毕业设计46智能去电控制器的设计配套翻译.docx
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毕业设计46智能去电控制器的设计配套翻译.docx
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毕业设计46智能去电控制器的设计配套翻译
Theapplicationofmicrocontroller
inclosedcaptionsystem
Abstract
ThispaperdescribesournewlydesignedmicrocontrollersforClosedCaptionsystemapplication.ThesemicrocontrollersintegratetheClosedCaptiondecodingfunctionandotherfunctionsrequiredforTVsetcontrol.
1.Introduction
MicrocontrollersthatutilizetheClosedCaptionfunctionhavebeendeveloped.TheClosedCaptiondecodingfunctionmustbeprovidedforallTVsetssoldintheU.S.fronJuly1993.
Thesebasicsystemdevelopmentguidelineswereasfollows:
(1)Thesystemmustprovidestabilizedreception.
(2)Thesystemshouldofferlow-costoperation.
Thekeywordforthisdevelopmentwasfull-function.InregulationsestablishedonApril12,1991,theFCCspecifiedthetextmodeasbeingoptional,thusreflectingthatcommitteeonlow-costsystems.WithourgoalofsupplyingClosedCaptionhardwareasanewinformationmedium,wedecidedtodevelopasystemsatisfyingthespecificationsforalloptions.Lastyearweintroducedtheadd-ontypeofClosedCaptionDecoderLSIkitdesignedforeasyinstallationintoexistingTVsets.TheClosedCaptiondecodingfunctionisimplementedefficientlybymicrocontrollersdescribedinthispaper.Thehigh-performance
On-ScreenDisplayfunctionforClosedCaptionapplicationcanbeusedforeasyTVsetoperation.
Thisnewmicrocontrollerisalowcost,highaccuracyinstrumentationthatrequiresonlyoneexternalresistortosetgainsof1to10,000.Furthermore,Thisnewmicrocontrollerfeatures32-leadSOICandDIPpackagingthatissmallerthandiscretedesignsandofferslowerpower,makingitagoodfitforclosedcaptionsystemandportable(orremote)applications.
Thisnewmicrocontroller,withitshighaccuracyof40ppmmaximumnonlinearity,lowoffsetvoltageof50µVmax,andoffsetdriftof0.6µV/°Cmax,isidealforuseinprecisiondataacquisitionsystems’transducerinterfaces.Furthermore,thelownoise,lowinputbiascurrent,andlowpowerofThisnewmicrocontrollermakeitwellsuitedformedicalapplications,suchasECGandnoninvasivebloodpressuremonitors.
Thelowinputbiascurrentof1.0nAmaxismadepossiblewiththeuseofprocessingintheinputstage.Thisnewmicrocontrollerworkswellasapreamplifierduetoitslowinputvoltagenoiseof9nV/Hzat1kHz,0.28µVp-pinthe0.1Hzto10Hzband,and0.1pA/Hzinputcurrentnoise.Also,Thisnewmicrocontrolleriswellsuitedformultiplexedapplicationswithitssettlingtimeof15µsto0.01%,anditscostislowenoughtoenabledesigns
withoneDUTperchannel.
2.SystemOverview
OurnewmicrocontrollersprovideTVsystemswiththeClosedCaptionfunctionwhenusedwiththeFrontEndLSI.SincetheFrontEndLSIisdesignedwithbipolartechnology,itprovidesverystableoperationevenunderweakorabnormalsignalconditions.Themicrocontrollersemployan8-bitCPUcoreandintegratetheClosedCaptiondecodingfunctionandallfunctionsrequiredforTVsetcontrol.ThisseriesofmicrocontrollersconsistofanEP-ROMversion,OTPROMversion,andmask-ROMversionsof8K,12K,16K,20K,24K,28Kand32K-byteROMcapacity.ExceptforROMcapacity,allotherfunctionsareexactlythesameforsimpleinstallationintodifferenttypesofTVsets.AmicrocontrollerandtheFrontEndLSIcanreplacetheexistingtunermicrocontrollerprovidingtheClosedCaptiondecodingfunction.Therefore,astabledecodingfunctioncanbeprovidedwithoutalargeexpenditureforparts.
2.1FrontEnd
ThisLSIreceivesthecompositevideosignalfromthevideosignalprocessorandextractstheCaptionDatafromthesignal.ThisLSIcontainsabipolardevicewithasynchronizingseparatorcircuit.BygeneratingtheHorizontalsynchronizingsignalandVerticalsynchronizingsignalbyitself,thisdeviceextractsthecaptionsignalfromline21.ThisLSIhastwoAFCblocks.AFC1isthestandardAFCblocktostabilizetheVCO(VoltageControlledOscillator)to32MH.ThesignalfromthevideoandanothersignalfromtheHorizontalC/DdividedVCOoutputaresenttoAFC1.AFC2istheadditionalAFCblocktosynchronizethephaseofVCOoutputforthecaptionsignal.Thisdesignenablestheclocktoberegeneratedwiththefrequencyandphasesynchronized.ThisLSIdetectsline21andonlyoutputstheslicedsignal,VCOoutputasclocksduringthedataperiod.Inotherwords,clocks,dataandthetransmissionsignal(TRANS)areoutputduringline21ofeachfield.Inaddition,thisLSIdiscriminatesbetweenoddandevenfieldsandtransfersthesignal(O/E).
