SAE J2284-4-201606

【实例简介】
SAE J2284-4 CANFD规范 The objective of SAE J2284-4 is to define a level of standardization in the implementation of a 500 kbps arbitration bus with CAN FD Data at 2 Mbps vehicle communication network using the Controller Area Network (CAN) protocol. The goal is to achieve a standard Electronic Control
Downloaded from SAE International by Tongji University, Thursday, August 04, 2016 SAE INTERNATIONAL J2284TM4JUN2016 Page 3 of 28 1. SCOPE This SAE Recommended Practice will define the Physical Layer and portions of the Data Link Layer of the Open Systems Interconnection model(Iso 7498)for a 500 kbps arbitration bus with CAN FD Data at 2 Mbps High-Speed CAN(HSC protocol implementation Both ECu and media design requirements for networks will be specified. Requirements will primarily address the CAn physical layer implementation Requirements will focus on a minimum standard level of performance from the HSc implementation. All ECUs and media shall be designed to meet certain component level requirements in order to ensure the Hsc implementation system level performance at 500 kbps arbitration bus with CAN FD Data at 2 Mbps. The minimum performance level shall be specified by system level performance requirements or characteristics described in detail in Section 6 of this document This document is designed such that if the Electronic Control Unit(ECU)requirements defined in Section 6 are met, then the system level attributes should be obtainable This document will address only requirements which may be tested at the ECU and media level. No requirements which apply to the testing of the HSc implementation as integrated into a vehicle are contained in this document. However, compliance with all ECU and media requirements will increase the possibility of communication compatibility between separately procured components and will greatly simplify the task of successfully integrating a HSc communication system in a vehicle 2. REFERENCES This specification takes precedence over all conflicts in the documents cited in this section 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323(inside USA andCanadaor+1724-776-4970(outsideUsa),www.Sae.org SAE J551-15 Vehicle Electromagnetic Immunity- Electrostatic Discharge(ESD) SAE J1213-1 Glossary of Vehicle Networks for Multiplexing and Data Communications SAE J1930 Electrical/Electronic Systems Diagnostic Terms, Definitions, Abbreviations, and Acronyms SAE J1962 Diagnostic Connector SAE J2190 Enhanced E/E Diagnostic Test Modes SAE J2962-2 Communication Transceivers Qualification Requirements- CAN SAE 970295 CAN Bit Timing Requirements Downloaded from SAE International by Tongji University, Thursday, August 04, 2016 SAE INTERNATIONAL J2284TM4JUN2016 Page 4 of 28 2.1.2 SO Publications Copiesofthesedocumentsareavailableonlineathttp://webstore.ansiorg so7498 Data processing systems-Open systems interconnection standard reference model lSO7637-1 Road vehicles-Electrical disturbance by conduction and coupling sO10605 Road vehicles- Test methods for electrical disturbances from electrostatic discharge lSO11451-2 Road vehicles Vehicle test methods for electrical disturbances from narrowband radiated electromagnetic energy -Part 2: Off-vehicle radiation sources SO11452-4 Road vehicles-Component test methods for electrical disturbances from narrowband radiated electromagnetic energy -Part 4: Harness excitation methods So11898-1:2015E) Road vehicles- Interchange of digital information -Controller area network(CaN). Part 1: Data link layer and physical signalling lso11898-2:2016(E Road vehicles-Interchange of digital information -Controller area network(CAN), Part 2: High-speed medium access unit SO14229 Road vehicles-Diagnostic systems- Specification of diagnostic services so26262 Road vehicles- Functional safety 2.1.3 Other publications CISPR 25 Limits and methods of measurement of radio disturbance characteristics for the Protection of receivers used on-Board vehicles AUTOSAR RElease 4.2.2 www.autosar.org 3. DEFINITIONs The definitions provided in SAE J1213-1 apply to this document. Additional or modified definitions, acronyms, and abbreviations included in this document or relevant to the communication of information in a vehicle are catalogued in this section 3.1 ARBITRATION BIT TIME See nominal bit time 3.2 CAN H The Can H bus wire is fixed to a mean voltage level during the recessive state and is driven in a positive voltage direction during the dominant bit state 3.3 CAN L The can L bus wire is fixed to a mean voltage level during the recessive state and is driven in a negative voltage direction during the dominant bit state 3. 