基于ARM嵌入式系统速成样机平台设计中英文翻译.docx

基于ARM嵌入式系统速成样机平台设计中英文翻译.docx

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基于ARM嵌入式系统速成样机平台设计中英文翻译

英文资料及中文翻译

1．英文资料

TheDesignofaRapidPrototypePlatformforARMBasedEmbeddedSystem

Hardwareprototypeisavitalstepintheembeddedsystemdesign.Inthispaper,wediscussourdesignofafastprototypingplatformforARMbasedembeddedsystems,providingalow-costsolutiontomeettherequestofflexibilityandtestabilityinembeddedsystemprototypedevelopment.Italsoencouragesconcurrentdevelopmentofdifferentpartsofsystemhardwareaswellasmodulereusing.

ThoughthefastprototypingplatformisdesignedforARMbasedembeddedsystem,ourideaisgeneralandcanbeappliedtoembeddedsystemofothertypes.

I.INTRODUCTION

Embeddedsystemsarefoundeverywhere,includingincellulartelephones,pagers,VCRs,camcorders,thermostats,curbsiderental-carcheck-indevices,automatedsupermarketstockers,computerizedinventorycontroldevices,digitalthermometers,telephoneansweringmachines,printers,portablevideogames,TVset-topboxes--thelistgoeson.Demandforembeddedsystemislarge,andisgrowingrapidly.

Inordertodelivercorrect-the-first-timeproductswithcomplexsystemrequirementsandtime-to-marketpressure,designverificationisvitalintheembeddedsystemdesignprocess.Apossiblechoiceforverificationistosimulatethesystembeingdesigned.Ifahigh-levelmodelforthesystemisused,simulationisfastbutmaynotbeaccurateenough,withalow-levelmodeltoomuchtimemayberequiredtoachievethedesiredlevelofconfidenceinthequalityoftheevaluation.Sincedebuggingofrealsystemshastotakeintoaccountthebehaviorofthetargetsystemaswellasitsenvironment,runtimeinformationisextremelyimportant.Therefore,staticanalysiswithsimulationmethodsistooslowandnotsufficient.Andsimulationcannotrevealdeepissuesinrealphysicalsystem.

Ahardwareprototypeisafaithfulrepresentationofthefinaldesign,guarantyingitsreal-timebehavior.Anditisalsothebasictooltofinddeepbugsinthehardware.Forthesereasons,ithasbecomeacrucialstepinthewholedesignflow.Traditionally,aprototypeisdesignedsimilarlytothetargetsystemwithalltheconnectionsfixedonthePCB（printedcircuitboards）.

Asembeddedsystemsaregettingmorecomplex,theneedsforthoroughtestingbecomeincreasinglyimportant.Advancesinsurface-mountpackagingandmultiple-layerPCBfabricationhaveresultedinsmallerboardsandmorecompactlayout,makingtraditionaltestmethods,e.g.,externaltestprobesand"bed-of-nails"testfixtures,hardertoimplement.Asaresult,acquiringsignalsonboards,whichisbeneficialtohardwaretestingandsoftwaredevelopment,becomesinfeasible,andtrackingbugsinprototypebecomesincreasinglydifficult.Thustheprototypedesignhastotakeaccountoftestability.However,simplyaddingsometestpointsisnotenough.Iferrorsontheprototypearedetected,suchasmisconnectionsofsignals,itcouldbeimpossibletocorrectthemonthemultiple-layerPCBboardwithallthecomponentsmounted.Allthesewouldleadtoanotherroundofprototypefabrication,makingdevelopmenttimeextendandcostincrease.

Besidestestability,itisimportanttomaintainhighflexibilityduringdevelopmentoftheprototypeasdesignspecificationchangesarecommon.Nowadayscomplexsystemsareoftennotbuiltfromscratchbutareassembledbyreusingpreviouslydesignedmodulesoroff-the-shelfcomponentssuchasprocessors,memoriesorperipheralcircuitryinordertocopewithmoreaggressivetime-to-marketconstraints.Followingthetop-downdesignmethodology,lotsofeffortinthedesignprocessisspentondecomposingthecustomers,requirementsintoproperfunctionalmodulesandinterfacingthemtocomposethetargetsystem.

SomepreviousresearchworkshavesuggestedthatFPLDs（fieldprogrammablelogicdevice）couldbeaddedtothefinaldesigntoprovideflexibilityasFPLDscanofferprogrammableinterconnectionsamongtheirpinsandmanymoreadvantages.However,extradevicesmayincreaseproductioncostandpowerdissipation,weakeningthemarketcompetitionpowerofthetargetsystem.Toaddresstheseproblems,therearealsosuggestionsthatFPLDscouldbeusedinhardwareprototypeasanintermediateapproach[1]-[3],whereasthiswouldstillbringmuchadditionalworktotheprototypedesign.Moreover,modulesontheprototypecannotbereuseddirectly.Inindustry,therehavebeencompaniesthatprovidecommercialsolutionsbasedonFPLDsforrapidprototyping[4].TheirproductsareaimedatSOC（systemonachip）functionalverificationinsteadofembeddedsystemdesignanddevelopment.

