Logic Guidex Users Guide
User Manual: saleae -
Open the PDF directly: View PDF .
Page Count: 23
SaleaeUserGuide1.1.15
1 Copyright2012SaleaeLLC.AllRightsReserved.
Logic&Logic16User’sGuide
Hello,andthanksforusingLogic.Wehopethisguidewillansweranyquestionsyoumighthave,butif
notpleasedoletusknowatsupport@saleae.com
Warning:UsingLogicorLogic16totestequipmentpoweredbyACMAINspowercanbehazardousto
equipment.Battery‐powered,wall‐wartpowered,andUSBpoweredequipmentisgenerallysafe.For
anythingelsepleasemakesuretoreadthesectionSafetyandEquipmentProtection.
HappyDebugging!
Contents
Logic&Logic16User’sGuide........................................................................................................................1
InstallingtheSoftware..................................................................................................................................3
InstallationonWindows&Mac............................................................................................................3
InstallationonLinux..............................................................................................................................3
UsingtheHardware......................................................................................................................................4
Connectingthewireharness................................................................................................................4
Logic16Wireharnesses........................................................................................................................4
TestClips...............................................................................................................................................4
ConnectingdirectlytoIDEheaders.......................................................................................................4
DisconnectLogicfromyourcircuitwhentheUSBisunplugged..........................................................4
SafetyandEquipmentProtection.........................................................................................................4
UsingtheSoftware........................................................................................................................................6
QuickTips..............................................................................................................................................6
UsingtheTrigger...................................................................................................................................6
Navigatingthedatadisplay...................................................................................................................6
SaleaeUserGuide1.1.15
2 Copyright2012SaleaeLLC.AllRightsReserved.
TimingMeasurements..........................................................................................................................7
PlacingTimingMarkers.........................................................................................................................8
SavingandOpeningaSession...............................................................................................................8
ExportingData......................................................................................................................................8
SavingScreenshots..............................................................................................................................10
SelectingtheDisplayRadix(i.e.Hex,Decimal,etc.)...........................................................................10
UsingProtocolAnalyzers....................................................................................................................
11
Hiding,un‐hiding,andreorderingchannels.......................................................................................12
Resettingthetrigger,channelnames,channelorderingandchannelvisibility.................................12
Hidingthechannellabelsand/ortrigger............................................................................................13
Workingwithtabs...............................................................................................................................13
SwitchingbetweenmultipleSaleaelogicanalyzers...........................................................................15
ChangingtheLogic16channels...........................................................................................................16
Crosstalk(andLogic16inputvoltageselection).................................................................................17
SaleaeCommunitySite...............................................................................................................................19
SDKs–DeviceSDKandAnalyzerSDK..................................................................................................19
Forum..................................................................................................................................................19
Betasoftwarereleases........................................................................................................................19
DataIntegrity..............................................................................................................................................20
MaximumSampleRate.......................................................................................................................20
Maximumsamplerate,andlongcaptures–Logic16.........................................................................21
SafetyandEquipmentProtection...............................................................................................................22
ContactingUs..............................................................................................................................................23
SaleaeUserGuide1.1.15
3 Copyright2012SaleaeLLC.AllRightsReserved.
InstallingtheSoftware
InstallationonWindows&Mac
Downloadthelatestversionfromoursite,here:http://www.saleae.com/downloads.Doubleclick&
installlikeanyotherapplication.
Note:WindowsXPUsers:Pleasedownloadthe32‐bitversionofthesoftware.
Note:Vista&Windows7Users:Pleasedownloadtheeither32‐bitor64‐bitinstallationdependingon
yourversionofWindows.Youcanfindoutbyright‐clickingComputerinthestartmenu,andchoosing
Properties.
OSXTigerUsers:Theapplicationneedstobeunzippedbeforeitcanbeinstalled.
InstallationonLinux
1. Downloadthelatestversionfromoursite,here:here:http://www.saleae.com/downloads.
2. Thereisnoinstaller,youcanunziptheapplicationanywhereyoulike,perhapsyourhome
folder,oryourdesktop.Youcanstartusingitonyourdesktop,andmoveitlaterifyoulike.
