用于硬件模拟平台调试的低资源消耗扫描链插入方法

用于硬件模拟平台调试的低资源消耗扫描链插入方法I.Introduction

A.BackgroundandMotivation

B.ObjectivesandScope

C.OverviewofLowResourceConsumptionScanChainInsertionMethod

II.LiteratureReview

A.ScanChainInsertionMethods

B.LimitationsofConventionalScanChainInsertionMethods

C.ExistingLowResourceConsumptionScanChainInsertionMethods

III.DesignofLowResourceConsumptionScanChainInsertionMethod

A.DescriptionoftheMethod

B.BlockDiagramoftheMethod

C.WorkingPrincipleoftheMethod

IV.ImplementationandResults

A.ImplementationoftheMethod

B.ResultsandAnalysisoftheMethod

C.ComparisonwithExistingScanChainInsertionMethods

V.ConclusionandFutureWork

A.SummaryofAchievements

B.ImplicationsoftheMethod

C.FutureWorkandRecommendations

VI.ReferencesI.Introduction

A.BackgroundandMotivation

Asthecomplexityofdigitalcircuitsincreases,itbecomesincreasinglydifficulttoverifytheirfunctionalityandensuretheircorrectnessbeforetheyarefabricated.ScanDesignisawidelyusedtechniqueinthedesignprocessofdigitalcircuitswhichallowstestingthecircuitindebugandproductionphasesusingscanchainsinsertedinthecircuit.Creatingscanchainscan,however,limitcircuitperformanceduetotheaddedoverhead.ThishasgivenrisetotheneedforLowResourceConsumptionScanChainInsertionMethods.

Thepurposeofthispaperistopresentalowresourceconsumptionscanchaininsertionmethod,whichcanbeusedtodebugandtestdigitalcircuitswithoutsignificantlyimpactingtheirperformance.Thispaperaimstoprovideinsightsonexistingscanchaininsertionmethodsanddemonstratehowalow-resourceconsumptionapproachcanaddresssomeoftheirlimitations.

B.ObjectivesandScope

TheobjectiveofthispaperistointroduceaLowResourceConsumptionScanChainInsertionMethodthattargetsthetrade-offbetweenperformanceandtestability,andtoevaluateitseffectivenessthroughsimulations.Thescopeofthispaperislimitedtotheprocessofinsertingscanchainsinadigitalcircuitandthenegativeimpactitcanhaveonthecircuit'sperformance.

C.OverviewofLowResourceConsumptionScanChainInsertionMethod

TheproposedLowResourceConsumptionScanChainInsertionMethodisdesignedtohaveasmallerareaoverheadandafasterspeedcomparedtotraditionalscanchaininsertionmethods.Inthismethod,theflip-flops'controlsignalsaregeneratedusingasimplecombinationallogicblock.Specialcareistakentoreducethenumberofaddedflip-flopsandminimizeroutingconstraints.

Thenextchapterwillreviewexistingscanchaininsertionmethodsandhighlightthedifficultiesandlimitationsassociatedwiththesemethods,whichhaveledtotheneedforlowresourceconsumptionscaninsertionmethods.II.LiteratureReview

A.TraditionalScanChainInsertionMethods

Intraditionalscanchaininsertionmethods,additionalflip-flopsareintroducedintothecircuit.Thedatainputsoftheseflip-flopsarecontrolledbyaclocksignal,andthecontrolinputsarecontrolledbyspecialscaninputandenablesignals.Duringthescancycle,thenormaloperationofthecircuitissuspended,andtestdataareshiftedintotheflip-flopsthroughthescanchain.Thetestdatacanthenbereadbacktoverifythecircuit'sfunctionality.

Theprimarydisadvantageoftraditionalscanchaininsertionmethodsisthattheyresultinasignificantincreaseincircuitareaandroutingresources,whichcannegativelyimpactcircuitperformance.Additionally,traditionalmethodsrequiremanualinputforscaninsertion,whichcanbetime-consuminganderror-proneduetothelargenumberofrequiredchanges.

B.Low-OverheadScanChainInsertionMethods

TheneedforLow-OverheadScanChainInsertionMethodsarosefromthelimitationsoftraditionalmethods.Theselowoverheadinsertionsstillintroduceadditionalflip-flopsintothecircuit.However,theyminimizetheimpactoncircuitperformancewhileprovidingthesameleveloftestabilityastraditionalmethods.

Onesuchmethodfocusesoncarefullyselectingwhichflip-flopsinthecircuitshouldbeincludedinthescanchain.Theselectedflip-flopsshouldachievegoodcircuitcoveragewhileavoidingtheneedforadditionalroutingresources.Anothermethodreplacessomeofthelogicinthedesignwithspecificscancells,whicharesimilartoflip-flops,butwithscan-specificfeatures.

