Xilinx Constraints Guide PDF
Preview Xilinx Constraints Guide
Constraints Guide UG625(v. 14.5)April1,2013 TTTThhhhiiiissss ddddooooccccuuuummmmeeeennnntttt aaaapppppppplllliiiieeeessss ttttoooo tttthhhheeee ffffoooolllllllloooowwwwiiiinnnngggg ssssooooffffttttwwwwaaaarrrreeee vvvveeeerrrrssssiiiioooonnnnssss:::: IIIISSSSEEEE DDDDeeeessssiiiiggggnnnn SSSSuuuuiiiitttteeee 11114444....5555 tttthhhhrrrroooouuuugggghhhh 11114444....7777 FFFFoooorrrr iiiinnnnffffoooorrrrmmmmaaaattttiiiioooonnnn rrrreeeellllaaaattttiiiinnnngggg ttttoooo IIIISSSSEEEE DDDDeeeessssiiiiggggnnnn SSSSuuuuiiiitttteeee ttttiiiimmmmiiiinnnngggg ccccoooonnnnssssttttrrrraaaaiiiinnnnttttssss,,,, sssseeeeeeee tttthhhheeee TTTTiiiimmmmiiiinnnngggg CCCClllloooossssuuuurrrreeee UUUUsssseeeerrrr GGGGuuuuiiiiddddeeee ﴾﴾﴾﴾UUUUGGGG666611112222﴿﴿﴿﴿.... NoticeofDisclaimer Theinformationdisclosedtoyouhereunder(the"Materials")isprovidedsolelyfortheselectionanduse ofXilinxproducts. 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Revision History Date Version Revision 04/01/2011 14.5 RemovedVccoSenseMode(VCCOSENSEMODE)constraint 01/18/2012 13.4 • MovedtimingconstraintsmaterialtotheTimingClosureUserGuide(UG612). • Removedsentence“TNM_NETisapropertynormallyusedinconjunctionwithan HDLdesigntotagaspecificnet.” • RemovedreferencetoFSMStyle(FSM_STYLE)constraint. ItiscoveredinXSTUser GuideforVirtex-6,Spartan-6,and7SeriesDevices(UG687). • CorrectedsyntaxforTimingGroup(TIMEGRP)constraintunderPatternMatchingUCF SyntaxExampleTwo. 10/19/2011 13.3 Removedsentence“TheRISINGandFALLINGkeywordsmayalsobeusedwithTNM.” AddedDIFF_TERMsupportforVirtex®-6devices. ChangeddefaultunitsforbothINPUT_JITTERandSYSTEM_JITTERconstraintsfromps tons. AddedinformationthatOFFSETConstraintsdonotallowpredefinedgroups. UpdatedPOST_CRCINITFlagforSpartan-6devices. AddednewVccoSenseMode(VCCOSENSEMODE)constraint. 06/22/2011 13.2 AddedSpartan®-6tolistofsupporteddeviceswhereappropriate. ForPULLUP(Pullup)constraint,addedinformationthatNGDBuildignoresthefollowing: •DEFAULTKEEPER=FALSE•DEFAULTPULLUP=FALSE•DEFAULTPULLDOWN =FALSE Constraints Guide 2 www.xilinx.com UG625 (v. 14.5) April 1, 2013 Date Version Revision ForIODELAY_GROUP(IODELAYGroup)constraint,addedinformationunderLimitations withLOCandArchitectureSupport ForAreaGroup(AREA_GROUP)constraint,addedNote:Allcomponentscanbeconstrained bytheCLOCKREGIONrangeexceptIOBandBUF. ForCONFIG_MODE(ConfigurationMode)constraint,addednewarchitecturesupport andnewvalues. ForBEL(BEL)constraint,removedVHDLexample. 03/01/2011 13.1 AddedVCCAUX_IOandMARK_DEBUGconstraints. ConstraintsGuide UG625(v. 14.5)April1,2013 www.xilinx.com 3 Table of Contents RevisionHistory....................................................................................................2 Chapter 1 Constraint Types.........................................................................................9 AttributesandConstraints....................................................................................9 CPLDFitter...........................................................................................................11 LogicalConstraints..............................................................................................12 PhysicalConstraints.............................................................................................13 MappingDirectives.............................................................................................14 PlacementConstraints.........................................................................................15 RoutingDirectives...............................................................................................17 SynthesisConstraints..........................................................................................18 TimingConstraints..............................................................................................19 ConfigurationConstraints...................................................................................20 Chapter 2 Entry Strategies for Xilinx Constraints...................................................21 ConstraintsEntryMethods..................................................................................21 ConstraintsEntryTable.......................................................................................21 SchematicDesign.................................................................................................24 VHDLAttributes..................................................................................................24 VerilogAttributes.................................................................................................25 UserConstraintsFile(UCF).................................................................................27 UCFandNCFFileSyntax....................................................................................28 PhysicalConstraintsFile(PCF)...........................................................................31 NetlistConstraintsFile(NCF).............................................................................33 ConstraintsEditor................................................................................................33 ISEDesignSuite..................................................................................................35 PlanAhead............................................................................................................35 SettingConstraintsinPACE................................................................................39 PartialDesignPinPreassignment.......................................................................39 FPGAEditor.........................................................................................................41 XSTConstraintFile(XCF)...................................................................................43 ConstraintPriority...............................................................................................43 Chapter 3 Xilinx Constraints.....................................................................................45 ConstraintInformation........................................................................................45 AreaGroup...........................................................................................................46 AsynchronousRegister........................................................................................55 Send Feedback Constraints Guide 4 www.xilinx.com UG625 (v. 14.5) April 1, 2013 BEL........................................................................................................................57 BlockName..........................................................................................................60 BUFG....................................................................................................................62 ClockDedicatedRoute........................................................................................65 Collapse................................................................................................................67 ComponentGroup...............................................................................................69 ConfigurationMode.............................................................................................70 CoolCLOCK.........................................................................................................73 DataGate..............................................................................................................75 DCICascade.........................................................................................................77 DCIValue.............................................................................................................79 Default..................................................................................................................80 DiffTerm..............................................................................................................83 DirectedRouting..................................................................................................85 Disable..................................................................................................................87 Drive.....................................................................................................................89 Enable...................................................................................................................92 EnableSuspend....................................................................................................94 Fast........................................................................................................................95 Feedback...............................................................................................................97 File.........................................................................................................................99 Float....................................................................................................................101 FromThruTo......................................................................................................103 FromTo...............................................................................................................105 FSMStyle...........................................................................................................108 HierarchicalBlockName...................................................................................109 HIODELAYGroup.............................................................................................111 HierarchicalLookupTableName.....................................................................112 HSet....................................................................................................................114 HUSet.................................................................................................................115 InputBufferDelayValue..................................................................................117 IFDDelayValue.................................................................................................119 InTerm................................................................................................................121 InputRegisters...................................................................................................123 InternalVrefBank..............................................................................................124 IOB......................................................................................................................125 InputOutputBlockDelay.................................................................................128 IODELAYGroup................................................................................................130 ConstraintsGuide Send Feedback UG625(v. 14.5)April1,2013 www.xilinx.com 5 InputOutputStandard......................................................................................132 Keep....................................................................................................................135 KeepHierarchy..................................................................................................137 Keeper.................................................................................................................140 Location(LOC)...................................................................................................142 Locate..................................................................................................................145 LockPins............................................................................................................158 LookupTableName...........................................................................................159 Map.....................................................................................................................162 MarkDebug.......................................................................................................163 MaxFanout.........................................................................................................165 MaximumDelay.................................................................................................168 MaximumProductTerms..................................................................................170 MaximumSkew.................................................................................................171 MCBPerformance..............................................................................................173 MIODELAYGroup............................................................................................175 NoDelay.............................................................................................................176 NoReduce..........................................................................................................178 OffsetIn..............................................................................................................180 OffsetOut...........................................................................................................184 OpenDrain.........................................................................................................188 OutTerm.............................................................................................................190 Period..................................................................................................................192 Pin.......................................................................................................................199 PostCRC.............................................................................................................200 PostCRCAction.................................................................................................201 PostCRCFrequency..........................................................................................203 PostCRCINITFlag............................................................................................204 PostCRCSignal.................................................................................................206 PostCRCSource.................................................................................................207 Priority................................................................................................................208 Prohibit...............................................................................................................209 Pulldown............................................................................................................213 Pullup.................................................................................................................215 PowerMode........................................................................................................217 Registers.............................................................................................................219 RelativeLocation(RLOC)..................................................................................221 RelativeLocationOrigin....................................................................................239 Send Feedback Constraints Guide 6 www.xilinx.com UG625 (v. 14.5) April 1, 2013 RelativeLocationRange....................................................................................242 SaveNetFlag......................................................................................................245 SchmittTrigger...................................................................................................247 SIMCollisionCheck..........................................................................................249 Slew....................................................................................................................251 Slow....................................................................................................................254 Stepping..............................................................................................................256 Suspend..............................................................................................................257 SystemJitter.......................................................................................................259 Temperature........................................................................................................261 TimingIgnore.....................................................................................................263 TimingGroup.....................................................................................................266 TimingSpecifications........................................................................................272 TimingName......................................................................................................275 TimingNameNet...............................................................................................281 TimingPointSynchronization..........................................................................285 TimingThruPoints............................................................................................288 TimingSpecificationIdentifier.........................................................................292 USet....................................................................................................................297 UseInternalVREF..............................................................................................299 UseLUTNM.......................................................................................................301 UseRelativeLocation........................................................................................303 UseLowSkewLines..........................................................................................306 VCCAUX.............................................................................................................308 VCCAUX_IO......................................................................................................309 Voltage................................................................................................................311 VREF...................................................................................................................313 WireAnd............................................................................................................315 XBLKNM............................................................................................................316 Appendix Additional Resources.............................................................................319 ConstraintsGuide Send Feedback UG625(v. 14.5)April1,2013 www.xilinx.com 7 Send Feedback Constraints Guide 8 www.xilinx.com UG625 (v. 14.5) April 1, 2013 Chapter 1 Constraint Types ThischapterdiscussestheconstrainttypesdocumentedinthisGuide. Note Fordetailedinformationaboutusingtimingconstraintstoachievetimingclosure, seetheTimingClosureUserGuide(UG612). Attributes and Constraints Somedesignersusethetermsattributeandconstraintinterchangeably. Otherdesigners givethemdifferentmeanings. Inaddition,certainlanguageconstructsusetheterms attributeanddirectiveinsimilar,butnotidentical,senses. Xilinx®usesthetermsattributes andconstraintsasdefinedbelow. Attributes Anattributeisapropertyassociatedwithadevicearchitectureprimitivecomponent thatgenerallyaffectsaninstantiatedcomponentfunctionalityorimplementation. Attributesarepassedbymeans: • Genericmaps(VHDL) • Defparamsorinlineparameterpassedwhileinstantiatingtheprimitivecomponent (Verilog) AllattributesaredescribedintheXilinxLibrariesGuidesasapartoftheprimitive componentdescription. Attributes Examples • INITonaLUT4component • CLKFX_DIVIDEonaDCM Implementation Constraints TheConstraintsGuidedocumentsimplementationconstraints. AnimplementationconstraintisaninstructiongiventotheFPGAimplementationtools todirectthemapping,placement,timingorotherguidelinestofollowwhileprocessing anFPGAdesign. ImplementationconstraintsaregenerallyplacedintheUserConstraintsFile(UCF). Theymayalsobeplacedin: • TheHardwareDescriptionLanguage(HDL)code • Asynthesisconstraintsfile. ConstraintsGuide Send Feedback UG625(v. 14.5)April1,2013 www.xilinx.com 9 Chapter 1:Constraint Types Implementation Constraints Examples • Location(LOC)(placement) • PERIOD(timing) Send Feedback Constraints Guide 10 www.xilinx.com UG625 (v. 14.5) April 1, 2013
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