4 CAN ACTIVITY FILTER TIME Duration for which the bus needs to be continuously in the same state to enable the signal to pass the bus wake-up filter Downloaded from SAE International by Tongji University, Thursday, August 04, 2016 SAE INTERNATIONAL J2284TM4JUN2016 Page 5 of 28 3.5 CAN BUS Subnet where a number of ECUs communicate via a two-wire link(CAN_H, CAN_L)and where the Controller Area Network protocol is used as data link layer(DLL) 3.6 CAN IDENTIFIER Bit pattern of 11 bits or 29 bits, located at the beginning of a message that denotes message content and also reflects message priority. 3.7 CLASSICAL CAN MESSAGE Bus message according to ISo 11898: 1993/Amd. 1: 1995(E). Bus message according to iso 11898-1: 2015(E)where the fdf bit is dominant, also known as can 2.0 3. 8 CAN FD MESSAGE Bus message according to ISo 11898-1: 2015(E)where the fdf bit is recessive. A CAN FD message typically employs different bit rates in the data field and in the arbitration field 3.9 DATA BIT TIME Length of a single bit in those parts of CAn FD messages where a dedicated separately configurable data bit time is used The data bit time is not used anywhere in classical can messages and is not used in those can fd messages where the brS bit is dom inant 3.10 DATA LINK LAYER Provides the reliable transfer of information across the Physical Layer. This includes message qualification and error contro 3.11 DATA SAMPLE POINT (tsAMPLE) The sample point is the time within the bit period at which the single data sample captures the state of the bus. the programmable sample point is located between tsEG1 and tsEG2. Equation 1 shows the relationship of tsAMPLE to tsEG2 sample tbiT-tsEG2 ∈Eq.1) 3.12 DIAGNOSTIC CONNECTOR Provides the electrical connection between off-Board and on Board ecus. For some vehicles the diagnostic connector is the sae j1962 connector 3.13 DISABLING OF DLC MATCHING When this functionality is supported and active, then the bus transceiver will not compare message data length code(DLC values as to whether or not they match to configured DLC values when scanning messages for presence of valid wake-up requests 3. 14 DOMINANT STATE The dominant state is represented by a differential voltage greater than a minimum threshold between the CAn L and CAN H bus wires. The dominant state overwrites the recessive state and represents a logic 0"bit value 3.15 ELECTRONIC CONTROL UNIT(ECU) An On-or off-vehicle electronic assembly from which CAN SAE J2284-4 messages may be sent and/or received Downloaded from SAE International by Tongji University, Thursday, August 04, 2016 SAE INTERNATIONAL J2284TM4JUN2016 Page 6 of 28 3. 16 ECU Delay( tEcu An ECUs loop delay includes the following four delays a. Transmitter Propagation Delay(tTx, this includes device delay and slew) b. Receiver Propagation Delay(tRx) C. Receiver Logic Delay (tLoGic) d. Common Mode Choke(tcHK, optional, Includes both Tx and Rx choke delays ECU (tx +tRX+ tLOGIC + tcHK) (Eq.2) 3.17 Fd Receive/Fd Transmit Status flags indicating whether the bus controller employs CAN FD data bit timing presently 3.18 HANDLE Hardware object label of one or multiple LlC frames(LPDU) Identifies hardware element used for transaction. Used to facilitate cancellation of pending message transmission requests 3.19 MEDIA The physical entity which conveys the electrical (or equivalent means of communicationtransmission between ECUs on the network (e. g, unshielded twisted pair wires). Media is defined as all elements between the connector pins of the communicating ECUs through which the signals pass 3.20 MEDIA DELAY (tBus Media delay is defined as the time required for a signal to pass through the media at the longest specified distance(see Table 1 in 5.3, Table 2 in 5. 4, and table 3 in 5.5) 3.21 MUST The word Mustis used to indicate that a binding requirement exists on components or devices which are outside the scope of this specification 3.22 NOMINAL BIT TIME Length of a single bit in Classical CAN messages. Length of a single bit in CAN FD messages except where data bit timing applies. Also known as arbitration bit time 3.23 PCS STATUS ndicates what logical level is presently being received or transmitted and whether or not CAn FD data bit timing applies presently. For details see ISo 11898-1: 2015(E) Downloaded from SAE International by Tongji University, Thursday, August 04, 2016 SAE INTERNATIONAL J2284TM4JUN2016 Page 7 of 28 3.24 PHYSICAL LAYER Concerns the transmission of an unstructured bit stream over physical media deals with the mechanical electrical unctional, and procedural characteristics to access the physical media 3.25 PROTOCOL Formal set of conventions or rules for the exchange of information between ECUs. This includes the specification of frame administration, frame transfer, and physical layer 3.26 RADIATED EMISSIONS Radiated Emissions consists of energy that emanate from the can bus wires. Electric field strength in dbuv/m is the typical measure of radiated emissions 3.27 RADIATED IMMUNITY a property that ensures that the can bus wires will not suffer degraded functional operation within its intended electromagnetic environment 3.28 RECESSIVE STATE The recessive state is represented by an inactive state differential voltage that is approximately 0. The recessive state represents a logic“1” bit value. 