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1、 Reference number ISO 22896:2006(E) ISO 2006 INTERNATIONAL STANDARD ISO 22896 First edition 2006-11-15 Road vehicles Deployment and sensor bus for occupant safety systems Vhicules routiers Bus de dploiement et de capteurs pour les systmes de scurit des occupants Copyright International Organization
2、for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 01:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22896:2006(E) PDF disclaimer This PDF file may contain embedded typefaces.
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5、for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2006 All rights reserved. Unless otherwise specified, no part
6、of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56
7、CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2006 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing
8、, Bernie Not for Resale, 04/05/2007 01:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22896:2006(E) ISO 2006 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Terms and definitions. 1 3 Abbreviations 3 4 General. 4 5 System architecture 5 5.1 Genera
9、l. 5 5.2 Deployment bus 5 5.3 Sensor bus 5 5.4 Combined sensor and deployment bus . 6 6 Physical Layer. 6 6.1 Bus medium 6 6.2 Bus topology. 6 6.3 Bus load. 8 6.4 Bus signals 10 6.5 Bit coding 12 6.6 Fault tolerance 15 6.7 Use of analogue safing on a deployment bus . 17 6.8 Bus signal parameters . 1
10、8 7 Data Link Layer. 22 7.1 Bus Idle 22 7.2 Addresses 22 7.3 Message frames 24 7.4 Bit fields within a frame 32 8 Application Layer 35 8.1 General. 35 8.2 Common D-Frame commands. 36 8.3 Memory layout of slaves 37 8.4 Application Layer for deployable devices 42 8.5 Application Layer for sensor devic
11、es. 47 Annex A (informative) In-car address programming for daisy-chain systems 50 Annex B (informative) Guideline for definition of deviations from standard parameters 51 Annex C (informative) Rationale of functionality 52 Annex D (informative) Latency time analysis for interrupts from smart sensor
12、s . 53 Annex E (informative) CRC examples 56 Annex F (informative) Deployable devices 57 Annex G (informative) Slave manufacturer identification codes. 60 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Ber
13、nie Not for Resale, 04/05/2007 01:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22896:2006(E) iv ISO 2006 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bod
14、ies). 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 committee has been established has the right to be represented on that committee. International organizations, governmental and
15、 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 electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives,
16、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 member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies cast
17、ing 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 identifying any or all such patent rights. ISO 22896 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3
18、, Electrical and electronic equipment. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 01:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- IN
19、TERNATIONAL STANDARD ISO 22896:2006(E) ISO 2006 All rights reserved 1 Road vehicles Deployment and sensor bus for occupant safety systems 1 Scope This International Standard is a specification of a serial communications bus protocol for automotive occupant restraint systems. It covers Physical Layer
20、 and Data Link Layer and those parts of the Application Layer that are not supplier-specific. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 analogue safing using a special bus level (LS0-level) for confirmation of deploy messages 2.2 bitmap
21、 addressing method of addressing one or several slaves at a time by assigning each bit of the address field to a different slave 2.3 bus level one out of four levels of the differential bus voltage, whereof one forms the Power Phase and the other three are used for representation of a data bit durin
22、g the Data Phase 2.4 command part of a D-Frame, transmitted by the master, defining the purpose of the frame 2.5 CRC field part of a D-Frame or S-Frame 2.6 data field part of a D-Frame 2.7 Data Phase part of a data bit providing the bit value 2.8 deploy command family four commands for control of de
23、ployable devices 2.9 deployable device irreversible actuator Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 01:17:59 MDTNo reproduction or networking permitted without lic
24、ense from IHS -,-,- ISO 22896:2006(E) 2 ISO 2006 All rights reserved 2.10 D-Frame type of frame primarily used for diagnostic communication and actuation of deployable devices 2.11 differential bus voltage differential voltage between the two bus wires 2.12 duty cycle percentage of a bit time that i
25、s assigned to the Power Phase 2.13 E-bit bit in a D-Frame indicating an error or a “read” command 2.14 half-rate mode used for sensors that shall not reply in every S-Frame 2.15 hold-up capacitor capacitor supplying power to a slave during the Data Phase 2.16 latency time worst-case duration between
26、 the occurrence of an interrupt requesting event in the sensor and the actual start of an S-Frame polling message 2.17 LS0-level bus level indicating an error, a bus interrupt or a “0” with analogue safing 2.18 L0-level bus level indicating a “0” 2.19 L1-level bus level indicating a “1” 2.20 master
27、device responsible for communication on the bus and for power distribution over the bus 2.21 Multi-Sharing mode used in S-Frames for dynamic assignment of slave data to the first slot 2.22 node master or slave 2.23 point-to-point addressing addressing used for communication between the master and on
28、e slave Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 01:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22896:2006(E) ISO 2006 All ri