3. DoubleclicktheLogicexecutabletostarttheprogram.
4. Ifyoulike,makealinktotheLogicapplicationforyourdesktoporapplicationmenuordock.
5. Notethatwhereveryoudecidetoputthelogicapplication,itmustallstaytogetherinthesame
folderstructure,anditmusthavewritepermissions.
6. WhenconnectingtoLogic,youmaygetamessagefromtheapplicationthatitdoesn’thave
permissionstoconnecttoLogic.Ifthishappens,runtheinstall_driverscriptintheapplication’s
Driverfolder.
32‐bitvs.64‐bit:PleasechoosetheversionappropriateforyourLinuxDistribution.
64‐bitUsers:Pleasenotethatasof1.1.5,youwon’tbeabletoloadsessionssavedwithother
versions(platformdistributions)oftheLogicsoftware.However,otherLogicsoftwaredistributions
willbeabletoloadsessionsthatyousave.Sorryforthetrouble–we’llgetthisfixed.
SaleaeUserGuide1.1.15
4 Copyright2012SaleaeLLC.AllRightsReserved.
UsingtheHardware
Connectingthewireharness
Todeterminethecorrectwayofattachingthewireharness,lookonthebackofyourdeviceforthe
groundsymbol:
Thenfindthegraywireonthewireharness.Thisisthegroundwire.ItwillhaveaGROUNDlabelnear
itsend:
Logic16Wireharnesses
Logic16usestwo9‐wireharnesses.Onthebottomofthedevice,thesearelabeledAandB.Ais
channels0‐7,andBischannels8‐15.
Notethatyoudon’tneedtohavebothharnessespluggedinifyou’reonlyusingthefirst8channels.
TestClips
Youcanconnectyourtestleads(fromthewireharness)totheprovidedtestclips.Theymightrequire
quiteabitofforcebeforethey“click.”
ConnectingdirectlytoIDEheaders
Insomesituations,youwillbeabletoplugthetestleadsdirectlyintoIDEheadersonyourPCB,which
canbeveryconvenient.FornewPCBdesigns,werecommendincludingheadersforthingsyoumight
needtolookatduringfirmwaredevelopment.Youonlyneedtosolderintheheadersifyouhavean
issue,andtheycanberemovedinthefinalPCBrevisionsifneeded.Thesewillserveasnicetestpoints
foranoscilloscopeaswell.Don’tforgettowireinsomegroundpinsaswell.
DisconnectLogicfromyourcircuitwhentheUSBisunplugged
YoushoulddisconnectLogicfromyourcircuitwhenitisnotconnectedtoyourcomputer.IfLogicisnot
poweredbytheUSB,itcanputaloadonyourcircuitthatcancompromisesignalintegrity.
SafetyandEquipmentProtection
Ingeneral,LogicandLogic16maynotbeusedwithDUTs(devicesundertest)whicharenotelectrically
isolatedfromMAINs(wallpower).Thisisbecausethelogicanalyzersharesacommongroundwithyour
computer,whichtypicallyisgroundedwithrespecttoMAINsearthground.Thiscreatesapotential
SaleaeUserGuide1.1.15
5 Copyright2012SaleaeLLC.AllRightsReserved.
shortcircuitpathforanynon‐isolatedMAINs‐derivedvoltages,viathelogicanalyzer’sgroundinput(s).
Formoredetails,pleaserefertothesectiononSafetyandEquipmentProtectionneartheendofthis
User’sGuide.
SaleaeUserGuide1.1.15
6 Copyright2012SaleaeLLC.AllRightsReserved.
UsingtheSoftware
QuickTips
Almosteverythinghastooltipsthatoffersomeexplanationofwhatitdoes.
Mostfunctionshavekeyboardshortcuts,describedintheirmenuitemortheirtooltip.
