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1、DigitalFundamentalsTenthEditionFloydChapter11SummaryProgrammableLogicSPLD:(SimplePLDs)aretheearliesttypeofarraylogicusedforfixedfunctionsandsmallercircuitswithalimitednumberofgates.(ThePALandGALarebothSPLDs).CPLD:(ComplexPLDs)aremultipleSPLDsarraysandinter-connectionarraysonasinglech

2、ip.FPLD:(FieldProgrammableGateArray)areamoreflexiblearrangementthanCPLDs,withmuchlargercapacity.ProgrammableLogicDevices(PLDs)areICswithalargenumberofgatesandflipflopsthatcanbeconfiguredwithbasicsoftwaretoperformaspecificlogicfunctionorperformthelogicforacomplexcircuit.MajortypesofPL

3、Dsare:SummaryProgrammableLogicAdvantagestoPLDsincludeReducedcomplexityofcircuitboardsLowerpowerrequirementsLessboardspaceSimplertestingproceduresHigherreliabilityDesignflexibilitySummaryPALsandGALsPALshaveaonetimeprogrammable(OTP)array,inwhichfusesarepermanentlyblown,creatingtheprodu

4、cttermsinanANDarray.AllPLDscontainarrays.TwoimportantSPLDsarePALs(ProgrammableArrayLogic)andGALs(GenericArrayLogic).AtypicalarrayconsistsofamatrixofconductorsconnectedinrowsandcolumnstoANDgates.SimplifiedAND-ORarrayXAABBSummaryXAABBWhatfunctionisrepresentedbythearray?ExampleSolutionT

5、hefunctionrepresentsanXORgate.X=AB+ABPALsareprogrammedwithaspecializedprogrammerthatblowsselectedinternalfuselinks.Afterblowingthefuses,thearrayrepresentstheBooleanlogicexpressionforthedesiredcircuit.PALsandGALsSummaryTheGAL(GenericArrayLogic)issimilartoaPALbutcanbereprogrammed.Forth

6、isreason,theyareusefulfornewproductdevelopment(prototyping)andfortrainingpurposes.AABBXGALsweredevelopedbyLatticeSemiconductor.Theyarehighspeed,extremelyfastdevicesandcaninterfacewithboth3.3Vor5Vlogicsignals.PALsandGALsSummaryPALsandGALscanberepresentedwithasimplifieddiagram.Asinglel

7、inecanrepresentmultiplegateinputs.ThelogicshownisfortheXORgate,givenpreviously.InputbufferAABBSinglelinewithslashindicatingmultipleANDgateinputsFuseblownFuseintactABABAB+ABPALsandGALsSummaryPALsandGALshavelargearraylogicandincludeoutputlogicthatvariesincomplexity.Theoutputlogicisconn

8、ectedtoeachO