2.2MicrocontrollerSystemConfiguration
ThemicrocontrollerconsistsoftheCPUandotherfunctionsneededforTVcontrol,suchastheClosedCaptionOn-ScreenDisplayfunction(OSD),remotecontrolinputcircuitwithanoise
eliminationfunction,PWMoutputcapableofvideosystemcontrol,soundsystemcontrol,A/DconvertercapableofdetectingAFT,key-ininput,andserialI/O.AllofthesefunctionsandtheCPUarepackagedonasinglechip.Acontrolcodesetsthedisplayformat,position,andfourattributes:
color,italics,underline,andflash.ThesubsequentcharactersarepositionedasspecifiedintheOSDDisplayRAMwiththeseattributes.ThedecodeddataisstoredinthedisplayRAM,thenisconvertedtotheR,G,B,andBLsignalsbyusingtheGeneratorROMinformation.TheR,G,B,andBLsignalsaresynchronizedtotheverticalandhorizontalsynchronizationsignals,andtothedotclockgeneratedbythebuilt-incircuit.Thesesignalscarrytheattributeinformationandfontdatathatwillbedisplayedonthescreenaccordingtocurrentdisplayformat.
3.ClosedCaptionOn-ScreenDisplayFunction
3.1CircuitConfiguration
TheClosedCaptionOn-screenDisplayfunction(OSD)consistsofthecontrolblock,DisplayRAM,CharacterGeneratorROM,outputblockandoscillationcircuit.Thecontrolblockconsistsofthemodeandtimingcontrolcircuit,theverticalpositioncontrolcircuit,andthehorizontalpositioncontrolcircuit.ThisblockcontrolstheaccesstimingoftheDisplayRAMand
displaysoutputinvariousdisplaymodes.Theclosedcaptiondataineachfield,whichislevelslicedandcapturedbytheLSI,isseriallytransferredtotheDataRegisterofthismicrocontroller.Thetrailingedgeofthesignalgeneratesaninterrupt.Thisinterruptcausesthesoftwaretojudgethefields,checkdataparity,anddecodecaptiondata.ThedatalengthoftheDisplayRAMiseightbits.TosupporttheCaptionTextmodeandreducetheburdenonsoftwareunderOn-ScreenDisplaycontrol,theDisplayRAMisadaptabletoafull-screensize.Eachrowconsistsofonecolumnusedfortheinitialattributevalue,and32columnsusedforthedisplayarea.TheCharacterGeneratorROMhasacapacityof112pre-setcharacterfontsinClosedCaptionformatand16characterfonts.Theoutputblockcontrolcharacteroutputaccordingtothedisplayformatusedineachmode.
3.2ExistingDisplayRAMArchitecture
Ifthetimingofon-screendisplayissynchronizedtotheCPUclock,jitteroccurshorizontally.Thisiswhythattimingmustbesynchronizedtothedeflectionsystem.Therefore,adual-portRAMstructureisgenerallyusedintheDisplayRAMfortheTVcontrolmicrocontrollertoenableasynchronousaccessfromtheCPUandOSDcircuit.However,adual-portRAMrequiresmorespaceandincreasescost,therefore;asmaller-capacityDisplayRAMisusuallyprovidedtosolvethisproblem.Inthiscase,theDisplayRAMcanholdonlythedataforasmallpartofthescreen.Todisplayanentirescreen,theDisplayRAMdatamustbechangedeachtimethedisplaypositionismovedtoanothergroupofrows.Thisrequiresthedisplaycontrolroutineoftheprogramtobeexecutedveryquickly.Therefore,programhastobedesigned
verycarefullywithspecialdesigntechniques,thus,programwillbecomplicatedandittakeslongerdesignperiod.
3.3DisplayRAMArchitectureofthisMicrocontroller
Toimplementcaptionmodedisplay,atleast256bytesofmemoryarenecessarytostorethedata.Inthefull-screenTextMode,480bytesofmemoryarenecessarytostorethedata.Thisamountofmemorymustbepreparedeitherasdisplaymemoryordatamemory.Basedonourstudyandexamination,webelievethattheDisplayRAMarchitecturedescribedbelowfacilitatesthemostefficientimplementationpossibility:
(1)ProvidetheRAMwithfull-screencapabilityandthedisplaydatamemoryfunctions.
(2)EmploythesingleportstructureofthisRAMthatcanbeaccessedsimultaneouslyfromtheCPUanddisplaycontrolcircuitwithnorestrictions.ThesemeasuressolvetheproblemsdescribedinSection3.2andminimizethecostofprovidingTextModecapability.
4.SinglePortRAMimplementation
4.1TimingallocationonsingleportDisplayRAM
DisplayRAMisaccessedthroughtherowaddressandcolumnaddresssynchronizedbytheCPUclock.ForaccessfromtheCPU,therowaddressisspecifiedbytherowaddressregister;thecolumnaddressisspecifiedbythecolumnaddressregister.Foraccessfromthecaptiondisplaycircuit,therowaddressoftheDisplayRAMisdeterminedbytheverticalpositionofthecharactertobedisplayed.ThecolumnaddressoftheDisplayRAMisdeterminedbythehorizontalpositionofthecharactertobedisplayed.The32charactershavetobedisplayedinoneline
andeachcharacterconsistsofaneight-dothorizontalattributespecificationcodeaccordingtothemodeused.Italics,flash,underline,andcharactercolorarespecifiedinthecaptionandtextmodes.Characterbackgroundcolorandcharactercolorarespecifiedin16-lineOSDmodeand8-lineOSDmode.
5.OtherFeaturesinOSDMode
ThefollowingOSDmodefeaturesarealsoprovided:
-8charactercolors
-8characterbackground/fringec
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