單片機LED顯示控制系統(tǒng)中英文對照外文翻譯文獻

單片機LED顯示控制系統(tǒng)中英文對照外文翻譯文獻原文：DesignofLEDDisplayControlSystemBasedonAT89C52SingleChipMicrocomputerAbstract—ThispaperintroducesdisplaydesignprocessabouthardwareandsoftwarebasedonAT89C52singlechipmicrocomputer.Weuseasimpleexternalcircuittocontrolthedisplayscreen,whichsizeis32×192.Thedisplayscreenalsocandisplaythesizeofthesix32×32dotmatrixChinesecharactersbyadynamicscanmode,andcanbedividedintotwosmalldisplayscreen,whichcandisplaytwenty-fourChinesecharacterswhosesizeis16×16.Wecanmodifythecodetochangethecontentofthedisplay,subtitlescanachievescrollingfunctionandthescrollspeedcanbeadjustedaccordingtorequirements,subtitlescanalsoachievepausefunction.TheChinesecharactercodestoredinexternaldatamemory,thecapacityofdatamemoryisexpandedaccordingtotherequirementsofChinesecharacterswewanttoshow.Thisdisplayscreenhasadvantagesofsmallvolume,fewhardwareandsimplecircuitstructure.IndexTerms—LED,ChineseCharacterDisplay,AT89C52I.INTRODUCTIONLEDdisplayhasbecomeanimportantsymbolofthecitylighting,modernizationandinformationsocietywithcontinuousimprovementandbeautificationofpeople'slivingenvironment[6].LEDlightscanbeseeninthelargeshoppingmalls,railwaystation,docks,undergroundstation,avarietyofmanagementwindowandsoon.LEDbusinesshasbecomeafast-growingnewindustry,ahugemarketspaceandbrightprospects[9].Thetext,pictures,animationandvideoaredisplayedbyLED’slight,andcontentcanbechanged.Somecomponentsarethedisplaydevicesofthemodularstructure,andwhichusuallyconsistsofadisplaymodule,controlsystemandpowersystem.ThedisplaymoduleisconstitutedbythelatticestructurewhichconsistsofLED,andisresponsibleforlight-emittingdisplay;thescreencandisplaytext,pictures,videoandsoonbycontrolsystemwhichcancontrollightordarkofLEDinthecorrespondingregion;Powersystemisresponsiblefortransforminginputvoltageandcurrentintovoltageandcurrentwhichthescreenneeds.LEDdotmatrixdisplayextracteddisplaycharacterfontthroughPC,andsenttothemicrocontroller,thendisplayedinthedotmatrixscreen,whichmainlyusedfordisplayofindoorandoutdoorcharacters.LEDdotmatrixdisplaycanbedividedintographicdisplay,imagedisplayandvideodisplaybydisplayedcontent.Comparedwiththeimagedisplay,thecharacteristicsofgraphicdisplayisnodifferenceingraycolorwhetheritismonochromeorcolordisplay.Therefore,graphicdisplayalsofailstoreflecttherichnessofcolor,andvideodisplaycannotonlyshowexercise,clearandfull-colorimages,butalsoshowtelevisionandcomputersignals.Althoughtherearesomedifferencesbetweenthethree,butthemostbasicprinciplesaresimilar[6].SCMhasexcellentcostperformance,smallsize,highreliability,strongcontrol,andwidelyusedinsmartinstruments,mechanicalandelectricalintegration,realtimeprocesscontrol,robotics,domesticappliances,fuzzycontrol,communicationssystemsandsoon.ThisarticledescribedthedesignbytheLEDdisplayrelevantprinciple,andthedesignofhardwareandsoftwarestructurearedescribedindetail,finally,wesimulatefortheoveralldesignandanalyzetheresults.II.SystemOverallStructureDesignSingleChipMicrocomputer(SCM)modelswereselectedaccordingtothetarget,function,reliability,cost,accuracyandspeedofthecontrolsystem.Accordingtotheactualsituationofthesubject,thechoiceofSCMmodelsmainlyconsideredfromthefollowingtwoaspects:First,SCMhasstronganti-interferenceability;Second,SCMhasahighercost-effective.DuetoMCS-51iswidelyusedinChina,hasmoreinformationandcancompatiblewiththemoreperipheralchipstoo,inparticular,ATMELCorporation,introducedanewgenerationmicrocontrollerin2003,thatis89Sseries,anditstypicalproductswithhighperformanceandlowcostmicrocontrollerisAT89C52.AT89C52isalowvoltage,high-performanceCMOS8-bitmicrocontroller,thechipincludes8KBread-onlyprogrammemory(PEROM)whicherasecanberepeated,256byterandomaccessdatamemory(RAM),devicesadopthigh-densitynonvolatilememorytechnologytoproduce,compatiblewiththestandardMCS-51instructionsetandthe8052products,whilethechipbuilt-ingeneral-purpose8-bitcentralprocessing(CPU),Flashstorageunit,canbeappliedtothemorecomplexcontrolapplications[10].ThesystemwasrealizedbythecircuitrywhichismadeupofAT89C52chip,Clockcircuit,resetcircuit,columnscandrivercircuit,linedrivecircuitandthesix32×32LEDdotmatrix,theoverallstructureofLEDcharactersdisplayisshowninFig.1.Adisplayunitiscomposedofdotmatrixandtwo74HC154.Linedatasignalisdividedintotwoparts,whichisgivenbythetwo8255Arespectively,butthe8255AdataarefromtheP0portthemastercontrollerAT89C52.Thecolumnscanningsignalofeachcharacterwasgivenbythetwo74HC154,the74HC15412piecesandwasdividedintosixgroups.Theinputsignalof74HC154wasgivenbytheP1.0~P1.3ofAT89C52.Externaldatamemory6264connectedwiththeAT89C52theP0port.Figure1TheoverallstructureofLEDcharactersdisplayIII.SYSTEMHARDWARECIRCUITDESIGNA.CircuitDesignofMCUControlSystemThesizeofChinesecharactersis32×32,butmicrocontrollerhas32I/Oport,andcan’tmeetdesignrequirements,sotheI/Oportmustexpand,thedataportexpansionwasimplementedbytwo8255A.ThedataportexpansionisshowninFig.2,74HC373istheaddresslatch,andlatchloweightaddress,theloweightaddresssignalsof6264providedbyit,butthehigheightaddresssignalsof6264providedbyP2.0~P2.4,Internalportof8255AwaschosenbyA0andA1.74HC139is2-4decoder,whoseinputsignalsareprovidedbyP2.6andP2.7ofSCM,andprovidedstrobefortheexternalI/Odevices,becausethesystemhasmorethanoneexternaldevice,makesurethattheycannotbegated,sothattheiraddressesistheonlyanddonotrepeat.TheclockcircuitofAT89C52composedof18,19feetfromtheclockside(XTALIandXTAL2),and12MHzcrystalX,capacitorC1andC2,anduseson-chiposcillatormode.Resetcircuitusesasimplepower-onresetcircuit,andmainlyconstituteofresistorR1,capacitorC3,connectedtotheAT89C52'sresetinputpin.Figure.2.SCMcontrolsystemcircuitBTheCircuitDesignofDisplayMemoryUnitThesizeofChinesecharactersis32×32inthedesign,eachcharactercomposedoffourpartswhichare(a),(b),(c),and(d),andeachpartcomposedoffourLEDmatrixwhichthesizeis8×8,circuitdecompositionmapofdisplayunitisshowninFig.3.