FlexRay and its Applications

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.

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