lin总线介绍

10June20051LINIntroductionWhatisLIN?WhydoweuseLIN?Where?SchemeandproductContent.10June20053WHAT?一、WhatisLIN?LIN(LocalInterconnectNetwork),局部互联网络，是一种低成本的串行通讯网络，用于实现汽车中的分布式电子系统控制。LIN的目标是为现有汽车网络(例如CAN总线)提供辅助功能，因此LIN总线是一种辅助的总线网络，在不需要CAN总线的带宽和多功能的场合比如智能传感器和制动装置之间的通讯，不需调整通讯的车身舒适系统等场合，使用LIN总线可大大节省成本LIN通讯是基于SCI(UART)数据格式，采用单主控制器/多从设备的模式，仅使用一根12V信号总线，和一个无固定时间基准的节点同步时钟线。这种低成本的串行通讯模式和相应的开发环境已经由LIN协会制定成标准。LIN的标准化将为汽车制造商以及供应商在研发应用操作系统降低成本10June20054二、WHY?Speed[bit/s]ByteflightopticalbusLINmaster-slavesinglewirebusnoquartzCAN-BeventtriggeredfaulttolerantdualwireCAN-CeventtriggereddualwireTTx(indefinition)timetriggeredfaulttol,dependable2x2wire25.6M20K2M1M125Kincrementalcostpernode[$]D2B,MOSTtokenringopticalbus124.51010June20055WHERE?三、LIN的应用场合典型的LIN总线应用是汽车中的联合装配单元，如门、方向盘、座椅、空调、照明灯、湿度传感器、电机等，对于这些成本比较敏感的单元LIN可以使那些机械元件如智能传感器、制动器或光敏器件得到较广泛的使用、这些元件可以很容易的连接到汽车网络中。并得到十分方便的维护和服务。在LIN实现的系统中通常将模拟信号量用数字信号量所替换，这将使总线性能优化。10June20056WHERE?在以下的汽车电子控制系统中使用LIN来实现将得到非常完美的效果1.车顶（湿度传感器、光敏传感器、信号灯控制、雨滴传感器、天窗）2.车门（车窗玻璃、中枢锁、车窗玻璃、后视镜、面板）3.车头、车尾（传感器、电子扇、灯组件）4.车内（组合开关、雨刷电机、无线电、空调、国内照明等）5.座椅（座椅电机、转速传感器、面板）10June20057FeaturesandPossibilitiesSinglemasterwithmultipleslavesconceptLowcostsilicon,basedUART/SCIinterfaceSelfsynchronizationwithoutquartzorceramicsresonatorintheslavesnodeLowcostsingle-wireimplementationSpeedupto20000bps10June20058Motorola车身网络方案Motorola’sschemeCANCANPowerTrainLightSub-BusITSWindowLiftInteriorLightLockMirrorLockMirrorLockLockSeatHtngSeatHtngInstrumentsCentralBodyCtrlClimateUniversalMotorUniversalPanelLightRoof1backbone,13nodes8subnets,1-8localnodes52nodestotalSt-WheelPanelx6HtngHtngSeatWiperTrunkWHtgUniversalLight10June20059LINTypicallyApplication•Door/window/seat:Mirror,CentralECU,Switch,WindowLift,SeatControlSwitch,DoorLock,etc.Roof:(highamountofwiring)RainSensor,LightSensor,LightControl,SunRoof…(RainSensorneedstobeinterrogatedevery10-20ms)Seat:manySeatPositionMotors,OccupancySensor,ControlPanelSteeringWheel:(verymanycontrolsaregoingtobepositionedonthesteeringwheel)CruiseControl,Wiper,TurningLight,…Optional:ClimateControl,Radio,Telephone,etc.Climate:manySmallMotorsControlPanelLight:Beam,Foglight,FlashLight…10June200510电子扇喷水雨刮器SteeringwheelECUControlLineLINBUSCANBUS转向灯远灯近灯雾灯转向灯远灯近灯雾灯CAN总线LIN总线LIN总线倒车灯刹车灯夜灯转向灯刹车灯夜灯转向灯倒车灯线束面板中控单元牌照灯电源线10June200511LINProtocolVersionDaimler-ChryslerAUDIVWVolvoBMWLINSpecVCTConsortiumformedin1998.FiveCarmanufacturersONESemiconductorSupplier(Motorola)OnetoolSupplier(VCT)VersionLIN1.0isissuedon01/07/99VersionLIN1.1isissuedon06/03