FlexRay
Enabler for Future
Automotive System Architectures
3rd March 2005
Genf
Dr. Günter Reichart - BMW Group
Requirements driven evolution of functions and
systems - mapped on BMW car series
Df
7 Series
Functions (absolute)
5 Series
Df
7 Series
3 Series
s
ent
m
e
uir d
Req base esign
d
tem
s
y
S
5 Series
7 Series
Df
3 Series
5 Series
3 Series
?
+ Driver information
+ Driver assistance
+ Drive-by-Wire
– Change from
analog tech./
digital bussystems
–
–
–
–
–
– Advanced technologies
– New design methods
– Defined interfaces
n:m-connection
Data rates
Deterministic
Technology
CAN
Time
page 2
Situation snapshot of in-car E/E systems and
architectures
Ÿ Increasing requirements (legal, functional and safety) demand for further
electric/electronic systems
Ÿ Mechatronic will replace mechanic (e.g. Drive-by-Wire)
Ÿ New functions (e.g. driver assistance) need higher data exchange between
functional domains
m
DMRG
CC
RDS -TMC
BMW Navigation System
Navigation
domain
ACC
Driver Control
domain
DSC
DBC
HC
ASC
EDC
Chassis
Stability
domain
ABS
Environment
Car
page 3
System Architecture - Complexity Management
Lessons learned …
è Complexity by introducing many communication systems in a single car platform
BMW 7 Series – Network
Goal:
Reduction of variants in
specific communication
systems
CAN
MOST
CAN
byteflight
CAN
à Locally "open" Architecture
+
+
Functional Networking
(Customer View)
Inter• Communication
dependencies
• Driver Information
• Driver Assistance
+
Common
Open System
Functional
Networking
(Technology)
• by wire
Architecture Forward
Standardization
page 4
Requirements for a common communication system
mapped to the automotive application domains
• X-by-wire systems
è
Dependability and fault containment
• Chassis systems
è
Determinism
• Powertrain systems
è
High bandwidth
• Future backbone for open
systems architectures
è
Flexibility and high bandwidth
Requirements
FlexRay
MOST
CAN
LIN
Control
Communications
page 5
Requirements for Open System Architecture
Ÿ Displacement of functional modules beyond domain boundaries
Ÿ Strategy for reduction in technology variety is mandatory
and it requires new feature integration
Ÿ Flexibility of hardware
Ÿ Approach must be based on future standards
Ÿ Standardized interfaces
Ÿ Support by development methods and tools
page 6
FlexRay History
1998 Analysis:
CAN
/
TTP
/
MOST
Experience in BMW / DC / Bosch / GM
/
byteflight
Experience in BMW
Start of communication between BMW and DaimlerChrysler
Since
Since
1999
Realization: Future requirements are not fulfilled by existing protocols
1999
Consequences: Start of cooperation
2000
FlexRay Consortium founded by BMW, DaimlerChrysler, Motorola, Philips
2000
Realization of FlexRay System together with semiconductor industry
10/2000
Bosch joins FlexRay Consortium
09/2001
General Motors joins FlexRay Consortium
04/2002 - 10/2002
Ford Motor Company, Mazda and Fiat join as Premium Associate Members
Q3/2003
Volkswagen joins the FlexRay Consortium
Q4/2003
Toyota, Honda, Nissan join the FlexRay Consortium as PAMs
06/2004
Release of FlexRay Specifications, SW & tools available to the general public
Q3/2004
PSA, Renault join the FlexRay Consortium as Premium Associate Members
page 7
Scope of the Consortium
The scope of the Consortium is to develop jointly an innovative
communications network of very high quality which consists of the complete
communication infrastructure and includes inter alia the specifications for
the serial communications protocol, the transceiver, the hardware and
software interfaces and conformance/certification procedures. This will
serve as the basis for the development, production and implementation of
certain communications networks for automotive applications.
The ultimate objective of the Consortium is the factual industry-wide
recognition of a new standard for a deterministic automotive network which
shall be open to use and development by third parties.
page 8
De-facto Automotive Standard
Core Members
Premium Associate Members
ContiTeves
BMW Group
Bosch
Delphi
Denso
Fiat
DaimlerChrysler
General Motors
Ford Motor
Honda
Mazda
Freescale
(Motorola)
Philips
Nissan
Peugeot Citroen
Renault
Toyota
Volkswagen
Tyco Electronics
Volvo
Associate Members
AMS
ATMEL
Avidyne
Berata
EADS
Elmos
ESG
Esterel
Fujitsu
Hella
Hitachi
Hyundai
Infineon
Mitsubishi
NEC
Nidec
Pacifica
Porsche
Renesas
RWTÜV
SiemensVDO
SP
ST Micro
Subaru
Sumitomo
Texas Instruments
ThyssenKrupp Automotive
TRW
Visteon
Yazaki
Development Members
Cadence
CANway
CapeWare
Cardec
CRST
DECOMSYS
dSpace
ETAS
IXXAT
MicroSys
National Instruments
NSI
3SOFT
Softing
SystemA
TecWings
TZM
Vector Informatik
Volcano
Weise GmbH
page 9
Structure of the Consortium - Mechanisms
Executive Board
Strategy,
Scientific, Technical
Spokesperson
Administrator
Technical Project leader
Steering Committee
Technical Working Groups
page 10
Working Group Structure
Requirement Group
Requirement Spec
Protocol Group
Physical Layer
Group
Feedback
FlexRay Specs
Feedback
Verification
Test Group
Scientific
Proof Group
FMEA Group
page 11
FlexRay - the communication system (1/3)
Features
Ÿ Forward-standardization – an objective from the beginning
§ OEMs, TIER1s and semiconductor vendors
are represented in the FlexRay consortium
Ÿ Bandwidth
Host
§ No limitation due to protocol mechanisms
§ Current design focus: 10 Mbit/s
Ÿ Scalability
§ Single channel / Dual channel
§ Mixed configuration
FlexRay
Communication
Controller
BGA
BD: Bus Driver
BG: Bus Guardian (optional) Channel A
BDA BGB
BDB
Channel B
page 12
FlexRay - the communication system (2/3)
Ÿ Flexibility
Frame ID:
Equivalent to Slot number; implicitly denotes the sender
Sync Bit
Null Frame Indication
NM indication
Open to many network topologies
Electrical and optical Physical Layer
Dynamic and static segments in communication cycle
Frame ID
Reserved
§
§
§
§
Header CRC
Covered Area
Frame ID
Length
Header
CRC
Cycle
12 bits
7 bits
11 bits
6 bits
Message ID
Data
NM
Data
Data
16 bits
Data
CRC
CRC
CRC
24 bits
0 ... 254 Bytes
1111
Header Segment
Payload Segment
FlexRay Frame 5 + (0 ... 254) + 3 Bytes
Trailer Segment
page 13
FlexRay - the communication system (3/3)
Ÿ Deterministic
§ Stringent deterministic by TDMA media access (Time Division Multiple
Access) in static segment
§ Limited deterministic by FTDMA media access (Flexible Time Division
Multiple Access) in dynamic segment
Ÿ Safety
§ Distributed Clock Synchronization
- Offset and Rate Correction
§ Bus Guardian
§ CRC
- Header CRC
- Frame CRC
- Hamming Distance of 6
page 14
FlexRay Bus Access Method
Communication Cycle 1
Static Segment
Cycle 2
Dynamic Segment
Static
Slot
9
1
3
4
5
6
7
7
1
2
3
5
6
8
13
...
Channel A
9
8
10
...
Channel B
time
Node A
ID: 1, 5,10
Node B
ID: 2
Node C
ID: 3, 8
Node D
ID: 4, 7
Node E
ID: 6, 13
page 15
FlexRay Time Triggered Communication
Composability in the Time Domain
Communication Cycle
Static Segment
Dynamic Segment
ECU
A
C
G
K
A
Dynamic Segment
Static Segment
B
3 5
F
I
L 1
6
B
Static Segment
Frame
A BCD
Dynamic Segment
FGH I
K L 1 2 3 4 5 6
Time Slot
Dynamic Segment
Static Segment
D
SystemIntegration
H
2 4
C
page 16
Benefits of the FlexRay Technology
•
Ÿ
Provide a communication infrastructure for future generation highspeed control applications in vehicles such as advanced powertrain,
chassis, and by-wire systems.
High bandwidth (net data rate 5 Mbps at gross 10 Mbps), flexible use
of bandwidth
Ÿ
Deterministic behavior (guaranteed transmission time for frames in
the static segment)
Ÿ
Synchronization of tasks in distributed control systems
Ÿ
Cycle times < 2 ms
Ÿ
Reliable data communication
Ÿ
Facilitation of system integration
Ÿ
Reserves for future functional extensions
Ÿ
Possibility to implement future real Drive-by-Wire functions without
page 17
mechanical back-up
FlexRay Roadmap
page 18
Standard-Structure model with FlexRay as underlying
Communication Layer
Operating System
Application
A
...
Application
B
Application
Mgt.
Configuration via Database
API Interfaces
Libraries
of Standards
(floating point, integer,
type conversion)
Middleware
Fixed APIs for each possible technology
FlexRay
Diagnosis
Message-Mgt.
(CAN,
MOST,
FTcom
Transport Layer
Network
Mgt.
HW AbstractionLayer (I/O)
Other)
HW-Driver
EEPROM Driver
FlexRay Controller + Transceiver (HW)
Bus (in certain topologies)
page 19
Activities around the FlexRay protocol
Ÿ Physical Layer development proceeding in parallel
Ÿ HW features to support future network management
concepts
§ ie. Network Management Indication Bit and Network Management Vector
Ÿ OSEKtime
§ OSEK enhancement for time triggered operation
Ÿ FTcom: Fault Tolerant communication layer for OSEK
architecture
§ specification and pilot-implementations available
Ÿ FIBEX (FIeld Bus EXchange format)
§ XML-exchange format based on a generic bus model enables interoperability
between databases and development tools
Enabler for OSAR
page 20
Summary
• FlexRay is a communication system targeted at high-speed control
applications in vehicles such as advanced powertrain, chassis, and
by-wire systems.
• FlexRay supports these applications by providing architectural
flexibility through scalability and functional alternatives.
• FlexRay is expected to be the de-facto communication standard for
high-speed automotive control applications.
page 21
Thank you for your attention!
www.flexray.com