Data Sheet

USBProtocolSuiteUserManual 265
RecordingRulesActionsandActionProperties TeledyneLeCroyCorporation
Filter‐Out
FilteringStart‐of‐Frames(SOF's)inUSB2.0capturescaninhibittheabilityofthe
softwaretodecodeupperlayers(transferandabove)properly.TheSOFisusedasa
delimiteroftrafficintheanalysisheuristics,anditsabsencecancauseafailureto
recognizewhethertransactionsshouldbejoinedintoagiventransfer.Ifyouare
seeingtransfersthatdonotappearcorrect(forexample,attheSCSIlevel),andyou
havefilteredSOF's,itisrecommendedthatyourepeatthecapturewithfilteringof
SOF'sturnedoff.
Similarly,ifITPpacketsarefilteredfromaUSB3.1capture,itisimpossibleto
distinguishbetweenfalseandrealsequenceerrors,soitisnotrecommendedto
filterthese.Iftheyarefiltered,sequenceerrorsshouldbeignored.
Trigger
Triggerpositionintheresultingtracecannotalwaysbedeterminedprecisely,dueto
hardwarelimitations.In>95%ofthecases,thetriggerpacketshowninthetracefile
istheonewhichcausedthetrigger.Intheotherexceptioncases,itshouldstill
alwaysbewithinthreepacketsoftheactualtriggeringevent.
StopRecording
Thiswillstoprecordingveryquicklyafterthetriggerconditionoccurs,butrequiresa
smallamountofpost‐triggertrafficbeforeitcompletes.Thisisdonesothatatrigger
onapacketwillstillallowtheremainingpartofthatpackettobecaptured.Forthis
reason,itisnotrecommendtouseStopRecordingactionforeventswhicharenot
followedbyanymoretraffic,suchasTerm‐Off.Inthesecases,therecordingwill
appearstuckwaitingfortheadditionalsmallamountofactivity.
ErrorEventActionProperties
Figure 5.39: Event Properties: Actions Dialog.
YoucansetInternalTriggering,ExternalTriggering,Sequencing,andFiltering.