Inthispaper,wediscussourdesignofaRapidPrototypingPlatformforARMbasedEmbeddedSystem,providingalowcostsolutiontomeettherequestofflexibilityandtestabilityinembeddedsystemprototypedevelopment.Italsoencouragesconcurrentdevelopmentofdifferentpartsofsystemhardwareaswellasmodulereusing.Therestofthepaperisorganizedasfollows.Insection2,wediscussthedetailsofourrapidprototypingplatform.Section3showstheexperimentalresults,followedbyanoverallconclusioninsection4.

II.THEDESIGNOFARAPIDPROTOTYPINGPLATFORM

A.Overview

ARMbasedembeddedprocessorsarewildlyusedinembeddedsystemsduetotheirlow-cost,low-powerconsumptionandhighperformance.AnARMbasedembeddedprocessorisahighlyintegratedSOCincludinganARMcorewithavarietyofdifferentsystemperipherals[5].Manyarmbasedembeddedprocessors,e.g.[6]-[8],adoptasimilararchitectureastheoneshowninFig.1.

Theintegratedmemorycontrollerprovidesanexternalmemorybusinterfacesupportingvariousmemorychipsandvariousoperationmodes（synchronous,asynchronous,burstmodes）.Itisalsopossibletoconnectbus-extendedperipheralchipstothememorybus.Theon-chipperipheralsmayincludeinterruptcontroller,OStimer,UART,I2C,PWM,AC97,andetc.Someoftheseperipheralssignalsaremultiplexedwithgeneral-purposedigitalI/Opinstoprovideflexibilitytouserwhileotheron-chipperipherals,e.g.USBhost/client,mayhavededicatedperipheralsignalpins.Byconnectingorextendingthesepins,usermayusetheseonchipperipherals.Whentheon-chipperipheralscannotfulfilltherequirementofthetargetsystem,extraperipheralchipshavetobeextended.

ThearchitectureofanARMbasedembeddedsystemisshowninFig.2.Thewholesystemiscomposedofembeddedprocessor,memorydevices,andperipheraldevices.Toenablerapidprototyping,theplatformshouldbecapableofquicklyassemblingpartsofthesystemintoawholethroughflexibleinterconnection.OurbasicideaistoinsertareconfigurableinterconnectionmodulecomposedbyFPLDintothesystemtoprovideadjustableconnectionsbetweensignals,andtoprovidetestabilityaswell.Todeterminewheretoplacethismodule,wefirstanalyzethearchitectureofthesystem.

TheembeddedsystemshowninFig.2canbedividedintotwoparts.Oneistheminimalsystemcomposedoftheembeddedprocessorandmemorydevices.Theotherismadeupofperipheraldevicesextendeddirectlyfromon-chipperipheralinterfacesoftheembeddedprocessor,andspecificperipheralchipsandcircuitsextendedbythebus.

Theminimalsystemisthecoreoftheembeddedsystem,determiningitsprocessingcapacity.Theembeddedprocessorsarenowroutinelyavailableatclockspeedsofupto400MHz,andwillclimbstillfurther.Thespeedofthebusconnectingtheprocessorandthememorychipsisexceeding100MHz.Aspin-to-pinpropagationdelayofaFPLDisinthemagnitudeofafewnanoseconds,insertingsuchadevicewillgreatlyimpairthesystemperformance.

Theperipheralsenabletheembeddedsystemtocommunicateandinteractivewiththecircumstanceintherealworld.Ingeneral,peripheralcircuitsarehighlymodularizedandindependenttoeachother,andtherearehardlyneedsforflexibleconnectionsbetweenthem.

Hereweapplyareconfigurableinterconnectionmoduletosubstitutetheconnectionsbetweenmicrocomputerandtheperipherals,whichenablesflexibleadjustingofconnectionstofacilitateinterfacingextendedperipheralcircuitsandmodules.Asthespeedofthedatacommunicationbetweentheperipheralsandtheprocessorismuchslowerthanthatintheminimalsystem,theFPLDsolutionisfeasible.

Followingthisidea,wedesigntheRapidPrototypingPlatformasshowninFig.3.WedefinetheinterfaceICBbetweentheplatformandtheembeddedprocessorcoreboarthatholdstheminimalsystemofthetargetembeddedsystem.TheinterfaceIPBbetweentheplatformandperipheralboardsthatholdextendedperipheralcircuitsandmodulesisalsodefined.Theseenableustodevelopdifferentpartsofthetargetembeddedsystemconcurrentlyandtocomposethemintoaprototyperapidly,andencouragemodulereusingaswell.Thetwointerfacesareconnectedbyareconfigurableinterconnectmodule.Therearealsosomecommonlyusedperipheralmodules,e.g.RS232transceivermodule,busextendedEthernetmodule,AC97codec,PCMCIA/CompactFlashCardslot,andetc,ontheplatformwhichcanbeinterfacedthroughthereconfigurableinterconnectmoduletoexpeditetheembeddedsystemdevelopment.

B.ReconfigurableInterconnectModule

Withthefacilityofstate-of-artsFPLDs,wedesignareconfigureinterconnectionmoduletointerconnect,monitorandtestthebusandI/Osignalsbetweentheminimalsystemandperipherals.

Asthebusaccessingobeysspecificprotocolandhascontrolsignalstoidentifythedatadirection,theinterconnectionofthebuscanbeeasilyrealizedbydesigningacorrespondingbustransceiverintotheFPLD,whereastheinterconnectionoftheI/Osismorecomplex.AsI/Osaremultiplexedwithon-chipperipheralss