FlexRay and its Applications E-Book

Dominique Paret

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 421

Veröffentlichungsjahr: 2012

Beschreibung

An authoritative yet highly accessible guide to the design and operation of the FlexRay bus, the latest protocol for automotive network communications A translation of the French edition, originally published in January 2011, this work is the result of numerous training courses that Dominique Paret has given in companies, and it provides detailed explanations of the design and operation of the FlexRay bus. Comprised of five parts the book covers: the FlexRay concept and its communication protocol; the FlexRay physical layer; synchronization and global time and; architecture of a node, components and development aid tools for hardware and software. * Provides comprehensive treatment of the FlexRay network, including its implementation through a real automotive application * Includes the latest specifications (Version 3) concluded by the FlexRay consortium widely expected to become the industry standard * Written by an author with in-depth experience of automotive electronics, including FlexRay, and presenter of specialist training courses to the industry * Includes a review of industrial tools to help design and implement a FlexRay based distributor application

Leseprobe

Table of Contents

Title Page

Copyright

Preface

List of Abbreviations

Part A: ‘Secure Real Time’ Applications

Chapter 1: Reminders about the CAN Protocol

1.1 The Limitations of CAN

1.2 ‘Event-Triggered’ and ‘Time-Triggered’ Aspects

Chapter 2: The TTCAN Protocol

2.1 TTCAN—ISO 11898-4

2.2 Session Layer

2.3 Principle of Operation of TTCAN

Chapter 3: Emergence of ‘X-by-Wire’ Systems

3.1 High Throughput and X-by-Wire

3.2 Redundancy

3.3 High-Level Application Requirements

3.4 High-Level Functional Requirements

Part B: The FlexRay Concept and its Communication Protocol

Chapter 4: The Genesis of FlexRay

4.1 The TTP/C Protocol

4.2 FlexRay

4.3 The FlexRay Consortium

4.4 The Aim of FlexRay

Chapter 5: FlexRay and Real Time

5.1 Physical Time

5.2 Local Time

5.3 Global View at Network Level—Global Time

5.4 Summarising: Time and its Hierarchies in FlexRay

Chapter 6: The FlexRay Protocol

6.1 History

6.2 General—Channels, Cycles, Segments and Slots

6.3 Channels and Cycles

6.4 Segments

6.5 Communication Frames

6.6 ‘SW—Symbol Window’ Segment

6.7 ‘NIT—Network Idle Time’ Segment

Chapter 7: Access to the Physical Layer

7.1 Definition of Tasks

7.2 Execution of the Communication Cycle

7.3 Frame ID (11 Bits)

7.4 Arbitration Grid Level

7.5 Conditions of Transmission and Access to the Medium during the Static Segment

7.6 Conditions of Transmission and Access to the Medium during the Dynamic Segment

7.7 Similarity of the Use of the Dynamic Segment to the Network Access of the CAN Protocol

7.8 Some Additions in the Case of FlexRay Being Used with Two Channels

Appendices of Part B

Appendix B1: Examples of Applications

The BMW X5 (Development Code L6)

A Little Strategy

Global View of the Parameters of the FlexRay System

Desired Functional Parameters

Description and Justification of the Implemented Choice

Appendix B2: Scheduling Problems—Application of the FlexRay Protocol to Static and Dynamic Segments

Introduction

Problems of ‘Real Time’ Systems

FlexRay

Scheduling Real Time Systems

Different Approaches to Real Time Scheduling

Scheduling in Single-Processor Systems

Algorithms Based on Priorities

Scheduling Communications in Distributed Systems

Problem of Task Allocation in a Distributed System

Scheduling Communications

Policy of Assigning Priorities

Class of Scheduling Problem

Scheduling Algorithm

Conclusion

Part C: The FlexRay Physical Layer

Chapter 8: Creation and Transmission (Tx) of the FlexRay Signal

8.1 Creation of the Signal

8.2 Physical Representation of Bits

8.3 Line Driver ‘Tx’

Chapter 9: Medium, Topology and Transport of the FlexRay Signal

9.1 Medium

9.2 Effects Linked to Propagation

9.3 Topologies and Consequences for Network Performance

9.4 Single-Channel, Dual-Channel and Multi-Channel Communication Topologies

9.5 The FlexRay Topologies

9.6 Examples of Topologies

Chapter 10: Reception of the FlexRay Signal

10.1 Signal Reception Stage

10.2 Processing of the Received Signal by the Communication Controller

Chapter 11: The Bit Error Rate (BER)

