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电子与信息工程学院本科毕业论文(设计)外文文献翻译译文题目：8-bitMicrocontrollerWith8KBytesFlashAT89C52学生姓名：吴远超专业：电气工程及其自动化指导教师：倪浩2012年11月外文资料8-bitMicrocontrollerWith8KBytesFlashAT89C52FeaturesCompatiblewithMCS-51™Products8KBytesofIn-SystemReprogrammableFlashMemoryEndurance:1,000Write/EraseCyclesFullyStaticOperation:0Hzto24MHzThree-levelProgramMemoryLock256x8-bitInternalRAM32ProgrammableI/OLinesThree16-bitTimer/CountersEightInterruptSourcesProgrammableSerialChannelLow-powerIdleandPower-downModesDescriptionTheAT89C52isalow-power,high-performanceCMOS8-bitmicrocomputerwith8KbytesofFlashprogrammableanderasablereadonlymemory(PEROM).ThedeviceismanufacturedusingAtmel’shigh-densitynonvolatilememorytechnologyandiscompatiblewiththeindustry-standard80C51and80C52instructionsetandpinout.Theon-chipFlashallowstheprogrammemorytobereprogrammedin-systemorbyaconventionalnonvolatilememoryprogrammer.Bycombiningaversatile8-bitCPUwithFlashonamonolithicchip,theAtmelAT89C52isapowerfulmicrocomputerwhichprovidesahighly-flexibleandcost-effectivesolutiontomanyembeddedcontrolapplications.PinConfigurationsBlockDiagramPinDescriptionVCCSupplyvoltage.GNDGround.Port0Port0isan8-bitopendrainbi-directionalI/Oport.Asanoutputport,eachpincansinkeightTTLinputs.When1sarewrittentoport0pins,thepinscanbeusedashigh-impedanceinputs.Port0canalsobeconfiguredtobethemultiplexedlow-orderaddress/databusduringaccessestoexternalprogramanddatamemory.Inthismode,P0hasinternalpull-ups.Port0alsoreceivesthecodebytesduringFlashprogrammingandoutputsthecodebytesduringprogramverification.Externalpull-upsarerequiredduringprogramverification.Port1Port1isan8-bitbi-directionalI/Oportwithinternalpull-ups.ThePort1outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort1pins,theyarepulledhighbytheinternalpull-upsandcanbeusedasinputs.Asinputs,Port1pinsthatareexternallybeingpulledlowwillsourcecurrent(IIL)becauseoftheinternalpull-ups.Inaddition,P1.0andP1.1canbeconfiguredtobethetimer/counter2externalcountinput(P1.0/T2)andthetimer/counter2triggerinput(P1.1/T2EX),respectively,asshowninthefollowingtable.Port1alsoreceivesthelow-orderaddressbytesduringFlashprogrammingandverification.Port2Port2isan8-bitbi-directionalI/Oportwithinternalpull-ups.ThePort2outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort2pins,theyarepulledhighbytheinternalpull-upsandcanbeusedasinputs.Asinputs,Port2pinsthatareexternallybeingpulledlowwillsourcecurrent(IIL)becauseoftheinternalpull-ups.Port2emitsthehigh-orderaddressbyteduringfetchesfromexternalprogrammemoryandduringaccessestoexternaldatamemoriesthatuse16-bitaddresses(MOVX@DPTR).Inthisapplication,Port2usesstronginternalpull-upswhenemitting1s.Duringaccessestoexternaldatamemoriesthatuse8-bitaddresses(MOVX@RI),Port2emitsthecontentsoftheP2SpecialFunctionRegister.Port2alsoreceivesthehigh-orderaddressbitsandsomecontrolsignalsduringFlashprogrammingandverification.Port3Port3isan8-bitbi-directionalI/Oportwithinternalpull-ups.ThePort3outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort3pins,theyarepulledhighbytheinternalpull-upsandcanbeusedasinputs.Asinputs,Port3pinsthatareexternallybeingpulledlowwillsourcecurrent(IIL)becauseofthepull-ups.Port3alsoservesthefunctionsofvariousspecialfeaturesoftheAT89C51,asshowninthefollowingtable.Port3alsoreceivessomecontrolsignalsforFlashprogrammingandverification.RSTResetinput.Ahighonthispinfortwomachinecycleswhiletheoscillatorisrunningresetsthedevice.ALE/PROGAddressLatchEnableisanoutputpulseforlatchingthelowbyteoftheaddressduringaccessestoexternalmemory.Thispinisalsotheprogrampulseinput(PROG)duringFlashprogramming.Innormaloperation,ALEisemittedataconstantrateof1/6theoscillatorfrequencyandmaybeusedforexternaltimingorclockingpurposes.Note,however,thatoneALEpulseisskippedduringeachaccesstoexternaldatamemory.Ifdesired,ALEoperationcanbedisabledbysettingbit0ofSFRlocation8EH.Withthebitset,ALEisactiveonlyduringaMOVXorMOVCinstruction.Otherwise,thepinisweaklypulledhigh.SettingtheALE-disablebithasnoeffectifthemicrocontrollerisinexternalexecutionmode.PSENProgramStoreEnableisthereadstrobetoexternalprogrammemory.WhentheAT89C52isexecutingcodefromexternalprogrammemory,PSENisactivatedtwiceeachmachinecycle,exceptthattwoPSENactivationsareskippedduringeachaccesstoexternaldatamemory.EA/VPPExternalAccessEnable.EAmustbestrappedtoGNDinordertoenablethedevicetofetchcodefromexternalprogrammemorylocationsstartingat0000HuptoFFFFH.Note,however,thatiflockbit1isprogrammed,EAwillbeinternallylatchedonreset.EAshouldbestrappedtoVCCforinternalprogramexecutions.Thispinalsoreceivesthe12-voltprogrammingenablevoltage(VPP)duringFlashprogrammingwhen12-voltprogrammingisselected.XTAL1Inputtotheinvertingoscillatoramplifierandinputtotheinternalclockoperatingcircuit.XTAL2Outputfromtheinvertingoscillatoramplifier.SpecialFunctionRegistersAmapoftheon-chipmemoryareacalledtheSpecialFunctionRegister(SFR)spaceisshownintheTable1.Notethatnotalloftheaddressesareoccupied,andunoccupiedaddressesmaynotbeimplementedonthechip.Readaccessestotheseaddresseswillingeneralreturnrandomdata,andwriteaccessesw