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TheGeneralSituationofAT89C511TheapplicationofAT89C51Microcontrollersareusedinamultitudeofcommercialapplicationssuchasmodems,motor-controlsystems,airconditionercontrolsystems,automotiveengineandamongothers.Thehighprocessingspeedandenhancedperipheralsetofthesemicrocontrollersmakethemsuitableforsuchhigh-speedevent-basedapplications.However,thesecriticalapplicationdomainsalsorequirethatthesemicrocontrollersarehighlyreliable.Thehighreliabilityandlowmarketriskscanbeensuredbyarobusttestingprocessandapropertoolsenvironmentforthevalidationofthesemicrocontrollersbothatthecomponentandatthesystemlevel.IntelPlatformEngineeringdepartmentdevelopedanobject-orientedmulti-threadedtestenvironmentforthevalidationofitsAT89C51automotivemicrocontrollers.ThegoalsofthisenvironmentwasnotonlytoprovidearobusttestingenvironmentfortheAT89C51automotivemicrocontrollers,buttodevelopanenvironmentwhichcanbeeasilyextendedandreusedforthevalidationofseveralotherfuturemicrocontrollers.TheenvironmentwasdevelopedinconjunctionwithMicrosoftFoundationClasses(AT89C51).Thepaperdescribesthedesignandmechanismofthistestenvironment,itsinteractionswithvarioushardware/softwareenvironmentalcomponents,andhowtouseAT89C51.1.1IntroductionThe8-bitAT89C51CHMOSmicrocontrollersaredesignedtohandlehigh-speedcalculationsandfastinput/outputoperations.MCS51microcontrollersaretypicallyusedforhigh-speedeventcontrolsystems.Commercialapplicationsincludemodems,motor-controlsystems,printers,photocopiers,airconditionercontrolsystems,diskdrives,andmedicalinstruments.TheautomotiveindustryuseMCS51microcontrollersinengine-controlsystems,airbags,suspensionsystems,andantilockbrakingsystems(ABS).TheAT89C51isespeciallywellsuitedtoapplicationsthatbenefitfromitsprocessingspeedandenhancedon-chipperipheralfunctionsset,suchasautomotivepower-traincontrol,vehicledynamicsuspension,antilockbraking,andstabilitycontrolapplications.Becauseofthesecriticalapplications,themarketrequiresareliablecost-effectivecontrollerwithalowinterruptlatencyresponse,abilitytoservicethehighnumberoftimeandeventdrivenintegratedperipheralsneededinrealtimeapplications,andaCPUwithaboveaverageprocessingpowerinasinglepackage.Thefinancialandlegalriskofhavingdevicesthatoperateunpredictablyisveryhigh.Onceinthemarket,particularlyinmissioncriticalapplicationssuchasanautopilotoranti-lockbrakingsystem,mistakesarefinanciallyprohibitive.Redesigncostscanrunashighasa$500K,muchmoreifthefixmeans2backannotatingitacrossaproductfamilythatsharethesamecoreand/orperipheraldesignflaw.Inaddition,fieldreplacementsofcomponentsareextremelyexpensive,asthedevicesaretypicallysealedinmoduleswithatotalvalueseveraltimesthatofthecomponent.Tomitigatetheseproblems,itisessentialthatcomprehensivetestingofthecontrollersbecarriedoutatboththecomponentlevelandsystemlevelunderworstcaseenvironmentalandvoltageconditions.Thiscompleteandthoroughvalidationnecessitatesnotonlyawell-definedprocessbutalsoaproperenvironmentandtoolstofacilitateandexecutethemissionsuccessfully.IntelChandlerPlatformEngineeringgroupprovidespostsiliconsystemvalidation(SV)ofvariousmicro-controllersandprocessors.Thesystemvalidationprocesscanbebrokenintothreemajorparts.Thetypeofthedeviceanditsapplicationrequirementsdeterminewhichtypesoftestingareperformedonthedevice.1.2TheAT89C51providesthefollowingstandardfeatures:4KbytesofFlash,128bytesofRAM,32I/Olines,two16-bittimer/counters,afivevectortwo-levelinterruptarchitecture,afulldupleserialport,on-chiposcillatorandclockcircuitry.Inaddition,theAT89C51isdesignedwithstaticlogicforoperationdowntozerofrequencyandsupportstwosoftwareselectablepowersavingmodes.TheIdleModestopstheCPUwhileallowingtheRAM,timer/counters,serialportandinterruptsys-temtocontinuefunctioning.ThePower-downModesavestheRAMcontentsbutfreezestheoscillatordisablingallotherchipfunctionsuntilthenexthardwarereset.Figure1-2-1BlockDiagram1.3PinDescriptionVCC:Supplyvoltage.GND:Ground.Port0:Port0isan8-bitopen-drainbi-directionalI/Oport.Asanoutputport,eachpincansinkeightTTLinputs.When1sarewrittentoport0pins,thepinscanbeusedashighimpedanceinputs.Port0mayalsobeconfiguredtobethemultiplexedloworderaddress/databusduringaccessestoexternalprogramanddatamemory.InthismodeP0hasinternalpullups.Port0alsoreceivesthecodebytesduringFlashprogramming,andoutputsthecodebytesduringprogramverification.Externalpullupsarerequiredduringprogramverification.Port1:Port1isan8-bitbi-directionalI/Oportwithinternalpullups.ThePort1outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort1pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port1pinsthatareexternallybeingpulledlowwillsourcecurrent(IIL)becauseoftheinternalpullups.Port1alsoreceivesthelow-orderaddressbytesduringFlashprogrammingandverification.Port2:Port2isan8-bitbi-directionalI/Oportwithinternalpullups.ThePort2outputbufferscansink/sourcefourTTLinputs.When1sarewrittentoPort2pinstheyarepulledhighbytheinternalpullupsandcanbeusedasinputs.Asinputs,Port2pinsthatareexternallybeingpulledlowwillsourcecurrent(IIL)becauseoftheinternalpullups.Port2emitstheh