FlexRay and its ApplicationsReal Time Multiplexed Network
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
Preface xiii List of Abbreviations xvii Part A 'SECURE REAL TIME' APPLICATIONS 1 Reminders about the CAN Protocol 3 1.1 The Limitations of CAN 3 1.2 'Event-Triggered' and 'Time-Triggered' Aspects 4 2 The TTCAN Protocol 7 2.1 TTCAN – ISO 11898-4 7 2.2 Session Layer 8 2.3 Principle of Operation of TTCAN 8 3 Emergence of ‘X-by-Wire’ Systems 11 3.1 High Throughput and X-by-Wire 11 3.2 Redundancy 11 3.3 High-Level Application Requirements 13 3.4 High-Level Functional Requirements 14 Part B THE FLEXRAY CONCEPT AND ITS COMMUNICATION PROTOCOL 4 The Genesis of FlexRay 19 4.1 The TTP/C Protocol 19 4.2 FlexRay 20 4.3 The FlexRay Consortium 20 4.4 The Aim of FlexRay 23 5 FlexRay and Real Time 29 5.1 Physical Time 29 5.2 Local Time 30 5.3 Global View at Network Level – Global Time 32 5.4 Summarising: Time and its Hierarchies in FlexRay 36 6 The FlexRay Protocol 41 6.1 History 41 6.2 General – Channels, Cycles, Segments and Slots 41 6.3 Channels and Cycles 44 6.4 Segments 47 6.5 Communication Frames 57 6.6 'SW – Symbol Window' Segment 74 6.7 'NIT – Network Idle Time' Segment 76 7 Access to the Physical Layer 77 7.1 Definition of Tasks 77 7.2 Execution of the Communication Cycle 80 7.3 Frame ID (11 Bits) 80 7.4 Arbitration Grid Level 81 7.5 Conditions of Transmission and Access to the Medium during the Static Segment 83 7.6 Conditions of Transmission and Access to the Medium during the Dynamic Segment 84 7.7 Similarity of the Use of the Dynamic Segment to the Network Access of the CAN Protocol 88 7.8 Some Additions in the Case of FlexRay Being Used with Two Channels 89 Appendices of Part B 91 Appendix B1 Examples of Applications 93 The BMW X5 (Development Code L6) 93 A Little Strategy 93 Global View of the Parameters of the FlexRay System 95 Desired Functional Parameters 96 Description and Justification of the Implemented Choice 97 Appendix B2 Scheduling Problems – Application of the FlexRay Protocol to Static and Dynamic Segments 103 Introduction 103 Problems of ‘Real Time’ Systems 104 FlexRay 108 Scheduling Real Time Systems 109 Different Approaches to Real Time Scheduling 113 Scheduling in Single-Processor Systems 116 Algorithms Based on Priorities 116 Scheduling Communications in Distributed Systems 120 Problem of Task Allocation in a Distributed System 121 Scheduling Communications 121 Policy of Assigning Priorities 126 Class of Scheduling Problem 127 Scheduling Algorithm 128 Conclusion 129 Part C THE FLEXRAY PHYSICAL LAYER 8 Creation and Transmission (Tx) of the FlexRay Signal 135 8.1 Creation of the Signal 135 8.2 Physical Representation of Bits 136 8.3 Line Driver ‘Tx’ 138 9 Medium, Topology and Transport of the FlexRay Signal 143 9.1 Medium 143 9.2 Effects Linked to Propagation 146 9.3 Topologies and Consequences for Network Performance 147 9.4 Single-Channel, Dual-Channel and Multi-Channel Communication Topologies 151 9.5 The FlexRay Topologies 153 9.6 Examples of Topologies 159 10 Reception of the FlexRay Signal 165 10.1 Signal Reception Stage 165 10.2 Processing of the Received Signal by the Communication Controller 170 11 The Bit Error Rate (BER) 175 11.1 Integrity of Signal and BER 175 11.2 Eye Diagram 175 11.3 Relationship between the Integrity of the Signal, the Eye Diagram and the BER 180 12 Modelling and Simulating the Performance of a Network 185 12.1 Modelling and Simulating the Performance of a Network and its Topology 185 12.2 Modelling the Elements of the Network 185 12.3 Simulation 188 13 Summary on the Physical Layer of FlexRay 193 Part D SYNCHRONISATION AND GLOBAL TIME 14 Communication Cycle, Macrotick and Microtick 197 14.1 The FlexRay Time Hierarchy 197 14.2 Synchronisation in a Network of TDMA–FlexRay Type 198 14.3 Proposed Solution to the Problem 202 14.4 Application and Implementation of Corrective Values 214 14.5 Summary 218 15 Network Wakeup, Network Startup and Error Management 223 15.1 Network Wakeup Phase 223 15.2 Network Startup Phase 225 15.3 Error Management 226 16 FlexRay v3.0 