基于51单片机信号发生器的设计外文翻译Word下载.docx

基于51单片机信号发生器的设计外文翻译Word下载.docx

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学生姓名冉乾乾

专业电子信息工程

班级电信002学号********

指导教师金印彬

2014年5月

TheSCMandµ

Vision2

一、PrincipleofMCU

Single-chipisanintegratedonasinglechipacompletecomputersystem.Eventhoughmostofhisfeaturesinasmallchip,butithasaneedtocompletethemajorityofcomputercomponents:

CPU,memory,internalandexternalbussystem,mostwillhavetheCore.Atthesametime,suchasintegratedcommunicationinterfaces,timers,real-timeclockandotherperipheralequipment.Andnowthemostpowerfulsingle-chipmicrocomputersystemcanevenvoice,image,networking,inputandoutputcomplexsystemintegrationonasinglechip.

Alsoknownassingle-chipMCU（Microcontroller）,becauseitwasfirstusedinthefieldofindustrialcontrol.Onlybythesingle-chipCPUchipdevelopedfromthededicatedprocessor.ThedesignconceptisthefirstbyalargenumberofperipheralsandCPUinasinglechip,thecomputersystemsothatsmaller,moreeasilyintegratedintothecomplexanddemandingonthevolumecontroldevices.INTELtheZ80isoneofthefirstdesigninaccordancewiththeideaoftheprocessor,Fromthenon,theMCUandthedevelopmentofadedicatedprocessorpartedways.

Earlysingle-chip8-bitorallofthefour.OneofthemostsuccessfulisINTEL'

s8031,becausetheperformanceofasimpleandreliableaccesstoalotofgoodpraise.Sincethenin8031todevelopasingle-chipmicrocomputersystemMCS51series.Basedonsingle-chipmicrocomputersystemofthesystemisstillwidelyuseduntilnow.Asthefieldofindustrialcontrolrequirementsincreaseinthebeginningofa16-bitsingle-chip,butnotidealbecausethepricehasnotbeenverywidelyused.Afterthe90'

swiththebigconsumerelectronicsproductdevelopment,single-chiptechnologyisahugeimprovement.INTELi960SerieswithsubsequentARMinparticular,abroadrangeofapplications,quicklyreplacedby32-bitsingle-chip16-bitsingle-chiphigh-endstatus,andenterthemainstreammarket.Traditional8-bitsingle-chipperformancehasbeentherapidincreaseinprocessingpowercomparedtothe80'

storaiseafewhundredtimes.Atpresent,thehigh-end32-bitsingle-chipfrequencyover300MHz,theperformanceofthemid-90'

scloseontheheelsofaspecialprocessor,whiletheordinarypriceofthemodeldroppedtooneU.S.dollars,themosthigh-endmodels,only10U.S.dollars.Contemporarysingle-chipmicrocomputersystemisnolongeronlythebare-metalenvironmentinthedevelopmentanduseofalargenumberofdedicatedembeddedoperatingsystemiswidelyusedinthefullrangeofsingle-chipmicrocomputer.InPDAsandcellphonesasthecoreprocessingofhigh-endsingle-chiporevenadedicateddirectaccesstoWindowsandLinuxoperatingsystems.

Morethanadedicatedsingle-chipprocessorsuitableforembeddedsystems,soitwasuptotheapplication.Infactthenumberofsingle-chipistheworld'

slargestcomputer.Modernhumanlifeusedinalmosteverypieceofelectronicandmechanicalproductswillhaveasingle-chipintegration.Phone,telephone,calculator,homeappliances,electronictoys,handheldcomputersandcomputeraccessoriessuchasamouseintheDepartmentareequippedwith1-2singlechip.Andpersonalcomputersalsohavealargenumberofsingle-chipmicrocomputerintheworkplace.Vehiclesequippedwithmorethan40Departmentofthegeneralsingle-chip,complexindustrialcontrolsystemsandevensingle-chipmayhavehundredsofworkatthesametime!

SCMisnotonlyfarexceedsthenumberofPCandotherintegratedcomputing,evenmorethanthenumberofhumanbeings.

Hardwaveintroduction

The8051familyofmicrocontrollersisbasedonanarchitecturewhichishighlyoptimizedforembeddedcontrolsystems.ItisusedinawidevarietyofapplicationsfrommilitaryequipmenttoautomobilestothekeyboardonyourPC.SecondonlytotheMotorola68HC11ineightbitprocessorssales,the8051familyofmicrocontrollersisavailableinawidearrayofvariationsfrommanufacturerssuchasIntel,Philips,andSiemens.Thesemanufacturershaveaddednumerousfeaturesandperipheralstothe8051suchasI2Cinterfaces,analogtodigitalconverters,watchdogtimers,andpulsewidthmodulatedoutputs.Variationsofthe8051withclockspeedsupto40MHzandvoltagerequirementsdownto1.5voltsareavailable.Thiswiderangeofpartsbasedononecoremakesthe8051familyanexcellentchoiceasthebasearchitectureforacompany'

sentirelineofproductssinceitcanperformmanyfunctionsanddeveloperswillonlyhavetolearnthisoneplatform.

