机械毕业设计英文外文翻译20SJA1000独立的CAN控制器.docx

机械毕业设计英文外文翻译20SJA1000独立的CAN控制器.docx

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机械毕业设计英文外文翻译20SJA1000独立的CAN控制器

附录A英文原文

SJA1000—Stand-aloneCANcontroller

1.INTRODUCTION

TheSJA1000isastand-aloneCANControllerproductwithadvancedfeaturesforuseinautomotiveandgeneralindustrialapplications.ItisintendedtoreplacethePCA82C200becauseitishardwareandsoftwarecompatible.Duetoanenhancedsetoffunctionsthisdeviceiswellsuitedformanyapplicationsespeciallywhensystemoptimization,diagnosisandmaintenanceareimportant.

ThisreportisintendedtoguidetheuserindesigningcompleteCANnodesbasedontheSJA1000.Thereportprovidestypicalapplicationcircuitdiagramsandflowchartsforprogramming.

2.OVERVIEW

Thestand-aloneCANcontrollerSJA10001hastwodifferentModesofOperation:

1.BasicCANMode（PCA82C250compatible）.

2.PeliCANMode.

UponPower-uptheBasicCANModeisthedefaultmodeofoperation.Consequently,existinghardwareandsoftwaredevelopedforthePCA82C250canbeusedwithoutanychange.InadditiontothefunctionsknownfromthePCA82C250,someextrafeatureshavebeenimplementedinthismodewhichmakethedevicemoreattractive.However,theydonotinfluencethecompatibilitytothePCA82C250.

ThePeliCANModeisanewmodeofoperationwhichisabletohandleallframetypesaccordingtoCANspecification2.0B.FurthermoreitprovidesacoupleofenhancedfeatureswhichmakestheSJA1000suitableforawiderangeofapplications.

2.1SJA1000Features

ThefeaturesoftheSJA1000canbeclusteredintothreemaingroups:

1.Well-establishedPCA82C200Functions

FeaturesofthisgrouphavealreadybeenimplementedinthePCA82C250.

2.ImprovedPCA82C200Functions

PartlythesefunctionshavealreadybeenimplementedinthePCA82C250.However,intheSJA1000theyhavebeenimprovedintermsofspeed,sizeorperformance.

3.EnhancedFunctionsinPeliCANMode

InPeliCANModetheSJA1000offersacoupleofErrorAnalysisFunctionssupportingdiagnosis,systemmaintenanceandoptimization.FurthermorefunctionsforgeneralCPUsupportandSystemSelfTesthavebeenaddedinthismode.

2.2CANNodeArchitecture

GenerallyeachCANmodulecanbedividedintodifferentfunctionalblocks.TheconnectiontotheCANbuslinesisusuallybuiltwithaCANTransceiveroptimizedfortheapplications.ThetransceivercontrolsthelogiclevelsignalsfromtheCANcontrollerintothephysicallevelsonthebusandviceversa.

ThenextupperlevelisaCANControllerwhichimplementsthecompleteCANprotocoldefinedintheCANSpecification8.Oftenitalsocoversmessagebufferingandacceptancefiltering.

AlltheseCANfunctionsarecontrolledbyaModuleControllerwhichperformsthefunctionalityoftheapplication.Forexample,itcontrolsactuators,readssensorsandhandlestheman-machineinterface（MMI）.

AsshowninFigure1theSJA1000stand-aloneCANcontrollerisalwayslocatedbetweenamicrocontrollerandthetransceiver,whichisanintegratedcircuitinmostcases.

Figure1CANModuleSet-up

2.3BlockDiagram

ThefollowingfigureshowstheblockdiagramoftheSJA1000.

TheCANCoreBlockcontrolsthetransmissionandreceptionofCANframesaccordingtotheCANspecification.

TheInterfaceManagementLogicblockperformsalinktotheexternalhostcontrollerwhichcanbeamicrocontrolleroranyotherdevice.EveryregisteraccessviatheSJA1000multiplexedaddress/databusandcontrollingoftheread/writestrobesishandledinthisunit.AdditionallytotheBasicCANfunctionsknownfromthePCA82C250,newPeliCANfeatureshavebeenadded.Asaconsequenceofthis,additionalregistersandlogichavebeenimplementedmainlyinthisblock.

Figure2:

BlockDiagramSJA1000

TheTransmitBufferoftheSJA1000isabletostoreonecompletemessage（ExtendedorStandard）.WheneveratransmissionisinitiatedbythehostcontrollertheInterfaceManagementLogicforcestheCANCoreBlocktoreadtheCANmessagefromtheTransmitBuffer.

Whenreceivingamessage,theCANCoreBlockconvertstheserialbitstreamintoparalleldatafortheAcceptanceFilter.WiththisprogrammablefiltertheSJA1000decideswhichmessagesactuallyarereceivedbythehostcontroller.

AllreceivedmessagesacceptedbytheacceptancefilterarestoredwithinaReceiveFIFO.Dependingonthemodeofoperationandthedatalengthupto32messagescanbestored.Thisenablestheusertobemoreflexiblewhenspecifyinginterruptservicesandinterruptprioritiesforthesystembecausetheprobabilityofdataoverrunconditionsisreducedextremely.

3.SYSTEM

Forconnectiontothehostcontroller,theSJA1000providesamultiplexedaddress/databusandadditionalread/writecontrolsignals.TheSJA1000couldbeseenasaperipheralmemorymappedI/Odeviceforthehostcontroller.

3.1SJA1000Application

ConfigurationRegistersandpinsoftheSJA1000allowtouseallkindsofintegratedordiscreteCANtransceivers.Dueto