基于RS485总线的多机通信系统设计.docx

河南理工大学毕业设计（论文）说明书-4-摘要在多机通信领域．由于单片机具有灵活高效的多机通信功能和价格优势应用越来越广泛但由于单片机的收发信号都是TTI电平驱动能力和抗干扰性有限实用中常配合其它总线实现互联RS-485总线就是其中之一。RS-485总线是平衡差分传输抗干扰性好最远可传输4000m可互联多达128个单片机非常适台组成多机通信系统。在多机通信中最重要的是保证通信有条不紊地进行因此需要严格的通信协议和完善的通信软件本文将重点介绍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。本文介绍一种利用单片机本身所提供的串行通讯口采用自定义串行通信协议加上总线驱动器如MAX481、MAX483、MAX485、MAX487等组合成简单的RS－485通讯网络完成单片机间的多机通讯。关键词:单片机；串行通信；RS－485总线：多机通信协议AbstractIncomputercommunicationfield.BecauseofthesinglechipmicrocomputerhasflexibleandefficientcomputercommunicationfunctionandpriceadvantageusedmoreandmorewidelybutbecauseofthesinglechipmicrocomputertosendandreceivesignalsareTTIleveldriveandanti-interferenceabilityislimitedpracticalcooperationwithotherbusrealizeinInternetRS-485busisoneofthem.RS-485busisabalanceddifferentialtransmissionanti-jammingofthegoodandasfaras4000mcouldbetransmittedinterconnectedasmanyas128singlechipmicrocomputerverycomfortableacompositioncomputercommunicationsystem.Incomputercommunicationthemostimportantistoensurethatcommunicationsinanorderlywayandthereforeneedtostrictcommunicationprotocolandperfectcommunicationsoftwarethispaperwillfocusonintroducesappliedinalargeprojectsingle-chipcomputercommunicationassociationPutthecommunicationsoftwaredesignmethod.ThispaperintroducesamicrocontrolleritselfprovidetheserialcommunicationmouthusecustomserialcommunicationprotocolplusthebusdrivesasMAX481MAX483MAX485MAX487combinedintosimpleRS-485communicationnetworkfinishbetweenthesinglechipcomputercommunication.Keywords:SCM;Serialcommunication;RS-485bus:computercommunicationagreement目录第1章绪论11.1课题研究背景与意义11.2单片机多机通信发展1第2章总体介绍32.1系统组成32.2RS-48532.3多机通信原理4第3章硬件设计及原理63.180C51单片机硬件结构63.2最小应用系统设计73.2.1时钟电路73.2.2复位电路83.3总线驱动芯片9第4章系统问题及其解决124.1通