/00VersionLIN1.2isissuedon17/11/00VersionLIN1.3isissuedon13/12/02VersionLIN2.0isissuedon16/09/03OpenSpecification.LIN2.0isasupersetofLIN1.3.Newfeatures:•Enhancedchecksum,•Reconfigurationanddiagnostics•Automaticbaudratedetection•Response_errorstatusmonitoring10June200512LINStandard-OverviewSoftwareLevelHardwareLevelECU(LINrelevantfunctionsonly)OperatingSystemBusTransceiverApplicationCommunicationManagerVehicleNetworkLINAPISpecificationLINProtocolSpecificationLINPhysicalLayerSpec.LINConfig.LanguageLINConformanceTestSpecificationLINDiagnostic&ConfigurationSpec.InterfacebetweennetandapplicationprogramBitrate,clocktolerances,etcDatalinklayerProvidediagnosticmsgsandnodeconfig.10June200513HierarchicalNetworkStructureFlatNetwork•CAN+AutomotiveStandardBus+CompatiblewithMainBus-Expensive(DieSize/DualWire)HierarchicalNetwork•SubnetsarenecessarytoreduceBusloadonmainBus•Solutionexamples:•SerialSubBus-nostandardBusSystem-notcompatiblewithMainBus+inexpensive+SCI-Based:Interfaceexistsevenoncheapdevices+InterfacecaneasilybereconstructedbyASICorCPLD+ProtocolcanbedoneinSoftware10June200514Sub-Network:LINvs.CANECU&GatewayCANSCISatellite1SCISatellite2LINphysIFSCILINphysIFSatellite3SCILINphysIFSatellite4SCILINphysIFLINphysIFECU&GatewayCANSatellite1Satellite2Satellite3Satellite4CANCANCANCANLINCAN-BCostFactors:CANModuleDualWireInterfaceCrystal5Vsupplyforbus2ndWire/ConnectorCANphysIFCANphysIFCANphysIFCANphysIFCANphysIFCANphysIF5V5V5V5V5V5VCAN-CCAN-B10June20051510June200516SubBusConceptBasicRequirements:•SatisfyNeedforaStandardforSubBusses•Costdriven:ThesolutionmustbecheaperthanCAN•Reliability:SameLevelasCANexpected•LongTermSolution•LogicalExtensiontoCAN•Scalable:CapabilitytoextendSystemswithadditionalnodes•LoweringCostofSatellitenodes:NoCrystalorResonatorEasyimplementationSimpleStateMachines•LowReactionTime(100msmax)•PredictableWorstCaseTiming10June200517LINConcept•TechnicalSolution–Lowcostsingle-wireimplementation(enhancedISO9141)–Speedupto20Kbit/s(limitedforEMI-reasons)–SingleMaster/MultipleSlaveConceptNoarbitrationnecessary–LowcostsiliconimplementationbasedoncommonUART/SCIinterfacehardwareAlmostanyMicrocontrollerhasnecessaryhardwareonchip–SelfsynchronizationwithoutcrystalorceramicsresonatorintheslavenodesSignificantcostreductionofhardwareplatform–Guaranteedlatencytimesforsignaltransmission(Predictability)–Hasitsuniversalstandard10June200518Master/SlaveProtocolMasterhascontroloverthewholeBusandProtocolThemastercontrolswhichmessageatwhattimeistobetransferredoverthebu