文献翻译——基于单片机的多点温度检测系统的设计

第1页外文文献资料BasedonSCMmulti-functionaltemperaturetestingsystemdesign1、prefaceWiththedevelopmentofsocietyandthetechnologicalprogress,peoplepaymoreandmoreattentiontotheimportanceoftemperaturedetectionanddisplay.Temperaturedetectionandstatusdisplaytechnologyandequipmenthasbeenwidelyappliedinindustries,productsonthemarketemergeinendlessly.Temperaturetestingandalsograduallyadopttheautomaticcontroltechnologytorealizethemonitor.Thistopicisatemperaturetestingandstatusofthemonitoringsystem.2、SystemsolutionsThissystemUSESthemonolithicintegratedcircuitAT89C51asthissystem.Thewholesystem,thehardwarecircuitincludingpowersupplycircuit,sensor,thetemperaturedisplaycircuitcircuit,upperalarmcircuit.Thealarmingcircuitcanbemeasuredinuppertemperaturerange,screamingvoicealarm.ThebasicprincipleforthetemperaturecontrolDSl8B20:whenthetemperaturesignalacquisitiontoaftertemperaturesignalsenttohandle,AT89C51temperaturetoLCDscreen,SCMaccordingtoinitializetheuppertemperaturesetting,namely,ifthejudgementoftemperaturethanthehighesttemperaturecoolingfanisstarted,Ifthetemperatureislessthanthelowesttemperaturesettingonalarmdevice.3、Thesystemhardwaredesign（1）AT89C51SCMareintroducedTheAT89C51isalow-power,high-performanceCMOS8-bitmicrocomputerwith4KbytesofFlashprogrammableanderasablereadonlymemory(PEROM)and128bytesofdatarandom-accessmemory(RAM).ThedeviceismanufacturedusingATMELCo.shigh-densitynonvolatilememorytechnologyandiscompatiblewiththeindustry-standardMCS-51instructionsetandpin-out.Theon-chipFlash第2页allowstheprogrammemorytobereprogrammedin-systemorbyaconventionalnonvolatilememoryprogrammer.Bycombiningaversatile8-bitCPUwithFlashonamonolithicchip,theATMELCo.sAT89C51isapowerfulmicrocomputerwhichprovidesahighly-flexibleandcost-effectivesolutiontomanyembeddedcontrolapplications.Features:CompatiblewithinstructionsetofMCS-51products4Kbytesofin-systemreprogrammableFlashmemoryEndurance:1000write/erasecyclesFullystaticoperation:0Hzto24MHzThree-levelprogrammemorylock1288-bitinternalRAM32programmableI/OlinesTwo16-bitTimer/CountersSixinterruptsourceProgrammableserialchannelLow-poweridleandPower-downmodesFunctionCharacteristicDescription:TheAT89C51providesthefollowingstandardfeatures:4KbytesofFlashmemory,128bytesofRAM,32I/Olines,two16-bittimer/counters,afivevectortwo-levelinterruptarchitecture,afullduplexserialport,on-chiposcillatorandclockcircuitry.Inaddition,theAT89C51isdesignedwithstaticlogicforoperationdowntozerofrequencyandsupportstwosoftwareselectablepowersavingmodes.TheIdleModestopstheCPUwhileallowingtheRAM,timer/counters,serialportandinterruptsystemtocontinuefunctioning.ThePower-downModesavestheRAMcontentsbutfreezestheoscillatordisablingallotherchipfunctionsuntilthenexthardwarereset.PinDescription:VCC:Supplyvoltage第3页GND:GroundPort0:Port0isan8-bitopen-drainbi-directionalI/Oport.Asanoutputport,eachpincansinkeightTTLinputs.When1sarewrittentoport0pins,thepinscanbeusedashighimpedanceinputs.Port0mayalsobeconfiguredtobethemultiplexedloworderaddress/busduringaccessestoexternalprogramanddatamemory.InthismodeP0hasinternalpullups.Port0alsoreceivesthecodebytesduringFlashprogramming,andoutputsthecodebytesduringprogramverification.Externalpullupsarerequiredduringprogramverification.Port1:Port1isan8-bitbidirectionalI/Oportwithinternalpullups.ThePort1outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort1pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port1pinsthatareexternallybeingpulledlowwillsourcecurrent(IIL)becauseoftheinternalpullups.Port1alsoreceivesthelow-orderaddressbytesduringFlashprogrammingandverification.Port2:Port2isan8-bitbi-directionalI/Oportwithinternalpullups.ThePort2outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort2pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port2pinsthatareexternallybeingpulledlowwillsourcecurrent(IIL)becauseoftheinternalpullups.Port2emitsthehigh-orderaddressbyteduringfetchesfromexternalprogrammemoryandduringaccessestoexternaldatamemorywhichuses16-bitaddresses(MOVXDPTR).Inthisapplication,itusesstronginternalpullupswhenemitting1s.Duringaccessestoexternaldatamemorywhichuses8-bitaddresses(MOVXRI).Port2emitsthecontentsoftheP2SpecialFunctionRegister.Port2alsoreceivesthehigh-orderaddressbitsandsomecontrolsignalsduringFlashprogrammingandverification.第4页Port3:Port3isan8-bitbi-directionalI/Oportwithinternalpullups.ThePort3outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort3pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port3pinsthatareexternallybeingpulledlowwillsourcecurrent(IIL)becauseofthepullups.Port3alsoreceivessomecontrolsignalsforFlashprogrammingandverification.RST:Resetinput.Ahighonthispinfortwomachinecycleswhiletheoscillatorisrunningresetsthedevice.ALE/:AddressLatchEnableoutputpulseforlatchingthelowbyteoftheaddressduringaccessestoexternalmemory.Thispinisalsotheprogrampulseinput()duringFlashprogramming.InnormaloperationALEisemittedataconstantrateof1/6theoscillatorfrequency,andmaybeusedforexternaltimingorclockingpurposes.Note,however,thatoneALEpulseisskippedduringeachaccesstoexternalDataMemory.Ifdesired,ALEoperationcanbedisabledbysettingbit0ofSFRlocation8EH.Withthebitset,ALEisactiveonlyduringaMOVXorMOVCinstruction.Otherwise,thepinisweaklypulledhigh.SettingtheALE-disablebithasnoeffectifthemicrocontrollerisinexternalexecutionmode.：ProgramStoreEnableisthereadstrobetoexternalprogrammemory.WhentheAT89C51isexecutingcodefromexternalprogrammemory,isactivatedtwiceeachmachinecycle,exceptthattwoactivationsareskippedduringeachaccesstoexternaldatamemory.EA/VPP：ExternalAccessEnable.EAmustbestrappedtoGNDinordertoenablethedevicetofetchcodefromexternalprogrammemorylocationsstartingat0000HuptoFFFFH.Note,however,thatiflockbit1isprogrammed,EAwillbeinternallylatchedonreset.EAshouldbestrappedtoVCCforinternalprogramexecutions.