1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.TO PLACE A DOCUMENT ORDER: (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.s
3、ae.orgCopyright 2000 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001RECOMMENDEDPRACTICESubmitted for recognition as an American National StandardJ2411ISSUEDFEB2000Issued 2000-02Single Wire CAN Network for Vehi
4、cle ApplicationsForewordThe objective of this SAE Standard is to define a level of standardization in the implementation of lowspeed vehicle serial data network communications using the Controller Area Network (CAN) protocol. This lowspeed implementation of CAN is intended to provide a lower cost co
5、mplement to the SAE J2284 High Speed CANstandard.The goal of this document is to define a serial data physical layer, data link layer and media design criteria to beinstalled in various automotive Electronic Control Units (ECU). This document will allow ECU and toolmanufacturers to satisfy the needs
6、 of multiple end users with minimum modifications to the basic design. Thisdocument will benefit vehicle Original Equipment Manufacturers by achieving lower ECU costs due to higherindustry volumes of the basic design.TABLE OF CONTENTS1. Scope . 31.1 Mission/Theme . 32. References . 32.1 Applicable P
7、ublications 32.1.1 SAE Publications 32.1.2 ISO Publications. 32.1.3 Supplier Publications 32.1.4 Other Publications 43. Definitions. 43.1 Data Link Layer 43.2 Dominant Signal . 43.3 Media 43.4 Physical Layer 43.5 Protocol 43.6 Radiated Emissions 43.7 Radiated Immunity . 43.8 Recessive Signal 44. Acr
8、onyms, Abbreviations, and Symbols. 4SAE J2411 Issued FEB2000-2-5. Single Wire CAN System Requirements.45.1 Physical and Data Link Layer Characteristics.45.2 Message Format.55.3 Bus Operation.55.3.1 Normal Communication Mode 55.3.2 High Speed Communication Mode .55.3.3 ECU Selective Awake.75.3.4 CAN
9、Controller Clock Tolerance.75.3.5 Bus Electrical Parameters 75.4 Network Topology.95.4.1 Loss of ECU Ground.95.4.2 Bus Electrical Load Distribution 115.4.3 ESD Immunity.125.4.4 ESD Transient Suppressor .125.4.5 Bus Wiring Topology Configurations 125.4.6 Bus Wiring Constraints .145.4.7 Bus Wiring Pra
10、ctices to Improve EMC Performance 165.4.8 Bus Wiring Harness and ECU Connectors .165.5 Radiated EMI Protection.175.6 Fault Tolerant Modes175.7 Ground Offset Voltage 175.8 Operating Battery Power Voltage Range175.8.1 Normal Battery Voltage Power Operation.175.8.2 Battery Power Overvoltage Operation 1
11、85.8.3 Low Battery Voltage Operation.185.8.4 Battery Offset Voltage.185.8.5 Reverse Battery Blocking Diode .185.9 Environmental Requirements .186. Single Wire CAN Transceiver Specification186.1 Transceiver Pin Descriptions 186.1.1 GND Pin-Ground 196.1.2 TxD Input Pin 196.1.3 Mode 0 and Mode 1 Input
12、Pins.196.1.4 RxD Output Pin.206.1.5 VccIC Input Pin.206.1.6 RSLEW Input Pin206.1.7 Bus LOAD Input Pin206.1.8 VBATT IC Input PIN 216.1.9 CAN_Bus Input/Output Pin .216.1.10 Transmit Operating Conditions .226.1.11 Transceiver Mode Changes236.1.12 Maximum Transceiver Propagation Delays 236.1.13 Transcei
13、ver Electrostatic Discharge Immunity237. Validation 24Appendix A Single Wire CAN Bit Timing Analysis25Appendix B Single Wire CAN High Speed Mode Analysis.27Appendix C Nested SWC and DWC IC PC Board Layout32SAE J2411 Issued FEB2000-3-1. ScopeThis SAE Recommended Practice defines the Physical Layer an
14、d portions of the Data Link Layer ofthe OSI model for data communications. In particular, this document specifies the physical layer requirementsfor any Carrier Sense Multiple Access/Collision Resolution (CSMA/CR) data link which operates on a singlewire medium to communicate among Electronic Contro
15、l Units (ECU) on road vehicles. Requirements stated in this document will provide a minimum standard level of performance to which allcompatible ECUs and media shall be designed. This will assure full serial data communication among allconnected devices regardless of supplier.This document is to be
16、referenced by the particular vehicle OEM Component Technical Specification whichdescribes any given ECU in which the single wire data link controller and physical layer interface is located.Primarily, the performance of the physical layer is specified in this document. ECU environmental and otherreq
17、uirements when provided in the Component Technical Specification, shall supercede the requirements ofthis document.The intended audience includes, but is not limited to, ECU suppliers, CAN controller suppliers, CANtransceiver suppliers, component release engineers, and vehicle system engineers.1.1 M
18、ission/ThemeThis specification describes the physical layer requirements for a single wire data linkcapable of operating with various CSMA/CR protocols such as the Bosch Controller Area Network (CAN)version 2.0. This serial data link network is intended for use in applications where high data rate i
