SJA1000-独立的CAN控制器外文文献翻译、中英文翻译

I附录A英文原文SJA1000—Stand-aloneCANcontroller1.INTRODUCTIONTheSJA1000isastand-aloneCANControllerproductwithadvancedfeaturesforuseinautomotiveandgeneralindustrialapplications.ItisintendedtoreplacethePCA82C200becauseitishardwareandsoftwarecompatible.Duetoanenhancedsetoffunctionsthisdeviceiswellsuitedformanyapplicationsespeciallywhensystemoptimization,diagnosisandmaintenanceareimportant.ThisreportisintendedtoguidetheuserindesigningcompleteCANnodesbasedontheSJA1000.Thereportprovidestypicalapplicationcircuitdiagramsandflowchartsforprogramming.2.OVERVIEWThestand-aloneCANcontrollerSJA10001hastwodifferentModesofOperation:1.BasicCANMode(PCA82C250compatible).2.PeliCANMode.UponPower-uptheBasicCANModeisthedefaultmodeofoperation.Consequently,existinghardwareandsoftwaredevelopedforthePCA82C250canbeusedwithoutanychange.InadditiontothefunctionsknownfromthePCA82C250,someextrafeatureshavebeenimplementedinthismodewhichmakethedevicemoreattractive.However,theydonotinfluencethecompatibilitytothePCA82C250.ThePeliCANModeisanewmodeofoperationwhichisabletohandleallframetypesaccordingtoCANspecification2.0B.FurthermoreitprovidesacoupleofenhancedfeatureswhichmakestheSJA1000suitableforawiderangeofapplications.2.1SJA1000FeaturesThefeaturesoftheSJA1000canbeclusteredintothreemaingroups:1.Well-establishedPCA82C200FunctionsFeaturesofthisgrouphavealreadybeenimplementedinthePCA82C250.2.ImprovedPCA82C200FunctionsPartlythesefunctionshavealreadybeenimplementedinthePCA82C250.However,intheSJA1000theyhavebeenimprovedintermsofspeed,sizeorperformance.3.EnhancedFunctionsinPeliCANModeInPeliCANModetheSJA1000offersacoupleofErrorAnalysisFunctionssupportingdiagnosis,systemmaintenanceandoptimization.FurthermorefunctionsforgeneralCPUsupportandSystemSelfTesthavebeenaddedinthismode.2.2CANNodeArchitectureGenerallyeachCANmodulecanbedividedintodifferentfunctionalblocks.TheconnectiontotheCANbuslinesisusuallybuiltwithaCANTransceiveroptimizedfortheapplications.ThetransceivercontrolsthelogiclevelsignalsfromtheCANcontrollerintothephysicallevelsonthebusandviceversa.ThenextupperlevelisaCANControllerwhichimplementsthecompleteCANprotocoldefinedintheCANSpecification8.Oftenitalsocoversmessagebufferingandacceptancefiltering.AlltheseCANfunctionsarecontrolledbyaModuleControllerwhichperformsthefunctionalityoftheapplication.Forexample,itcontrolsactuators,readssensorsandhandlestheman-machineinterface(MMI).AsshowninFigure1theSJA1000stand-aloneCANcontrollerisalwayslocatedbetweenamicrocontrollerandthetransceiver,whichisanintegratedcircuitinmostcases.Figure1CANModuleSet-up2.3BlockDiagramThefollowingfigureshowstheblockdiagramoftheSJA1000.TheCANCoreBlockcontrolsthetransmissionandreceptionofCANframesaccordingtotheCANspecification.TheInterfaceManagementLogicblockperformsalinktotheexternalhostcontrollerwhichcanbeamicrocontrolleroranyotherdevice.EveryregisteraccessviatheSJA1000multiplexedaddress/databusandcontrollingoftheread/writestrobesishandledinthisunit.AdditionallytotheBasicCANfunctionsknownfromthePCA82C250,newPeliCANfeatureshavebeenadded.Asaconsequenceofthis,additionalregistersandlogichavebeenimplementedmainlyinthisblock.Figure2:BlockDiagramSJA1000TheTransmitBufferoftheSJA1000isabletostoreonecompletemessage(ExtendedorStandard).WheneveratransmissionisinitiatedbythehostcontrollertheInterfaceManagementLogicforcestheCANCoreBlocktoreadtheCANmessagefromtheTransmitBuffer.Whenreceivingamessage,theCANCoreBlockconvertstheserialbitstreamintoparalleldatafortheAcceptanceFilter.WiththisprogrammablefiltertheSJA1000decideswhichmessagesactuallyarereceivedbythehostcontroller.AllreceivedmessagesacceptedbytheacceptancefilterarestoredwithinaReceiveFIFO.Dependingonthemodeofoperationandthedatalengthupto32messagescanbestored.Thisenablestheusertobemoreflexiblewhenspecifyinginterruptservicesandinterruptprioritiesforthesystembecausetheprobabilityofdataoverrunconditionsisreducedextremely.3.SYSTEMForconnectiontothehostcontroller,theSJA1000providesamultiplexedaddress/databusandadditionalread/writecontrolsignals.TheSJA1000couldbeseenasaperipheralmemorymappedI/Odeviceforthehostcontroller.3.1SJA1000ApplicationConfigurationRegistersandpinsoftheSJA1000allowtouseallkindsofintegratedordiscreteCANtransceivers.Duetotheflexiblemicrocontrollerinterfaceapplicationswithdifferentmicrocontrollersarepossible.Figure3TypicalSJA1000Application3.2PowerSupplyTheSJA1000hasthreepairsofvoltagesupplypinswhichareusedfordifferentdigitalandanaloginternalblocksoftheCANcontroller.1.VDD1/VSS1:internallogic(digital).2.VDD2/VSS2:inputcomparator(analog).3.VDD3/VSS3:outputdriver(analog).ThesupplyhasbeenseparatedforbetterEMEbehaviour.ForinstancetheVDD2canbede-coupledviaanRCfilterfornoisesuppressionofthecomparator.3.3ResetForaproperresetoftheSJA1000astableoscillatorclockhastobeprovidedatXTAL1oftheCANcontroller,seealsochapter3.4.Anexternalresetonpin17issynchronizedandinternallylengthenedto15TXTAL.ThisguaranteesacorrectresetofallSJA1000registers(see1).Notethatanoscillatorstart-uptimehastobetakenintoaccountuponpower-up.3.4OscillatorandClockingStrategyTheSJA1000canoperatewiththeon-chiposcillatororwithexternalclocksources.AdditionallytheCLKOUTpincanbeenabledtooutputtheclockfrequencyforthehostcontroller.Figure4showsfourdifferentclockingprinciplesforapplicationswiththeSJA1000.IftheCLKOUTsignalisnotneeded,itcanbeswitchedoffwiththeClockDividerregister(ClockOff=1).ThiswillimprovetheEMEperformanceoftheCANnode.ThefrequencyoftheCLKOUTsignalcanbechangedwiththeClockDividerRegister:CLKOUT=fXTAL/ClockDividerfactor(1,2,4,6,8,10,12,14).UponpoweruporhardwareresetthedefaultvaluefortheClockDividerfactordependsontheselectedinterfacemode(pin11).Ifa16MHzcrystalisusedinIntelmode,thefrequencyatCLKOUTis8MHz.InMotorolamodeaClockDividerfactorof12isuseduponresetwhichresultsin1,33MHzinthiscase.Figure4ClockingSchemes3.4.1SleepandWake-upUponsettingtheGoToSleepbitintheCommandRegister(BasicCANmode)ortheSleepModebitintheModeRegister(PeliCANmode)theSJA1000willenterSleepModeifthereisnobusactivityandnointerruptispending.Theoscillatorkeepsonrunninguntil15CANbittimeshavebeenpassed.ThisallowsamicrocontrollerclockedwiththeCLKOUTfrequencytoenteritsownlowpowerconsumptionmode.Ifoneofthreepossiblewake-upconditionsoccurstheoscillatorisstartedagainandaWake-upinterruptisgenerated.AssoonastheoscillatorisstabletheCLKOUTfrequencyisactive.3.5CPUInterfaceTheSJA1000supportsthedirectconnectiontotwofamousmicrocontrollerfamilies:80C51and68xx.WiththeMODEpinoftheSJA1000theinterfacemodeisselected.IntelMode:MODE=high.MotorolaMode:MODE=low.Theconnectionfortheaddress/databusandtheread/writecontrolsignalsinbothIntelandMotorolamodeisshowninFigure5.ForPhilips8-bitmicrocontrollersbasedonthe80C51familyandthe16-bitmicrocontrollerswithXAarchitecturetheIntelModeisused.Forothercontrollersadditionalgluelogicisnecessaryforadaptationoftheaddress/databusandthecontrolsignals.However,ithastobemadesurethatnowritepulsesaregeneratedduringpower-up.AnotherpossibilityistodisabletheCANcontrollerwithahigh-levelonthechipselectinputinthistime.Figure5CPUInterfaceoftheSJA10003.6PhysicalLayerInterfaceForcompatibilitypurposeswiththePCA82C250,theSJA1000includesananalogreceiveinputcomparatorcircuit.Thisintegratedcomparatorcanbeusedifthetransceiverfunctionisrealizedwithdiscretecomponents.Figure6SJA1000ReceiveInputComparatorIfanexternalintegratedtransceivercircuitisusedandthecomparatorbypassfunctionisnotenabledintheClockDividerRegister,theRX1inputhastobeconnectedtoareferencevoltageof2.5V(referencevoltageoutputofexistingtransceivercircuits).Figure6showstheequivalentcircuitsforbothconfigurations:CBP=activeandCBP=inactive.Additionallythepathforthewake-upsignalisdrawn.Forallnewapplicationswhereanintegratedtransceivercircuitisused,itisrecommendedtoactivatethecomparatorbypassfunctionoftheSJA1000(Figure7).Ifthisfunctionisenabled,aschmitt-triggerinputisusedandtheinternalpropagationdelayTD2ismuchshorterasthedelayTD1.ofthereceivecomparator.Thishasapositiveimpactonthemaximumbuslength6.Additionally,itwillreducethesupplycurrentinsleepmodesignificantly.Figure7Standardapplicationwithintegratedtransceivercircuit附录B英文翻译SJA1000—独立的CAN控制器1.介绍控制器局部网CAN是一个串行的异步的多主机的通讯协议SJA1000是一个独立的CAN控制器它在汽车和普通的工业应用上有先进的特征由于硬件和软件的兼容它将会替代PCA82C250。它与PCA82C250相比具有更先进的特征因此特别适合于轿车内的电子模块传感器制动器的连接和通用工业应用中特别是系统优化系统诊断和系统维护时特别重要。本文倾向于在设计SJA1000为基础的CAN节点上引导用户同时还提供典型的应用电路图和用于编程的流程图。2.概述独立的CAN控制器SJA1000有2个不同的操作模式：1.BasicCAN模式(PCA82C250兼容)。2.PeliCAN模式。上电时BasicCAN模式是默认的操作模式因此已经使用PCA82C250开发出的硬件和软件可以直接被SJA1000使用而不用作任何修改PeliCAN模式是操作的新模式它能够处理所有的CAN2.0B定义的帧类型而且它还提供一些增强功能使SJA1000能应用于更宽的领域。2.1SJA1000特征SJA1000的特征能分成3组：1.已建立好的PCA82C250功能这组的特征在PCA82C250里已经生效。2.提高的PCA82C200功能部份这些功能在PCA82C250里已经生效但是在SJA1000里它们在速度大小和性能方面已得到提高。3.在PeliCAN模式里的增强功能在PeliCAN模式里SJA1000支持一些错误分析功能如支持系统诊断系统维护系统优化而且这个模式里也加入了对一般CPU的支持和系统自身测试的功能。2.2CAN节点结构一般来说每个CAN模块能够被分成不同的功能块CAN总线的连接通常由被优化的CAN收发器建立收发器控制逻辑电平信号从CAN控制器到达总线上的物理层反之亦然。上面一层是一个CAN控制器它执行在CAN规约里定义的CAN协议它通常用于信息缓冲和验收滤波。而所有这些CAN功能都被一个模块控制器控制它用于执行功能性的应用例如控制调节器读传感器和处理人机接口MMI。如图1所示，SJA1000独立的CAN控制器总是位于微型控制器和收发器之间在一般情况下这个控制器是一个集成电路。图1CAN模块装置2.3方块图下图是SJA1000的方块图。图2SJA1000的方块图根据CAN规约CAN核心模块控制CAN帧的发送和接收。接口管理逻辑完成对外部主控制器的连接该控制器能可以是微型控制器或其他器件经过SJA1000复用的地址/数据总线访问寄存器和控制读/写选通信号都在这里处理另外除了PCA82C200已有的BasicCAN功能还加入了一个新的PeliCAN功能因此附加的寄存器和逻辑电路主要在这块里生效。SJA1000的发送缓冲器能够存储一个完整的信息扩展的或标准的无论什么时候主控制器初始化发送接口管理逻辑会迫使CAN核心块从发送缓冲器读CAN信息。当收到一个信息时CAN核心块将串行位流转换成用于验收滤波器的并行数据通过这个可编程的滤波器SJA1000能确定哪些信息实际上被主控制器收到。所有收到的信息由验收滤波器接收并存储在接收FIFO储存信息的多少由工作模式决定而最多能存储32个信息因为数据溢出的可能性被大大降低这使用户能更灵活地指定中断服务和中断优先级。3.系统为了连接到主控制器SJA1000提供一个复用的地址/数据总线和附加的读/写控制信号SJA1000能被看作外围存储器并为主控制器映射I/O设备。3.1SJA1000应用SJA1000的寄存器和管脚配置允许它使用于各种各样的集成的或分立的CAN收发器这使不同微控制器之间的接口能够被灵活运用。一个包括80C51微型控制器和PCA82C250收发器的典型SJA1000应用图如图3所示CAN控制器功能作为一个时钟源复位信号由外部复位电路产生在这个例子里SJA1000的片选由微控制器的P2.7口控制否则这个片选输入必须接到VSS也可以通过地址解码控