11.1 Integrity of Signal and BER

11.2 Eye Diagram

11.3 Relationship between the Integrity of the Signal, the Eye Diagram and the BER

Chapter 12: Modelling and Simulating the Performance of a Network

12.1 Modelling and Simulating the Performance of a Network and its Topology

12.2 Modelling the Elements of the Network

12.3 Simulation

Chapter 13: Summary on the Physical Layer of FlexRay

Part D: Synchronisation and Global Time

Chapter 14: Communication Cycle, Macrotick and Microtick

14.1 The FlexRay Time Hierarchy

14.2 Synchronisation in a Network of TDMA–FlexRay Type

14.3 Proposed Solution to the Problem

14.4 Application and Implementation of Corrective Values

14.5 Summary

Chapter 15: Network Wakeup, Network Startup and Error Management

15.1 Network Wakeup Phase

15.2 Network Startup Phase

15.3 Error Management

Chapter 16: FlexRay v3.0

16.1 Protocol Enhancements

16.2 Physical Layer Enhancements

16.3 FlexRay and ISO

16.4 FlexRay in Other Industries

Part E: Architecture of a Node, Components and Development Aid Tools

Chapter 17: Architecture of a FlexRay Node

17.1 The Major Components of a Node

17.2 Architecture of the Processor and Protocol Manager

Chapter 18: Electronic Components for the FlexRay Network

18.1 The Component Range

18.2 EMC and EMC Measurements

18.3 Protection from ESD

18.4 Conformity Tests

18.5 Bus Guardian

Chapter 19: Tools for Development, Integration, Analysis and Testing

19.1 The V-Shaped Development Cycle

19.2 DaVinci Network Designer (Point 1 of the V Cycle)

19.3 CANoe.FlexRay

19.4 FlexRay CANalyzer (Covers Points 2, 4 and 5 of the V Cycle)

19.5 Test and Diagnostics (Point 6 of the V Cycle)

19.6 Features of the FlexRay Protocol

19.7 Communication Interface

Chapter 20: Implementation of FlexRay Communication in Automotive Logic Controllers

20.1 FlexRay and AUTOSAR

20.2 The AUTOSAR Partnership

20.3 Communication in an AUTOSAR System

Appendix of Part E

Chapter 21: Conclusion

Appendix 1: The Official Documents

Appendix 2: Principal Parameters of the FlexRay Protocol

Bibliography

Index

This edition first published 2012

©2012 by John Wiley & Sons, Ltd.,

The original French version published 2011 by Dunod, Paris

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Preface

Why this book now?

Today, protocols for multiplexed industrial networks such as CAN, LIN and others are relatively mature, and only a few aspects such as ‘Time-Triggered Protocol’ and ‘X-by-Wire’ systems continue to evolve.

On the two latter subjects, little information or technical training is available to engineers, technicians or students. We hope that this book will at least partly fill this gap.

I waited for a long time before again dipping my pen into the inkwell of my PC(!). I preferred to wait until there were no announcements of the ‘free shave tomorrow …’ type in sight. Which, of course, as usual, took a long time … Version 2.1, revision A of FlexRay was delivered officially to the public in March 2005, then some minor modifications and additions (conformity tests) called rev. 2.1 A and B were added in November 2006, and finally, at the end of 2010, there was 3.0, which clarified some points of detail.

Above all, this book is not intended to give a literal translation of the standard, the original version of which can be downloaded free from the official website of the FlexRay Consortium (www.flexray.com). Instead, its aim is to act as an introduction and a detailed teaching presentation of the technical principles and operation of the FlexRay protocol. It is also aimed at giving newcomers an overall view of the concepts and applications.

The aims which FlexRay was intended to achieve (speed and security of communication, flexibility in operation, real time, distributed intelligence, network topologies, and so on) made it necessary to design the structure of the communication protocol so that it is directly related to the physical performance of the physical layer. When you read this book, always keep in mind the concerns generated by the physical layer (the medium and its management). Ideally, just as in music (see below), it would be necessary to present the communication protocol and the physical layer and their interactions simultaneously and in parallel … which is mechanically difficult for a publisher, however experienced!

Something else you should know is that the content of the FlexRay protocol is dense, and includes numerous technical concepts which collide with each other, become confused with each other and intersect with each other, which makes it difficult to choose a plan for presenting the various chapters.

