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高等教育自学考试本科毕业论文基于AT89C51单片机倒车防撞报警系统设计考生姓名：准考证号：专业层次：院（系）：指导教师：职称：重庆科技学院二O一二年8月15日摘要随着社会经济的发展交通运输业日益兴旺，汽车数量在大幅攀升。交通拥挤情况也日趋严重，撞车事件屡屡发生，造成了不可避免的人身伤亡和经济损失，针对这种情况，设计一种响应快，可靠性高且较为经济的汽车防撞预警系统势在必行，超声波测距法是最常见的一种距离测距方法，本文介绍的就是利用超声波测距法设计的一种倒车防撞报警系统。论文的内容是基于AT89C51单片机结合于一体，设计出一种基于AT89C51单片机的倒车防撞报警系统。该系统采用软、硬件结合的方法，具有模块话和多用化的特点。论文概述了超声波检测的发展及基本原理，阐述了超声波传感器的原理及特性。对于系统的一些主要参数进行了讨论，并且在介绍超声波测距系统功能的基础上，提出了系统的总体构成，通过多种发射接收电路设计方案比较，得出了最佳设计方案，并对系统各个设计单元的原理进行了介绍。对组成各系统电路的芯片进行了介绍，并阐述了它们的工作原理。论文介绍了系统的软件结构，通过编程来实现系统功能。最后，通过对系统的误差分析，给出了系统的改进方案。关键词：单片机超声波AT89C51AbstractWiththedevelopmentofsocietyandeconomyoftransportationindustryisbooming,thenumberofcarsinthesharprise.Trafficcongestionhasbecomemoreandmoreserious,thecrashoccurredrepeatedly,resultingfromtheinevitablecasualtyandeconomicloss,inviewofthissituation,designakindoffastresponse,highreliabilityandmoreeconomycarcollisionavoidancewarningsystemtobeimperative,ultrasonicrangingmethodisthemostcommontypeofdistancemeasuringmethod,thispaperdescribestheuseofultrasoniclocatingdesignaback-draftanti-collisionalarmsystem.ThecontentofthethesisisbasedontheAT89C51single-chipintegration,designbasedonAT89C51back-draftanti-collisionalarmsystem.Thesystemusesacombinationofhardwareandsoftware,themethodofmodule,andmulti-usecharacteristics.Thispapersummarizesthedevelopmentandbasicprincipleofultrasonicdetection,introducestheprincipleandcharacteristicsofultrasonicsensor.Someofthemainparametersforthesystemwerediscussed,andintroducingultrasonicrangingsystemfunctionsbasis,theoverallcompositionofthesystem,throughavarietyoftransmittingandreceivingcircuitdesigncomparison,thebestdesignscheme,andvarioussystemdesignunitthispaperintroducestheprincipleof.Onthecompositionofthesystemcircuitchipareintroduced,andelaboratedtheprinciplesoftheirwork.Thispaperintroducesthesoftwarestructureofsystem,programmedtorealizethefunctionofthesystem.Finally,throughtheanalysisofsystemerror,animprovedschemeispresented.Keywords:singlechipultrasonicAT89C51目录1超声检测发展综述........................................................................................................................12超声波介绍.................................................................................................................................22.1超声波传感器及其测距原理...........................................................................................22.2什么是超声波...................................................................................................................22.3压电式超声波传感器简介...............................................................................................22.4频率特性...........................................................................................................................42.5指向特性...........................................................................................................................53单片机倒车防撞报警系统各组成单元方案设计.....................................................................63.1发射接收电路方案设计...................................................................................................63.2系统显示电路设计...........................................................................................................73.3系统报警电路设计...........................................................................................................73.4单片机复位电路...............................................................................................................83.5时钟电路...........................................................................................................................93.6稳压电源...........................................................................................................................94系统硬件及软件实现.................................................................................................................104.1单片机的选择.................................................................................................................104.2AT89C51的主要性能参数..............................................................................................104.3AT89C51的结构..............................................................................................................104.4CX20106芯片介绍..........................................................................................................114.5系统软件结构.................................................................................................................124.6硬件连接方法.................................................................................................................124.7超声波发射程序..............................................................................................................124.8超声波接收及显示程序.................................................................................................134.91602显示初始化写指令写数据程序............................................................................144.10蜂鸣报警程序...............................................................................................................18结束语.............................