3.29 PROPAGATION DELAY(tPROP Part of bit cell that serves compensation of data signal delay times in a network. Because CAN is an arbitrating protocol the propagation delay must take into account the time required for a signal to make a complete round trip from one can controller to another and back. this translates to Equation 3 or 4 PRoP=2(tIx+tRx+tLoGic+tcHK+ tBus) (Ea.3) or prop- 2(tecu+ tBus) (Eq 3.30 SECONDARY SAMPLE POINT (SSP) Sample point that applies to data bit timing in CAn FD(BRS recessive messages when the transmitter delay compensation functionality is configured to be enabled/active. The transmitting bus controller automatically determines/adapts/delays the location of the sample point based on observed data signal delay of the particular transmitter implementation, unless transmitter delay compensation disabled 3.31 SELECTIVE WAKE-UP BUS TRANSCEIVER Bus transceiver capable to monitor bus messages while in low power mode and capable to generate a wake-up interrupt when valid messages present on the bus match configured message content(identifier, data field) Downloaded from SAE International by Tongji University, Thursday, August 04, 2016 SAE INTERNATIONAL J2284TM4JUN2016 Page 8 of 28 3.32 SHALL le word"Shall" is to be used in the following ways: a. To state a binding requirement on the Can interfaces which comprise the ECU, which is verifiable by external manipulation and/or observation of an input or output b. To state a binding requirement upon an eCU that is verifiable through a review of the document 3.33 SHOULD The word "Should"is used to denote a preference or desired conformance 3.34 SPLIT BUS TERMINATION Bus termination where the resistance between CAN H and CAN L is split into two parts of equal value. Resistance center tap connected to ground via a capacitor unless otherwise specified 3.35 SYNCHRONIZATION JUMP WIDTH (tsjw) This time interval is the maximum amount of time by which tsEG1 may be lengthened or tsEG2 shortened to compensate for synchronization differences between ECUs on the Can network. This is accomplished automatically in the Can controller as a basic part of the protocol. However, the amount of skew tolerated is adjustable by software programming 3.36 SYNCHRONIZATION SEGMENT (tSYNC SEG) This time interval is used to synchronize all ECUs on the bus. If all ECUs are fully synchronized, then all bit edges occur in this interval, which has a fixed period of one Time Quantum 3.37 TIME QUANTUM (to) This is the basic unit of time for bit timing. This time is derived from the microcontroller's oscillator clock and is programmable based on the can controller's divide register values 3.38 TRANSMITTER DELAY COMPENSATION (TDC) or data bit timing in CAN FD messages the transmitting Can controller automatically will compensate the signal delay caused by the ECU-internal transmitter implementation, unless TDc functionality disabled. Functionality inactive for arbitration bit timing in CAN FD messages and generally inactive in classical CAN messages. For details see ISo 11898-1 2015(E) 3.39 TSEG1(tsEG1) This time interval is used to compensate for positive phase errors in synchronization between ECUs on the network. If an edge occurs during this interval, tsEG1 is lengthened to compensate for synchronization differences with other ECUs on the CAN network. TsEG1 is equivalent to the combination of the Prop Seg and Phase Seg 1 parts of the bit period defined in sO11898-12015(E) 3.40 TSEG2(tsEG2 This time interval is used to compensate for negative phase errors in synchronization between ECUs on the network. If an edge occurs during this interval, tsEG2 is shortened to compensate for synchronization differences with other ECUs on the CAN network. T SEG2 is equivalent to the Phase Seg2 part of the bit period defined in ISo 11898-1: 2015(E) 3. 41 WILL The word is used to state an immutable law of physics Downloaded from SAE International by Tongji University, Thursday, August 04, 2016 SAE INTERNATIONAL J2284TM4JUN2016 Page 9 of 28 4. ACRONYMS ASIL Automotive Safety Integrity Level BRS Bit rate switch CAN Controller area network CAN FD CAN with flexible data rate CAN ID CAN Identifier DLC Data Length Code ECU Electronic Control unit EMC ElectroMagnetic Compatibility ESD Electrostatic Discharg ESI Error status Indicator FD Flexible Data Rate(message format) FDF Flexible data rate format HSC High-Speed CaN International Standardization organization kbps Kilo Bits per second LLC Logical Link Control (layer) LPDU LLC Protocol Data Unit (frame) MAC Media Access Control ( layer) Mbps Mega Bits Per Second NOP Non-operating(only survival is demanded) OBD I On Board Diagnostics(level 2) PCS Physical Coding Sub-layer R Resistive load between can h and can l Bus Termination Resistance(125 Q2 nominal SAE SAE International Vbatt Power supply for the ECUs present in a communication network(12V nominal) VDiff Differential bus voltage (VDiff VCAN H-VCAN L) 5. SYSTEM LEVEL ATTRIBUTES OF THE NE TWORK This section describes System Level performance attributes of a 500 kbps HSc network for automotive vehicle applications It is up to the particular system owner to ensure that network level limits in this chapter are met. This HSc network is based on so11898-1 and so11898-2 re leases stated in section 2.1.2 with the modifications and additions described as follows 5.1 Message Format All ECU CAN interfaces shall, at a minimum, conform to the Iso 11898-1(Road vehicles -Controller area network(CAN) Part 1: Data link layer and physical signalling)and Iso 11898-2(Road vehicles- Controller area network( Can)- Part 2: High-speed medium access unit ), releases as stated in section 2.1.2. For details, see sections 6 and 7 later in this document All ECUs intended for use in a subnet according to J2284-4 shall, at a minimum, be passive to CAN FD format frames meaning shall not send error frames against and shall not increase ECU-internal error counters when syntactically correct CAN FD format frames with bit rates stated below in this document are present All ECUs that utilize the 11-bit base frame identifier shall be, at a minimum, passive to the 29-bit extended frame identifier All SAE J2284-4 compliant ECUs that support OBD Il requirements shall fully support a 29-bit extended frame identifier The encoding of the 11-bit identifier field shall be vehicle manufacturer specific. The CAN requirement( see CAN 2.0 protocol specification and superseded Iso 11898-1 CAN documents)specifying that the 7 most significant bits(ID-28-ID-22)must not be all recessive shall not be enforced in hardware by SAE J2284-4 CAN protocol implementations shall be capable to transmit and receive all identifier bit com binations without any restrictions The maximum message frame shall consist of the CAN identifier(CAN ID)plus 64 data bytes Downloaded from SAE International by Tongji University, Thursday, August 04, 2016 SAE INTERNATIONAL J2284TM-4JUN2016 Page 10 of 28 5.2 Communication rate Classical CAn messages and can fd messages where the bit brs is dominant shall utilize a single communication rate of 500 kbps Can Fd messages where the bit brs is recessive shall utilize a communication rate of 500 kbps for arbitration end of frame fields, and syntax error notifications and shall utilize 2 Mbps for message data fields (i.e. from sample point of BRS bit to sample point of CRC Delimiter bit 5.3 Basic Communication network parameters The intent of this standard is to specify data communication for networks with these properties Table 1-Basic communication network parameters Parameter ymbo Minimum Maximum Units Conditions Number of nodes(bus interfaces Nnd 2 Data communication operating GND-OP Volts ground offset voltage Network level overall differential R 70 Ohms resistive load (Wiring) Resistance between any two R Ohms bus transceiver can h to can h (Can L to Can L)pins Maximum propagation time between 300 ns any two ECUs 1. Directly connected within a particular subnet 2. Between any two ECUs in a subnet 3. Between can H and can L 4. Intends to reflect the bus wiring resistive behavior 5. Includes one way wiring delay and node loading delay 5.4 Topology and Termination The wiring topology of this network supports a linear structure, including dais y-chain configurations, and including bus cable stubs. The bus shall be terminated in a way so that the network level overall resistive load between the Can H and Can_ L wires will be consistent to line item Rl in table 1. termination shall be located at each end of the bus. termination units shall establish a defined resistance between the Can H and can L wires. two bus termination units shall be present in a subnet. Each of two termination units shall meet the requirements stated in section 6. 4 5.4. 1 Multiple on-Board ecU Configuration The topology requirements for a network containing more than one ECU On-Board the vehicle are specified in Figure 1 and Table 2. Note, presence of bus termination is needed, otherwise the network will not work 【实例截图】
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