第5页Thispinalsoreceivesthe12-voltprogrammingenablevoltage(VPP)duringFlashprogramming,forpartsthatrequire12-voltVPP.XTAL1：Inputtotheinvertingoscillatoramplifierandinputtotheinternalclockoperatingcircuit.XTAL2：Outputfromtheinvertingoscillatoramplifier.Ready/:TheprogressofbyteprogrammingcanalsobemonitoredbytheRDY/outputsignal.P3.4ispulledlowafterALEgoeshighduringprogrammingtoindicateBUSY.P3.4ispulledhighagainwhenprogrammingisdonetoindicateREADY.OscillatorCharacteristics：XTAL1andXTAL2aretheinputandoutput,respectively,ofaninvertingamplifierwhichcanbeconfiguredforuseasanon-chiposcillator.Eitheraquartzcrystalorceramicresonatormaybeused.Todrivethedevicefromanexternalclocksource,XTAL2shouldbeleftunconnectedwhileXTAL1isdriven.Therearenorequirementsonthedutycycleoftheexternalclocksignal,sincetheinputtotheinternalclockingcircuitryisthroughadividebytwofliptrigger,butminimumandmaximumvoltagehighandlowtimespecificationsmustbeobserved.IdleMode：Inidlemode,theCPUputsitselftosleepwhilealltheon-chipperipheralsremainactive.Themodeisinvokedbysoftware.Thecontentoftheon-chipRAMandallthespecialfunctionsregistersremainunchangedduringthismode.Theidlemodecanbeterminatedbyanyenabledinterruptorbyahardwarereset.Itshouldbenotedthatwhenidleisterminatedbyahardwarereset,thedevicenormallyresumesprogramexecution,fromwhereitleftoff,uptotwomachinecyclesbeforetheinternalresetalgorithmtakescontrol.On-chiphardwareinhibitsaccesstointernalRAMinthisevent,butaccesstotheportpinsisnotinhibited.Toeliminatethepossibilityofan第6页unexpectedwritetoaportpinwhenIdleisterminatedbyreset,theinstructionfollowingtheonethatinvokesIdleshouldnotbeonethatwritestoaportpinortoexternalmemory.Power-downMode:Inthepower-downmode,theoscillatorisstopped,andtheinstructionthatinvokespower-downisthelastinstructionexecuted.Theon-chipRAMandspecialfunctionregistersretaintheirvaluesuntilthepower-downmodeisterminated.Theonlyexitfrompower-downisahardwarereset.Resetredefinesthespecialfunctionregistersbutdoesnotchangetheon-chipRAM.TheresetshouldnotbeactivatedbeforeVCCisrestoredtoitsnormaloperatinglevelandmustbeheldactivelongenoughtoallowtheoscillatortorestartandstabilize.ProgramMemoryLockBits:Whenlockbit1isprogrammed,thelogiclevelattheEApinissampledandlatchedduringreset.Ifthedeviceispoweredupwithoutareset,thelatchinitializestoarandomvalue,andholdsthatvalueuntilresetisactivated.ItisnecessarythatthelatchedvalueofEAbeinagreementwiththecurrentlogiclevelatthatpininorderforthedevicetofunctionproperly.ProgrammingtheFlash:TheAT89C51isnormallyshippedwiththeon-chipFlashmemoryarrayintheerasedstate(thatis,contents=FFH)andreadytobeprogrammed.Theprogramminginterfaceacceptseitherahigh-voltage(12-volt)oralow-voltage(VCC)programenablesignal.Thelow-voltageprogrammingmodeprovidesaconvenientwaytoprogramtheAT89C51insidetheuserssystem,whilethehigh-voltageprogrammingmodeiscompatiblewithconventionalthirdpartyFlashorEPROMprogrammers.TheAT89C51isshippedwitheitherthehigh-voltageorlow-voltageprogrammingmodeenabled.