ISO 17458-4:2013

INTERNATIONAL ISO
STANDARD 17458-4
First edition
2013-02-01
Road vehicles— FlexRay
communications system —
Part 4:
Electrical physical layer specification
Véhicules routiers — Système de communications FlexRay —
Partie 4: Spécification de la couche d'application électrique

Reference number
©
ISO 2013
©  ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

Contents Page
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 10
3.3 Symbols . 12
4 Document reference according to OSI model . 13
5 Conventions . 14
5.1 General . 14
5.2 Notational and parameter prefix conventions . 14
5.3 Important preliminary notes . 15
6 Communication channel basics . 16
6.1 Objective. 16
6.2 Propagation delay . 16
6.3 Frame TSS length change . 18
6.4 Symbol length change . 18
6.5 FES1 length change . 19
6.6 Collisions. 19
6.7 Stochastic jitter . 20
6.8 Wakeup patterns . 20
7 Principle of FlexRay networking . 22
7.1 Objective. 22
7.2 Interconnection of nodes . 22
7.3 Electrical signalling . 23
8 Network components . 24
8.1 Objective. 24
8.2 Cables . 24
8.3 Connectors . 25
8.4 Cable termination . 25
8.5 Termination concept . 27
8.6 Common mode chokes . 27
8.7 DC bus load . 27
9 Network topology . 28
9.1 Objective. 28
9.2 Point-to-point connection . 29
9.3 Passive star . 29
9.4 Linear passive bus . 30
9.5 Active star network . 31
9.6 Cascaded active stars . 32
9.7 Hybrid topologies . 32
9.8 Dual channel topologies . 33
10 Asymmetric delay budget . 33
10.1 Objective. 33
10.2 Basic topology for asymmetric delay budget. 34
10.3 Definition of Test Planes . 34
10.4 Requirements to the asymmetric delay budget . 36
10.5 Definition of maximum asymmetric delay portions . 36
10.6 Other networks . 43
11 Signal integrity . 43
11.1 Objective . 43
11.2 Mask test at TP1 / TP11 . 44
12 Electrical bus driver . 49
12.1 Overview . 49
12.2 Operation modes . 50
12.3 Operation mode transitions . 51
12.4 Bus driver – communication controller interface . 53
12.5 Bus driver – bus guardian interface (optional) . 57
12.6 Bus driver – host interface . 57
12.7 Bus driver – power supply interface . 61
12.8 Bus driver - level shift interface (optional) . 63
12.9 Bus driver - bus interface . 63
12.10 Bus driver – wakeup interface (optional) . 77
12.11 Remote wakeup event detector (optional) . 78
12.12 Bus driver behaviour under fault conditions . 80
12.13 Bus driver functional classes . 85
12.14 Bus driver signal summary . 87
13 Active Star . 88
13.1 Overview . 88
13.2 Hardware overview . 88
13.3 Signal timing . 90
13.4 Active star device operation modes . 98
13.5 Autonomous power moding flag (APM flag) . 100
13.6 Branch operating states . 101
13.7 Branch transmitter and receiver circuit . 104
13.8 Active star - communication controller interface (optional) . 105
13.9 Active star – bus guardian interface (optional) . 115
13.10 Active star – host interface (optional) . 115
13.11 Active star – power supply interface . 115
13.12 Active star – level shift interface (optional) . 118
13.13 Active star – bus interface . 118
13.14 Active star – wake interface (optional) . 119
13.15 Active star functional classes . 119
13.16 Active star behaviour under fault conditions . 120
13.17 Active star signal summary . 122
14 Interface definitions . 123
14.1 Overview . 123
14.2 Communication controller – bus driver interface . 123
14.3 Host . 126
15 General features for FlexRay physical layer parts . 127
15.1 Objective . 127
15.2 Voltage limits for digital output signals . 127
15.3 Input voltage thresholds for digital signals . 127
15.4 ESD protection on chip level (HBM) . 128
15.5 ESD protection on chip level (IEC61000-4-2) . 128
15.6 ESD protection on ECU level . 128
15.7 Operating temperature . 128
15.8 Serial peripheral interface (SPI) . 129
Annex A (informative) Application notes . 131

