单片机温度控制系统外文翻译外文文献英文文献中英翻译.docx

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单片机温度控制系统外文翻译外文文献英文文献中英翻译

DesignoftheTemperatureControlSystemBasedonAT89C51

ABSTRACT

TheprincipleandfunctionsofthetemperaturecontrolsystembasedonmicrocontrollerAT89C51arestudied,andthetemperaturemeasurementunitconsistsofthe1-WirebusdigitaltemperaturesensorDS18B20。

Thesystemcanbeexpectedtodetectthepresettemperature,displaytimeandsavemonitoringdata。

Analarmwillbegivenbysystemifthetemperatureexceedstheupperandlowerlimitvalueofthetemperaturewhichcanbesetdiscretionarilyandthenautomaticcontrolisachieved，thusthetemperatureisachievedmonitoringintelligentlywithinacertainrange。

Basingonprincipleofthesystem,itiseasytomakeavarietyofothernon-linearcontrolsystemssolongasthesoftwaredesignisreasonablychanged。

Thesystemhasbeenprovedtobeaccurate，reliableandsatisfiedthroughfieldpractice。

KEYWORDS:

AT89C51；microcontroller；DS18B20；temperature

1INTRODUCTION

Temperatureisaveryimportantparameterinhumanlife。

Inthemodernsociety,temperaturecontrol（TC）isnotonlyusedinindustrialproduction，butalsowidelyusedinotherfields.Withtheimprovementofthelifequality,wecanfindtheTCapplianceinhotels,factoriesandhomeaswell.AndthetrendthatTCwillbetterservethewholesociety，soitisofgreatsignificancetomeasureandcontrolthetemperature.BasedontheAT89C51andtemperaturesensorDS18B20,thissystemcontrolstheconditiontemperatureintelligently。

Thetemperaturecanbesetdiscretionarilywithinacertainrange.ThesystemcanshowthetimeonLCD，andsavemonitoringdata;andautomaticallycontrolthetemperaturewhentheconditiontemperatureexceedstheupperandlowerlimitvalue.Bydoingsoitistokeepthetemperatureunchanged。

Thesystemisofhighanti-jamming,highcontrolprecisionandflexibledesign；italsofitstheruggedenvironment。

Itismainlyusedinpeople’slifetoimprovethequalityoftheworkandlife.Itisalsoversatile，sothatitcanbeconvenienttoextendtheuseofthesystem。

Sothedesignisofprofoundimportance.Thegeneraldesign,hardwaredesignandsoftwaredesignofthesystemarecovered.

1。

1Introduction

The8-bitAT89C51CHMOSmicrocontrollersaredesignedtohandlehigh—speedcalculationsandfastinput/outputoperations.MCS51microcontrollersaretypicallyusedforhigh—speedeventcontrolsystems.Commercialapplicationsincludemodems，motor—controlsystems,printers,photocopiers,airconditionercontrolsystems，diskdrives,andmedicalinstruments。

TheautomotiveindustryuseMCS51microcontrollersinengine—controlsystems,airbags,suspensionsystems,andantilockbrakingsystems（ABS）。

TheAT89C51isespeciallywellsuitedtoapplicationsthatbenefitfromitsprocessingspeedandenhancedon-chipperipheralfunctionsset，suchasautomotivepower-traincontrol,vehicledynamicsuspension,antilockbraking，andstabilitycontrolapplications.Becauseofthesecriticalapplications,themarketrequiresareliablecost—effectivecontrollerwithalowinterruptlatencyresponse，abilitytoservicethehighnumberoftimeandeventdrivenintegratedperipheralsneededinrealtimeapplications,andaCPUwithaboveaverageprocessingpowerinasinglepackage。

Thefinancialandlegalriskofhavingdevicesthatoperateunpredictablyisveryhigh.Onceinthemarket,particularlyinmissioncriticalapplicationssuchasanautopilotoranti-lockbrakingsystem，mistakesarefinanciallyprohibitive。

Redesigncostscanrunashighasa＄500K，muchmoreifthefixmeans2backannotatingitacrossaproductfamilythatsharethesamecoreand/orperipheraldesignflaw。

Inaddition，fieldreplacementsofcomponentsisextremelyexpensive,asthedevicesaretypicallysealedinmoduleswithatotalvalueseveraltimesthatofthecomponent。

Tomitigatetheseproblems,itisessentialthatcomprehensivetestingofthecontrollersbecarriedoutatboththecomponentlevelandsystemlevelunderworstcaseenvironmentalandvoltageconditions。

Thiscompleteandthoroughvalidationnecessitatesnotonlyawell—definedprocessbutalsoaproperenvironmentandtoolstofacilitateandexecutethemissionsuccessfully。

IntelChandlerPlatformEngineeringgroupprovidespostsiliconsystemvalidation（SV）ofvariousmicro—controllersandprocessors。

Thesystemvalidationprocesscanbebrokenintothreemajorparts。

Thetypeofthedeviceanditsapplicationrequirementsdeterminewhichtypesoftestingareperformedonthedevice。

1.2TheAT89C51providesthefollowingstandardfeatures

4KbytesofFlash，128bytesofRAM，32I/Olines，two16-bittimer/counters，afivevectortwo-levelinterruptarchitecture,afulldupleser—ialport，on—chiposcillatorandclockcircuitry.Inaddition，theAT89C51isdesignedwithstaticlogicforoperationdowntozerofrequencyandsupportstwosoftwareselectablepowersavingmodes.TheIdleModestopstheCPUwhileallowingtheRAM,timer/counters,serialportandinterruptsys—temtocontinuefunctioning。