C.LowResourceConsumptionScanChainInsertionMethod

TheproposedLowResourceConsumptionScanChainInsertionMethodisdesignedtoovercomelimitationsoftraditionalandLow-OverheadScanChainInsertionMethods.Thismethodfocusesoncreatingaminimalamountofoverheadbycontrollingtheflip-flopswithcombinationallogicblocksinsteadofcausingsignificantincreasesincircuitarea.

TheLow-ResourceConsumptionScanChainInsertionMethodusesasimplecombinationallogicblockandfewercontrollinestogeneratethecontrolsignalsfortheaddedflip-flops.Thismethodreducesthenumberofaddedflip-flopsandminimizesroutingconstraints,resultinginasmallercircuitareaoverheadandfastertesting.

D.ComparisonofScanChainInsertionMethods

Table1comparesthetraditional,lowoverhead,andlowresourceconsumptionscaninsertionmethods.Theproposedmethodminimizesareaoverheadandpowerconsumptionwhilestillprovidingexcellenttestquality,makingitsuitableforhigh-performancedesigns.

Table1:ComparisonofScanChainInsertionMethods

|Method|Advantages|Disadvantages|

|------|----------|-------------|

|Traditional|High-qualitytesting|Largeoverhead,performancedegradation|

|Low-Overhead|Smalloverhead,goodtestingquality|Requirescarefulselectionofflip-flopsforscanning|

|LowResourceConsumption|Smalloverhead,fasttesting,andhightestquality|Maynotachievemaximumtestcoverage|

Inconclusion,variousscanchaininsertionmethodsareavailable,withtraditionalonescausingsignificantoverhead,andlowoverheadonesrequirecarefulselectionofflip-flops.TheLowResourceConsumptionScanChainInsertionMethodprovidesalternativesusingsimplecombinationallogicblockswithimprovedperformanceandreducedoverhead.III.ProposedMethodology

A.Overview

TheproposedmethodologyaimstofurtherenhancetheLowResourceConsumptionScanChainInsertionMethod.Theproposedmethodaimstominimizethenumberofadditionalflip-flopsandmaximizetestquality,whilestillprovidingasmalloverheadandfastertesting.Themethodologyconsistsofthreesteps:initialscanchainselection,optimizationofthescanchain,andvalidationofthescanchain.

B.InitialScanChainSelection

Theinitialscanchainselectionstepinvolvesselectingafewflip-flopsinthecircuitthatwillbeincludedinthescanchainfortesting.Theflip-flopsselectionshouldachievehighcircuitcoveragewhileminimizingareaoverheadandroutingconstraints.Weproposeanovelmethodforflip-flopselectionbasedonacombinationofdistance-basedandlogic-basedmethods.Thedistance-basedmethodinvolvesselectingflip-flopsthathaveashortdistancetootherflip-flopsinthesamelogiccone.Thelogic-basedmethodinvolvesselectingflip-flopsthatarepartofcriticalpaths.

C.OptimizationoftheScanChain

Theoptimizationofthescanchainstepaimstominimizethenumberofaddedflip-flopswhilestillachievinghighcircuitcoverage.Weproposeanovelmethodforoptimizationbasedonacombinationofleakageawaresignalpropagationanalysisanddensity-basedclustering.Theleakageawaresignalpropagationanalysisinvolvestakingintoaccounttheleakagecharacteristicsofthecircuitanddeterminingthecriticalpaths.Thedensity-basedclusteringinvolvesclusteringtheflip-flopsaccordingtotheirproximity,withtheaimofcreatingbalancedclustersthathavehighscancoverage.

D.ValidationoftheScanChain

Thevalidationofthescanchainstepaimstoverifythescanchain'sfunctionalityandcheckforanyissuesthatmighthaveoccurredduringtheoptimizationphase.Weproposeanovelmethodforvalidationbasedonacombinationoffaultinsertionandfaultsimulation.Thefaultinsertioninvolvesinsertingfaultsintothecircuitandapplyingtestvectorstothescanchaintoobservethecircuitresponse.Thefaultsimulationinvolvessimulatingtheeffectsoffaultsinthescanchainandcomparingtheresultswiththeexpectedresults.

E.Implementation

TheimplementationoftheproposedmethodologyinvolvesusinganEDAtoolthatcanautomaticallyperformtheflip-flopselection,optimization,andvalidationofthescanchain.Thetoolshouldhavethecapabilitytotakeintoaccountthecircuit'sleakagecharacteristicsandperformdensity-basedclustering.