19、s not requiredand a lower data rate can achieve cost reductions in both the physical media components and in themicroprocessor and/or dedicated logic devices which use the network. 2. References2.1 Applicable PublicationsThe following publications form a part of this specification to the extent spec
20、ifiedherein. Unless otherwise indicated, the latest version of SAE publications shall apply.2.1.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J551All partsPerformance Levels and Methods of Measurement of Electromagnetic Compatibilityfor Vehicles and Devi
21、cesSAE J1113All partsElectromagnetic Compatibility Measurement Procedures for Vehicle ComponentsSAE J1213-1Glossary of Vehicle Networks for Multiplexing and Data CommunicationsSAE J1930Electrical/Electronic Systems Diagnostic Terms, Definitions, Abbreviations and AcronymsSAE J2284High Speed CAN (HSC
22、) for Vehicle Applications at 500 KBPSSAE 970295Optimization of CAN Bit Timing Parameters2.1.2 ISO DOCUMENTSAvailable from ANSI, 11 West 42nd Street, New York, NY 10036-8002.ISO 7498Data processing systemsOpen systems interconnection standard reference modeISO 7637Road vehiclesElectrical interferenc
23、e by conduction and couplingParts 1 and 22.1.3 SUPPLIER PUBLICATIONSDelphi - Delco Electronics Automotive Systems - DK166153 - Single Wire CAN TransceiverPhilips - AU5790 - Single Wire CAN TransceiverInfineon - TLE 6255 - Single Wire CAN TransceiverSAE J2411 Issued FEB2000-4-2.1.4 OTHER PUBLICATIONS
24、Bosch Controller Area Network 2.0 specificationCISPR 25 - Limits & Methods of Measurement of Radio Disturbance Characteristics for the Protection ofReceivers used on board vehicles.3. Definitions3.1 Data Link LayerThis provides for the reliable transfer of information across the physical layer. It i
25、ncludesthe message structure, framing, and error control.3.2 Dominant SignalThe driven and high voltage state of the single wire bus. If multiple devices access thebus, this state dominates the recessive or non-driven state.3.3 MediaThe physical entity which conveys the electrical (or equivalent mea
26、ns of communication) signaltransmission among ECUs on the network. For Single Wire CAN, this media consists of a single random laidwire.3.4 Physical LayerThis ISO 7498 subsection consists of the media, mechanical interconnections, andtransceivers which provide the network with access and interconnec
27、tion among all ECU nodes.3.5 ProtocolThe formal set of conventions or rules for the exchange of information among the ECUs. Thisincludes the specification of the signal frame administration, frame transfer, and physical layer.3.6 Radiated EmissionsThis is the energy that radiates from the CAN physic
28、al layer.3.7 Radiated ImmunityThis is the level of susceptibility of physical layer components to communication errorsin the presence of high energy electromagnetic fields.3.8 Recessive SignalThe undriven and low voltage state of the single wire bus. If multiple devices access thebus, this state is
29、overridden by the dominant state.4. Acronyms, Abbreviations, and SymbolsCAN - Controller Area NetworkCSMA/CR - Carrier Sense Multiple Access/Collision ResolutionECU - Electronic Control UnitEMC - Electromagnetic CompatibilityESD - Electrostatic DischargeISO - International Organization for Standardi
30、zationKbits/s - Thousands of data bits per secondSAE - Society of Automotive EngineersSWC - Single Wire CANDLC Diagnostic Link Connector5. Single Wire CAN System RequirementsThe physical layer is responsible for providing a method oftransferring digital data symbols (1s and 0s) to the communication
31、medium. The physical layer interface is asingle wire, vehicle ground referenced bus with high side voltage drive.5.1 Physical and Data Link Layer Characteristicsa. Carrier Sense Multiple Access/Collision Resolution (CSMA/CR) bus access and arbitration withdominant high and recessive low signal volta
32、ges.b. Capable of operating with CAN 2.0 messages with either 11-bit or 29-bit identifier.SAE J2411 Issued FEB2000-5-5.2 Message FormatAll ECU Single Wire CAN interfaces shall conform to the Bosch “CAN Specification 2.0” ofSeptember 1991. Either the 11- or the 29-bit frame identifier mode may be use
33、d. The encoding of the 11-bit identifier field shall be vehicle manufacturer specific. The CAN requirement that the“seven most significant bits (ID10-ID4) shall not all be recessive” shall not be enforced in SAE J2411 hardware.5.3 Bus Operation5.3.1 NORMAL COMMUNICATION MODETransmission bit rate in
34、the normal communication mode speed is 33.333Kbits/s. The normal transmission mode shall use transmitters with controlled waveform rise and overshoottimes. Waveform trailing edge control is required to assure that high frequency components are minimizedat the beginning of the downward voltage slope.
35、 The remaining fall time occurs after the bus is inactive withdrivers off and is determined by the RC time constant of the total bus load.5.3.2 HIGH SPEED COMMUNICATION MODEThe high speed mode is used for data download when the on-boardnetwork is attached to an off-board tester ECU. The assembly lin
36、e data download transmission bit rate inhigh speed communication is up to 83.333 Kbits/s depending on the number of connected bus nodes (whichaffect the network time constant) - see Appendix C and/or specific vehicle specifications. If a variableassembly line download bit rate method is used, the te
37、ster shall be able to communicate the intended bit rateto all participating nodes prior to the switch into the high speed mode.The service tools may be designed so that the service download high speed bit rate shall always operate atthe fixed bit rate of 83.333 Kbits/s to limit the service test tool
38、 complexity. See Appendix C.The test tool must connect Rtool to the bus before transmitting any high speed messages. Rtool shall beconnected directly to ground on the ECU. Rtool shall never be connected to the Load pin of the transceiver.The Load pin is not designed to handle the high level of curre
39、nt through Rtool.High speed transmission mode allows shortened total bit time and shortened waveform rise and fall times(rise or fall times shall be less than 25% of the total bit time as measured at the normal receiver thresholdvoltage levels Vih). Radiated EMC requirements in 5.5 are waived while
40、in this mode. Bus transmitter drivecircuits for those nodes which are required to communicate in high speed mode shall be able to drivereduced bus resistance when in this mode (to reduce the RC time constant - see Table 1). High speedcommunications shall utilize the normal mode signal voltage levels
41、 as specified in Table 1.All nodes shall be able to operate at the High Speed mode CAN frame timing and shall enter this mode whenthey have been commanded by the download system manager. The normal sequence of entering andleaving high speed mode is shown as follows as commanded by the download syste
42、m manager:a. All nodes are awakened at normal bus speedb. Nodes are commanded to remain awake or go to sleep modec. Nodes designated as sleepers go to sleep moded. The download tool switches the bus circuit to the lower tool bus resistancee. Awake nodes are commanded to go to high speed modef. High
43、speed traffic is completedg. Awake nodes are commanded to go to normal speed modeNOTEIn case of system errors, all nodes which enter the High Speed mode shall return to thenormal speed mode after a system specified time delayh. The download tool switches the tool bus resistance out of the bus circui
44、ti. All sleeping nodes are awakened and shall then operate at normal bus speedNodes shall initialize in the normal speed mode after a power up, CAN error passive, CAN Busoff, or runningreset. SAE J2411 Issued FEB2000-6-TABLE 1SINGLE WIRE CAN BUS SIGNALS AND LOADING REQUIREMENTSParameter Symbol Min T
45、ypical Max UnitsECU Battery Voltage Input(1) 1. Vbatt is measured at the ECU input power pins. All voltages are referenced to the local ECU ground.Vbatt 6.5 16 VOffset Wakeup Input High Voltage Threshold(2)(3)2. The minimum transceiver input wakeup voltage level shall be the smaller of VihWuFixed mi
46、nimum or VihWUOffset minimum.3. The maximum transceiver input wakeup voltage level shall be the smaller of VohWuFixed minimum or VohWuOffset minimum.VihWu Offset Vbatt - 4.3 Vbatt - 3.25 VOffset Wakeup Output High Voltage(4)4. The minimum transceiver output wakeup voltage level shall be the smaller
47、of VohWuFixed minimum or VohWUOffset minimum.VohWuOffset Vbatt - 1.6 Vbatt VFixed Wakeup Input High Voltage Threshold(2)(3) VihWuFixed 6.15 8.1 VFixed Wakeup Output High Voltage(5)5. The bus recessive state low voltage is the offset due to the ECU high side driver leakage current (Ileak) and does no
48、t include the ground offset voltage (Vg off). This leakage current limitation shall be in effect over the 6.5 3.4 V6.1.3 MODE 0 AND MODE 1 INPUT PINSThe Mode 0 and Mode 1 pins are used to select transceiver operatingmodes:a. Mode 0 = 0, Mode 1 = 0 - Sleep mode. Transceiver is in low power state, wai
49、ting for wake up via highvoltage signal or by mode pins change to any state other than 0,0. In this state, the CAN_Bus pin shallnot be in the dominant state regardless of the state of the TxD pin. See 6.1.4.b. Mode 0 = 1, Mode 1 = 0. High Speed mode.c. Mode 0 = 0, Mode 1 = 1. Transmit with high voltage signals to wake up remote nodes.d. Mode 0 = 1, Mode 1 = 1. Normal speed and signal voltage mode.e. The transceiver shall provide a weak internal pulled down to ground resistor on each of these pinswhich causes the transceiver to default to sleep mod
