DS18B20单片机中英文对照外文翻译文献.docx

DS18B20单片机中英文对照外文翻译文献.docx

《DS18B20单片机中英文对照外文翻译文献.docx》由会员分享，可在线阅读，更多相关《DS18B20单片机中英文对照外文翻译文献.docx（19页珍藏版）》请在冰豆网上搜索。

DS18B20单片机中英文对照外文翻译文献

（文档含英文原文和中文翻译）

中英文对照外文翻译文献

TheintroductiontoTheDS18B20

1.DESCRIPTION

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°Cto+125°C（-67°Fto+257°F）

●±0.5°CAccuracyfrom-10°Cto+85°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,thisnotificationtechniquecannotbeusedsincethebusmustbepulledhighbyastrongpullupduringtheentiretemperatureconversion.

TheDS18B20outputtemperaturedataiscalibratedindegreesCelsius;forFahrenheitapplications,alookuptableorconversionroutinemustbeused.Thetemperaturedataisstoredasa16-bitsign-extendedtwo’scomplementnumberinthetemperatureregister（seeFigure2）.Thesignbits（S）indicateifthetemperatureispositiveornegative:

forpositivenumbersS=0andfornegativenumbersS=1.IftheDS18B20isconfiguredfor12-bitresolution,allbitsinthetemperatureregisterwillcontainvaliddata.For11-bitresolution,bit0isundefined.For10-bitresolution,bits1and0areundefined,andfor9-bitresolutionbits2,1,and0areundefined.Table1givesexamplesofdigitaloutputdataandthecorrespondingtemperaturereadingfor12-bitresolutionconversions.

bit7bit6bit5bit4bit3bit2bit1bit0

LSByte

23

22

21

20

2-1

2-2

2-3

2-4

bit15bit14bit13bit12bit11bit10bit9bit8

MSByte

S

S

S

S

S

26

25

24

Figure2.TemperatureRegisterFormat

TEMPERATURE

DIGITALOUTPUT

（BINARY）

DIGITALOUTPUT

（HEX）

+125℃

0000011111010000

07D0H

+25.0625℃

0000000110010001

0191H

0℃

0000000000000000

0000H

-25.0625℃

1111111001101111

FE6FH

-55℃

1111110010010000

FC90H

Table1.Temperature/DataRelationship

5.64-BITLASEREDROMCODE

EachDS18B20containsaunique64–bitcode（seeFigure3）storedinROM.Theleastsignificant8bitsoftheROMcodecontaintheDS18B20’s1-Wirefamilycode:

28h.Thenext48bitscontainauniqueserialnumber.Themostsignificant8bitscontainacyclicredundancycheck（CRC）bytethatiscalculatedfromthefirst56bitsoftheROMcode.The64-bitROMcodeandassociatedROMfunctioncontrollogicallowtheDS18B20tooperateasa1-Wiredeviceusingtheprotocoldetailedinthe1-WireBusSystemsection.

8-BITCRC

48-BITSERIALNUMBER

8-BITFAMILYCODE

MSBLSBMSBLSBMSB

Figure3.64-BitLaseredROMCode

6.MEMORY

TheDS18B20’smemoryisorganizedasshowninFigure4.ThememoryconsistsofanSRAMscratchpadwithnonvolatileEEPROMstorageforthehighandlowalarmtriggerregisters（THandTL）andconfigurationregister.NotethatiftheDS18B20alarmfunctionisnotused,theTHandTLregisterscanserveasgeneral-purposememory.

Byte0andbyte1ofthescratchpadcontaintheLSBandtheMSBofthetemperatureregister,respectively.Thesebytesareread-only.Bytes2and3provideaccesstoTHandTLregisters.Byte4containstheconfigurationregisterdata.Bytes5,6,and7arereservedforinternalusebythedeviceandcannotbeoverwritten.Byte8ofthescratchpadisread-onlyandcontainstheCRCcodeforbytes0through7ofthescratchpad.TheDS18B20generatesthisCRCusingthemethoddescribedintheCRCGenerationsection.

Dataiswrittentobytes2,3,and4ofthescratchpadusingtheWriteScratchpad[4Eh]command;thedatamustbetransmittedtotheDS18B20startingwiththeleastsignificantbitofbyte2.Toverifydataintegrity,thescratchpadcanberead（usingtheReadScratchpad[BEh]command）afterthedataiswritten.Whenreadingthescratchpad,dataistransferredoverthe1-Wirebusstartingwiththeleastsignificantbitofbyte0.TotransfertheTH,TLandconfigurationdatafromthescratchpadtoEEPROM,themastermustissuetheCopyScratchpad[48h]command.

Byte0

TemperatureLSB

Byte1

TemperatureMSB

Byte2

THRegisterforhightemperature

Byte3

TLRegisterforlowtemperature

Byte4

ConfigurationRegister

Byte5

Reserved（FFH）

Byte6

Reserved（OCH）

Byte7

Reserved（IOH）

Byte8

CyclicRedundancyChecks（CRC）

Figure4.DS18B20MemoryMap

7.CONFIGURATIONREGISTER

Byte4ofthescratchpadmemorycontainstheconfigurationregister,whichisorganizedasillustratedinFigure5.TheusercansettheconversionresolutionoftheDS18B20usingtheR0andR1bitsinthisregisterasshowninTable2.Thepower-updefaultofthesebitsisR0=1andR1=1（12-bitresolution）.Notethatthereisadirecttradeoffbetweenresolutionandconversiontime.Bit7andbits0to4intheconfigurationregisterarereservedforinternalusebythedeviceandcannotbeoverwritten.

BIT7BIT6BIT5BIT4BIT3BIT2BIT1BIT0

TM

R1

R0

1

1

1

1

1

Figure5.ConfigurationRegister

R0

R1

RESOLUTION（BITS）

MAXCONVERSIONTIME

0

0

1

1

0

1

0

1

9

10

11

12

93.75ms

187.5ms

375ms

750ms

Table2.ThermometerResolutionConfiguration

8.1-WIREBUSSYSTEM

The1-Wirebussystemusesasinglebusmastertocontroloneormoreslavedevices.TheDS18B20isalwaysaslave.Whenthereisonlyoneslaveonthebus,thesystemisreferredtoasa“single-drop”system;thesystemis“multi-drop”iftherearemultipleslavesonthebus.Alldataandcommandsaretransmittedleastsignificantbitfirstoverthe1-Wirebus.Thefo