UsingtheTrigger
Tip:mouse‐overthetriggerbuttonsforadescription.
Thetriggerlooksforasingleedge.Tousethetrigger,theremustbeoneedgespecified.
Youcanalsospecifythatotherinputsmustbeinparticularstates(highorlow)whentheedge
occurs.
Pre‐triggerdatawillbecollectedfortheregionoftimebeforethetriggerisfound(totheextent
thetriggerisnotimmediatelyfound).YoucanconfigurethisamountunderOptions‐
>Preferences
Thetimewherethetriggerisfoundistimezerointhedisplay.
Navigatingthedatadisplay
Clickanddragthedisplaytomoveit
SaleaeUserGuide1.1.15
7 Copyright2012SaleaeLLC.AllRightsReserved.
Usethescrollwheelonyourmousetozoominandout
Alternatively,usethearrowkeystozoomandpan(The+/‐keysalsozoom)
To“jumptonext,”moveyourmouseto,andclickthebuttonthatwillappearnearattheendsof
thegraphs.YoucanusethekeysN(next)andP(previous)aswell.(thisappliestothechannel
thatwaslastusedbythemouse)
TimingMeasurements
Tip:Moveyourmouseovereachmeasurementlabelforadescription.
Width:Thetimebetweentheselectedtwosuccessivesignaltransitions.
Period:Thetimeelapsedbetweentheselectedthreesuccessivesignaltransitions.
Frequency:Thefrequencycomputedbydividingone(1)bythetimeelapsedbetweenthe
selectedthreesuccessivesignaltransitions.
DutyCycle:The%oftimethesignalishigh(1)duringtheselectedthreesuccessivesignal
transitions.
Byte:Thenumericalrepresentationofall8channelscombinedintoonebyte,atthespecified
location.
T1:TheabsolutetimespecifiedbythelocationoftheT1timingmarker.
T2:TheabsolutetimespecifiedbythelocationoftheT2timingmarker.
|T1‐T2|:Thetimeelapsedbetweenthetimingmarkers.
Toshoworhideparticularmeasurements,usethesettingsbutton.
SaleaeUserGuide1.1.15
8 Copyright2012SaleaeLLC.AllRightsReserved.
PlacingTimingMarkers
Single‐clicktheT1orT2label.(oruse1and2keysonyourkeyboard)
Moveyourmousetothedesiredlocation.Notethatyoucanstillpanandzoom.
Singleclicktoplacethemarker.Yourmousemustnotbemovingwhenyouplacethemarker.
Tomovethemarkerafterithasbeenplaced,clickit.
Tocancelplacingamarker,right‐clickorpresstheescapekey.
SavingandOpeningaSession
Tosaveasessionthatincludesdata,pressCTRL‐S(CMD‐SonaMac)orselectthisfunctionfrom
theOptionsmenu.
Tosaveasessionthatcontainsonlysettings,pressCTRL‐SHIFT‐S(CMD‐SHIFT‐SonaMac),or
selectthisfunctionfromtheOptionsmenu.
Toopenasessionofanytype,dragitintothesoftware,orpressCTRL‐O(CMD‐OonaMac),or
selectthisfunctionfromtheOptionsmenu.
ExportingData
Toexportdata,selectOptions‐>ExportData(CTRL‐E).
SaleaeUserGuide1.1.15
9 Copyright2012SaleaeLLC.AllRightsReserved.
ChannelstoExport:Selectwhichchannelsyouwouldliketoexport
SamplestoExport:Selectthetimeperiodoverwhichyouwouldliketoexportsamples
o Tip:Ifyouareusingtimingmarkers,youcanexportjustthedatabetweenthem.This
optionwillonlyappearinthelistiftwotimingmarkershavealreadybeenplaced.
ExportFormat–Binary
o Youcanselectifyouwantdataoutputtedforeverysample,oronlyforsamplesthatare
differentthanpriorsamples.Notethatifyouexportonlychangesinthedata,a64‐bit
samplenumberiswrittenbeforeeachsampleinthefile.
o Ifyouaren’texportingallofthechannels,youcanchoosetoleavethebitsintheir
originalchannellocations,ortohavethemshiftedrighttofillanyunusedpositions.