Author's note

To cover this subject of ‘multiplexed networks’ correctly, this book describes many patented technical principles which are subject to the operation of licences and their associated rights (bit coding, communication techniques, and so on), and which have already been published in official, professional technical texts or communications, or during public conferences or seminars—but above all, which must be used according to the legal rules in force.

How to read this book

In a previous book (Multiplexed Networks for Embedded Systems: CAN, LIN, FlexRay, Safe-by-Wire), we provided an overview, which was complete at the time, of this evolving field, using long technical introductions on these subjects. Today, this book, which is entirely about FlexRay, is dense because virtually all the ‘real’ subjects—principles, components, applications, security, and so on—are approached in practical terms. Also, to avoid discouraging the reader who is trying to understand these devices, we have put great stress on teaching so that the link between theoretical, technological, economic and so on aspects can be constantly established.

The challenge is therefore to present everything in the clearest, most suitable manner. After long reflection and long oscillations,1 it has been necessary to choose a comprehensive presentation so that you, the Reader, can find your way easily through the maze of all these emerging communication principles and new protocols. We also advise you, before approaching the technical details which will be explained in the following chapters, to take the trouble to read the next few lines, which are intended to explain the why and how of the plan of this book and how to use it.

The aim of the introduction is to make your mouth water by giving a general survey of the applications which daily affect the motor vehicle and embedded systems of all types. Obviously, everything we have written in this book can be generalised to industrial applications of all kinds (control of machine tools and production lines, avionics, rail transport, building automation, transport of digital images, and so on).

The first part (A) is a reminder of the CAN protocol, a quick mention of the operation and contents of the TTCAN protocol and a review of the latest applications of ‘X-by-Wire’ type. We will briefly discuss the functional and application limits of CAN, and we will consider ‘event-triggered’ and ‘time-triggered’ communication systems, and all the implications which that consideration generates for so-called ‘secure real time’ applications.

In the second part (B) we will present, progressively, FlexRay and its protocol, in terms of communication cycles, decomposition of cycles into frames, format and content of frames, omitting any consideration of clock synchronisation between nodes.

Then, in the third part (C), we will go on to the analysis of the physical layer and the basic concepts of bit coding, propagation and topologies which can be used, and their effects. The problems of network synchronisation in operation and during the wakeup and startup phases are the subject of the fourth part (D). We will consider the architecture of a node, components of a FlexRay network, AUTOSAR and the range of associated hardware and software tools for providing support for development simulations, verification stages, production, maintenance, and so on in the fifth and final part (E).

A little music in this brutal world

Let us finish this introduction on a lighter (musical) note. Very serious discussions with some friends and FlexRay designers one day led us to the conclusion that a FlexRay system could be seen as a little like a musical score. The protocol description represents the melody in a treble key, and the physical layer represents the accompaniment in a bass key. In fact, with FlexRay as for reading a musical score, it is necessary to succeed in following the score not only by reading the two horizontal staves simultaneously, but also by reading the score ‘vertically’, to recreate the whole correctly. Additionally, like any well-informed musician, it is necessary to read ahead while playing! Welcome to FlexRay for musicians and future musicians!

I wish you good and productive reading throughout the pages of this book—above all, enjoy it, because I didn't write it for myself but for you! If there is still a shadow of a doubt about the subject and form of this book, your (constructive ) comments, remarks, questions and so on are always welcome by e-mail to my address, [email protected].

Thanks

The subject of multiplexed communication systems and networks is growing day by day, and very many skilled people are working in these fields. Luckily, I have had the opportunity to meet many of them, and consequently it is very difficult for me to thank everyone individually.

Nevertheless, I must address some special thanks to several groups of people:

To numerous colleagues and friends of Philips/NXP Semiconductors of Nijmegen (Netherlands) and Hamburg (Germany), with whom I have had the pleasure of working for long years on these subjects, and, taking the risk of making some people jealous, more particularly Messrs Hannes Wolff, Bernd Elend, Thomas Shuermann, Peter Bürhing, Peter Hank, Burkhard Bauer, Karsten Penno, Patrick Heuts, Matthias Muth, the numerous ‘Hans’ and other colleagues in the Netherlands, and the numerous ‘Peters’ and other colleagues in Germany.To the long-standing international friends in the field of multiplexed buses in motor vehicles, Messrs Florian Hartwich, Bernd Müller, Thomas Führer of the R. Bosch company, Florian Bogenberger of Motorola/Freescale and Wolfhard Lawrenz of C & S.