Thebasicarchitectureconsistsofthefollowingfeatures:

•aneightbitALU

•32descreteI/Opins（4groupsof8）whichcanbeindividuallyaccessed

•two16bittimer/counters

•fullduplexUART

•6interruptsourceswith2prioritylevels

•128bytesofonboardRAM

•separate64KbyteaddressspacesforDATAandCODEmemory

One8051processorcycleconsistsoftwelveoscillatorperiods.Eachofthetwelveoscillatorperiodsisusedforaspecialfunctionbythe8051coresuchasopcodefetchesandsamplesoftheinterruptdaisychainforpendinginterrupts.Thetimerequiredforany8051instructioncanbecomputedbydividingtheclockfrequencyby12,invertingthatresultandmultiplyingitbythenumberofprocessorcyclesrequiredbytheinstructioninquestion.Therefore,ifyouhaveasystemwhichisusingan11.059MHzclock,youcancomputethenumberofinstructionspersecondbydividingthisvalueby12.Thisgivesaninstructionfrequencyof921583instructionspersecond.Invertingthiswillprovidetheamountoftimetakenbyeachinstructioncycle（1.085microseconds）.

二、TheIntroductionofAT89C51

一Description

TheAT89C51isalow-power,high-performanceCMOS8-bitmicrocomputerwith4KbytesofFlashprogrammableanderasablereadonlymemory（PEROM）.ThedeviceismanufacturedusingAtmel’shigh-densitynonvolatilememorytechnologyandiscompatiblewiththeindustry-standardMCS-51instructionset.Theon-chipFlashallowstheprogrammemorytobereprogrammedin-systemorbyaconventionalnonvolatilememoryprogrammer.Bycombiningaversatile8-bitCPUwithFlashonamonolithicchip,theAtmelAT89C51isapowerfulmicrocomputerwhichprovidesahighly-flexibleandcost-effectivesolutiontomanyembeddedcontrolapplications.

二Functioncharacteristic

TheAT89C51providesthefollowingstandardfeatures:

4KbytesofFlash,128bytesofRAM,32I/Olines,two16-bittimer/counters,one5vectortwo-levelinterruptarchitecture,afullduplexserialport,one-chiposcillatorandclockcircuitry.Inaddition,theAT89C51isdesignedwithstaticlogicforoperationdowntozerofrequencyandsupportstwosoftwareselectablepowersavingmodes.TheIdleModestopstheCPUwhileallowingtheRAM,timer/counters,serialportandinterruptsystemtocontinuefunctioning.ThePower-downModesavestheRAMcontentsbutfreezestheoscillatordisablingallotherchipfunctionsuntilthenexthardwarereset.

PinDescription

VCC：

Supplyvoltage.

GND：

Ground.

Port0

Port0isan8-bitopen-drainbi-directionalI/Oport.Asanoutputport,eachpincansinkeightTTLinputs.When1sarewrittentoport0pins,thepinscanbeusedashigh-impedanceinputs.Port0mayalsobeconfiguredtobethemultiplexedaddress/databusduringaccessestoexternalprogramanddatamemory.InthismodeP0hasinternalPull-upresistor.Port0alsoreceivesthecodebytesduringFlashprogramming,andoutputsthecodebytesduringProgramverification.ExternalPull-upresistorsarerequiredduringProgramverification.

Port1

Port1isan8-bitbi-directionalI/OportwithinternalPull-upresistors.ThePort1outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort1pinstheyarepulledhighbytheinternalPull-upresistorsandcanbeusedasinputs.Asinputs,Port1pinsthatareexternallybeingpulledlowwillsourcecurrent（IIL）becauseoftheinternalPull-upresistors.Port1alsoreceivesthelow-orderaddressbytesduringFlashprogrammingandverification.

Port2

Port2isan8-bitbi-directionalI/OportwithinternalPull-upresistor.ThePort2outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort2pinstheyarepulledhighbytheinternalPull-upresistorandcanbeusedasinputs.Asinputs,Port2pinsthatareexternallybeingpulledlowwillsourcecurrent,becauseoftheinternalPull-upresistor.Port2emitsthehigh-orderaddressbyteduringfetchesfromexternalprogrammemoryandduringaccessestoexternaldatamemorythatuse16-bitaddresses.Inthisapplication,itusesstronginternalPull-upresistorwhenemitting1s.Duringaccessestoexternaldatamemorythatuse8-bitaddresses,Port2emitsthecontentsoftheP2SpecialFunctionRegister.Port2alsoreceivesthehigh-orderaddressbitsandsomecontrolsignalsduringFlashprogrammingandverification.

Port3

Port3isan8-bitbi-directionalI/OportwithinternalPull-upresistor.ThePort3outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort3pinstheyarepulledhighbytheinternalPull-upresistorandcanbeusedasinputs.Asinputs,Port3pinsthatareexternallybeingpulledlowwillsourcecurrent（IIL）becauseofthePull-upresistor.Port3alsoservesthefunctionsofvariousspecialfeaturesoftheAT89C51aslistedbelow:

Port3alsoreceivessomecontrolsignalsforFlashprogrammingandverification.

RST

Resetinput.Ahighonthispinfortwomachinecycleswhiletheoscillatorisrunningresetsthedevice.

ALE/PROG

AddressLatchEnableoutputpulseforlatchingthelowbyteoftheaddressduringaccessestoext