TheEighthInternationalConferenceonElectronicMeasurementandInstrumentsICEMI2007ResearchontheIntelligentDisplayInstrumentforConstructionMachineryBasedonEmbeddedRTOSXuChuanpeiLiZhiHuCongWangWeiDept.ofElectronicEngineeringGuiLinUniversityofElectronicTechnology,Guilin,541004China)Abstract:Takingtheintelligentwheelloaderasaninstance,thispaperresearchesontheintelligentdisplayinstrumentforConstructionMachinerybasedonembeddedRTOS.AstructureofembeddedsystembasedonRTOSisproposed,anddesignsofboththehardwareandsoftwarearecompleted.ThesystemtakestheTMS320LF2407AchipoftheTIasthehardwareplatform,andthereal-timeoperatesystemofC/OS-asthesoftwareplatform；completesreal-timemonitoringandmanagementoftheconstructionmachinerybytheCANbuscommunicatingwiththemaincontroller.Keywords:EmbeddedSystem；C/OS-；TMS320LF2407A；CANBus；DisplayInstrument1IntroductionTheconstructionmachinerydisplayinstrumentistheimportantinterfacebetweenthedriverandtheconstructionmachinerytocommunicateinformation,whichplaysavitalroletotheconstructionmachinerysecurityandtheeconomy.Inrecentyears,alongwiththeconstructionmachineryelectronictechnologydevelopment,theinformationwhichdisplayedontheconstructionmachineryinstrumentisunceasinglyincreasing.Thetraditionalmechanicalindicatorforconstructionmachinerycombinationinstrumentismoreandmoreunabletomeettheactualneeds.Particularly,withthecomputer,themicroelectronanddifferentkindsoffieldbuscommunicationbecomewidespreadapplications,takingtheembeddedmicroprocessorasthecoreintelligentdigitaldisplayinstrumentwouldbeaninevitabletrendfortheconstructionmachineryinstrumentdevelopment.Thispapercombinesthereal-timeembeddedtechnology,theCANbustechnology,thetouch-screentechnologyandtheGPSpositiontechnologytogethertoapplytotheconstructionmachineryLCDmonitor,withthewheeledloaderastheresearchobject,andresearchesontheintelligentdisplayinstrumentforconstructionmachinery.2SystemArchitectureThearchitectureoftheonboardintelligentdisplayinstrumentsystemiscomposedofthepowersourcemodule,theDSPmodule,theLCDmodule,themechanicalkeyboardmodule,thetouch-screenmodule,theGPSorientationmodule,theADsupplementallightingsamplemodule,theCANcommunicationinterfacemoduleandthesoundalarmingmodulesetc.,whichareshownasfigure1.TMS320LF2407AControllerC/OS-IIRTOSPowersourcemoduleADmoduleSupply-lightingsampleMechanicalkeyboardmoduleCANmoduleWheeledloadermaincontrollerSCImoduleGPSPositionmoduleLCDDisplayTouch3.3V-5VlevelisolateTurning-lampsampleOpto-isolateTurningcontrolSoundalarmingmodulesFig.1IntelligentDisplayInstrumentSystemArchitectureThepowersourcemoduledealswiththevehicle+24Vpowersourcewiththefilterconditions；removesthepossiblenoises,outputsforthemaincontrollermoduleandtheLCD.Thepowersourceis4-8241-4244-1135-1/07/$25.002007IEEE.Authorizedlicenseduselimitedto:JILINUNIVERSITY.DownloadedonDecember17,2008at06:08fromIEEEXplore.Restrictionsapply.TheEighthInternationalConferenceonElectronicMeasurementandInstrumentsICEMI2007transformedto+3.3Vand+5VconstantvoltagesupplypowerforothermodulesintheLCD.TheDSPmoduleincludsTMS320LF2407Achip,extendprogramanddatamemory,resetchipetc.,whichisthehardwareplatformofthisembeddedreal-timeoperatingsystem.TheLCDdisplaymoduleisthehumanmachineinterfaceusedfordisplayingallkindsofstatusinformationofthewheeledloaderwhichistransmittedthroughtheCANbus.Themechanicalkeyboardandthetouch-screenaretheinstrumentstoachievetheoperatorcontrollingandmonitoringwheeledloaderwithallkindofstatusintime.TheGPSpositionmoduletransmitsthewheeledloadergeographicalpositioninformationtothedisplayinstrumentaboutthewheeledloaderthroughtheSCI.Thedisplayinstrumenttransmitstheinformationtothemaincontrollerforprocessingontime.Consequently,thelong-distancesupervisorcentercanreal-timequerythewheeledloadersworkingpositionbytheGPRSwirelessnetwork.Whenthelighteningofthewheeledloadersworkingenvironmentisinsufficient,theADsupplementallightingsamplemoduleautomaticallyopensasupplementallighttostrengthenthebrightness,whichisconvenientforoperatorcontrolling.TheCANbusmoduleisthekeyforthedisplayinstrumentandthewheeledloadermaincontrollercommunication.ThedisplayinstrumentcouldgetallkindsofoperationalparametersandthedataoftheentirewheeledloaderonlythroughtheCANcommunication,andcouldcontrolthewheeledloadertocarryonthecorrespondingfunctionaloperations,whichisakeypositiontoconnectthedisplayinstrumentandthemaincontroller.Whenthewheeledloaderworkswithsomefaults,thedisplayinstrumentcouldpromptalarmsbythespeechalarmingmodule,whichcouldinformtheoperatorimmediatelytocarryonprocessingtothesefaults,thusmayavoidgreateconomicloss.TheembeddedsystemsoftwareachievestointelligentLCDmonitoronthewheeledloaderandinteractdatawiththewheeledloadermaincontrollerbasedonthisplatformofhardwarefunctionmodule.3SystemHardwareDesignThedisplayinstrumentisresponsiblefordisplaying,monitoring,processingandcontrollingofallkindsofparametersofthewheeledloadermaincontrollerwhicharereceivedfromtheCANinterface.Accordingtothefunctionsoftheintelligentdisplay,itcanbedividedintofollowingmodulecircuitstodesign:1)TheprocessorofTMS320LF2407Amaincircuit(includestheCANinterface)；2)Keystrokegatheringcircuit；3)Touch-screenmodule；4)Powersourceprocessingmodule；5)GPSpositionmodule；6)Liquidcrystalinterfacecontrolcircuit；7)Speechchipcontrolcircuit；8)Distinctionchangescircuitetc.Theschematicsystemhardwareisshownasfigure2.TMS320LF2407AextendprogramanddatamemoryAddBusDataBuswheeledloadermaincontrollerCANLevelisolation74LVTH245LCDTouchIOGPSSCIMechanicalKeysSupplementallightingturning-lampsampleADCopto-couplerSCICANIOADC1IOPOWERFig.2SchematicsystemhardwarecircuitAccordingtothesystemhardwareplatform,dividetheresourcesontheplanofthemicroprocessorDSPLF2407A:1)1channelADinput,usestheon-chipADCmodule(ADC1)；2)12mechanicalkeystrokesampling,achieveswithIOPE0IOPE7andXINT1；3)2channelswitchinputs(left-rightturnsignallamp),usestwoIOport；4)CommunicationwithGPSusingon-chipSCImodule；5)CANbusinterface,usingon-chipCANcontroller；6)ControlofthespeechchipwiththeIOport；4-825Authorizedlicenseduselimitedto:JILINUNIVERSITY.DownloadedonDecember17,2008at06:08fromIEEEXplore.Restrictionsapply.TheEighthInternationalConferenceonElectronicMeasurementandInstrumentsICEMI20077)Thedatamemoryandtheprogrammemoryextendinterface(D0-D15,A0-A15)；8)TheJTAGsimulationinterface,thecrystaloscillatorclockinput,resetsignal,thepowersourcepinetc.BecausetheTMS320LF2407Aworkson3.3Vvoltage,inordertoavoidleveltransforming,thesystemusestwopiecesofCY7C1021CV33chipswhichmadeinCypressCorporationtoexpandsystemexternalmemoryspace.CY7C1021CV33isoneofthe64Kbyte,16bitstaticRAM,3.3Vpowersupply.InordertoadapttheDSPofTMS320LF2407A3.3Vworkingvoltageandsatisfythelowpowerconsumptionfeatures,SN65HVD232isselectedforCANbustransceiverofTICorporation.ItisonekindofCANbusdevicewith3.3V/5Vmixedvoltage.Thistransceiverfeaturesasflows:thesignaltransferratecanachieve1Mbps(signaldistanceis40m),andquitelowmaintenancecurrent.Thusitusesforquiteideallylowpowerconsumption.InthedesignusingthisCANbustransceivertocommunicatebetweenthedisplayinstrumentandthemaincontrollerofintelligentwheelloader.Inthedesign,consideringthatitmustcontrolandprocesstheheadandtailrainwiper,theheadandtaillamp,thefrontheadlamp,thesprayingofwater,thesmalllamp,theworkpump,theparking,thenamelysentinformation,thealarminformation,themenuoperationofthewheelloaderetc.,12mechanicalkeystrokearedesignedinthissystemactingasman-machineinteractionmethodforthedisplayinstrumentandthewheelloadermaincontrol.Aftertheoverallevaluation,CM320240-7SLYBofShenzhenBrilliantCrystalTechnologyCO.LTDisselectedfortheliquidcrystalmodule.ItisasectionproperattentiontobothChineseandEnglishwritingandthecartographypatternspotmatrixliquidcrystaldisplaymodule,thebluecolorbacklight,includebuild-in512KBytetheROMglyphcode,candisplayChinesecharacter,numericcharacter,Englishletter,Japaneseletter,Europeanletteretc.,andincludesbuild-inTwoPagedisplaymemory.Inthecharacterpattern,itcanreceivethestandardChinesecharacterencodingtodisplayChinesedirectly,butdoesnotneedtoenterthecartographypatterntodepictChinese.Itcancutmuchmicroprocessortime,promoteliquidcrystaldisplayChineseefficiently.Itsupports4/8of6800/8080MCUinterface,includebuild-in8*8keyboardscanningKeyScan,supportscreenrollsuphorizontallyandrollsupvertically,insidesitconstructs512ByteSRAMtobepossibletomakethecharactercustom,providetheChineseandEnglishcharacteralignandinside10-BitADCsupporttouch-screenapplication.Becauseofthoseadvantages,soweusedtheRA8803withitstouch-screenfunctionforthetouch-screenfunctionprograminthedesigns.WhentheprocessorofLF2407Aworksin40MHz,itcanresultintimingconfusionbecausetheRA8803workingfrequencycannotfollowDSPworkingfrequencybyfar.Consideringtheabovefactor,IOPBofDSPisselectedasthedatalineconnecttoLCDdataportDB0DB7,usingIOofIOPFastheLCDtimingcontrolwiretooperatetheliquidcrystal.Althoughitsspeedisslow,itcanguaranteethesystemwithstability.4SoftwareDesignoftheSystemThetaskdivisionandthepriorityassignmentarebasedonthefunctionrequirements.Thefunctionsofthedisplayinstrumentrequiredaregivenasfollows:Itshouldgainthereal7-timedata,faultinformation,remindingmessages,shortmessagesbycommunicatingwiththemaincontrollerofthewheelloader,andthendisplayonLCD；8Sampleskeystrokeofmechanicalkeyboard；controlsthemaincontrollertocarryonthecorrespondingoperationthroughdifferentkeystrokeinformation.9OnechannelADsample.SamplesonechannelanalogvaluethroughtheDSPADCfunction,thatistosay,itcarriesonmakinguplightgathering:wheninsidecablightisinsufficient,thelightlampisturnedonautomatically；:Touch-screeninformationgathering.Thetouch-screenfunction,insteadofthemechanicalkeyboard,canfacilitatethedrivermuchbetterto4-826Authorizedlicenseduselimitedto:JILINUNIVERSITY.DownloadedonDecember17,2008at06:08fromIEEEXplore.Restrictionsapply.TheEighthInternationalConferenceonElectronicMeasurementandInstrumentsICEMI2007operating.Accordingtothewheelloaderoperator；soperationinformation,aturningdirectionisdecided,andthenlightentheturninglampasthecorrespondingchanges.Accordingtothedriver,thecontrolcommandshouldberespectivelysenttothemaincontrollerofthewheelloaderandtheexecutivecomponentsoflight,rainblows,andbrake,thenthedisplayinstrumentshouldreadthefeedbackandjudgetheexecutingimplementationworkingconditions.=ItshouldgainthelatitudeandlongitudeinformationbytheSCIcorrespondencebetweenthedisplayinstrumentandtheGPSmodule,anduploadtimingtostoretheinformationinthemaincontrolleraccordingtothedemand.Task4,systeminitializationincludesstartingthesystemclock,systeminitialization,initializationkeystrokegainingprocedure,thetouch-screenfunction,thefaultinformationpointertable,startingalarmfunction.Thedividingreasonisgivenasfollows:TheC/OS-IIclockTICKinterruptiscompletedbythereal-timeclock,butthe2407chipdoesnothavethistimer,soitshouldusegeneraltimerT1tocomplete.Thefollowingtipsshouldbepaidattention:ClearinterruptflagintheTICKinterrupt.7thetimershouldbestartedupinthehighestpriority8duty,ifitisstartedupbeforeOSStart()starts,thesystemwillcollapse.Thefunctionsofkeyboardsample,touch-screenandsoonaffectthelateroperationdirectly.Andthefaultinformationtablesaffectthefollowingfaultdisplaying.Ifthealarmflagisopened,itcangivethespeechalarmforthefaultofthewheelloaderatthefirsttime.Allofthesebelongtoaninitializationpart,andneedtobestartedbeforeothertasks；thereforewegroupthemasawholetask.Task5,taskforCANcommunication.Ifthedisplayinstrumentnormallylinkswiththemaincontroller,itgetsallkindsofparametersofthemaincontrollerimmediately,andshowsdynamicallyonLCDafterbeingprocessed.Thedivisionreasonsareshownasbelow:Accessingandupdatingthereal-timeofthemaincontrollerdataisveryimportanttotheoperators.Theoperatorsneedtogetthestatesofthemachineintime.Therefore,thecommunicationbetweentheCANbusandthemaincontrollerisessentialtothedesign,sowetakeitastheonlyinferiortasktoopeningtheclock.Task6,taskforsupplementallightingsample.Forty-eightLEDswouldautomaticallyturnontohelptheoperatorsbyimprovingtheintensityoflightwhenthewheelloaderisworkingatlightinsufficientlyorinthedark.Itopensanalarmattheendofthetask.Theworkingconditionofwheelloaderisgenerallysobadthatthelightiscomparativelydim,sowetakethetask6asanindependentmoduleandg