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1江苏财经职业技术学院综合毕业实践说明书（论文）标题：利用AT89S52型单片机智能电子称系统系别：电子工程系专业：电子信息工程技术学号：0810502321姓名：潘保成指导教师：孙振伟2011年5月11日智能电子秤设计2摘要本设计系统以单片机AT89S52为控制核心，实现电子秤的基本控制功能。在设计系统时，为了更好地采用模块化设计法，分步设计了各个单元功能模块。系统的硬件部分包括最小系统部分、数据采集部分、人机交互界面和系统电源四大部分。最小系统部分主要包括AT89S52和扩展的外部数据存储器；数据采集部分由称重传感器，信号的前期处理和A/D转换部分组成，包括运算放大器AD620和A/D转换器ICL7135；人机界面部分为键盘输入，四位LED数码显示器，可以直观的显示重量的具体数字以及方便的输入数据，使用方便；系统电源以LM317和LM337为核心设计电路以提供系统正常工作电源。系统的软件部分应用单片机C语言进行编程，实现了该设计的全部控制功能。该电子秤可以实现基本的称重功能（称重范围为0～9.999Kg，重量误差不大于±0.005Kg）,并发挥部分的显示购物清单的功能，可以设置日期和设定十种商品的单价，还具有超量程和欠量程的报警功能。本系统设计结构简单，使用方便，功能齐全，精度高，具有一定的开发价值。关键词：电阻应变式传感器A/D单片机液晶显示智能电子称设计3ABSTRACTThedesignofthesystemwiththemonolithicintegratedcircuitAT89S52asthecoretorealizethebasicelectroniccontrolfunctions.Inthedesignofthesystem,inordertobetterthemodularizeddesignmethod,theunitstepfunctionmoduledesign.Thesystemincludeshardware,dataacquisitionsystemminimum,man-machineinterfaceandthesystemofpower.TheminimumsystempartsincludingAT89S52andtheexpansionofexternaldatastorage,Datacollectedbyweighingtransducer,signalprocessingandtheA/Dconversionparts,includingtheamplifierAD620andA/DconverterICL7135,Fortheman-machineinterfacepartialkeyboardinput,fourLEDdigitaldisplay,canshowthespecificweightandfigureofinputdata,useconvenient,InLM317LM337andpowersystemasthecorecircuitdesigntoprovidenormalworkofthesystem.TheapplicationofSCMsystemsoftwarepartClanguageprogram,thedesignofallcontrolfunction.Itcanrealizethebasicelectronicweighingfunction(weighingtherangeof0-9.999Kg,weighterrorisnotmorethan±0.005Kg),andplayapartoftheshowshoppinglistoffunction,cansetthedateandsetthepriceofgoods,andtenhassuperrangeandlessrangealarmfunction.Thesystemdesignissimpleinstructure,easytouse,completefunction,highprecision,hascertainvalue.【Keyword】ResistancestrainsensorA/Dsingle-chipliquidcrystaldisplay智能电子秤设计4目录摘要.................................................................................................................................................2ABSTRACT..................................................................................................................................3【Keyword】................................................................................................................................3目录...................................................................................................................................................4引言...................................................................................................................................................12系统方案设计.............................................................................................................................12.1电子秤的组成结构..............................................................................................................12.1.1电子秤的基本结构.......................................................................................................12.1.2电子秤的工作原理.......................................................................................................22.2电子秤设计的要求及基本思路..........................................................................................22.2.1电子秤设计的要求.......................................................................................................22.2.2电子秤设计的基本思路...............................................................................................22.3单片机的选型......................................................................................................................32.4数据采集模块......................................................................................................................32.4.1传感器...........................................................................................................................32.4.2前级放大器...................................................................................................................62.4.3A/D转换器...................................................................................................................82.5人机交互界面模块..............................................................................................................92.5.1键盘输入.......................................................................................................................92.5.2输出显示.....................................................................................................................103电子秤硬件的设计与制作.......................................................................................................103.1AT89S52的主控电路........................................................................................................103.1.1AT89S52芯片.............................................................................................................103.1.2主控电路的设计.........................................................................................................123.2电子秤的信号处理流程....................................................................................................123.2.1称重数据处理.............................