DS18B20单片机中英文对照外文翻译文献Word格式文档下载.docx

DS18B20单片机中英文对照外文翻译文献Word格式文档下载.docx

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TheDS18B20digitalthermometerprovides9-bitto12-bitCelsiustemperaturemeasurementsandhasanalarmfunctionwithnonvolatileuserprogrammableupperandlowertriggerpoints.TheDS18B20communicatesovera1-Wirebusthatbydefinitionrequiresonlyonedatalineforcommunicationwithacentralmicroprocessor.Ithasanoperatingtemperaturerangeof-55°

Cto+125°

Candisaccurateto±

0.5°

Covertherangeof-10°

Cto+85°

C.Inaddition,theDS18B20canderivepowerdirectlyfromthedataline（“parasitepower”）,eliminatingtheneedforanexternalpowersupply.

EachDS18B20hasaunique64-bitserialcode,whichallowsmultipleDS18B20stofunctiononthesame1-Wirebus.Thus,itissimpletouseonemicroprocessortocontrolmanyDS18B20sdistributedoveralargearea.ApplicationsthatcanbenefitfromthisfeatureincludeHVACenvironmentalcontrols,temperaturemonitoringsystemsinsidebuildings,equipment,ormachinery,andprocessmonitoringandcontrolsystems.

2.FEATURES

●Unique1-Wire®

InterfaceRequiresOnlyOnePortPinforCommunication

●EachDevicehasaUnique64-BitSerialCodeStoredinanOn-BoardROM

●Multi-dropCapabilitySimplifiesDistributedTemperature-SensingApplications

●RequiresNoExternalComponents

●CanBePoweredfromDataLine;

PowerSupplyRangeis3.0Vto5.5V

●MeasuresTemperaturesfrom-55°

C（-67°

Fto+257°

F）

●±

CAccuracyfrom-10°

C

●ThermometerResolutionisUserSelectablefrom9to12Bits

●ConvertsTemperatureto12-BitDigitalWordin750ms（Max）

●User-DefinableNonvolatile（NV）AlarmSettings

●AlarmSearchCommandIdentifiesandAddressesDevicesWhoseTemperatureisOutsideProgrammedLimits

●SoftwareCompatiblewiththeDS1822

●ApplicationsIncludeThermostaticControls,IndustrialSystems,ConsumerProducts,Thermometers,orAnyThermallySensitiveSystem

3.OVERVIEW

Figure1showsablockdiagramoftheDS18B20,andpindescriptionsaregiveninthePinDescriptiontable.The64-bitROMstoresthedevice’suniqueserialcode.Thescratchpadmemorycontainsthe2-bytetemperatureregisterthatstoresthedigitaloutputfromthetemperaturesensor.Inaddition,thescratchpadprovidesaccesstothe1-byteupperandloweralarmtriggerregisters（THandTL）andthe1-byteconfigurationregister.Theconfigurationregisterallowstheusertosettheresolutionofthetemperatureto-digitalconversionto9,10,11,or12bits.TheTH,TL,andconfigurationregistersarenonvolatile（EEPROM）,sotheywillretaindatawhenthedeviceispowereddown.

TheDS18B20usesMaxim’sexclusive1-Wirebusprotocolthatimplementsbuscommunicationusingonecontrolsignal.Thecontrollinerequiresaweakpullupresistorsincealldevicesarelinkedtothebusviaa3-stateoropen-drainport（theDQpininthecaseoftheDS18B20）.Inthisbussystem,themicroprocessor（themasterdevice）identifiesandaddressesdevicesonthebususingeachdevice’sunique64-bitcode.Becauseeachdevicehasauniquecode,thenumberofdevicesthatcanbeaddressedononeDS18B20busisvirtuallyunlimited.The1-Wirebusprotocol,includingdetailedexplanationsofthecommandsand“timeslots,”iscoveredinthe1-WireBusSystemsection.

AnotherfeatureoftheDS18B20istheabilitytooperatewithoutanexternalpowersupply.Powerisinsteadsuppliedthroughthe1-WirepullupresistorviatheDQpinwhenthebusishigh.Thehighbussignalalsochargesaninternalcapacitor（CPP）,whichthensuppliespowertothedevicewhenthebusislow.Thismethodofderivingpowerfromthe1-Wirebusisreferredtoas“parasitepower.”Asanalternative,theDS18B20mayalsobepoweredbyanexternalsupplyonVDD.

Figure1.DS18B20BlockDiagram

4.OPERATION—MEASURINGTEMPERATUR

ThecorefunctionalityoftheDS18B20isitsdirect-to-digitaltemperaturesensor.Theresolutionofthetemperaturesensorisuser-configurableto9,10,11,or12bits,correspondingtoincrementsof0.5°

C,0.25°

C,0.125°

C,and0.0625°

C,respectively.Thedefaultresolutionatpower-upis12-bit.TheDS18B20powersupinalow-poweridlestate.ToinitiateatemperaturemeasurementandA-to-Dconversion,themastermustissueaConvertT[44h]command.Followingtheconversion,theresultingthermaldataisstoredinthe2-bytetemperatureregisterinthescratchpadmemoryandtheDS18B20returnstoitsidlestate.IftheDS18B20ispoweredbyanexternalsupply,themastercanissue“readtimeslots”（seethe1-WireBusSystemsection）aftertheConvertTcommandandtheDS18B20willrespondbytransmitting0whilethetemperatureconversionisinprogressand1whentheconversionisdone.IftheDS18B20ispoweredwithparasitepower,thisnotificationtechniquecannotbeusedsincethebusmustbepulledhighbyastrongpullupduringtheentiretempe