数字逻辑设计及应用教学英文课件：Lec10-Chap 6.ppt

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1、1DigitalLogicDesignandApplicationLecture#10CombinationalLogicDesignPracticesDocumentationStandardandCircuitTimingUESTC,Spring20132Chapter6CombinationalLogicDesignPracticesHowtoconceiveacomplexsystem?––structuredthinkingSomeusefulcombinationalcomponents36.1DocumentationS

2、tandardAdocumentationpackagecontainthefollowingitems:Specification:descriptionofinterfaceandfunctionBlockdiagram:system’smajorfunctionmoduleandtheirbasicinterconnectionsSchematicdiagram（P360Figure6-17）Timingdiagram（P363Figure6-19）StructuredlogicdevicedescriptionCircuitdes

3、cription:explainshowthecircuitworksinternally4schematicdiagram51.BlockDiagramsAblockdiagramshowstheinputs,outputs,functionalmodules,internaldatapaths,andimportantcontrolsignalsofasystem.P345Figure6-162.GateSymbols7EquivalentGateSymbolsundertheGeneralizedDemorgan’sTheorem

4、inverterbufferANDNANDNORORORNORNANDAND83.ActiveLevelsactivelevelactivehighandactivelowasserted:asignalisatitsactivelevelnegated/deasserted:signalisnotatitsactivelevelsignalnameActivelevelsforpinsLogicFunctionsareperformedinsidethesymbolicoutlines.READYREQUESTGOREADY_LREQU

5、EST_LGO_LIndicateanActive-LowPin与门和或门的输入为1才能确保其输出9Example:activelevelsABFSignalactivestate:switch—off,lamp—lightABF000010100111Switch:1－offLamp:1－lightABFSwitch:0－offLamp:0－lightABF000011101111ABFF=A+B=(A’·B’)’AND:theoutputisassertedifandonlyifallitsinputsareasserted.Posi

6、tiveLogic1：HighLevel0：LowLevelActiveHighActiveLow10Example:activelevelsABFActivestate:switch—off,lamp—lightAND:theoutputisassertedifandonlyifallitsinputsareasserted.ABFABFInversionbubbleactive-lowpinnormalgatesNonnormalgatsLogicFunctionsareperformedinsidethesymbolicout

7、lines.115.Bubble-to-BubbleLogicDesignP353bubble-to-bubblelogicdesignrules127.DrawingLayoutflatschematicstructure13Hierarchicalschematicstructure14timingdiagramGOREADYDATtDATtDATGOREADYDATtRDYtRDYCausalityandPropagationDelay6.2CircuitTiming15GOREADYDATGOREADYDATtRDYmintRDY

8、maxMinimumandmaximumdelays6.2CircuitTiming166.2CircuitTimingpropagationdelayTiminganalysis:worst