SaleaeUserGuide1.1.15
10 Copyright2012SaleaeLLC.AllRightsReserved.
o Youcanchoosetoexporteachsampleasan8,16,32,or64‐bitword.
ExportFormat–VCD
o VCDstandsforValueChangeDump,andisacommonformatfordigitaldata.
ExportFormat–CSV
o Choosethisformattoexportdataascommaortabdelimited,humanreadabletext.
o Youcanoptionallyincludecolumnheadingsforthedata
o Youcanusesamplenumber(i.e.1,2,3,4)ortimestamps(i.e..00123s)tospecifythe
timeasamplerepresents.Thisoccupiesthefirstcolumn.
o Youcancombineallthechannelsintoasinglenumber,oryoucanexporteachbitinits
owncolumn.
o Youcanexporteverysample,oronlysamplesthathavechanged.
SavingScreenshots
Youcantakeascreenshotofallorpartoftheapplication,andeithersaveittoafile,orcopyit
totheclipboard.YoucanfindthisintheOptionsmenu,orusethekeyboardshortcuts.
SelectingtheDisplayRadix(i.e.Hex,Decimal,etc.)
UsethisOptionsmenuitem(orthekeyboardshortcuts)toquicklytogglebetweenthedifferent
displaymodes.
SaleaeUserGuide1.1.15
11 Copyright2012SaleaeLLC.AllRightsReserved.
UsingProtocolAnalyzers
Toaddaprotocolanalyzer,selectonefromthemenuintheAnalyzerspanel.
Protocolanalyzerscanshareinputswithotheranalyzers.Thiscanbeusefulinsomecases,such
asSPI.
Afteryouadd(oredit)ananalyzer,itimmediaterunsagainstanydatayouhavecollected.
Toexportdatafromananalyzer,pressthesmallfileiconnexttoit.(Centerbutton).
Ifyouneedtochangethedisplayformat(radix)ofaparticularanalyzer,youcandothisfromthe
Analyzersettingsmenu.
SaleaeUserGuide1.1.15
12 Copyright2012SaleaeLLC.AllRightsReserved.
Hiding,un‐hiding,andreorderingchannels
Youcanhidechannelsyouaren’tusing.(Notethatthisisdifferentthanturningoffchannels–whichyou
candowithLogic16toincreasesamplingspeed)
Moveyourmouseoverthechannellabelareaofthescreen.Idropdownmenubuttonwillappear.You
canHidechannels,Show(un‐hide)them,andMove(reorder)them.
Resettingthetrigger,channelnames,channelorderingandchannelvisibility
Sometimesyoumaywanttostartfromafreshslate,andyoudon’twanttodothisoneitematatime.
UsetheResetoptiontodothis.
SaleaeUserGuide1.1.15
13 Copyright2012SaleaeLLC.AllRightsReserved.
Hidingthechannellabelsand/ortrigger
Toclearupadditionalscreenspace,youcanoptionallyhideboththechannellabeland/orthetrigger.
FindthisundertheOptionsmenuitem.
Workingwithtabs
Tabsletyousavemultiplecaptures,andswitchbetweenthem.
TheCaptureTab
ThemostimportantthingtoknowisthatyoucanonlycapturenewdatafromtheCapturetab,whichis
thesmalltabwiththemagnifyingglasslogo.
SaleaeUserGuide1.1.15
14 Copyright2012SaleaeLLC.AllRightsReserved.
Addingnewtabs
Afteryoucollectdata,theCaptureTabwillchange,addingabuttontooneside.Clickthisbuttonto
moveyournewdataintoitsowntab.
Renamingatab
Clicktab’stexttoeditit.Notethatatabmustbeactivebeforeitcanbeedited.
Pressenter,orclickoutsidethetextareatostopediting.
Reorderingtabs
Youcanreordertabshoweveryoulike,bydraggingthem.