（A）(B) (C) (D)Figure.3.CircuitdecompositionmapofdisplayunitThelinesignalsof(a)~(b)aregivenbytwo8255A,1PA0~1PA7and1PB0~1PB7arePAandPBportof8255A-1,2PA0~2PA7and2PB0~2PB7arePAandPBportof8255A-2,therightfiguresrepresentcolumnscansignalswhichisgivenby74HC154.16columnstrobesareprovidedby74HC154,(a)~(d)requireseightsignal,respectively,so(a)and(b)sharea74HC154,(c)and(d)shareda74HC154.Displayacharacterneedtwo74HC154whichprovidecolumnscansignals.Whenthecircuitworks,the(a)~(d)isgatedbyscanningsignalinproperorder,onlyonewasgatedatatime,andothercolumnsareextinguished,thedisplayeddataisgivenbytwopiecesof8255Asimultaneously,thehumaneyewillseeastablecharacterbecauseofthehumaneye'spersistenceofvision.Inaddition,becausetheChinesecharacterforeachdisplayneeds128bytesstoragespace,butAT89C52microcontrollerchipisonly256bytesdatamemory,itisfarlessthanthedesignrequirements,sowetheexpandedstoragespaceby8K×8externaldatamemory6264.(a)(b)JOURNALOFCOMPUTERS,VOL.6,NO.4,APRIL2011719?2011ACADEMYPUBLISHERCTheDesignofRanksDataUnitCircuitInte18255Aisauniversalprogrammableparallelinput/outputinterfacechip.Itsfunctioncanbesetthroughthesoftwareprogram,andhasastrongversatility.ItcanbedirectlythroughtheCPUdatabusconnectedtoexternaldevices,easytouseandflexible.Inte18255Ainterfacechiphasthree8-bitparallelinputandoutputports,programmingmethodscanbeusedtosetthreeportsasinputportsoroutputports.Chipsworkhavethebasicinputandoutput,strobeinput/outputandbidirectionalinput/output.WhenthedataweretransmittedbydatabusofCPU,itscanchoosetounconditionallytransfer,querytransmissionorinterrupttransmission.DuringInte18255Achipthree-port,theportCcanbeusedasnotonlythedataport,butalsothecontrolport.WhentheportCistakenasadataport,itcanbeusedasnotonly8-bitdataport,butalsoseparatelyastwo4-bitdataport,andeachbitoftheportCcanbeoperated,cansetaparticularbittoinputoroutput,soprovideconvenientconditionsforbitscontrol.Figure.4.Figure.4.LinedataunitcircuitLinedataunitcircuitIndesignofthedisplayunitcircuit,thelinesdataaregivenbytwo8255A,asisshowninFigure4.ThisdesignusesdynamicdisplaymeanstodisplayChinesecharacters,whichcanbecontrolledthebythemeansoflineorcolumnscanning,Thesystemusesthemethodofcolumnscanningtocontrolscreen,SpecificcolumnscanningcircuitisshowninFigure5.Columnscanningcircuitcomposedof12piecesof74HC154.Twopiecesof74HC154provided32strobestodisplayacharacter.Theinputsignalof74HC154isP1.0~P1.3whichisprovidedbyAT89C52tocontrolscreen,but12piecesof74HC154wereusedinthedesign,theyworkaccordingtotheorder,theinputofanotherpieceof74HC154isP1.4~P1.7whichisprovidedbyAT89C52tocontrolscreen.Figure.5.columnscanunitcircuitFigure.6.SerialCommunicationInterfaceCircuitDSerialCommunicationInterfaceCircuitPCandSCMarelinkedviaaserialcommunicationinterface.InordertoimplementserialcommunicationfunctionbetweenMCUandPC,andserialinterfacelevelofSCMwillbechangedintostandardRS-232Clevel[11].WheretheoutputvoltageofPC’sRS-232Cportis±12V.MCUandPC,takingintoaccounttheshortdistancecommunication,andmicrocontrollerismainlyresponsibleforreceivingcommandsanddata,sothePCisdirectlyconnectedwiththemicrocontroller,thisisthesimplestconnectionmethod.thesignalswhichisfromPC’sTXD-sidewerechangedintoacurrentsignalthroughthecommunicationcircuit,theinfraredlightemittingdiodesofoptocouperhavecurrentwhenasignaloccurs,thelightsignalswhichisemittedbydiodeprojectedontotheandphototransistor,convertedtoelectricsignal,theninputtothemicrocontrollerRXDside,sophotoelectricconversionisimplemented,andelectricaliscompletelyisolatedtoavoidthefeedbackandinterferencewhichisproducedbyoutputside.asisshowninFigure6IV.SOFTWAREDESIGNTheentiresoftwaredesignmainlycomposesofdisplayprogramandcommunicationprogram.TheChinesecharacterstobedisplayedonthescreen,characterandotherdatafortransmissioncontrolanddisplayfunctionswereachievedbydynamicscan.RealtimecommunicationpartswhichcommunicatewithPCreceivedatainformationbySCMserialdisruption,soreal-timedatainformationtransmissionwithPCwasimplemented.ThehostcomputersoftwarewasimplementedbyVisualBasic.Inthestandardserialcommunication,MSCOMMwhichisthepowercommunicationcontrolisprovidedbyVB,itcansettheserialcommunicationofdatasentandreceived,andtheserialcommunicationportstatus,messageformatsandprotocolsareset,directlysenddatabyPC’sRS-232/RS-485serialport.InordertorealizedtoPCreliablecommunicationwithSCM,andensurethatbothsideshavethesamedataformatandbaudrate[11],thisdesignusesRS-232communications,a10bitsdataformat,9600bit/sbaudrate.APrinciplesofChinesecharactersdotmatrixdisplayandSub-codesChineseTimesNewRomanfontwhichisUCDOSwastakenasanexample,eachwordcomposedof16×16dotmatrix.Thatis,everywordofthenationalstandardChinesecharacterlibraryexpressedbythe256lattice.Wecanunderstandeachpointasapixel,andtheshapeofeachwordunderstoodasanimage.Infact,thischaracterdisplayscreennotonlycandisplayChinesecharacters,butalsocandisplayanygraphicswithinthescopeof256pixels.Duetothebusofmicrocontrolleristhe8-bit,andawordneedtosplitintotwoparts,asisshownfigure7.Figure.7.PrinciplesofChinesecharactersdisplayInordertounderstandChinesecharactersdotmatrixcompositionlaw,atfirst,thecharacterscodewasobtainedbycolumnscanningmethod.Chinesecharactersaredividedintoupperpartandlowerpart,theupperpartcomposedof8×16lattice,thelowerpartwasalsoformedbythe8×16lattice.ThefirstcolumnoftheupperleftcornerwhichwastheupperpartwasshownbyColumnscanningmethodfirst,namely,P00~P07portof0column,directionwasP00~P07,Chinesecharacterfor"large"wasdisplayed,P05wason,theotherisoff.Thatis,binaryis00000100,andconverttohexadecimalas04h.Afterthefirstcolumnoftheupperpartwasover,andcontinuetoscanthebottomhalfofthefirstcolumn,ItcanbeseenfromFigure7,thiscolumnisnotonall,thatis,binarywas00000000,hexwas00h.Accordingtothismethod,thesecondcolumn,thirdcolumn,untilthesixteenthwasscannedinturn.Characters"big"scancodecanbedrawn.04H,00H,04H,02H,04H,02H,04H,04H04H,08H,04H,30H,05H,0C0H,0FEH,00H05H,80H,04H,60H,04H,10H,04H,08H04H,04H,0CH,06H,04H,04H,00H,00HItcanbeseenfromthisprinciple,nomatterwhatfontorimagedisplay,wecanusethismethodtoanalyzethescancodeandappearsonthescreen.Althoughabovemethodsallowustofigureoutthecodeforcharacterdot-matrixprocess,butrelyonmanualmethodsforcharactercodeisaverycomplicatedmatter.Tothisend,Fontsoftwareisusedtofindthecharactercode,thecontenttodisplayisenteredafterthesoftwareopens,fontandsizecanbechosenaccordingtorequirements,youcanselectmodulobyroworbycolumn.Pressthemodulusbutton,thehexadecimaldatacharactercodecanbeautomaticallygenerated,weneedtocopythedataintotheprogram.B.AddressAssignmentthePortandDataMemoryInthisdesign,weusedto8255A,6264andotherexternaldevices,andtheirgatingisnotthesame,sostrobeiscontrolled,whichinvolvestheaddressallocationproblem.Inthesystem,theaddresscodeof8255Ais3FFCH~3FFFHand7FFCH~7FFFH,theaddresscodeof6264is0A000H~0BFFFH.Inaddition,memory6264isdividedintofourzones,eachspacesizeis2K,theTABLEI.correspondingaddresscodeis0A000H~0A7FFH,0A800H~0AFFFH,0B000H~0B7FFH,0B800H~0BFFFHrespectively.Table1andtable2showtheaddressallocationofthe8255Aand6264respectivelyTABLEII.6264INTERNALPARTIONTABLEZoningcategoriesA15~A0PartitionsizeAddresscodingFirstdistrict1010000000000000~10100111111111112K0A000H~0A7FFHSeconddistrict1010100000000000~10101111111111112K0A800~0AFFFHThirddistrict1011000000000000~10110111111111112K0B000H~0B7FFHFourthdistrict1011100000000000~10111111111111112K0B8000~0BFFFHC.SoftwareprocessSoftwareprogramcomposedofthebeginning,initialization,displayprogram,front,whichthemainprogramandsubroutineflowchartareshowninFigure.8.andFigure9.Charactercodestoredinthestaticmemory6264,andtheSCMwillwaitforsignalisgiven,thatis,theinputsignalofSCMpinP3.0.WhenP3.0isfromlowtohigh,displayprogrambegintoberun.First,controlwordswrittento8255Acontrolport,8255Aworkintheformofmode0inthedesign.Aftercontrolwordwasfinished,thedatawillbedisplayedwhichistransferredtothe8255Afromthe6264,thedisplaydataisoutputforfourtimesbecausethelinewidthofthecharactersscreenis32,arowofdataisinputandtransportedfromtoptobottomeach,signalofthefirstrowswhichiscontrolledbySCMisgatedafterdatatransmissionisover,sothefirstcolumndataisdisplayed,thencalldelayprocedurestodisplaythecontentsofthestable.thenextcolumnofdataisreadafterdelayproceduresisover,andthenextrowisgated,sothatthesecondcolumnofdataisalsodisplayed,andsoon,becausethescreensizeis32×192,192rowsareshown,and192rowsconstituteanimage.Then,scanningbeginfromthefirstcolumn,andthestartingaddressofdisplaydatabackwardshiftonthebasisoftheoriginal,whichhasanaddressoverflowissues,itwillassignstartaddresstotheaddresspointerwhenthedataaddressisoverflow,thedisplaydatacontentwillbeconstantlyrepeated.FlowchartofcommunicationwithPCandSCMisshowninFigure10.Real-timecommunicationpartswhichcommunicatewithPCreceivedatainformationbySCMserialdisruption,soreal-timedatainformationtransmissionwithPCwasimplemented.startstartInitializationCalldisplayprogramAdjustthedatapointerDisplayisover？YNFigure.8TheflowchartofmainprogramYYDelay1msTurnoffdisplayadjustthepointerWhethertodisplaythefinishedcharacter？Whethertodisplaythetime？endbeginSetadisplaytimeSetchipselectanddatapointerChecktheupperdataanddisplayOfcharactersChecktheupperdataanddisplayOfcharactersYNNFigure.9Theflowchartofsubroutine

CommunicationInitializationCommunicationInitializationWaitingforPCtotransferdataWhetherthedatareceivedisstartflag?Startedtoreceivedatadeterminewhetherthereisanendmark?CalculatingatatalofthecodeReceivednumber,Howmuchweredividedintoscreen?InterruptreturnContinuetoreceivedataYNNYFigure.10FlowchartofcommunicationwithPCandSCMV.SIMULATIONRESULTSANDANALYSISAfterthehardwareandsoftwaredesignfinished,thecontentofthedesignwassimulatedbyProteus,andmodifycircuitoroptimizetheprogramaccordingtothesimulationresults.ProteussoftwarewhichisEDAtoolsoftwareispublishedbytheBritishLabcenterelectronicscompanies(thesoftwareagentinChinaistheGuangzhouElectronicTechnologyCo.Ltd.vane)[7].ItnotonlyhassimulationfunctionsofotherEDAtools,butalsosimulatesmicrocontrollersandperipheraldevices.Itisthebestsimulationtoolformicrocontrollerandexternaldevice.AlthoughtheProteusjuststartedinthedomestic,loversofSCM,theteachersofteachinginSCMandscienceandtechnologyworkerswhichengagedinSCMalllovethissoftware.Proteusistheworld'sleadingEDAtools(simulationsoftware),fromtheschematiclayout,debuggingcodetotheMCUandtheexternalcircuitcosimulation,akeyswitchtothePCBdesign,completedesignwasrealizedfromconcepttoproduct.ItIsonlysimulationsoftwareplatformwhichiscomposedofcircuitsimulationsoftware,PCBdesignsoftwareandthevirtualmodel,theprocessormodelsupports8051,HC11,PIC10/12/16/18/24/30/DsPIC33,AVR,ARM,8086,andMSP430,etc.CortexandtheDSPfamilyofprocessorswereincreasedin2010,andwillincreaseotherseriesprocessormodel.Inthecompilationside,italsosupportsIAR,KeilandMATLABandsoon.APCBdesignandcomponentassemblyTakingintoaccountthenumberofcomponentsusedinthisdesignisnottoomuch,weusedthesingleroutingstrategy,anduseasmallamountofjumperwiresonthetopfloor.Thecircuitarenotstringentrequirementsforcomponentsparameters,aslongasthecomponentselectioniscorrect,nodamage,goodcircuitboardmanufacturingprocess,allelectroniccomponentscanbeassembledintothecorrectweldingprocedure,andtodownloadprogramanddebugprogram.WhenPCBboardwasproducedanddebugged,ICthatis20pinshouldbeinstalledintheAT89C52position,inordertothemicrocontrollercantakedownfromthecircuitboard,andwriteprogram.BSimulationScrollofChinesecharacterswasimplementedbysoftwareprogramming,wetakeawholeseriesofimageswhichwasimplementedbyColumnscansignalstoaframe,hereis192rows.Thenthenextframedatabackwardshiftonthebasisofthefirstframedata,anddynamicdisplaycanbegenerated.TheimagesresultofthesimulationisshowninFigure11.Figure.11theimagesresultofthesimulationThesimulationresultsshowsthatsimulationisconsistentwiththeoreticalanalysis,thedatadistributionofthememoryiscorrect,thedatacorrectlystoredintothedatamemory,thedisplayshowsthecontentsoftheprogramisthedatatobedisplayed,thedisplaycanalsobeachievedpauseanddisplayspeedisadjustable,indicatingthatthedesignofthehardwareandsoftwarearepossible.Afterthecompilationandsimulationofprogramwasaccomplished,preparinganeditorthatcanwritetheAT89C52,andconnectedwiththehostcomputerhardware,thatis,wecanwriteAT89C52chipanddownload,then,themicrocontrollerAT89C52whichiswrittenprograminsertintotheICthathas40pins.Whenpowerisconnected,wecandebugandrun,Asthesystemcircuitrequireforparametersofthecomponentsisnotveryhigh,aslongasthedeviceisbetter,theparameterscanmeettherequirements,andworkimmediatelyafterweldingassembly.VI.CONCLUSIONLEDdisplaysystemthatwasdesignedadoptedthehostcomputerandslavestructure,thehostcomputerisPC,andcommunicatedwithslavecomputerdisplaysystemthroughtheserialcommunicationinterface,whichcanimplementstringmodification,displaymodesettings,timesettingsandotherfunctions;TheslavemainlyimplementdisplayofLEDdotmatrixdisplayscreenwhichwascontrolled