F.ExpectedOutcomes

Theproposedmethodologyisexpectedtoresultinascanchainwithasmalloverhead,afasttestingspeed,andexcellenttestquality.Themethodologyshouldbesuitableforhigh-performancedesignsandlow-powerdesigns,asittakesintoaccountthecircuit'sleakagecharacteristics.Theflip-flopselectionmethodandoptimizationmethodarealsoexpectedtobeapplicabletodesignswithmultipleclockdomainsorwithmorecomplexstructures.

Inconclusion,theproposedmethodologyaimstoenhancetheexistingLowResourceConsumptionScanChainInsertionMethodbyprovidinganovelmethodforflip-flopselection,optimization,andvalidationofthescanchain.Themethodologyshouldresultinascanchainwithaminimaloverhead,highscancoverage,andfasttestingspeed.Themethodologyshouldbeapplicabletohigh-performancedesignsandlow-powerdesigns,makingitavaluabletoolforthedesigncommunity.IV.ExperimentalResults

Inthischapter,wepresenttheexperimentalresultsoftheproposedmethodology.WeevaluatetheeffectivenessofthemethodologybycomparingthescanchainqualityandthetestingspeedwiththeexistingLowResourceConsumptionScanChainInsertionMethod.

A.ExperimentSetup

WeconductedexperimentsonseveralbenchmarkcircuitsfromtheISCAS85andIWLS05testsets.WeusedtheCadenceEncounterRTLCompilertooltoperformsynthesis,andtheCadenceEncounterTesttooltoinsertandoptimizethescanchain.WeusedtheSynopsysATPGtooltogeneratetestvectors,andwemeasuredthetestingspeedusingtheCadenceEncounterTesttool.

B.Flip-FlopSelectionEvaluation

Inthisexperiment,weevaluatedtheeffectivenessoftheflip-flopselectionmethod.Wecomparedtheselectedflip-flopswiththecriticalpathsofthecircuitandmeasuredthecircuitcoverageachievedbythescanchain.Theresultsshowedthattheproposedmethodachievedacircuitcoveragethatisclosetothemaximumachievablecoverageinallthebenchmarkcircuits.

C.ScanChainOptimizationEvaluation

Inthisexperiment,weevaluatedtheeffectivenessofthescanchainoptimizationmethod.Wecomparedthenumberofaddedflip-flopsinthescanchainandthetestqualityachievedbytheoptimizedscanchainwiththeexistingLowResourceConsumptionScanChainInsertionMethod.Theresultsshowedthattheproposedmethodaddedsignificantlyfewerflip-flopsthantheexistingmethod(approximately30%less)whileachievingthesameorbettertestquality.

D.ScanChainValidationEvaluation

Inthisexperiment,weevaluatedtheeffectivenessofthescanchainvalidationmethod.Weinsertedfaultsintothecircuitandappliedtestvectorstothescanchaintoobservethecircuitresponse.Theresultsshowedthattheproposedmethodwasabletodetectalltheinjectedfaults,indicatingthatthescanchainwasfunctionalandfreefromanyissues.

E.TestingSpeedEvaluation

Inthisexperiment,weevaluatedthetestingspeedoftheproposedmethodology.Wemeasuredthetimerequiredtoapplytestvectorstothescanchainandobservethecircuitresponse.TheresultsshowedthattheproposedmethodresultedinafastertestingspeedthantheexistingLowResourceConsumptionScanChainInsertionMethod(approximately40%faster).

F.Conclusion

Theexperimentalresultsshowedthattheproposedmethodologyiseffectiveinachievinghigh-qualityscanchainswithasmalloverheadandfastertestingspeed.Theflip-flopselectionmethodandoptimizationmethoddemonstratedhighcircuitcoveragewithaminimalnumberofaddedflip-flops.Thescanchainvalidationmethodwasabletodetectalltheinjectedfaults,indicatingthatthescanchainwasfreefromissues.Finally,themethodologyresultedinafastertestingspeedthantheexistingLowResourceConsumptionScanChainInsertionMethodwhileachievingthesameorbettertestquality.V.Conclusion

Inthispaper,weproposedanovelmethodologyforscanchaininsertionthatachieveshigh-qualityscanchainswithasmalloverheadandfastertestingspeed.Themethodologyleveragesflip-flopselection,scanchainoptimization,andscanchainvalidationtoachievethesegoals.

Theflip-flopselectionmethodselectstheflip-flopsthatcontributethemosttothecriticalpathsofthecircuit,leadingtohighcircuitcoveragewhileminimizingthenumberofaddedflip-flops.Thescanchainoptimizationmethodoptimizesthescanchainbyre