第7页TheAT89C51codememoryarrayisprogrammedbyte-by-byteineitherprogrammingmode.Toprogramanynonblankbyteintheon-chipFlashmemory,theentirememorymustbeerasedusingthechiperasemode.ProgrammingAlgorithm:BeforeprogrammingtheAT89C51,theaddress,dataandcontrolsignalsshouldbesetupaccordingtotheFlashprogrammingmodetable.ToprogramtheAT89C51,takethefollowingsteps:1.Inputthedesiredmemorylocationontheaddresslines.2.Inputtheappropriatedatabyteonthedatalines.3.Activatethecorrectcombinationofcontrolsignals.4.RaiseEA/VPPto12Vforthehigh-voltageprogrammingmode.5.PulseALE/oncetoprogramabyteintheFlasharrayorthelockbits.Thebyte-writecycleisself-timedandtypicallytakesnomorethan1.5ms.Repeatsteps1through5,changingtheaddressanddatafortheentirearrayoruntiltheendoftheobjectfileisreached.DataPolling:TheAT89C51featuresDataPollingtoindicatetheendofawritecycle.Duringawritecycle,anattemptedreadofthelastbytewrittenwillresultinthecomplementofthewrittendatumonPO.7.Oncethewritecyclehasbeencompleted,truedataarevalidonalloutputs,andthenextcyclemaybegin.Datapollingmaybeginanytimeafterawritecyclehasbeeninitiated.ProgramVerify:IflockbitsLB1andLB2havenotbeenprogrammed,theprogrammedcodedatacanbereadbackviatheaddressanddatalinesforverification.Thelockbitscannotbeverifieddirectly.Verificationofthelockbitsisachievedbyobservingthattheirfeaturesareenabled.ChipErase:第8页TheentireFlasharrayiserasedelectricallybyusingthepropercombinationofcontrolsignalsandbyholdingALE/lowfor10ms.Thecodearrayiswrittenwithall“1”s.Thechiperaseoperationmustbeexecutedbeforethecodememorycanbere-programmed.ReadingtheSignatureBytes:Thesignaturebytesarereadbythesameprocedureasanormalverificationoflocations030H,031H,and032H,exceptthatP3.6andP3.7mustbepulledtoalogiclow.Thevaluesreturnedareasfollows:(030H)=1EHindicatesmanufacturedbyATMEL(031H)=51HindicatesAT89C51single-chip(032H)=FFHindicates12Vprogramming(032H)=05Hindicates5VprogrammingProgrammingInterface:EverycodebyteintheFlasharraycanbewrittenandtheentirearraycanbeerasedbyusingtheappropriatecombinationofcontrolsignals.Thewriteoperationcycleisselftimedandonceinitiated,willautomaticallytimeitselftocompletion.（2）ThesensorDS18B20Inthetraditionalanalogsignaldistancetemperaturemeasuringsystem,needgoodsolveleaderrorcompensation,multi-pointmeasurementerrorandamplifyingcircuitswitchingtechnologiessuchaszerodrifterrorproblem,canachievehighmeasuringaccuracy.Anothergeneralmonitoringsiteoftheelectromagneticenvironmentisverybad,allkindsofjammingsignalisstronger,thesimulatedtemperaturesignalinterferenceandvulnerabletoproducemeasurementerrorandmeasuringprecision5.Therefore,intemperaturemeasuringsystem,thestronganti-jammingcapabilityofthenewdigitaltemperaturesensoristhemosteffectivetosolvetheseproblems,comparedwithothertemperaturesensorDSl820hasthefollowingfeatures:第9页(1)theuniquesinglelineinterfaceway.DSl820inconnectionwiththemicroprocessoronlyneedoneinterfacetoimplementlineDSl820microprocessorsandtwo-waycommunication.(2)morefunctionsimplifiesdistributedtemperaturedetectionapplication.(3)DSl820inusewithoutanyperipheraldevices.(4)power,voltagerangedataavailablefrom3.0Vto5.5V.(5)canmeasuretemperaturerangefrom-55degreesc+to125,incrementalvalue0.5c,Fahrenheittemperaturerangefrom-67to+257,incrementalvalue0.9.