ThePower—downModesavestheRAMcontentsbutfreezestheoscil–latordisablingallotherchipfunctionsuntilthenexthardwarereset。

1.3PinDescription

VCCSupplyvoltage。

GNDGround。

Port0：

Port0isan8-bitopen—drainbi—directionalI/Oport.Asanoutputport，eachpincansinkeightTTLinputs.When1sarewrittentoport0pins,thepinscanbeusedashighimpedanceinputs.Port0mayalsobeconfiguredtobethemultiplexedloworderaddress/databusduringaccessestoexternalprogramanddatamemory.InthismodeP0hasinternalpullups.Port0alsoreceivesthecodebytesduringFlashprogramming,andoutputsthecodebytesduringprogramverification。

Externalpullupsarerequiredduringprogramverification.

Port1:

Port1isan8-bitbi-directionalI/Oportwithinternalpullups.ThePort1outputbufferscansink/so-urcefourTTLinputs.When1sarewrittentoPort1pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs。

Asinputs,Port1pinsthatareexternallybeingpulledlowwillsourcecurrent（IIL）becauseoftheinternalpullups。

Port1alsoreceivesthelow-orderaddressbytesduringFlashprogrammingandverification.

Port2：

Port2isan8-bitbi-directionalI/Oportwithinternalpullups.ThePort2outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort2pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port2pinsthatareexternallybeingpulledlowwillsourcecurrent（IIL）becauseoftheinternalpullups.Port2emitsthehigh—orderaddressbyteduringfetchesfromexternalprogrammemoryandduringaccessestoPort2pinsthatareexternallybeingpulledlowwillsourcecurrent（IIL）becauseoftheinternalpullups.Port2emitsthehigh—orderaddressbyteduringfetchesfromexternalprogrammemoryandduringaccessestoexternaldatamemorythatuse16—bitaddresses（MOVX@DPTR）.Inthisapplication,itusesstronginternalpull-upswhenemitting1s。

Duringaccessestoexternaldatamemorythatuse8-bitaddresses（MOVX＠RI）,Port2emitsthecontentsoftheP2SpecialFunctionRegister。

Port2alsoreceivesthehigh-orderaddressbitsandsomecontrolsignalsdurinFlashprogrammingandverification.

Port3:

Port3isan8—bitbi—directionalI/Oportwithinternalpullups。

ThePort3outputbufferscansink/sou—rcefourTTLinputs.When1sarewrittentoPort3pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs。

Asinputs,Port3pinsthatareexternallybeingpulledlowwillsourcecurrent（IIL）becauseofthepullups。

Port3alsoservesthefunctionsofvariousspecialfeaturesoftheAT89C51aslistedbelow:

RST：

Resetinput.Ahighonthispinfortwomachinecycleswhiletheoscillatorisrunningresetsthedevice.

ALE/PROG：

AddressLatchEnableoutputpulseforlatchingthelowbyteoftheaddressduringaccessestoexternalmemory。

Thispinisalsotheprogrampulseinput（PROG）duringFlashprogramming。

InnormaloperationALEisemittedataconstantrateof1/6theoscillatorfrequency,andmaybeusedforexternaltimingorclockingpurposes.Note，however，thatoneALEpulseisskippedduri-ngeachaccesstoexternalDataMemory。

Ifdesired，ALEoperationcanbedisabledbysettingbit0ofSFRlocation8EH。

Withthebitset,ALEisactiveonlyduringaMOVXorMOVCinstruction.Otherwise,thepinisweaklypulledhigh。

SettingtheALE—disablebithasnoeffectifthemicrocontrollerisinexternalexecutionmode.

PSEN:

ProgramStoreEnableisthereadstrobetoexternalprogrammemory.WhentheAT89C51isexecutingcodefromexternalprogrammemory,PSENisactivatedtwiceeachmachinecycle，exceptthattwoPSENactivationsareskippedduringeachaccesstoexternaldatamemory.

EA/VPP：

ExternalAccessEnable。

EAmustbestrappedtoGNDinordertoenablethedevicetofetchcodefromexternalprogrammemorylocationsstartingat0000HuptoFFFFH.Note,however，thatiflockbit1isprogrammed,EAwillbeinternallylatchedonreset。

EAshouldbestrappedtoVCCforinternalprogramexecutions.Thispinalsreceivesthe12—voltprogrammingenablevoltage（VPP）duringFlashprogramming,forpartsthatrequire12-voltVPP。

XTAL1：

Inputtotheinvertingoscillatoramplifierandinputtotheinternalclockoperatingcircuit。

XTAL2：

Outputfromtheinvertingoscillatoramplifier.OscillatorCharacteristicsXTAL1andXTAL2aretheinputandoutput,respectively,ofaninvertingamplifierwhichcanbeconfiguredforuseasanon-chiposcillator,asshowninFigure1.Eitheraquartzcrystalorceramicresonatormaybeused。

Todrivethedevicefromanexternalclocksource，XTAL2shouldbeleftunconnectedwhileXTAL1isdrivenasshowninFigure2.Therearenorequirementsonthed