It would be ungrateful not to thank also the numerous colleagues in the profession, and motor vehicle and equipment manufacturers, whom I meet regularly either at working meetings or at ISO, for their remarks and comments about the editing of this book, thanks to whom we all hope that this subject of multiplexed buses will blossom as it deserves.

Finally, I am very glad to thank Ms Manuela Philipsen of the ‘Marcom’ team of NXP Semiconductors in Eindhoven, for the numerous documents and photographs which she has been kind enough to supply to me for years to illustrate these books. Even more finally, I am also immensely grateful to the Vector Informatik GmbH company of Stuttgart (Mr Uwe Kimmerley and the whole FlexRay team) and Vector France SAS of Paris (Mr Henri Belda, Mr Jean-Philippe Dehaene, Ms Hassina Rebaïne and Ms Rim Guernazi) for their technical and logistical support, their participation in the editing of certain chapters and for having had the kindness to agree to supply numerous very fine educational illustrations to enrich this book. In fact, this type and quality of teaching aid is fundamental to good distribution of knowledge, and in Vector's case is part of very rich support for professional training which is useful for spreading a technique and a technology. Setting up such support requires a large investment in time and money, and authorisation to publish them—even in part—really deserves to be welcomed as much as the quality of their content. So a big thank you for having done and authorised that.

Dominique Paret

[email protected]

1 All (1 - Γ2) and (voltage) standing wave ratios included (naturellement).

List of Abbreviations

ABSanti braking systemADCanalogue to digital conversionAPaction pointAutosarautomotive open system architectureBDbus driverBERbit error rateBSSbyte start sequenceCANcontroller area networkCAPLCommunication Access Programming LanguageCAScollision avoidance symbolCCcommunication controllerCDDCANdela Data DiagnosticCDFcumulative distribution functionCHIcontroller-host interfaceCIDchannel idle delimiterCPUcentral processing unitCPU/ECUcentral processing unit/electronic control unitCRCcyclic redundancy checkCSEVchannel status error vectorCSSclock synchronization startupDLCdata length codingDLLdynamic link libraryDPIdirect power injectionDTSdynamic trailing sequenceECCerror correction codeECUelectronic control unitEMBelectromechanical brakingEMCelectromagnetic compatibilityEPLelectrical physical layerEPLANelectrical physical layer application notesESDelectrostatic dischargeFESframe end sequenceFIFOfirst in, first outFSEVframe status error vectorFSSframe start sequenceFTDMAflexible time division multiple accessGTDMAglobal time division multiple accessHILhardware in the loopLINlocal interconnect networkMTsmacroticksMTSmedia access test symbolNITnetwork idle timeNRZno return to zeroOEMoriginal equipment manufacturerOSoperating systemsOSIopen systems interconnectionOSI/ISOopen systems interconnection/International Standard OrganisationPDFprobability density functionPDUsprotocol data unitsPLLphase locked loopPSprotocol specificationRFradio frequencyRTErun time environmentSBCssystem basic chipsSDdynamic segmentSHFsuper high frequencySOCstart of cycleSTstatic segmentSWsymbol windowSWCssoftware componentsTDMAtime division multiple accessTRPtime reference pointTSLtest set libraryTSStransmission start sequenceTTCANtime-triggered communication on CANTT-Etime-triggered externalTT-Ltime-triggered localTTP/CTime Triggered Protocol Class CTxtransmissionUHFultra high frequencyVDRvoltage-dependent resistorsVFBvirtual functional busWCETworst case execution timeWUPwakeup patternWUSwakeup symbol

Part A

‘Secure Real Time’ Applications

Chapter 1

Reminders about the CAN Protocol

As an introduction to this chapter, we will remind you of some general points about all the architectures of embedded systems, and starting from now we will take a very surprising turn by passing judgement on the properties of the well-known controller area network (CAN) protocol, presenting its principal limitations and finally imagining solutions which open up new horizons for decades to come.

1.1 The Limitations of CAN

Firstly, the concept of CAN, which was designed almost 30 years ago, is perfect for current applications, and will remain perfect for very many applications. However, time passes, and some of the inherent limitations of CAN, which have been known since its genesis, are now clearly visible. They are: