system. In multi-machine communication, it is crucial to ensure that the communication proceeds in an orderly manner, so strict communication protocols and complete communication software are required. This paper focuses on the design method of the single-chip microcontroller's multi-machine communication protocol and communication software applied to a large-scale project. By utilizing the serial communication port provided by the single-chip microcontroller itself, adopting a custom serial communication protocol, and combining it with bus drivers such as MAX481, MAX483, MAX485, MAX487, etc., a simple RS485 communication network is formed to achieve multi-machine communication between single-chip microcontrollers.