1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Part 5: High-speed medium access unit with low-power modeICS 43.040.15Road vehicles Controller area
2、 network (CAN) BRITISH STANDARDBS ISO 11898-5:2007BS ISO 11898-5:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2007 BSI 2007ISBN 978 0 580 55451 3Amendments issued since publicationAmd. No. Date CommentsCompliance with a British
3、 Standard cannot confer immunity from legal obligations.National forewordThis British Standard is the UK implementation of ISO 11898-5:2007.The UK participation in its preparation was entrusted to Technical Committee AUE/16, Electrical and electronic equipment.A list of organizations represented on
4、this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Reference numberISO 11898-5:2007(E)INTERNATIONAL STANDARD ISO11898-5First edition2007-06-15Road vehicl
5、es Controller area network (CAN) Part 5: High-speed medium access unit with low-power mode Vhicules routiers Gestionnaire de rseau de communication (CAN) Partie 5: Unit daccs au mdium haute vitesse avec mode de puissance rduite BS ISO 11898-5:2007ii iiiContents Page Foreword iv Introduction v 1 Scop
6、e . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Symbols and abbreviated terms . 2 5 Functional description of medium access unit (MAU) with low-power mode 2 5.1 General. 2 5.2 Physical medium attachment sub layer specification 2 6 Conformance tests . 5 6.1 General. 5 6.2 VSplitoutput f
7、unction. 5 6.3 Output voltage during low-power mode. 6 6.4 Internal resistance during low-power mode 6 6.5 Propagation delay during normal mode. 7 6.6 Wake-up filter time during low-power mode 7 6.7 Bus driver symmetry during normal mode 7 6.8 Input leakage current, unpowered device 8 7 Electrical s
8、pecification of high-speed medium access unit (HS-MAU). 8 7.1 Physical medium attachment sub layer specification 8 7.2 CAN node. 10 7.3 Medium dependent interface (MDI) specification, connector parameters 18 7.4 Physical medium specification . 18 Bibliography . 20 BS ISO 11898-5:2007iv Foreword ISO
9、(the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical comm
10、ittee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrote
11、chnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the memb
12、er bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifyi
13、ng any or all such patent rights. ISO 11898-5 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3, Electrical and electronic equipment. ISO 11898 consists of the following parts, under the general title Road vehicles Controller area network (CAN): Part 1: Data link layer
14、and physical signalling Part 2: High-speed medium access unit Part 3: Low-speed, fault-tolerant, medium-dependent interface Part 4: Time-triggered communication Part 5: High-speed medium access unit with low-power mode BS ISO 11898-5:2007vIntroduction ISO 11898 was first published as one document in
15、 1993. It covered the CAN data link layer as well as the high-speed physical layer. In the reviewed and restructured ISO 11898 series: Part 1 describes the data link layer including the logical link control (LLC) sub layer and the medium access control (MAC) sub layer as well as the physical signall
16、ing (PLS) sub layer; Part 2 defines the high-speed medium access unit (MAU); Part 3 defines the low-speed fault-tolerant medium access unit (MAU); Part 4 defines the time-triggered communication; Part 5 defines the power modes of the high-speed medium access unit (MAU). ISO 11898-1 and ISO 11898-2 h
17、ave been cancelled and replaced ISO 11898:1993. BS ISO 11898-5:2007blank1Road vehicles Controller area network (CAN) Part 5: High-speed medium access unit with low-power mode 1 Scope This part of ISO 11898 specifies the CAN physical layer for transmission rates up to 1 Mbit/s for use within road veh
18、icles. It describes the medium access unit functions as well as some medium dependent interface features according to ISO/IEC 8802-2. This part of ISO 11898 represents an extension of ISO 11898-2, dealing with new functionality for systems requiring low-power consumption features while there is no a
19、ctive bus communication. Physical layer implementations according to this part of ISO 11898 are compliant with all parameters of ISO 11898-2, but are defined differently within this part of ISO 11898. Implementations according to this part of ISO 11898 and ISO 11898-2 are interoperable and can be us
20、ed at the same time within one network. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendme
21、nts) applies. ISO 7637-3, Road vehicles Electrical disturbances from conduction and coupling Part 3: Electrical transient transmission by capacitive and inductive coupling via lines other than supply lines ISO 11898-2:2003, Road vehicles Controller area network (CAN) Part 2: High-speed medium access
22、 unit 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 11898-2 and the following apply. 3.1 VCC CAN node supply voltage of the physical layer used for the bus receiver, transmitter and optional split termination voltage VSplitduring normal mode NOTE T
23、ypical voltage of VCC is 5 V. 3.2 split termination voltage VSplitCAN node output voltage of split termination support output relative to ground signal of the module (GND) BS ISO 11898-5:20072 3.3 propagation time tPropCAN node signal propagation time measured from an edge at transmit data (TXD) inp
24、ut to the corresponding edge on receive data (RXD) output of the MAU 3.4 wake-up filter time tWakeCAN node duration of a dominant signal on the bus lines CAN_H and CAN_L for forcing a wake-up to the CAN NODE 3.5 wake-up pattern CAN node one or multiple consecutive dominant bus levels for at least tW
25、ake, each separated by a recessive bus level NOTE Figures within this part of ISO 11898 are using arrows as following: voltages + ; currents flowing from the positive to the negative pole. 4 Symbols and abbreviated terms For the purposes of this document, the symbols and abbreviated terms given in I
26、SO 11898-2 apply. 5 Functional description of medium access unit (MAU) with low-power mode 5.1 General The following description is valid for a two-wire differential bus. The values of the voltage levels, the resistances and the capacitances as well as the termination network are described in Clause
27、 7. 5.2 Physical medium attachment sub layer specification 5.2.1 General As shown in Figure 1 the bus line is terminated by termination network A and termination network B. These terminations are intended to suppress reflections. Besides this reflection-optimized termination structure, centralized s
28、ingle terminations are possible at limited bit rates and topologies. Figure 1 Suggested electrical interconnection BS ISO 11898-5:20073Two different termination models are recommended within the high-speed medium access unit according to Figures 1 and 2: termination with a single resistor between CA
29、N_H and CAN_L, and split termination dividing the single resistor into two resistors with the same value in series connection, while the centre tap is connected to a grounding capacitor and optionally to a dedicated splitsupply. Key 1 physical layer Figure 2 Termination variants, single resistor ter
30、mination and split termination In order to support low-power functionality, two different modes of operation are defined as follows. Normal mode: The behaviour during normal mode is described within ISO 11898-2. Low-power mode: Described within this part of ISO 11898. 5.2.2 Bus levels during normal
31、mode The bus can have one of the two logical states: recessive or dominant (see Figure 3). The bus is in the recessive state if the bus drivers of all CAN nodes are switched off. In this case, the mean bus voltage is generated by the termination and by the high internal resistance of each CAN nodes
32、receiving circuitry. In the recessive state, VCAN_Hand VCAN_Lare fixed to a mean voltage level, determined by the bus termination. Vdiffis less than a maximum threshold. The recessive state is transmitted during bus idle or a recessive bit. Figure 3 illustrates the maximum allowed differential reces
33、sive bus voltage. Typically, the differential voltage is about zero volts. Optionally the recessive bus state may become stabilized making use of a dedicated split termination voltage (VSplit). This optional output voltage of physical layer implementations according to this part of ISO 11898 may be
34、optionally connected to the centre tap of the split termination resistors. Whenever the receiver of a physical layer is not actively biasing towards 2,5 V, the optional VSplitshall become floating. A dominant bit is sent to the bus if the bus driver of at least one unit is switched on. This induces
35、a current flow through the terminating resistors, and consequently a differential voltage between the two wires of the bus. A differential voltage greater than a minimum threshold represents the dominant state. The dominant state overwrites the recessive state, and is transmitted during a dominant b