(6)supportmulti-pointnetworkfunction.MultipleDS1820canpickonthesamebusand,moretemperaturemeasurement.(7)9temperatureresolution.Measuringresultsinnineserialtransmissionwaythedigitalquantity.(8)usercansettemperaturealarmthreshold.(9)havesupertemperaturesearchfunction.DSl8B20principleofworkTheinternalstructureofDS18B20DSl8B20temperaturemeasurementprinciplediagramshowninfigure3.2.Lowtemperaturecoefficientgraphoscillationfrequencyvibrationproducttemperatureisusedtoproducewithfixedfrequency,pulsesignaltocounterl.Hightemperaturecoefficientcrystalstemperature-dependentitsoscillationfrequencychangesignificantly.Thesignalgeneratedasthecounter2inputpulses.Counter1,2andtemperatureregistersarecounterin-55degreespresetcorrespondingabasevalue.Counterltolowtemperaturecoefficientofthepulsesignalgeneratedcrystals,whenthecounterforsubtractioncountingthepresetvaluereducedto1,whenthetemperaturecounterOvaluewilladdl,counterthepresetvaluewillbelmanagain,tocounterthelstartlowtemperaturecoefficientofcrystaloscillatorpulsesignal,socyclecountuntilthecounter2,stopcountingtoOaccumulativetemperature,temperatureoftheregisterfortheregisterismeasuredvalues.Figure3.2accumulativeusedfortheslopecompensationandfixedtemperaturemeasurement,theoutputoftheprocessofnonlinearcorrectionislessthanthepresetvaluecounterl.第10页.AT89C51interfacemodeandDS18B20ChipDS18B20andtheconnectionhastwokinds:namelyparasiticpowerandexternalpowersupplymode.Parasiticpowerway:intheparasiticpowersupplymode,thesignalfromthesinglechipDS18B20inlinedrawingenergyduringthehighlevelintheDQenergystoredintheinternalcapacitance,lowlevelinsignalintheenergyconsumedduringthecapacitanceonworkinguntilhigh-levelcomingagaintoparasiticpower(battery).Parasiticpowermodehasthreeadvantages:1)distancemeasuringtemperature,withoutthelocalpowersupply.2)noconventionalpowerintheconditionreadstheROM.3)circuit,withonlyonemoreconciserootI/Orealizetemperaturemeasurement.WanttomakeprecisetemperatureconversionchipDS18B20,I/Olinemustensurethatthetemperatureconversionperiod,duetoprovideenoughenergyconversionintemperatureduringeachDS18B20,whenthecurrent1mAtoworkafewtemperaturesensorinthesameroothangingontheI/Omulti-pointtemperaturemeasurement,onlyby4.7Kandresistancewillnotbeabletoprovideenoughenergy,whichcannotbeswitchovertemperatureorerrors.Theexternalpowersourcesupplyway:intheexternalpowersupplymodes,DS18B20workpowerbyVDDpin,I/Oaccesslinedoesnotneedstrongpullup,thereisnoshortageofelectricitypower,canensureaccuracyandconversioninthebustheorycanbearticulatedmultiplesensorDS18B20,multipointtemperaturemeasuringsystem.ThissystemUSEStheexternalpowersource.ConnectionmethodisonefootgroundingandDS18B202feet(DQ)andAT89C51footanI/Oport,3feetlineup+5V.A89S52intheI/Oportand+5Vconnectionbetweena4.7Kpull-upresistors,toensurethenormaloperationofthedatacollection.Ifyouwanttotestsystem,composedmulti-pointtemperatureinthesamerootchipI/Oportinthesameline,andthemethodofconnectingtheparallelmorepiecesofDS18B20chip.