231 16.1 Protocol Enhancements 231 16.2 Physical Layer Enhancements 235 16.3 FlexRay and ISO 239 16.4 FlexRay in Other Industries 240 Part E ARCHITECTURE OF A NODE, COMPONENTS AND DEVELOPMENT AID TOOLS 17 Architecture of a FlexRay Node 245 17.1 The Major Components of a Node 245 17.2 Architecture of the Processor and Protocol Manager 245 18 Electronic Components for the FlexRay Network 249 18.1 The Component Range 249 18.1.1 FlexRay Protocol Manager 250 18.2 EMC and EMC Measurements 263 18.3 Protection from ESD 265 18.4 Conformity Tests 265 18.5 Bus Guardian 267 19 Tools for Development, Integration, Analysis and Testing 271 19.1 The V-Shaped Development Cycle 271 19.2 DaVinci Network Designer (Point 1 of the V Cycle) 271 19.3 CANoe.FlexRay 273 19.4 FlexRay CANalyzer (Covers Points 2, 4 and 5 of the V Cycle) 276 19.5 Test and Diagnostics (Point 6 of the V Cycle) 277 19.6 Features of the FlexRay Protocol 278 19.7 Communication Interface 280 20 Implementation of FlexRay Communication in Automotive Logic Controllers 283 20.1 FlexRay and AUTOSAR 283 20.2 The AUTOSAR Partnership 284 20.3 Communication in an AUTOSAR System 284 Appendix of Part E 291 21 Conclusion 297 Appendix 1 The Official Documents 299 Appendix 2 Principal Parameters of the FlexRay Protocol 301 Bibliography 311 Index 313
Dominique Paret, dp-Consulting, Paris, France Mr Paret worked at Philips for 15 years on automotive electronics projects including CAN (Controller Area Network), LIN (Local Interconnect Network), very high speed buses, time triggered concept – FlexRay, Safe by Wire, SBC (Single-board Computer), fail safe systems as well as identification, including smart cards, and RFID (radio frequency identification). He has also represented Philips in several standardization organizations such as the French National Body (AFNOR), ISO (International Organization for Standardization) working groups for radio frequency identification and other consortiums for electronic automotive standards. In addition to this, he lectures for several technical schools in France and Pretoria, South Africa, and is an experienced author, having written a number of books. Now he offers training and consultancy to the automotive industry.
FlexRay, developed and standardised by a consortium of motor vehicle and equipment manufacturers, differs from the CAN protocol in several ways. It has a higher throughput (up to 10 Mbit/s per channel and maximum two channel of communication), it supports different topologies (such as bus, linear passive, active/passive star and hybrid), and has fault tolerance mechanisms. All of these deliver improved reliability in operation. FlexRay and its Applications presents a timely overview as the technology gains increasing importance. Divided into four parts, this book covers FlexRay’s communication protocol, the FlexRay physical layers, synchronization and global time, and architecture of a node, components and development aid tools for hardware and software. Other key features include: authoritative and accessible guide to the design and operation of FlexRay applications detailed explanations of the latest protocol for automotive network communications, including the latest specifications (Version 3) concluded by the FlexRay consortium comprehensive treatment of the FlexRay network, including its implementation through a real automotive application a review of industrial tools to help readers design and implement a FlexRay based distributor application. This is essential reading for technicians; automotive system design engineers and design engineers of applications concerning motor vehicle and on-board systems of all types, such as control of machine tools and production lines, avionics, rail transport, building automation, and transmission of digital images. Dominique Paret’s book will appeal to engineers and other potential users of FlexRay in related industries such as avionics, also electrical and electronic engineering students majoring in automotive electronics, electronic information, network technology, and control engineering.