SaleaeUserGuide1.1.15
15 Copyright2012SaleaeLLC.AllRightsReserved.
ClosingTabs
Youcanclosetabsbyusingitsmenu.Thiscan’tbeundone,sobesuretosaveyoursessionifyouneed
to,beforeclosingthetab.
Copyingsettingsbetweentabs
Occasionallyyoumaymakechangesononetabyoumaywishtopropagatetoanothertab.Fromthe
tab’smenu,chooseCopy.
Forinstance,ifyousetupsomeanalyzersinonetab,andyouwantedtorunthemagainstdataina
differenttab,youcouldcopythem.Notethatthiswillreplaceanyanalyzersthatwerealreadyinthat
tab.
Tabs,andsavingyourdata
Whenyousaveyoursession,(Options‐>SaveSession‐>settings&data)youareonlysavingthesession
associatedwiththecurrentlyactivetab.Thereisn’taway(yet)tosaveallyourtabsatthesametime,or
tosavethemalltoasinglefile–a“sessionset”.Wewillbeaddingthiscapabilityinthefuture.
SwitchingbetweenmultipleSaleaelogicanalyzers
Whilethereisn’tawaytocollectfrommultipleSaleaelogicanalyzersatthesametime,youcanhave
morethanoneconnectedtoyourcomputer,whichcanbehelpfulinsomecircumstances.
Ifmorethanonelogicanalyzerisconnected,themenuitemConnectedDevicesitemwillappearinthe
Optionsmenu.
SaleaeUserGuide1.1.15
16 Copyright2012SaleaeLLC.AllRightsReserved.
ChangingtheLogic16channels
WithLogic16youcanselectwhichchannelstouse–andifyouneedfewerchannelsyoucansampleat
higherspeeds.ThissettingisintheOptionsmenu,underLogic16channels.Youcanselectfromoneof
thestandardoptions,orbemorespecificbychoosingSelectcustomchannels.
SaleaeUserGuide1.1.15
17 Copyright2012SaleaeLLC.AllRightsReserved.
Crosstalk(andLogic16inputvoltageselection)
Logic16hastwovoltagesettings,onefor1.8Vto3.6V,andanotherfor3.6Vto5V.
Thelowervoltagesettingsshouldworkinmostcircumstances.The5Vsettingisprovidedtoreducethe
likelihoodofchanneltochannelcrosstalkwhenusing5Vsignals.Crosstalkisdeveloped,atleastinpart,
byLogic16’slongleadwires,fastrise/falltimes,andisgreatestwhenusing5Vsignals.Logic16’sfront
endfiltersnoiselikethis,butonlyuptoapoint.Youshouldbeabletohave8differentsignals
simultaneouslyswitchwithoutseeingcrosstalkonadjacentsignals.
SaleaeUserGuide1.1.15
18 Copyright2012SaleaeLLC.AllRightsReserved.
Ifyouexperiencecrosstalk,besurebothgroundwiresareconnectedtoyourcircuitasthiscanmakea
dramaticdifference.
Unconnected(floating)inputsaremuchmoresusceptibletocrosstalk.Youmaywanttoturnofforhide
unusedsignals.ThisappliestobothLogicandLogic16.
SaleaeUserGuide1.1.15
19 Copyright2012SaleaeLLC.AllRightsReserved.
SaleaeCommunitySite
SDKs–DeviceSDKandAnalyzerSDK
Wehavecross‐platform,c++basedSDKsforgettingaccesstoLogicorLogic16atalowlevel,andfor
makingyourownprotocolanalyzerplugins.YoucangetaccesstothisSDKatourcommunitysite,at
saleae.com/community.
Forum
Toshareideasorissues,andtoconnectwithotherusers,headovertotheforuminthecommunitysite,
atsaleae.com/community.