29、ghts reserved 3 2.24 power level bus level forming the Power Phase 2.25 Power Phase part of a data bit during which the master transmits the power level 2.26 R-bit reserved bit in D-frames for future definition 2.27 SEL-bit bit used in S-Frames to control slaves configured for half-rate mode 2.28 S-
30、Frame type of frame used by the master to collect dynamic data from slaves periodically 2.29 signal address address assigned to peculiar signals provided by slaves, used in S-Frames for Multi-Sharing 2.30 slave device that is connected to the bus and is not the master 2.31 slave address bitmap part
31、of a D-Frame in which each bit corresponds to one slave 2.32 slot part of an S-Frame assigned to a certain slave to be filled with its data 2.33 Slot Length determines the number of data bits that a slot consists of 2.34 Sub-Slot sub-section of a slot 2.35 T-bit first bit of a frame, used to define
32、the frame type (S- or D-Frame) 3 Abbreviations ACU Airbag Control Unit ASIC Application-Specific Integrated Circuit CRC Cyclic Redundancy Check ECU Electronic Control Unit Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/111111100
33、1, User=Wing, Bernie Not for Resale, 04/05/2007 01:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22896:2006(E) 4 ISO 2006 All rights reserved HSD High Side Driver INT Interrupt LSB Least Significant Bit LSD Low Side Driver MSA Multi-Sharing Address MSB Most Sign
34、ificant Bit MTP Multi Time Programmable NVM Non Volatile Memory ORC Occupant Restraint Controller OTP One Time Programmable RAM Random Access Memory RCM Restraint Control Module ROM Read Only Memory SDM Sensing and Diagnostic Module SEL Select SOF Start Of Frame SSB Slot Start Bit 4 General Automoti
35、ve occupant restraint systems are controlled by a Sensing and Diagnostic Module (SDM), also called Airbag Control Unit (ACU), Restraint Control Module (RCM) or Occupant Restraint Controller (ORC), which is connected to peripheral devices: dynamic sensors with high update rates, e.g. for remote front
36、 and side impact sensing; static sensors with low update rates, e.g. buckle switches, seat position and occupancy sensors; actuators, especially deployable devices, e.g. squibs. The SDM is also referred to as “master”; the peripheral devices are also referred to as “slaves”. The bus provides a two-w
37、ire connection between the SDM and the peripheral devices and supplies power to the slaves. It offers bi-directional communication. The masters bus interface sends energy into the bus, the slaves bus interface extracts power from the bus. The master determines the bus speed and initiates all communi
38、cation by sending message frames on the bus. Slaves may transmit their data within these frames when requested by the master. Smart dynamic sensors (defined in 5.3) may send an interrupt to the master while the bus is idle or while there is diagnostic communication on the bus. The masters reaction t
39、o the interrupt is application specific and typically lets the master stop diagnostic communication and start polling of impact data instead. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for R
40、esale, 04/05/2007 01:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 22896:2006(E) ISO 2006 All rights reserved 5 The data is usually coded using differential bus voltage. On a bus, where several transmitters are sharing the same wiring, using voltage as the data
41、signal has a significant advantage over current, because it enables the transmitter to verify the data that it sent on the bus. This is the most reliable way to detect bus collisions, e.g. when two sensors are transmitting their data at the same time. For less critical data like diagnostics, reply d
42、ata from slaves can be coded using current, which allows connection of deployable slaves to the bus via isolation resistors (see 6.6.4.2). 5 System architecture 5.1 General The specification covers sensor busses, deployment busses and combined sensor/deployment busses. The bus shall support 64 slave
43、 addresses, of which three shall be reserved for special purposes. The actual number of slaves that can be connected to one bus is limited by the supply current for the slaves and by the pin capacitance of the slaves (see also Clause 6). Bandwidth limits shall also be considered. NOTE A single slave
44、 can incorporate the functionality of several slave addresses. 5.2 Deployment bus The deployment bus shall support deployable devices and static sensors. The bus shall provide point-to-point messages for diagnostic communications between master and slaves. Since the deployment bus shall support fast
45、 selective deployment of several deployable devices, the bus shall also provide a special deploy message, which allows individual deployment control of up to 12 devices at a time. There shall be four deploy messages available, each controlling 12 device addresses: address range 0b000000 0b001011; ad
46、dress range 0b010000 0b011011; address range 0b100000 0b101011; address range 0b110000 0b111011. In this way, up to 4 12 = 48 deployable devices can be controlled by one bus. The address 0b000000 should not be used as a slave address, because this address shall be the default address of all slaves t
47、hat have not been programmed yet. See also 7.2.1, 7.3.2 and 7.4.8. The deployment bus shall provide communication with and without a special “safing” signal, which may be used for additional differentiation between diagnostic communication and actual deploy commands. 5.3 Sensor bus The sensor bus sh
48、all support static and dynamic sensors. There may be two types of dynamic sensors. Raw-data sensors send time-critical data periodically to the SDM. Smart sensors send time-critical data event-driven only. Smart sensors can easily coexist with static sensors on the same bus. NOTE Raw-data sensors usually occupy the bus bandwidth all the time, while smart sensors usually need the full bandwidth only for a short time during an event. Copyright International Org