Specifications

EssentialsofCrestronProgramming
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84
AppleTVs
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TheVirtualPresentationRoomfeatures2AppleTVservers.Thissectionwilldiscuss
howtouseBuffersymbolsfordevicesthatuseasharedsetofbuttons.Thetouchpanel
projectprovidesonesubpagethatcontainsthetransportcontrolsforanAppleTV
device.ThissubpagecanbecalledupbyeitherofthetwoAp
pleTVsourcesinthe
SIMPLprogram.TheBuffersymbolallowstheprogramtodeterminewhichAppleTV
sourcethetransportbuttonswillcontrol.
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TheBuffersymbolcanbethoughtofasagatethatcanbeopenedorclosed,thus
controllingtheflowofda
ta.Whenthegateisopen,digitalsignalsareallowedtoflow
unalteredfromtheinputstothecorrespondingoutputs.Whenthegateisclosed,all
outputsignalsaresettologiclowandtheinputsignalshavenoeffectonthem.
Openingandclosingthegateishandledbythe<enable>input.Whenth
esignal
connectedtothisinputishigh,theBufferisenabled(thegateisopen),andwhenthis
signalislow,thesymbolisdisabled(thegateisclosed).
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ThesourceselectbuttonpressforAppleTV1willbeconnectedtothe<enable>inputof
oneBuffersymbol,whilethebuttonpressforAp
pleTV2willbeconnectedtothe
<enable>inputofasecondBuffersymbol.WhenagivenBufferisenabledthetransport
controlsignalswillflowuninterruptedtothecorrespondingIRport.
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NotefromtheexamplethatonlyoneBuffershouldbeenabledatanygiventime.Iftwo
Bufferswereenabledatonce,pressingthePLAYbuttonwouldcausemultiple
commandstobeissued,whichisnotwhatwewant.Therefore,theSIMPLprogram