Betasoftwarereleases
Weoccasionallyhavenewsoftwarereleaseswhichwethinkareprettygood,butdon’twanttorisk
disruptingalargenumberofusersifsomethinginitneedsfixing.Typicallythesereleasesturnouttobe
prettystableandhaveadditionalfeaturesandfixesthatthecurrentreleasedoesn’thave.Ifthereare
anybetareleases,they’llbeonthecommunitysite.
SaleaeUserGuide1.1.15
20 Copyright2012SaleaeLLC.AllRightsReserved.
DataIntegrity
LogicandLogic16maynotbeabletoachieveaparticularsamplerate(seethenextsections)butitwill
neverpresentdatawithsamplesmissing.Bydesignitstopsandnotifiesyouassoonasanydataislost.
MaximumSampleRate
GenerallyspeakingLogicisabletoachievesampleratesof24MHzwhennootherdevicesareonthe
USBhost,andyourcomputerisrespondingsufficientlyquickly.HoweveriftheUSBisservicingother
devices,orthecomputerisperforminginalatentmanner,asmallersamplerate,suchas16MHzor
12MHzmaybethefastestachievable.Thereasonforthisisasfollows:
LogicusesUSB2.0,andusestheUSBtransfertypeknownas“Bulk”.Whilethistransfertypehasthe
largesttheoreticalaveragebandwidth(significantlylargereventhanthe24MB/sneededbyLogic)it
alsohasthelowestpriority.Thismeansitmaybe“bumped”forotherUSBtrafficfromotherdevices.
ThesecondissueisthatLogichasverylimiteddevice‐sidememory.Specificallyithasx4512byte
buffers.ThesebuffersmustbeemptiedbytheUSBinsuchawaythattheyneverallbecomefullatthe
sametime.Ifthishappens,thelogicsoftwarewillreportthatthesampleratecouldnotbemaintained.
Thismeansthatevenifonaverage(whichwouldnormallybethecase)theUSBcangiveLogicatleast24
MB/s,itmustnotprioritizeotherdevicesontheUSBforsomuchtimethatLogic’ssmallbufferwould
overflow.ForthisreasonLogiccan’tguaranteethatitwilloperateatitsmaximum24MHz,asthisis
contingentonanumberoffactorsincludingcomputerperformance,USBbandwidthavailabilityand
latency,otherdriversthatmaybeusingtheUSB,etc.
Tomaximizethesampleratepossibleonyourcomputer,trythefollowing:
MakesurethatnootherapplicationsareconsumingsignificantCPUtime.
MakesureyouhaveenoughfreeRAMsothattheOSwillnothaveswapramtotheharddrive.
Thiswillbetooslow.
TryconnectingLogicdirectlytoyourcomputerinsteadofthroughaUSBhub.
MakesureotherdevicesontheUSBareminimallyactive.(i.e.notwebcams,harddrives,etc.)
TrydisconnectingotherperipheralsfromtheUSB,orswitchingLogictoaportservicedbya
differenthostcontroller.Youmayevenwanttotryadedicatedhostcontroller,suchasthisone
http://www.newegg.com/Product/Product.aspx?Item=N82E16815166014
IncreasetheprocesspriorityoftheLogicsoftware.
o Windows:FromtheWindowsTaskManager,selecttheProcessestab,andfindtheLogic
process.RightclickonthisitemandselectSetPriority‐>High.
o Linux:Fromthecommandline,navigatetothefolderwheretheLogicexecutableis.
Typenice–n3./Logic.SearchforLinuxniceonGoogleformoreinformation.
SaleaeUserGuide1.1.15
21 Copyright2012SaleaeLLC.AllRightsReserved.
Maximumsamplerate,andlongcaptures–Logic16
Logic16hasasignificantlylargerhardware‐sidebufferthanLogic,andthereforeismuchmoreimmune
tolatenciesintheUSB.ItisalsomorelikelythanLogictoreliablyoperateatitsmaximumspeedona
givencomputer.
Ifyouneedtocaptureforlongperiodsoftime,especiallytocatch“overnight”errorsintheact,we
recommendusingLogic16.
