PicoQuant MultiHarp 150 - Page 90

PicoQuantGmbH MultiHarpSoftwareV.3.1.0.0
22 MACT TTLout highwhenmeasurementrunning
23 GND GND ground(0V)
24 D3V3 DCout +3.3V/≤350mAsupplyforexternalhardwareadd-ons
25 GND GND ground(0V)
ThespecificationsforTTLsignalscanbefoundathttp://wikipedia.org/wiki/Transistor-transistor_logic.Notethat
forthehardwaredescribedhereamaximumhighlevelof3.3Vispermitted.
Forfurtherdetailsregardingsignalspecifications,notablythetriggeroutput(voltages,frequenciespulsewidths
etc.)seesection8.3.1.
Pins 1, 2, 3 and 4acceptTTLcompatiblesynchronizationsignalsthatwillberecordedasmarkersinTTTR
mode.Thepinsareinternallypulleddown,sothattheyareinactivewhenleftunconnected.Theactiveedgeis
choseninthesoftwaresettingsdialog.Rise/falltimesmustbe50nsorfaster.Bothhighandlowstatemustbe
atleast50nslong.Theclockperiodmaytherefore(inprinciple)beasshortas about 100ns butdatabus
throughputconstraintswillapply.EachmarkercreatesanadditionalTTTRrecord,sothatonemustensurenot
toswampthedatastreamwithtoomanymarkerrecords.Whenbandwidthgetstight,markerstakeprecedence
overphotonrecords,sothatexcessmarkertrafficcansuppressphotonrecords.Infastimagingapplicationsitis
thereforerecommendednottouseapixelclockbutalineclockonly.Becauseeachphotonhasatimetag,itis
usuallynotnecessarytouseanadditionalpixelclock.Formoreinformationonhowtousethemarkerinputs
seesection5.3.5.
Pin 17canbeusedtoconnecttheserialTXlineofaGPS/GLONASSreceiverfortimetransmissionviathe
NMEAZDAMessageprotocolat115.2kbps,3.3V.WehavesuccessfullytestedthiswiththeMini-T™GGdisci-
plinedclockmodulefromTrimbleInc.,USA.Seesection6.7forsuitableclocksourceselection.
Pins 19 and 20canbeusedtoimplementhardwaretriggeredmeasurements.Notethatthisrequirescustom
software(seetheDLLmanualandrelateddemos).
Pin 22isaTTLoutputthatgoeshighwhenameasurementisrunning.
Pin 24providesa3.3VDCsupplyvoltagethatexternalelectronicscanuse.Undernocircumstancesmustthis
linebeshortedtogroundorloadedinexcessofthespecifiedmaximumcurrent.
Pins 14, 18, 21, 23, and 25arethecommongroundfortheTTLsignalsandtheDCsupplyline.Theyarealso
connectedtothehousing.
Makesurenottoconfusethecontrolconnectorwithaconnectorforotherequipmentthatwouldphysicallyfitbut
mightleadtomutualdamage.Appropriatecablesfortypicalapplicationsofthecontrolportareavailablefrom
PicoQuant.
AtthebackofthehousingtheMultiHarpthereisastandardconnector for power supplythatincludestwo
fuses.Thefusesarethedevice’sonlyuserserviceableparts.Pleasefindtherequiredfusecurrentratingson
theproductlabelorinsection8.3.1.DoNOTreplacethefuseswithoneofhighercurrentratingthanspecified.
Useslowblowingfusesofthespecifiedratingonly.Ifthefuseblowsrepeatedlystopfurtherexperimentsand
contactsupport.
AtthebacktherealsoanotherfourSMAconnectorslabeled“TRGOUT”,“REFIN”,“REFOUT”,“PPSIN”.
TRG OUT isaprogrammabletriggeroutputforpulsedlightsources.Notethatthisisundersoftwarecontroland
mustbeusedwithgreatestcarewhenpotentiallydangerouslasersourcesaretriggeredfromit.Thetriggerrate
isprogrammablefrom0.1µsto1.678s(0.596Hzto10MHz).Thepulsewidthisabout10ns,thebaseline
levelisnear0Vandtheactivelevel(pulsepeak)isapproximately-0.7V.Whenalightsourceistriggeredfrom
thissignalthesamesignalmusttypicallybefedtothesyncinput.Thisrequiresproperimpedancematching
e.g.,bymeansofapowersplitter(reflection-freeT-pad).
REF INacceptsanindustrystandard10MHzclockreference,e.g.,fromafrequencynormal,anatomicclock,
oranotherMultiHarp.Whenthisclocksourceisselected(viasoftware)thentheMultiHarpwilllockitsinternal
PLLtothissignal.Notethatitmustnotbedisconnectedonceitisbeingusedastheactiveclocksource.
REF OUTbydefaultprovidesanindustrystandard10MHzclockoutputphaselockedtotheMultiHarp’sinternal
clock,e.g.,fortheREFINofanotherMultiHarp.OncetheMultiHarphaslockeditsinternalPLLtothissignalthe
clocksofthetwodeviceswillnotdriftapart.IftheMultiHarpisoperatedinWhiteRabbitmodethepinwilloutput
adifferentclockfrequency,namelytheWhiteRabbitsystemclockof125MHzdividedby4,i.e.31.25MHz.
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