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6.3USB-MODEVMInterfaceBoard
6.4ProgramDescription
6.4.1TouchScreenFunctionsPanel
6.4.2DataAcquisitionFunctionsPanel
6.4.3ConfigurationPanel
KitOperation
ThesimplediagramshowninFigure1showsonlythebasicfeaturesoftheUSB-MODEVMinterface
board.TheboardisbuiltaroundaTAS1020BstreamingaudioUSBcontrollerwithan8051-basedcore.
TheboardfeaturestwopositionsformodularEVMs,oronedouble-wideserialmodularEVMmaybe
installed.
ForusewiththeTSC2007,theTSC2007EVMisinstalledinthetopmostEVMslot,whichconnectsthe
TSC2007digitalcontrolinterfacetotheI
2
Cport,realizedusingtheTAS1020B.BecausetheTSC2007has
noaudiofeatures,thelowerEVMslot,whichisconnectedtotheTAS1020Bdigitalaudiointerface,isnot
used.
Asconfiguredfromthefactory,theboardisreadytousewiththeTSC2007EVMexceptforSW2,inwhich
caseatleastoneofSW2-1,SW2-2,andSW2-3mustbesettoOFF.
AftertheTSC2007EVM-PDKsoftwareinstallation(describedinSection6.2),evaluationanddevelopment
withtheTSC2007canbegin.
Thetouchscreenboxinthispanelisupdatedwhenatouchisdetectedonthetouchscreen.Asthetouch
screenisdrawnon,themotiononthetouchscreenistranslatedintopixelsonthisbox.Thesoftware
takesX,Y,andZreadingswhichareshowntotherightofthetouchscreenbox.Asthetouchpressureis
increased,thepixelsizeincreases;alightertouchresultsinsmallerpixelsizes.
TheZ-valuedisplayedisnotwhatisdescribedintheTSC2007datasheet,becauseinthedatasheet
equation,itisassumedthatthesheetresistanceofthetouchscreenbeingusedisknown.Thevalueused
inthisprogramiscalculatedbyEquation2oftheTSC2007datasheet,butwithoutmultiplyingitbythe
R
X-plate
resistance.Thisvaluerangesfrom0to3,andlarger,withlargernumbersrepresentingamore
forcefulpressonthescreen.UsingtheMaximumZValuetoDisplayknob,youcansetathresholdso
thattheprogramdoesnotdisplaylightlypressedpoints.Thisthresholdsettinghelpstoeliminatedisplay
ofspuriouspointsthatmayresultfromtouchscreenmechanicalbouncing.
ThedisplaycanbeclearedbypressingtheClearGraphbuttononthescreen.
TheTSC2007hasprovisionformeasuringoneauxiliaryinputvoltages(AUX1)andtemperature.This
paneldisplaysthemeasuredvaluesfortheseparameters.Measurementsareupdatedonlywhenthe
touchscreenisnotbeingpressed.
TemperatureisdisplayedusingbothmethodsdescribedintheTSC2007datasheet.UsingtheTEMP0
andTEMP1measurements,atemperaturereadingwith2°Cresolutionandaccuracyisachieved.Using
onlytheTEMP0measurement,areadingwith0.3°Cresolutionispossible,butthisoptionrequires
knowingtheTEMP0valueat+25°C;thiswouldnormallybeacalibrationthattheuserwouldperform.This
programassumesthatTEMP0=600mVat+25°C.
TheTSC2007canbeconfiguredtooperatein8-bitor12-bitresolutionmodes.Controloverthemode
usedisselectedinthispanel.
InthemiddleofthispanelisanindicatorlightthatshowstheI
2
CBusStatus.IftheTSC2007is
acknowledgingtheaddresssent,thelightisgreen;iftheTSC2007cannotacknowledge,thelightisred.
TheaddresstowhichtheTSC2007issetisshowninbinaryformatintheboxlabeledDeviceAddress
A1-A0.Theaddresssethereshouldbe"00"whenusingtheTSC2007EVM.EventhoughtheTSC2007
hastwopins,A0andA1,foruserstoselectfourdifferentI2Caddresses,theTSC2007EVmhasonlya
fixedaddress1001000b,whereA0=A1="0",becausebothA0andA1aretiedtoground.Seethe
TCS2007EVMschematicprovidedinthisdocument.
8TSC2007EVMandTSC2007EVM-PDKUser'sGuideSLAU199–March2007
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