SaleaeUserGuide1.1.15
22 Copyright2012SaleaeLLC.AllRightsReserved.
SafetyandEquipmentProtection
Theprimaryconcernforsafetyandequipmentprotectionisthegroundreturnpath.Logic’s(and
Logic16’s)groundinputisessentiallyshortedtothegroundofyourcomputer,andyourcomputer’s
groundislikelyconnectedtoearthground.ThereforeLogic’sgroundlinehasthepotentialtoprovidea
highcurrentgroundreturnpathtoadeviceundertest.ThiscanresultinthedestructionofLogic,the
USBhost,andintheworstcase,thecomputer.
LogicshouldnotbeusedwithDUTs(devicesundertest)whicharenotelectricallyisolated
fromMAINS(i.e.wallpower).Thereisoneexceptionoutlinedbelow,butitcomeswith
importantcaveatsandmustbefullyunderstood.Pleasecontactusifyouhaveanyconcerns.
o IfyouneedtotestaMAINs–connectedDUT,onepossiblesolutionistouseaLaptop,
runningonbatterypowerandnotconnectedtoanythingelse(suchasalikely‐grounded
LCDmonitor).ThiswillpreventLogicfromprovidingashortcircuitgroundreturnpath.
HOWEVER–thissetupintroducesanadditionalandveryserioussafetyconcern.The
reasonfortheMAINsearthgroundconnectioninthefirstplaceittopreventahigh
voltagefromconnectingtoachassiswhichcouldcauseelectricshocktoauser.A
groundedchassis,ifconnectedtoalargevoltage,willprovideashortcircuit,whichthen
blowsacircuitbreakerorfuseandremovesthehighvoltage,protectingauserfrom
potentialelectrocution.Ifyouusetheworkaroundpresentedhere,youmustensure
thatitisimpossibleforanyhighvoltagetobeconnectedtoanyofLogic’sinputs,and
especiallyLogic’sgroundlead.Lowvoltages(asmeasuredrelativetoearthground)–
whichwouldnotpresentariskofelectricshock–arepermissible.
o Isolationtransformers,suchasthosemadebyTripp‐lite:Thesetransformersprovidea
large1:1transformersothatthatthe“hot”ACpowerlinesareelectricallyisolatedfrom
MAINS.However,andcrucially,theyDONOTisolatetheMAINsearthground
connection,andsoarenotusefulforprovidingasolutiontothisissue.
DUTswhicharebatterypowered,orUSBpowered(fromthesamecomputerasLogic)are
acceptable.
o WhenusingUSBpoweredDUTs,specialcareshouldbetakentoavoidconnectingUSB
sourcedpowertoLogic'sground,asthisprovidesashort‐circuitreturnpath.
DUTspoweredbyACadapterswhichhaveonly2prongs,anddonothaveanearthground
connection(suchasmost"wallwarts")usuallyprovideMAINSisolatedpowerandaregenerally
acceptable.Theyalsoarelesslikelytobeabletosourceenoughcurrenttocauseserious
destruction.Wehighlyrecommendingtestingforgoodisolation.
o IfinanydoubtastoifLogic’sground‐‐and/orthegroundofyourDUT‐‐isisolated
fromMAINsearthground,useaMultimetertomeasuretheresistancetoearthground.
Atthistime,therearenocosteffectiveisolationproductsfor480MbitUSB(HighSpeedUSB)thatwe
areawareof.Therearefiberopticbasedsolutionsthatcostaround$1000.
SaleaeUserGuide1.1.15
23 Copyright2012SaleaeLLC.AllRightsReserved.
ContactingUs
You’realwayswelcometocontactusaboutanything.support@saleae.comistypicallythebestwayto
reachus,oronlineathttp://www.saleae.com/contact
We’remorethanhappytodiscussanyissueorquestionsyouhaveviaphone,too.Themostreliable
timetoreachusisintheafternoonsandearlyevening(Pacifictime).Ifyoumissus,pleasedoleavea
messageandwe’llcallyouback.510‐984‐2463