（3）LCD1602LCD第11页1602LCDmodulecanandmonolithicintegratedcircuitAT89C51directlyinterface.（4）BuzzerdrivercircuitDuetotheworkingcurrentbuzzeriscomparedcommonlybig,soI/Omicrocontrollerisnotdirectlydrivenbyamplifyingcircuit,soitisgenerallyusedtodrive,toenlargecurrenttransistor.WhenthetemperatureisbelowsixdegreesCelsius,alarm.4、ThedesignofthesoftwaresystemThissystemUSESAT89C51devicesasthecore,withDSl8B20afterthecollecteddata,andthetemperatureinsidethedatastorageAT89C51deposit,LCDdisplay,andcomparedwiththepriorvalue,andthentheoutputsignalbyMCUcontrolcircuitandalarmcircuitfan.Multi-functionaltemperaturetestingsystemsoftwaremainlyinclude:functiondeclarations,timedelayfunctionandDS18B20initializationfunction,readthetemperature,temperatureDS18B20dataintoaliquidcrystaldisplaycharacterssuchprograms.5、SummaryWiththecontinuousdevelopmentofindustryoftemperaturemeasurement,thehigherrequirement,andmoreandmorewidemeasuringrange,soaretherequirementsfortemperaturedetectiontechnologymoreandmoreisalsohigh.DSl8B20introducednewdigitaltemperaturesensorandAT89C51SCM,LCD1602LCDmoduleforconstructingthetemperaturetestingsystem.Thehardwarecircuitandmainprogramandsystemdesignofeachmodulesubroutines.ThissystemUSEStheDALLASisthedigitaltemperaturesensorDS18B20,plusA/Dcanoutputthedigitalquantity,thetemperaturesignaldirectlyconvertserialdigitalsignalprocessingformicrocomputer.Accordingly.Thissystemhasthehardwarecircuitstructureissimple,highprecision,andshowstheresultconversionclearstability,lowcostandsignificantadvantages.Intemperature第12页measurement,suchasgrainofintelligentbuilding,centralairconditioningoftheoccasiontotemperaturetestinghasgoodapplicationprospects.第13页中文翻译稿基于单片机的多点温度检测系统的设计一、引言随着社会的发展和技术的进步，人们越来越注重温度检测与显示的重要性。温度检测与状态显示技术与设备已经普遍应用于各行各业，市场上的产品层出不穷。温度检测及显示也逐渐采用自动化控制技术来实现监控。本课题就是一个温度检测及状态显示的监控系统。二、系统方案本系统采用AT89C51作为该系统的单片机。系统整体硬件电路包括，电源电路，传感器电路，温度显示电路，上下限报警电路等。报警电路可以在被测温度不在上下限范围内时，发出报警鸣叫声音。温度控制的基本原理为:当DSl8B20采集到温度信号后，将温度信号送至AT89C51中处理，同时将温度送到LCD液晶屏显示，单片机根据初始化设置的温度上下限进行判断处理，即如果温度大于所设的最高温度就启动风扇降温;如果温度小于所设定的最低温度就启动报警装置。三、系统硬件设计1.单片机AT89C51的介绍AT89C51是美国ATMEL公司生产的低电压，高性能COMS8位单片机，片内含4Kbytes的可反复擦写的只读程序存储器（PEROM）和128bytes的随机存取数据存储器（RAM），器件采用ATMEL公司的高密度、非易失性存储技术生产，兼容标准MCS-51指令系统，片内置通用8位中央处理器（CPU）和Flash存储单元，功能强大AT89C51单片机可为您提供许多高性价比的应用场合，可灵活应用于各种控制领域。主要性能参数：与MCS-51产品指令系统完全兼容4K字节可重擦写Flash闪速存储器1000次擦写周期全静态操作：0Hz24MHz三级加密程序存储器第14页1288字节内部RAM32个可编程I/O口线2个16位定时/计数器6个中断源可编程串行UART通道低功耗空闲和掉电模式功能特性概述：AT89C51提供以下标准功能：4K字节Flash闪速存储器，128字节内部RAM，32个I/O口线，两个16位定时/计数器，一个5向量两级中断结构，一个全双工串行通信口，片内振荡器及时钟电路。同时，AT89C51可降至0Hz的静态逻辑操作，并支持两种软件可选的节电工作模式。空闲方式停止CPU的工作，但允许RAM，定时/计数器。串行通信口及中断系统继续工作。掉电方式保存RAM中的内容，但振荡器停止工作并禁止其它所有部件工作直到下一个硬件复位。引脚功能说明：VCC：电源电压GND：地P0口：P0口是一组8位漏极开路型双向I/O口，也即地址/数据总线复用口。作为输出口用时，每位能吸收电流的方式驱动8个TTL逻辑门电路，对端口写“1”可作为高阻抗输入端用。在访问外部数据存储器或程序存储器时，这组口线分时转换地址（低8位）和数据总线复用，在访问期间即或内部上拉电阻。在Flash编程时，P0口接收指令字节，而在程序校验时，输出指令字节，校验时，要求外接上拉电阻。P1口：P1是一个带有内部上拉电阻的8位双向I/O口，P1的输出缓冲级可驱动（吸收或输出电流）4个TTL逻辑门电路。对端口写“1”，通过内部的上拉电阻把端口拉到高电平，此时可作输入口。作输入口使用时，因为内部存在上拉电阻，某个引脚被外部信号拉低时会