iv © ISO 2013 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 17458-4 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3,
Electrical and electronic equipment.
ISO 17458 consists of the following parts, under the general title Road vehicles — FlexRay communications
system:
 Part 1: General information and use case definition
 Part 2: Data link layer specification
 Part 3: Data link layer conformance test specification
 Part 4: Electrical physical layer specification
 Part 5: Electrical physical layer conformance test specification
Introduction
The FlexRay communications system is an automotive focused high speed network and was developed with
several main objectives which were defined beyond the capabilities of established standardized bus systems
like CAN and some other proprietary bus systems. Some of the basic characteristics of the FlexRay protocol
are synchronous and asynchronous frame transfer, guaranteed frame latency and jitter during synchronous
transfer, prioritization of frames during asynchronous transfer, single or multi-master clock synchronization,
time synchronization across multiple networks, error detection and signalling, and scalable fault tolerance.
The FlexRay communications system is defined for advanced automotive control applications. It serves as a
communication infrastructure for future generation high-speed control applications in vehicles by providing:
 A message exchange service that provides deterministic cycle based message transport;
 Synchronization service that provides a common time base to all nodes;
 Start-up service that provides an autonomous start-up procedure;
 Error management service that provides error handling and error signalling;
 Wakeup service that addresses the power management needs.
Since start of development the automotive industry world-wide supported the specification development. The
FlexRay communications system has been successfully implemented in production vehicles today.
The ISO 17458 series specifies the use cases, the communication protocol and physical layer requirements of
an in-vehicle communication network called "FlexRay communications system".
This part of ISO 17458 has been established in order to define the electrical physical layer of the FlexRay data
link.
To achieve this, it is based on the Open Systems Interconnection (OSI) Basic Reference Model specified in
ISO/IEC 7498-1 and ISO/IEC 10731, which structures communication systems into seven layers. When
mapped on this model, the protocol and physical layer requirements specified by ISO 17458 are broken into:
 Diagnostic services (layer 7), specified in ISO 14229-1 [7], ISO 14229-4 [9];
 Presentation layer (layer 6), vehicle manufacturer specific;
 Session layer services (layer 5), specified in ISO 14229-2 [8];
 Transport layer services (layer 4), specified in ISO 10681-2 [1];
 Network layer services (layer 3), specified in ISO 10681-2 [1];
 Data link layer (layer 2), specified in ISO 17458-2, ISO 17458-3;
 Physical layer (layer 1), specified in ISO 17458-4, ISO 17458-5;
in accordance with Table 1.
vi © ISO 2013 – All rights reserved

Table 1 — FlexRay communications system specifications applicable to the OSI layers
Vehicle manufacturer enhanced
Applicability OSI 7 layers FlexRay communications system
diagnostics
Application (layer 7) vehicle manufacturer specific ISO 14229-1, ISO 14229-4
Presentation (layer 6) vehicle manufacturer specific vehicle manufacturer specific
Seven layer
vehicle manufacturer specific ISO 14229-2
Session (layer 5)
according to
ISO 7498-1
vehicle manufacturer specific
Transport (layer 4)
and
ISO 10681-2
ISO/IEC
vehicle manufacturer specific
Network (layer 3)
Data link (layer 2) ISO 17458-2, ISO 17458-3
ISO 17458-4, ISO 17458-5
Physical (layer 1)
Table 1 shows ISO 17458 Parts 2 – 5 being the common standards for the OSI layers 1 and 2 for the FlexRay
communications system and the vehicle manufacturer enhanced diagnostics.
The FlexRay communications system column shows vehicle manufacturer specific definitions for OSI layers
3 – 7.
The vehicle manufacturer enhanced diagnostics column shows application layer services covered by
ISO 14229-4 which have been defined in compliance with diagnostic services established in ISO 14229-1, but
are not limited to use only with them. ISO 14229-4 is also compatible with most diagnostic services defined in
national standards or vehicle manufacturer's specifications. The presentation layer is defined vehicle
manufacturer specific. The session layer services are covered by ISO 14229-2. The transport protocol and
network layer services are specified in ISO 10681.