36、it. The dominant and recessive states are detected by transforming the differential voltages of the bus to the corresponding recessive and dominant voltage levels within the receive comparator. During arbitration, various CAN nodes may simultaneously transmit a dominant bit. In this case, Vdiffexcee
37、ds the Vdiffseen during a single operation. Single operations means that the bus is driven by one CAN node only. BS ISO 11898-5:20074 5.2.3 Bus levels during low-power mode During low-power mode, the bus drivers are entirely disabled. It is not possible to actively drive a differential level to the
38、bus lines using a physical layer within low-power mode. In contrast to the normal mode behaviour, the bus wires shall be pulled to the ground signal of the module (GND) via the high-ohmic internal input resistors Rinof the receiver. Thus, there is no active VCC supply required defining the bus level
39、s during low-power operation. The optional split termination voltage (VSplit) is disabled here and shall behave high-ohmic (floating) in order not to pull the bus into a certain direction. From a physical point of view, there are only the two defined operating conditions possible. The normal mode wi
40、th VCC/2 biasing whenever normal bus communication takes place and low-power mode with GND biasing whenever the system becomes shutdown. Key 1 normal mode 2 low-power mode 3 simplified transceiver bias implementation Figure 3 Physical bit representation and simplified bias implementation 5.2.4 Wake-
41、up out of low-power mode During low-power operation, a physical layer optionally shall monitor the bus lines CAN_H and CAN_L for wake-up events. Implementations supporting this feature shall make use of a differential bus comparator monitoring the bus line. A bus wake-up shall be performed if the bu
42、s shows one or multiple consecutive dominant bus levels for at least tWake, each separated by a recessive bus level. 5.2.5 Systems with unpowered nodes In order to allow undisturbed CAN communication in systems, which have a couple of nodes intentionally unpowered (e.g. ignition key controlled modul
43、es), while other nodes continue to communicate normally, it is important that these unpowered nodes affect the bus levels as little as possible. This requires that transceivers, which are temporarily unpowered, show a lowest possible leakage current to the bus lines inside the still communicating sy
44、stem. The lower the leakage current in the unpowered case, the better the system performance in the permanently supplied part of the network. Depending on the target application (permanently supplied or temporarily unsupplied) the maximum leakage parameter according to Table 4 can be tolerated (perm
45、anently supplied nodes) or should be reduced as far as possible (temporarily unsupplied nodes). BS ISO 11898-5:20075NOTE In contrast to a low-power mode, where the device is still supplied, unpowered means a physical disconnection from the power supply. 6 Conformance tests 6.1 General All conformanc
46、e tests for normal mode of operation are specified in ISO 11898-2. Besides these tests, some tests are added dealing with the optional VSplitfunctionality and the low-power mode behaviour. The figures and the formulae shown within this clause indicate the principles of how the electrical parameters
47、specified in Clause 7 should be verified. 6.2 VSplitoutput function 6.2.1 General VSplitis an optional output voltage supporting recessive bus stabilization. When this function is implemented, the behaviour of that output shall be measured as shown within the following clauses. 6.2.2 VSplitduring no
48、rmal mode The optional output VSplitdelivers an output voltage of VCC/2 during normal mode. According to Table 6, an output current of +500 A to GND (Figure 4 schematic A) and 500 A to VCC (Figure 4 schematic B) shall be adjusted with the resistor R, while the output voltage VSplitshall stay within
49、the limits. In unloaded condition (Figure 4 schematic C), the output voltage shall be checked according to Table 6 using a load resistance of W 1 M. Figure 4 Measurement of VSplitduring normal mode 6.2.3 VSplitduring low-power mode The optional output VSplitshall float during low-power mode (see Figure 5). The leakage current is defined in Table 6. BS ISO 11898-5:20076 Figure 5 Measurement of leakage current ISplitduring low-power mode 6.3 Output voltage during low-p
