ISO 17458-2:2013

INTERNATIONAL ISO
STANDARD 17458-2
First edition
2013-02-01
Road vehicles— FlexRay
communications system —
Part 2:
Data link layer specification
Véhicules routiers — Système de communications FlexRay —
Partie 2: Spécification de la couche de liaison de données

Reference number
©
ISO 2013
©  ISO 2013
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ii © ISO 2013 – All rights reserved

Contents Page
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Symbols . 7
3.3 Abbreviated terms . 7
4 Document overview . 10
5 Conventions . 11
5.1 General . 11
5.2 Notational conventions . 11
5.3 SDL conventions . 12
5.4 Bit rates . 15
5.5 Roles of a node in a FlexRay cluster . 15
5.6 Synchronisation methods . 15
5.7 Network topology considerations . 19
5.8 Example node architecture. 24
6 Protocol operation control . 29
6.1 Principles. 29
6.2 Description . 31
6.3 The protocol operation control process . 37
7 Coding and Decoding . 59
7.1 Principles. 59
7.2 Description . 59
7.3 Coding and decoding process . 77
7.4 Bit strobing process . 96
7.5 Wakeup pattern decoding process . 99
8 Frame Format . 103
8.1 Overview . 103
8.2 FlexRay header segment (5 bytes) . 103
8.3 FlexRay payload segment (0 – 254 bytes) . 108
8.4 FlexRay trailer segment . 111
8.5 CRC calculation details . 111
9 Media Access Control . 113
9.1 Principles. 113
9.2 Description . 123
9.3 Media access control process . 126
10 Frame and Symbol processing . 143
10.1 Principles. 143
10.2 Description . 143
10.3 Frame and symbol processing process . 149
11 Wakeup and Startup . 161
11.1 General . 161
11.2 Cluster wakeup . 162
11.3 Communication startup and reintegration . 167
12 Clock synchronisation . 190
12.1 Introduction . 190
12.2 Time representation . 191
12.3 Synchronisation process . 193
12.4 Startup of the clock synchronisation . 200
12.5 Time measurement . 204
12.6 Correction term calculation . 208
12.7 Clock correction. 220
12.8 Sync frame configuration . 223
12.9 Time gateway interface . 225
13 Controller Host Interface . 226
13.1 Principles . 226
13.2 Description . 227
13.3 Interfaces . 228
Annex A (normative) System parameters . 268
A.1 Protocol constants . 268
A.2 Performance constants . 270
Annex B (normative) Configuration constraints . 271
B.1 General . 271
B.2 Bit rates . 271
B.3 Parameters . 272
B.4 Calculation of configuration parameters for nodes in a TT-D cluster . 281
B.5 Configuration of cluster synchronisation method and node synchronisation role . 334
B.6 Calculation of configuration parameters for nodes in a TT-L cluster . 335
B.7 Calculation of configuration parameters for nodes in a TT-E cluster . 336
Annex C (normative) Wakeup application notes . 345
C.1 Scope . 345
C.2 Wakeup initiation by the host . 345
C.3 Host reactions to status flags signalled by the communication controller. 348
C.4 Retransmission of wakeup patterns . 349
C.5 Transition to startup . 349
C.6 Wakeup during operation . 350
Bibliography . 352

iv © ISO 2013 – All rights reserved

Foreword
ISO (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 committee 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 electrotechnical 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 member 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 identifying any or all such patent rights.
ISO 17458-2 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3,
Electrical and electronic equipment.
ISO 17458 consists of the following parts, under the general title Road vehicles — FlexRay communications
system:
 Part 1: General information and use case definition
 Part 2: Data link layer specification
 Part 3: Data link layer conformance test specification
 Part 4: Electrical physical layer specification
 Part 5: Electrical physical layer conformance test specification
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