基于单片机的数字日历毕业外文翻译（英文）

一SINGLECHIPBRIEFINTRODUCTIONAMICROCONTROLLERORMCUISACOMPUTERONACHIPITISATYPEOFMICROPROCESSOREMPHASIZINGSELFSUFFICIENCYANDCOSTEFFECTIVENESS,INCONTRASTTOAGENERALPURPOSEMICROPROCESSORTHEKINDUSEDINAPCTHEMAJORITYOFCOMPUTERSYSTEMSINUSETODAYAREEMBEDDEDINOTHERMACHINERY,SUCHASTELEPHONES,CLOCKS,APPLIANCES,VEHICLES,ANDINFRASTRUCTUREANEMBEDDEDSYSTEMUSUALLYHASMINIMALREQUIREMENTSFORMEMORYANDPROGRAMLENGTHANDMAYREQUIRESIMPLEBUTUNUSUALINPUT/OUTPUTSYSTEMSFOREXAMPLE,MOSTEMBEDDEDSYSTEMSLACKKEYBOARDS,SCREENS,DISKS,PRINTERS,OROTHERRECOGNIZABLEI/ODEVICESOFAPERSONALCOMPUTERTHEYMAYCONTROLELECTRICMOTORS,RELAYSORVOLTAGES,ANDREADSWITCHES,VARIABLERESISTORSOROTHERELECTRONICDEVICESOFTEN,THEONLYI/ODEVICEREADABLEBYAHUMANISASINGLELIGHTEMITTINGDIODE,ANDSEVERECOSTORPOWERCONSTRAINTSCANEVENELIMINATETHATINCONTRASTTOGENERALPURPOSECPUS,MICROCONTROLLERSDONOTHAVEANADDRESSBUSORADATABUS,BECAUSETHEYINTEGRATEALLTHERAMANDNONVOLATILEMEMORYONTHESAMECHIPASTHECPUBECAUSETHEYNEEDFEWERPINS,THECHIPCANBEPLACEDINAMUCHSMALLER,CHEAPERPACKAGEINTEGRATINGTHEMEMORYANDOTHERPERIPHERALSONASINGLECHIPANDTESTINGTHEMASAUNITINCREASESTHECOSTOFTHATCHIP,BUTOFTENRESULTSINDECREASEDNETCOSTOFTHEEMBEDDEDSYSTEMASAWHOLEEVENIFTHECOSTOFACPUTHATHASINTEGRATEDPERIPHERALSISSLIGHTLYMORETHANTHECOSTOFACPUEXTERNALPERIPHERALS,HAVINGFEWERCHIPSTYPICALLYALLOWSASMALLERANDCHEAPERCIRCUITBOARD,ANDREDUCESTHELABORREQUIREDTOASSEMBLEANDTESTTHECIRCUITBOARDTHISTRENDLEADSTODESIGNAMICROCONTROLLERISASINGLEINTEGRATEDCIRCUIT,COMMONLYWITHTHEFOLLOWINGFEATURESCENTRALPROCESSINGUNITRANGINGFROMSMALLANDSIMPLE4BITPROCESSORSTOSOPHISTICATED32OR64BITPROCESSORSINPUT/OUTPUTINTERFACESSUCHASSERIALPORTSUARTSOTHERSERIALCOMMUNICATIONSINTERFACESLIKEIC,SERIALPERIPHERALINTERFACEANDCONTROLLERAREANETWORKFORSYSTEMINTERCONNECTPERIPHERALSSUCHASTIMERSANDWATCHDOGRAMFORDATASTORAGEROM,EPROM,EEPROMORFLASHMEMORYFORPROGRAMSTORAGECLOCKGENERATOROFTENANOSCILLATORFORAQUARTZTIMINGCRYSTAL,RESONATORORRCCIRCUITMANYINCLUDEANALOGTODIGITALCONVERTERSTHISINTEGRATIONDRASTICALLYREDUCESTHENUMBEROFCHIPSANDTHEAMOUNTOFWIRINGANDPCBSPACETHATWOULDBENEEDEDTOPRODUCEEQUIVALENTSYSTEMSUSINGSEPARATECHIPSANDHAVEPROVEDTOBEHIGHLYPOPULARINEMBEDDEDSYSTEMSSINCETHEIRINTRODUCTIONINTHE1970SSOMEMICROCONTROLLERSCANAFFORDTOUSEAHARVARDARCHITECTURESEPARATEMEMORYBUSESFORINSTRUCTIONSANDDATA,ALLOWINGACCESSESTOTAKEPLACECONCURRENTLYTHEDECISIONOFWHICHPERIPHERALTOINTEGRATEISOFTENDIFFICULTTHEMICROCONTROLLERVENDORSOFTENTRADEOPERATINGFREQUENCIESANDSYSTEMDESIGNFLEXIBILITYAGAINSTTIMETOMARKETREQUIREMENTSFROMTHEIRCUSTOMERSANDOVERALLLOWERSYSTEMCOSTMANUFACTURERSHAVETOBALANCETHENEEDTOMINIMIZETHECHIPSIZEAGAINSTADDITIONALFUNCTIONALITYMICROCONTROLLERARCHITECTURESAREAVAILABLEFROMMANYDIFFERENTVENDORSINSOMANYVARIETIESTHATEACHINSTRUCTIONSETARCHITECTURECOULDRIGHTLYBELONGTOACATEGORYOFTHEIROWNCHIEFAMONGTHESEARETHE8051,Z80ANDARMDERIVATIVESCITATIONNEEDEDAMICROCONTROLLERALSOMCUORCISAFUNCTIONALCOMPUTERSYSTEMONACHIPITCONTAINSAPROCESSORCORE,MEMORY,ANDPROGRAMMABLEINPUT/OUTPUTPERIPHERALSMICROCONTROLLERSINCLUDEANINTEGRATEDCPU,MEMORYASMALLAMOUNTOFRAM,PROGRAMMEMORY,ORBOTHANDPERIPHERALSCAPABLEOFINPUTANDOUTPUTITEMPHASIZESHIGHINTEGRATION,INCONTRASTTOAMICROPROCESSORWHICHONLYCONTAINSACPUTHEKINDUSEDINAPCINADDITIONTOTHEUSUALARITHMETICANDLOGICELEMENTSOFAGENERALPURPOSEMICROPROCESSOR,THEMICROCONTROLLERINTEGRATESADDITIONALELEMENTSSUCHASREADWRITEMEMORYFORDATASTORAGE,READONLYMEMORYFORPROGRAMSTORAGE,FLASHMEMORYFORPERMANENTDATASTORAGE,PERIPHERALS,ANDINPUT/OUTPUTINTERFACESATCLOCKSPEEDSOFASLITTLEAS32KHZ,MICROCONTROLLERSOFTENOPERATEATVERYLOWSPEEDCOMPAREDTOMICROPROCESSORS,BUTTHISISADEQUATEFORTYPICALAPPLICATIONSTHEYCONSUMERELATIVELYLITTLEPOWERMILLIWATTSOREVENMICROWATTS,ANDWILLGENERALLYHAVETHEABILITYTORETAINFUNCTIONALITYWHILEWAITINGFORANEVENTSUCHASABUTTONPRESSORINTERRUPTPOWERCONSUMPTIONWHILESLEEPINGCPUCLOCKANDPERIPHERALSDISABLEDMAYBEJUSTNANOWATTS,MAKINGTHEMIDEALFORLOWPOWERANDLONGLASTINGBATTERYAPPLICATIONSMICROCONTROLLERSAREUSEDINAUTOMATICALLYCONTROLLEDPRODUCTSANDDEVICES,SUCHASAUTOMOBILEENGINECONTROLSYSTEMS,REMOTECONTROLS,OFFICEMACHINES,APPLIANCES,POWERTOOLS,ANDTOYSBYREDUCINGTHESIZE,COST,ANDPOWERCONSUMPTIONCOMPAREDTOADESIGNUSINGASEPARATEMICROPROCESSOR,MEMORY,ANDINPUT/OUTPUTDEVICES,MICROCONTROLLERSMAKEITECONOMICALTOELECTRONICALLYCONTROLMANYMOREPROCESSESTHEMAJORITYOFCOMPUTERSYSTEMSINUSETODAYAREEMBEDDEDINOTHERMACHINERY,SUCHASAUTOMOBILES,TELEPHONES,APPLIANCES,ANDPERIPHERALSFORCOMPUTERSYSTEMSTHESEARECALLEDEMBEDDEDSYSTEMSWHILESOMEEMBEDDEDSYSTEMSAREVERYSOPHISTICATED,MANYHAVEMINIMALREQUIREMENTSFORMEMORYANDPROGRAMLENGTH,WITHNOOPERATINGSYSTEM,ANDLOWSOFTWARECOMPLEXITYTYPICALINPUTANDOUTPUTDEVICESINCLUDESWITCHES,RELAYS,SOLENOIDS,LEDS,SMALLORCUSTOMLCDDISPLAYS,RADIOFREQUENCYDEVICES,ANDSENSORSFORDATASUCHASTEMPERATURE,HUMIDITY,LIGHTLEVELETCEMBEDDEDSYSTEMSUSUALLYHAVENOKEYBOARD,SCREEN,DISKS,PRINTERS,OROTHERRECOGNIZABLEI/ODEVICESOFAPERSONALCOMPUTER,ANDMAYLACKHUMANINTERACTIONDEVICESOFANYKINDITISMANDATORYTHATMICROCONTROLLERSPROVIDEREALTIMERESPONSETOEVENTSINTHEEMBEDDEDSYSTEMTHEYARECONTROLLINGWHENCERTAINEVENTSOCCUR,ANINTERRUPTSYSTEMCANSIGNALTHEPROCESSORTOSUSPENDPROCESSINGTHECURRENTINSTRUCTIONSEQUENCEANDTOBEGINANINTERRUPTSERVICEROUTINEISRTHEISRWILLPERFORMANYPROCESSINGREQUIREDBASEDONTHESOURCEOFTHEINTERRUPTBEFORERETURNINGTOTHEORIGINALINSTRUCTIONSEQUENCEPOSSIBLEINTERRUPTSOURCESAREDEVICEDEPENDENT,ANDOFTENINCLUDEEVENTSSUCHASANINTERNALTIMEROVERFLOW,COMPLETINGANANALOGTODIGITALCONVERSION,ALOGICLEVELCHANGEONANINPUTSUCHASFROMABUTTONBEINGPRESSED,ANDDATARECEIVEDONACOMMUNICATIONLINKWHEREPOWERCONSUMPTIONISIMPORTANTASINBATTERYOPERATEDDEVICES,INTERRUPTSMAYALSOWAKEAMICROCONTROLLERFROMALOWPOWERSLEEPSTATEWHERETHEPROCESSORISHALTEDUNTILREQUIREDTODOSOMETHINGBYAPERIPHERALEVENTMICROCONTROLLERPROGRAMSMUSTFITINTHEAVAILABLEONCHIPPROGRAMMEMORY,SINCEITWOULDBECOSTLYTOPROVIDEASYSTEMWITHEXTERNAL,EXPANDABLE,MEMORYCOMPILERSANDASSEMBLYLANGUAGEAREUSEDTOTURNHIGHLEVELLANGUAGEPROGRAMSINTOACOMPACTMACHINECODEFORSTORAGEINTHEMICROCONTROLLERSMEMORYDEPENDINGONTHEDEVICE,THEPROGRAMMEMORYMAYBEPERMANENT,READONLYMEMORYTHATCANONLYBEPROGRAMMEDATTHEFACTORY,ORPROGRAMMEMORYMAYBEFIELDALTERABLEFLASHORERASABLEREADONLYMEMORYSINCEEMBEDDEDPROCESSORSAREUSUALLYUSEDTOCONTROLDEVICES,THEYSOMETIMESNEEDTOACCEPTINPUTFROMTHEDEVICETHEYARECONTROLLINGTHISISTHEPURPOSEOFTHEANALOGTODIGITALCONVERTERSINCEPROCESSORSAREBUILTTOINTERPRETANDPROCESSDIGITALDATA,IE1SAND0S,THEYWONTBEABLETODOANYTHINGWITHTHEANALOGSIGNALSTHATMAYBEBEINGSENTTOITBYADEVICESOTHEANALOGTODIGITALCONVERTERISUSEDTOCONVERTTHEINCOMINGDATAINTOAFORMTHATTHEPROCESSORCANRECOGNIZETHEREISALSOADIGITALTOANALOGCONVERTERTHATALLOWSTHEPROCESSORTOSENDDATATOTHEDEVICEITISCONTROLLINGINADDITIONTOTHECONVERTERS,MANYEMBEDDEDMICROPROCESSORSINCLUDEAVARIETYOFTIMERSASWELLONEOFTHEMOSTCOMMONTYPESOFTIMERSISTHEPROGRAMMABLEINTERVALTIMER,ORPITFORSHORTAPITJUSTCOUNTSDOWNFROMSOMEVALUETOZEROONCEITREACHESZERO,ITSENDSANINTERRUPTTOTHEPROCESSORINDICATINGTHATITHASFINISHEDCOUNTINGTHISISUSEFULFORDEVICESSUCHASTHERMOSTATS,WHICHPERIODICALLYTESTTHETEMPERATUREAROUNDTHEMTOSEEIFTHEYNEEDTOTURNTHEAIRCONDITIONERON,THEHEATERON,ETCTIMEPROCESSINGUNITORTPUFORSHORTISESSENTIALLYJUSTANOTHERTIMER,BUTMORESOPHISTICATEDINADDITIONTOCOUNTINGDOWN,THETPUCANDETECTINPUTEVENTS,GENERATEOUTPUTEVENTS,ANDOTHERUSEFULOPERATIONSDEDICATEDPULSEWIDTHMODULATIONPWMBLOCKMAKESITPOSSIBLEFORTHECPUTOCONTROLPOWERCONVERTERS,RESISTIVELOADS,MOTORS,ETC,WITHOUTUSINGLOTSOFCPURESOURCESINTIGHTTIMERLOOPSUNIVERSALASYNCHRONOUSRECEIVER/TRANSMITTERUARTBLOCKMAKESITPOSSIBLETORECEIVEANDTRANSMITDATAOVERASERIALLINEWITHVERYLITTLELOADONTHECPUFORTHOSEWANTINGETHERNETONECANUSEANEXTERNALCHIPLIKECRYSTALSEMICONDUCTORCS8900A,REALTEKRTL8019,ORMICROCHIPENC28J60ALLOFTHEMALLOWEASYINTERFACINGWITHLOWPINCOUNTSINGLECHIPISANINTEGRATEDONASINGLECHIPACOMPLETECOMPUTERSYSTEMEVENTHOUGHMOSTOFHISFEATURESINASMALLCHIP,BUTITHASANEEDTOCOMPLETETHEMAJORITYOFCOMPUTERCOMPONENTSCPU,MEMORY,INTERNALANDEXTERNALBUSSYSTEM,MOSTWILLHAVETHECOREATTHESAMETIME,SUCHASINTEGRATEDCOMMUNICATIONINTERFACES,TIMERS,REALTIMECLOCKANDOTHERPERIPHERALEQUIPMENTANDNOWTHEMOSTPOWERFULSINGLECHIPMICROCOMPUTERSYSTEMCANEVENVOICE,IMAGE,NETWORKING,INPUTANDOUTPUTCOMPLEXSYSTEMINTEGRATIONONASINGLECHIPALSO，KNOWNASSINGLECHIPMCUMICROCONTROLLER,BECAUSEITWASFIRSTUSEDINTHEFIELDOFINDUSTRIALCONTROLONLYBYTHESINGLECHIPCPUCHIPDEVELOPEDFROMTHEDEDICATEDPROCESSORTHEDESIGNCONCEPTISTHEFIRSTBYALARGENUMBEROFPERIPHERALSANDCPUINASINGLECHIP,THECOMPUTERSYSTEMSOTHATSMALLER,MOREEASILYINTEGRATEDINTOTHECOMPLEXANDDEMANDINGONTHEVOLUMECONTROLDEVICESINTELTHEZ80ISONEOFTHEFIRSTDESIGNINACCORDANCEWITHTHEIDEAOFTHEPROCESSOR,FROMTHENON,THEMCUANDTHEDEVELOPMENTOFADEDICATEDPROCESSORPARTEDWAYSEARLYSINGLECHIP8BITORALLOFTHEFOURONEOFTHEMOSTSUCCESSFULISINTELS8031,BECAUSETHEPERFORMANCEOFASIMPLEANDRELIABLEACCESSTOALOTOFGOODPRAISESINCETHENIN8031TODEVELOPASINGLECHIPMICROCOMPUTERSYSTEMMCS51SERIESBASEDONSINGLECHIPMICROCOMPUTERSYSTEMOFTHESYSTEMISSTILLWIDELYUSEDUNTILNOWASTHEFIELDOFINDUSTRIALCONTROLREQUIREMENTSINCREASEINTHEBEGINNINGOFA16BITSINGLECHIP,BUTNOTIDEALBECAUSETHEPRICEHASNOTBEENVERYWIDELYUSEDAFTERTHE90SWITHTHEBIGCONSUMERELECTRONICSPRODUCTDEVELOPMENT,SINGLECHIPTECHNOLOGYISAHUGEIMPROVEMENTINTELI960SERIESWITHSUBSEQUENTARMINPARTICULAR,ABROADRANGEOFAPPLICATIONS,QUICKLYREPLACEDBY32BITSINGLECHIP16BITSINGLECHIPHIGHENDSTATUS,ANDENTERTHEMAINSTREAMMARKETTRADITIONAL8BITSINGLECHIPPERFORMANCEHASBEENTHERAPIDINCREASEINPROCESSINGPOWERCOMPAREDTOTHE80STORAISEAFEWHUNDREDTIMESATPRESENT,THEHIGHEND32BITSINGLECHIPFREQUENCYOVER300MHZ,THEPERFORMANCEOFTHEMID90SCLOSEONTHEHEELSOFASPECIALPROCESSOR,WHILETHEORDINARYPRICEOFTHEMODELDROPPEDTOONEUSDOLLARS,THEMOSTHIGHENDMODELS,ONLY10USDOLLARSCONTEMPORARYSINGLECHIPMICROCOMPUTERSYSTEMISNOLONGERONLYTHEBAREMETALENVIRONMENTINTHEDEVELOPMENTANDUSEOFALARGENUMBEROFDEDICATEDEMBEDDEDOPERATINGSYSTEMISWIDELYUSEDINTHEFULLRANGEOFSINGLECHIPMICROCOMPUTERINPDASANDCELLPHONESASTHECOREPROCESSINGOFHIGHENDSINGLECHIPOREVENADEDICATEDDIRECTACCESSTOWINDOWSANDLINUXOPERATINGSYSTEMSMORETHANADEDICATEDSINGLECHIPPROCESSORSUITABLEFOREMBEDDEDSYSTEMS,SOITWASUPTOTHEAPPLICATIONINFACTTHENUMBEROFSINGLECHIPISTHEWORLDSLARGESTCOMPUTERMODERNHUMANLIFEUSEDINALMOSTEVERYPIECEOFELECTRONICANDMECHANICALPRODUCTSWILLHAVEASINGLECHIPINTEGRATIONPHONE,TELEPHONE,CALCULATOR,HOMEAPPLIANCES,ELECTRONICTOYS,HANDHELDCOMPUTERSANDCOMPUTERACCESSORIESSUCHASAMOUSEINTHEDEPARTMENTAREEQUIPPEDWITH12SINGLECHIPANDPERSONALCOMPUTERSALSOHAVEALARGENUMBEROFSINGLECHIPMICROCOMPUTERINTHEWORKPLACEVEHICLESEQUIPPEDWITHMORETHAN40DEPARTMENTOFTHEGENERALSINGLECHIP,COMPLEXINDUSTRIALCONTROLSYSTEMSANDEVENSINGLECHIPMAYHAVEHUNDREDSOFWORKATTHESAMETIMESCMISNOTONLYFAREXCEEDSTHENUMBEROFPCANDOTHERINTEGRATEDCOMPUTING,EVENMORETHANTHENUMBEROFHUMANBEINGSTHEMONOLITHICINTEGRATEDCIRCUITSAIDTHATTHEMONOLITHICMICROCONTROLLER,ITISNOTCOMPLETESSOMELOGICALFUNCTIONTHECHIP,BUTINTEGRATESACOMPUTERSYSTEMTOACHIPONSUMMARYSPEAKINGACHIPHASBECOMEACOMPUTERITSVOLUMEISSMALL,THEQUALITYISLIGHT,ANDTHEPRICECHEAP,FORTHESTUDY,THEAPPLICATIONANDTHEDEVELOPMENTHASPROVIDEDTHECONVENIENTCONDITIONATTHESAMETIME,THESTUDYUSEMONOLITHICINTEGRATEDCIRCUITISUNDERSTANDSTHECOMPUTERPRINCIPLEANDTHESTRUCTUREBESTCHOICETHEMONOLITHICINTEGRATEDCIRCUITINTERIORALSOUSESWITHTHECOMPUTERFUNCTIONSIMILARMODULE,FORINSTANCECPU,MEMORY,PARALLELMAINLINE,BUTALSOHASWITHTHEHARDDISKBEHAVEIDENTICALLYTHEMEMORYCOMPONENT7WHATISDIFFERENTISITSTHESEPARTPERFORMANCEISOPPOSITEOURHOMEUSECOMPUTERWEAKMANY,BUTTHEPRICEISALSOLOW,GENERALLYDOESNOTSURPASS10YUANTHENMADESOMECONTROLELECTRICAPPLIANCEONEKINDWITHITISNOTTHEVERYCOMPLEXWORKFOOT,WEUSENOWTHECOMPLETELYAUTOMATICDRUMWASHER,THEPLATOONPETTICOATPIPEVCDANDSOONINSIDETHEELECTRICALAPPLIANCESMAYSEEITSFORMITISMAINLYTAKESTHECONTROLSECTIONTHECOREPARTITISONEKINDOFONLINELIKEREALTIMECONTROLCOMPUTER,ONLINELIKEISTHESCENECONTROL,NEEDSTOHAVETHESTRONGANTIJAMMINGABILITY,THELOWCOST,THISISALSOANDTHEOFFLINETYPECOMPUTERFORINSTANCEHOMEUSEPC,MAINDIFFERENCETHEMONOLITHICINTEGRATEDCIRCUITISDEPENDINGONTHEPROCEDURE,ANDMAYREVISEREALIZESTHEDIFFERENTFUNCTIONTHROUGHTHEDIFFERENTPROCEDURE,PARTICULARLYSPECIALUNIQUESOMEFUNCTIONS,THISISOTHERCOMPONENTNEEDSTOTAKETHEVERYBIGEFFORTTOBEABLETOACHIEVE,SOMEARETHEFLOWEREDBIGSTRENGTHISALSOVERYDIFFICULTTOACHIEVEONEISNOTTHEVERYCOMPLEXFUNCTION,IFDEVELOPSINTHE50SWITHTHEUS74SERIES,ORTHE60SSCD4000SERIESTHESEPUREHARDWAREDODECIDES,THEELECTRICCIRCUITCERTAINLYARCABIGPCBBOARDBUTIF,IFSUCCEEDEDINTHE70SWITHTHEUSPUTSINTHEMARKETTHESERIESMONOLITHICINTEGRATEDCIRCUIT,THERESULTWILLHAVETHEHUGEDIFFERENCEBECAUSEONLYTHEMONOLITHICINTEGRATEDCIRCUITCOMPILESTHROUGHYOUTHEPROCEDUREMAYREALIZETHEHIGHINTELLIGENCE,HIGHEFFICIENCY,ASWELLASREDUNDANTRELIABILITYTHECPUISTHEKEYCOMPONENTOFADIGITALCOMPUTERITSPURPOSEISTODECODEINSTRUCTIONRECEIVEDFROMMEMORYANDPERFORMTRANSFERS,ARITHMETIC,LOGIC,ANDCONTROLOPERATIONSWITHDATASTOREDININTERNALREGISTERS,MEMORY,ORI/OINTERFACEUNITSEXTERNALLY,THECPUPROVIDESONEORMOREBUSESFORTRANSFERRINGINSTRUCTIONS,DATA,ANDCONTROLINFORMATIONTOANDFROMCOMPONENTSCONNECTEDTOITAMICROCONTROLLERISPRESENTINTHEKEYBOARDANDINTHEMONITORINTHEGENERICCOMPUTERTHUSTHESECOMPONENTSAREALSOSHADEDINSUCHMICROCONTROLLERS,THECPUMAYBEQUITEDIFFERENTFROMTHOSEDISCUSSEDINTHISCHAPTERTHEWORDLENGTHSMAYBESHORT,THENUMBEROFREGISTERSSMALL,ANDTHEINSTRUCTIONSETSLIMITEDPERFORMANCE,RELATIVELYSPEAKING,ISPOOR,BUTADEQUATEFORTHETASKMOSTIMPORTANT,THECOSTOFTHESEMICROCONTROLLERSISVERYLOW,MAKINGTHEIRUSECOSTEFFECTIVEBECAUSETHEMONOLITHICINTEGRATEDCIRCUITTOTHECOSTISSENSITIVE,THEREFOREPRESENTOCCUPIESTHEDOMINANTSTATUSTHESOFTWAREISTHEMOSTPRELIMINARYASSEMBLYLANGUAGE7ITWASEXCEPTTHEBINARYMACHINECODEABOVETHEMOSTPRELIMINARYLANGUAGE,SINCEWHYWERESUCHPRELIMINARYMUSTUSEWHYHIGHLEVELDIDTHELANGUAGEALREADYACHIEVETHEVISUALIZATIONPROGRAMMINGLEVELNOTTOUSETHEREASONISVERYSIMPLE,ISTHEMONOLITHICINTEGRATEDCIRCUITDOCSNOTHAVEHOMECOMPUTERSUCHCPU,ANDALSOHASNOTLOOKEDLIKETHEHARDDISKSUCHMASSMEMORYEQUIPMENTINSIDEEVENIFAVISUALIZATIONHIGHERORDERLANGUAGECOMPILATIONSCRIPTONLYTHENABUTTON,ALSOWILLACHIEVESEVERALDOZENSKTHESIZESDOESNOTSPEAKANYTHINGREGARDINGTHEHOMEUSEPCHARDDISK,BUTSAYSREGARDINGTHEMONOLITHICINTEGRATEDCIRCUITCANNOTACCEPTTHEMONOLITHICINTEGRATEDCIRCUITINTHEHARDWARESOURCEASPECTSUSEFACTORMUSTVERYGAOCAIXING,THEREFOREASSEMBLY,ALTHOUGHPRIMITIVEACTUALLYMASSIVELYISUSING,SAMETRUTH,IFATTAINSSUPERCOMPUTERSONOPERATINGSYSTEMANDTHEAPPLICATIONSOFTWAREHOMEUSEPCTOCOMEUPTHEMOVEMENT,HOMEUSEPCCOULDALSONOTWITHSTANDITCANBESAIDTHATTHE20THCENTURYSURMOUNTEDTHREE“THEELECTRICITY“THETIME,NAMELYTHEELECTRICALTIME,THEELECTRONICAGEANDALREADYENTEREDCOMPUTERTIMEHOWEVER,THISKINDOFCOMPUTER,USUALLYREFERSTOTHEPERSONALCOMPUTER,ISCALLEDPCMACHINEITBYTHEMAINENGINE,THEKEYBOARD,THEMONITORANDSOONISCOMPOSEDALSOHASAKINDOFCOMPUTER,MOSTPEOPLEACTUALLYNOTHOWFAMILIARTHISKINDOFCOMPUTERISENTRUSTSWITHTHEINTELLIGENCEEACHKINDOFMECHANICALMONOLITHICINTEGRATEDCIRCUITALSOTOCALLMICROCONTROLLER,THISKINDOFCOMPUTERSSMALLESTSYSTEMONLYHASUSEDASTHENAMESUGGESTSAPIECEOFINTEGRATEDCIRCUIT,THENCARRIESONTHESIMPLEOPERATIONANDTHECONTROLBECAUSEITSVOLUMEISSMALL,USUALLYHIDESINISACCUSEDTHEMACHINERY“THEBELLY“ITINTHEENTIREINSTALLMENT,PLAYSISHAVINGLIKETHEHUMANBRAINSROLE,ITWENTWRONG,THEENTIREINSTALLMENTPARALYZEDNOW,THISKINDOFMONOLITHICINTEGRATEDCIRCUITSUSEDOMAINALREADYVERYWIDESPREAD,LIKETHEINTELLIGENTMEASURINGAPPLIANCE,THESOLIDWORKPAIDBYTIMECONTROL,THECOMMUNICATIONEQUIPMENT,THEGUIDANCESYSTEM,THEDOMESTICELECTRICAPPLIANCESANDSOON,ONCEEACHPRODUCTUSEDTHEMONOLITHICINTEGRATEDCIRCUIT,COULDGETUPCAUSESTHEEFFECTWHICHTHEPRODUCTTURNEDTOANEWGENERATION,OFTENBEFOREPRODUCTRANGECROWNBYADJECTIVEINTELLIGENCE,LIKEINTELLIGENCEWASHERANDSOONNOWSOMEFACTORYSTECHNICALPERSONNELOROTHEREXTRACURRICULARELECTRONICEXPLOITERDOCERTAINPRODUCTS,ARENOTTHEELECTRICCIRCUITARETOOCOMPLEX,ISTHEFUNCTIONISTOOSIMPLE,ANDISIMITATEDEXTREMELYEASILYINVESTIGATESITSREASON,POSSIBLYONCARD,INTHEPRODUCTHASNOTUSEDONTHEMONOLITHICINTEGRATEDCIRCUITOROTHERPROGRAMMABLELOGICALCOMPONENT二、AT89C51BRIEFINTRODUCTIONDESCRIPTIONTHEAT89C51ISALOWPOWER,HIGHPERFORMANCECMOS8BITMICROCOMPUTERWITH4KBYTESOFFLASHPROGRAMMABLEANDERASABLEREADONLYMEMORYPEROMTHEDEVICEISMANUFACTUREDUSINGATMELSHIGHDENSITYNONVOLATILEMEMORYTECHNOLOGYANDISCOMPATIBLEWITHTHEINDUSTRYSTANDARDMCS51INSTRUCTIONSETANDPINOUTTHEONCHIPFLASHALLOWSTHEPROGRAMMEMORYTOBEREPROGRAMMEDINSYSTEMORBYACONVENTIONALNONVOLATILEMEMORYPROGRAMMERBYCOMBININGAVERSATILE8BITCPUWITHFLASHONAMONOLITHICCHIP,THEATMELAT89C51ISAPOWERFULMICROCOMPUTERWHICHPROVIDESAHIGHLYFLEXIBLEANDCOSTEFFECTIVESOLUTIONTOMANYEMBEDDEDCONTROLAPPLICATIONSFUNCTIONCHARACTERISTICTHEAT89C51PROVIDESTHEFOLLOWINGSTANDARDFEATURES4KBYTESOFFLASH,128BYTESOFRAM,32I/OLINES,TWO16BITTIMER/COUNTERS,AFIVEVECTORTWOLEVELINTERRUPTARCHITECTURE,AFULLDUPLEXSERIALPORT,ONCHIPOSCILLATORANDCLOCKCIRCUITRYINADDITION,THEAT89C51ISDESIGNEDWITHSTATICLOGICFOROPERATIONDOWNTOZEROFREQUENCYANDSUPPORTSTWOSOFTWARESELECTABLEPOWERSAVINGMODESTHEIDLEMODESTOPSTHECPUWHILEALLOWINGTHERAM,TIMER/COUNTERS,SERIALPORTANDINTERRUPTSYSTEMTOCONTINUEFUNCTIONINGTHEPOWERDOWNMODESAVESTHERAMCONTENTSBUTFREEZESTHEOSCILLATORDISABLINGALLOTHERCHIPFUNCTIONSUNTILTHENEXTHARDWARERESETPINDESCRIPTIONVCCSUPPLYVOLTAGEGNDGROUNDPORT0PORT0ISAN8BITOPENDRAINBIDIRECTIONALI/OPORTASANOUTPUTPORT,EACHPINCANSINKEIGHTTTLINPUTSWHEN1SAREWRITTENTOPORT0PINS,THEPINSCANBEUSEDASHIGHIMPEDANCEINPUTSPORT0MAYALSOBECONFIGUREDTOBETHEMULTIPLEXEDLOWORDERADDRESS/DATABUSDURINGACCESSESTOEXTERNALPROGRAMANDDATAMEMORYINTHISMODEP0HASINTERNALPULLUPSPORT0ALSORECEIVESTHECODEBYTESDURINGFLASHPROGRAMMING,ANDOUTPUTSTHECODEBYTESDURINGPROGRAMVERIFICATIONEXTERNALPULLUPSAREREQUIREDDURINGPROGRAMVERIFICATIONPORT1PORT1ISAN8BITBIDIRECTIONALI/OPORTWITHINTERNALPULLUPSTHEPORT1OUTPUTBUFFERSCANSINK/SOURCEFOURTTLINPUTSWHEN1SAREWRITTENTOPORT1PINSTHEYAREPULLEDHIGHBYTHEINTERNALPULLUPSANDCANBEUSEDASINPUTSASINPUTS,PORT1PINSTHATAREEXTERNALLYBEINGPULLEDLOWWILLSOURCECURRENTIILBECAUSEOFTHEINTERNALPULLUPSPORT1ALSORECEIVESTHELOWORDERADDRESSBYTESDURINGFLASHPROGRAMMINGANDVERIFICATIONPORT2PORT2ISAN8BITBIDIRECTIONALI/OPORTWITHINTERNALPULLUPSTHEPORT2OUTPUTBUFFERSCANSINK/SOURCEFOURTTLINPUTSWHEN1SAREWRITTENTOPORT2PINSTHEYAREPULLEDHIGHBYTHEINTERNALPULLUPSANDCANBEUSEDASINPUTSASINPUTS,PORT2PINSTHATAREEXTERNALLYBEINGPULLEDLOWWILLSOURCECURRENT,BECAUSEOFTHEINTERNALPULLUPSPORT2EMITSTHEHIGHORDERADDRESSBYTEDURINGFETCHESFROMEXTERNALPROGRAMMEMORYANDDURINGACCESSESTOEXTERNALDATAMEMORYTHATUSE16BITADDRESSESINTHISAPPLICATION,ITUSESSTRONGINTERNALPULLUPSWHENEMITTING1SDURINGACCE