Data Sheet

TeledyneLeCroyCorporation USB3.1ElectricalTestModes
594 USBProtocolSuiteUserManual
12.14.1 Loopback Mode
TheVoyagerUSB3.1ElectricalTestwindowsupportsentrytothePolling.Loopback
substate.Forreceivertesting,thedeviceundertest(loopbackslave)isplacedinaspecial
testmodeandechoesbackapredefinedloopbackpattern.TheVoyagersystemcan
initiatethisspecialmode(loopbackmaster)andgeneratethebasicloopbackpattern.The
intendeduseofthisfeatureistoallowdesignerstotesttheirimplementationof
enteringLoopbackMode.ItisNOTintendedtobeusedforreceivertolerancetesting!
Fullcompliancetestingrequirestheadditionofjittertolerancemeasurementstothe
loopbackstream.Specializedequipment,suchasTeledyneLeCroy'sPERT
Receiver Tolerance Testsystem,shouldbeusedtointroducejitterandperformthefull
electricallayercompliancetestingprocess.
LoopbackModetestprocedure
1. ConnecttheDUTtotheExerciserport:
ForDeviceLoopback:AttachDUTtoPortA
ForHostLoopback:AttachDUTtoPortB
2. Setrecordingoptions:
ForDeviceDUTLoopback:SetVoyagerasHostEmulator
ForHostDUTLoopback:SetVoyagerasDeviceEmulator
3. IntheMiscUSB3.1tab,unchecktheFilter‐OutLogicalIdlesanFilter‐OutSKPs
option.
InitiatingloopbackmoderequiresthattheDUTsuccessfullylinktrainswiththeVoyager
exerciser.VerifythatthelinkreachesU0bypressingtheRecordbuttonandlookingat
trafficforLUP/LDNlinkcommands.
YoucanoptionallysettheanalyzertorecordtheLoopbacktraffictoverifythatthe
systementersloopback.IfyouelecttorecordLoopbacktraffic,itisrecommendedthat
yousetTriggerontheLoopbackcommandbysettingTriggeronTS2withloopbackbit
asserted.