APPLICATIONS FLEXRAY AND ITS WILEY REAL TIME MULTIPLEXED NETWORK. Dominique Paret. dp-consulting, Paris, France. Claygate, Esher, UK

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1 FLEXRAY AND ITS APPLICATIONS REAL TIME MULTIPLEXED NETWORK Dominique Paret dpconsulting, Paris, France Translated by Bill Chilcott Fellow of the Institute of Translation and Interpreting Claygate, Esher, UK WILEY A John Wiley &. Sons, Ltd., Publication

2 ISO Preface xiii List of Abbreviations xvii Part A 'SECURE REAL TIME' APPLICATIONS 1 Reminders about the CAN Protocol The Limitations of CAN 'EventTriggered' and 'TimeTriggered' Aspects The Probabilistic Side of CAN The Deterministic Side ofapplications 5 2 The TTCAN Protocol TTCAN Session Layer Principle of Operation of TTCAN 8 3 Emergence of 'XbyWire' Systems High Throughput and XbyWire Redundancy HighLevel Application Requirements The Number of Communication Systems is Growing The Electronic Architecture Must be Common to Several Vehicle Platforms Some Things the Architecture of the Communication Network and the Nodes Must Allow HighLevel Functional Requirements Speed of Communication Physical Layer Access to and Management of the Medium Synchronisation Method Network Topologies Requirements at System Level 16

3 Channels, What's vi Part B THE FLEXRAY CONCEPT AND ITS COMMUNICATION PROTOCOL 4 The Genesis of FlexRay The TTP/C Protocol FlexRay The Genesis offlexray The FlexRay Consortium The Aim of FlexRay A Flex(ible) Configuration Solutions 23 5 FlexRay and Real Time Physical Time Local Time Local Clock 'Clock Tick' and Microticks In Practice Global View at Network Level Global Time Concept of Global Time Macrotick (MT) And the Bit Time Happening to it Inside There? Summarising: Time and its Hierarchies in FlexRay 36 6 The FlexRay Protocol History General Cycles, Segments and Slots Philosophy of the Protocol Hierarchy and Overall Form offlexray Communication Channels and Cycles Communication Channel(s) Communication Cycle Segments A Little Philosophy about Static and Dynamic Segments and Their Purposes Slots and Minislots Static Segments and Slots Dynamic Segments and Minislots Summary Communication Frames Overview of Frames Common Constituent Parts of Static and Dynamic Frames Encapsulation and Coding of Frames of Logical Data in Slots and Minislots 62 for Frames which are Transported during Static and Dynamic Segments 64

4 Network Example Application vii 6.6 'SW Symbol Window' Segment 'NIT Idle Time' Segment 76 7 Access to the Physical Layer Definition of Tasks Execution of the Communication Cycle Frame ID (11 Bits) Arbitration Grid Level Basic Concepts Policy for Access to the Medium Conditions of Transmission and Access to the Medium during the Static Segment Conditions of Transmission and Access to the Medium during the Dynamic Segment Access to the Medium during the Dynamic Segment Particular, Difficult Choice of Hierarchy of Frame ID Example Similarity of the Use of the Dynamic Segment to the Network Access of the CAN Protocol Some Additions in the Case of FlexRay Being Used with Two Channels 89 Appendices of Part B 91 Appendix Bl 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 Static Segment 96 Dynamic Segment 97 Description and Justification of the Implemented Choice 97 General Composition of the FlexRay Communication Cycle 97 Details of the Parameters of the FlexRay System under Consideration 97 Appendix B2 Scheduling Problems of the FlexRay Protocol to Static and Dynamic Segments 103 Introduction 103 Problems of 'Real Time' Systems 104 Concepts of Reactive Systems and Time Constraints 104 Real Time Systems and Their Classification 104 Complexity ofdistributed Real Time Systems 106 Characteristics and Advantages of Distributed Systems 106 Heterogeneity in Distributed Real Time Systems 106 FlexRay 108

5 viii Scheduling Real Time Systems 109 Scheduling and Analysis ofschedulability 109 Class of a Scheduling Problem 110 Different Approaches to Real Time Scheduling 113 ClockDriven Scheduling 114 Round Robin Scheduling 114 Scheduling Based on Priorities 114 Workload Requested by a Synchronous Task 7} 115 Scheduling in SingleProcessor Systems 116 ClockDriven Scheduling 116 Algorithms Based on Priorities 116 Algorithms with Fixed Priorities 116 WorstCase Scenarios and Feasibility Tests in NonPreemptive FP Scheduling 117 Algorithms with Dynamic Priorities 119 Scheduling Communications in Distributed Systems 120 Problem of Task Allocation in a Distributed System 121 Scheduling Communications 121 ClockDriven Approach in Communications 122 Approach Based on Fixed Priorities in Communications 124 Scheduling Communications in FlexRay 125 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 Creation of the Signal Bit Encoding Bit Rate The Communication Controller (CC) Physical Representation of Bits Differential Voltage on the Medium Line Driver 'Tx' Rise Time/Fall Time Impedance Matching 'Ringing' EMC Filtering Electrostatic Discharge (ESD) Protection Medium, Topology and Transport of the FlexRay Signal Medium General 143

6 ix Conventional Propagation of the Signal on the Network Total Distances Used or Wanted on the Network or between Nodes Effects Linked to Propagation Propagation Delay Time Symmetrical Effects Reflection, Matching Topologies and Consequences for Network Performance First, a Little Light on the Obscurity of the Vocabulary Effects and Consequences of the Topology of a Network on its Performance Distances between Two Elements Distances between Several Nodes Relationships between Topologies, Electromagnetic Compatibility (EMC) and Electrostatic Discharge (ESD) Integrity of the Signal SingleChannel, DualChannel and MultiChannel Communication Topologies Topology of Systems of SingleChannel Type Topology of Systems of DualChannel Type The FlexRay Topologies PointtoPoint Link Link Using a Passive Linear Bus Link Using a Passive Linear Bus with Stubs A Star is Born!... Linkage by Star Examples of Topologies Example of Application for a 'BrakebyWire' Solution Reception of the FlexRay Signal Signal Reception Stage Triggering Threshold Unique Effects at the Start of Transmission and/or Reception of Frames Summary of the Effects of Truncation of the Complete Chain from Tx to Rx Processing of the Received Signal by the Communication Controller Acquisition of the Binary Flow Suppression of Disturbance/Noise Binary Alignment The Bit Error Rate (BER) Integrity of Signal and BER Eye Diagram Brief Reminder Jitter 176

7 X 11.3 Relationship between the Integrity of the Signal, the Eye Diagram andtheber BER Calculating the BER Bathtub Curve and BER Modelling and Simulating the Performance of a Network Modelling and Simulating the Performance of a Network and its Topology Modelling the Elements of the Network Simulation Models The Line Driver/Transceiver The Communication Line The EMC Filtering Dual Inductors Back to Reality Simulation Visit Monte Carlo, its Rock, its Casino and its Method Examples of Performance and Recommended Topologies Summary on the Physical Layer of FlexRay 193 Part D SYNCHRONISATION AND GLOBAL TIME 14 Communication Cycle, Macrotick and Microtick The FlexRay Time Hierarchy Communication Cycle Macrotick Synchronisation in a Network of TDMAFlexRay Type Statement of the Problem and Requirements to be Satisfied Requirements to be Met Proposed Solution to the Problem Introduction: Forewarned is Almost Cured Description of the Chosen Method of Ensuring Time Synchronisation ofthe Nodes of the Network 'All in One' Measurement Calculating the Corrective Values of Offset and Rate Application and Implementation of Corrective Values Offset and Offset Correction Rate and Rate Correction Where, When, How to Apply the Corrections? Summary Supplementary Note: Example of Time Hierarchy Network Wakeup, Network Startup and Error Management Network Wakeup Phase Node Wakeup Procedure 223

8 TimeTriggered TimeTriggered WUP xi Wakeup Frame Wakeup Pattern Network Startup Phase Error Management 'Never Give Up'Strategy Error Management States of the Protocol Errors on the Channels and Communication Frames FlexRay v Protocol Enhancements TTL TTE Local Master Synchronisation 233 External Synchronisation Physical Layer Enhancements From Network Implementation to Signal Integrity Focus Signal Integrity Improvements Timing Improvements Wakeup During Operation Interoperability of Different EPL Versions FlexRay and ISO FlexRay in Other Industries 240 Part E ARCHITECTURE OF A NODE, COMPONENTS AND DEVELOPMENT AID TOOLS 17 Architecture of a FlexRay Node The Major Components of a Node Architecture of the Processor and Protocol Manager Electronic Components for the FlexRay Network The Component Range FlexRay Protocol Manager Line Drivers and Active Stars EMC and EMC Measurements Protection from ESD Conformity Tests Bus Guardian Tools for Development, Integration, Analysis and Testing The VShaped Development Cycle DaVinci Network Designer (Point 1 of the V Cycle) CANoe.FlexRay Modelling, Simulation (Point 2 of the V Cycle) Integration (Point 4 of the V Cycle) FlexRay CANalyzer (Covers Points 2, 4 and 5 of the V Cycle) Test and Diagnostics (Point 6 of the V Cycle) Features of the FlexRay Protocol 278

9 xii 19.7 Communication Interface CANoe Real Time FlexRayStress CANape FlexRay Implementation of FlexRay Communication in Automotive Logic Controllers FlexRay and AUTOSAR The AUTOSAR Partnership Communication in an AUTOSAR System Functional Analysis, Virtual Function Bus Passing from Virtual to Real AUTOSAR FlexRay Communication Stack 287 Appendix of Part E Conclusion 297 Appendix 1 The Official Documents 299 Appendix 2 Principal Parameters of the FlexRay Protocol 301 Bibliography 311 Index 313

FLEXRAY AND ITS APPLICATIONS

FLEXRAY AND ITS APPLICATIONS FLEXRAY AND ITS APPLICATIONS REAL TIME MULTIPLEXED NETWORK Dominique Paret dp-consulting, Paris, France Translated by Bill Chilcott Fellow of the Institute of Translation and