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时间: 2019-12-24 19:39
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【应用手册】AN578:ManualPlacementofCMUPLLsandATXPLLsinStratixIVGXandGTDevicesThisapplicationnotedescribesthestepsinvolvedinthemanualplacementofCMUphase-lockedloops(PLLs)andATXPLLsinAltera’sStratix®IVGXandGTFPGAs.Altera’sQuartus®IIsoftwareautomaticallyplacestheCMUPLLsandATXPLLsbydefault.ThedefaultplacementofCMUPLLsbytheQuartusIIsoftwaremaynotbeoptimumforallbondedconfigurations,exceptforthePCIExpress(PIPE)×8bondedconfigurationandtheBasic×8bondedconfiguration.CheckthedefaultplacementtodecideifitisoptimumforskewrequirementsinyourBasic(PMADirect)×Nbondeddesign.Ifitisnot,manualplacementoftheCMUPLLsisrecommended.ThedefaultplacementofATXPLLsbytheQuartusIIsoftwareisperformedarbitrarilyforallbondedconfigurations,exceptforthePCIExpress(PIPE)×8bondedconfiguration.Checkthedefaultplacementtodecideifitisoptimumforskewrequirementsinyourdesign.Ifitisnot,manualplacementoftheATXPLLsisrecommended.ThisapplicationnoteusestheBasic(PMADirect)xNbondedconfigurationasanexamplescenario,whereskewisacriticalparameterandisdependentonthelocationofthetransmitterPLL(CMUPLLorATXPLL).AN578:ManualPlacementofCMUPLLsandATXPLLsinStratixIVGXandGTDevicesMay2009AN-578-1.0IntroductionThisapplicationnotedescribesthestepsinvolvedinthemanualplacementofCMUphase-lockedloops(PLLs)andATXPLLsinAltera’sStratixIVGXandGTFPGAs.Altera’sQuartusIIsoftwareautomaticallyplacestheCMUPLLsandATXPLLsbydefault.Thedefaultplacement……