INTERNATIONAL STANDARD ISO 17458-4:2013(E)

Road vehicles — FlexRay communications system — Part 4:
Electrical physical layer specification
1 Scope
This part of ISO 17458 specifies the electrical physical layer for FlexRay communications systems.
The electrical physical layer for FlexRay is designed for time-triggered networks with data-rates up to
10 Mbit/s to connect automotive electronic control units (ECUs). The medium that is used is dual wires.
Signalling on the bus is accomplished by asserting a differential voltage between those wires. Topology
variations range from point-to-point connections via linear passive busses and passive stars up to active star
topologies.
This part of ISO 17458 includes the definition of electrical characteristics of the transmission itself and also
documentation of basic functionality for bus driver (BD) and active star (AS) devices.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 17458-1, Road vehicles — FlexRay communications system — Part 1: General information and use case
definition
ISO 17458-2, Road vehicles — FlexRay communications system — Part 2: Data link layer specification
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 17458-1, ISO 17458-2 and the
following apply.
3.1.1
alternating current busload
AC busload
equivalent circuit of a passive star from transmitting view of the bus driver
3.1.2
active elements
components which work with power supply and amplifiers
3.1.3
active star network
AS network
all point-to-point connections plugged to an AS
3.1.4
activity
See "bus state"
NOTE activity distinguishes two states: Data_0 and Data_1.
3.1.5
Activity
signal to the Central_Logic when this communication path is not idle(see also NoActivity)
3.1.6
asymmetric delay budget
maximum bit-deformation in the time domain
NOTE It is derived from the specified synchronization and sampling procedure and the properties of their
implementation. When transmitting a FlexRay data stream the receiving CC must be able to detect the data without any
error. If the asymmetric delay of the data stream is higher than the asymmetric delay budget, the decoder samples faulty
bit values.
3.1.7
asymmetric delay
bit-deformation in the time domain when passing a data stream e.g. via a BD
EXAMPLE
A data steam is applied to the BD´s input TxD: …00100
The single 1 at the centre shall have a length of 100 ns
The BD passes the data stream to its output BP and BM.
The single 1 may be shortened or lengthened a little bit to e.g. 102 ns
In this case the asymmetric delay has to be determined to 2 ns.
3.1.8
bus driver – bus driver interface
BD-BD-interface
consideration of all involved effects of the timing of each BD/AS
NOTE The timing is specified based on measurement set-ups easy to be used. When connecting two BDs/ASs (via
e.g. a passive star) the resulting delays are not equal to twice the specified values.
3.1.9
bus guardian enable
BGE
input pin of the BD that allows deactivating the bus output stage of the BD
3.1.10
bias voltage
voltage source with high output impedance
3.1.11
bus minus
BM
bidirectional pin of the BD/AS to allow the BD/AS the access to the bus.
3.1.12
bus plus
BP
bidirectional pin of the BD/AS to allow the BD/AS the access to the bus.
3.1.13
branch
component within active star topologies
2 © ISO 2013 – All rights reserved

NOTE A branch can be built of a point-to-point connection, a linear bus or a passive star.
3.1.14
byte start sequence
BSS
pre-defined sequence of two bits (logical: 10) which is sent in front of each byte
3.1.15
bus guardian
BG
component which allows the node only to transmit during the pre-defined timing slots
3.1.16
bus state
status of the bus FlexRay communication
NOTE Several different states are visible due to the operating modes of the FlexRay system.
EXAMPLE
idle: there is no communication on the bus. Approximately 0 V differential voltage is measurable.
activity: there is an on-going communication on the bus. Approximately ±600 mV up to ±1 000 mV differential voltage is
measurable, etc.
3.1.17
cascade
topology character
NOTE If a topology uses more than 1 AS the wording "cascaded ASs" is used.
3.1.18
common mode
mode in which two test points are handled simultaneously against ground
EXAMPLE
common mode input impedance of the BD´s bus pins BP and BM to ground.
common mode voltage on the bus: ½ (uBP + uBM)
3.1.19
communication path
branches CC interface and Intra Star Interface
3.1.20
connection network
components like CMC, termination resistors, ESD protection circuits, lines on the PCB, connectors, etc
NOTE When implementing a FlexRay system each BD/AS has to be plugged to a FlexRay cable via these
components.
3.1.21
Data_0
bus-state "activity""where a logical 0 is transmitted
3.1.22
Data_1
bus-state "activity"" where a logical 1 is transmitted.
3.1.23
differential mode
mode in which two test points are handled against each other
EXAMPLE
differential mode input impedance of the BD´s bus pins BP and BM to ground.
differential mode voltage on the bus: (uBP - uBM).
differential mode impedance of the FlexRay cable
3.1.24
dummy load
summary of loads that can be applied to components which are specified by easy-to-use measurement set-
ups
EXAMPLE
dummy load at BP and BM: 40 Ω || 100 pF.
dummy load at RxD: 15 pF
3.1.25
eye-diagram
diagram that is visible when overlying edge synchronized measured bus signals
NOTE The shape of the eye allows specifying the bus-signals.
3.1.26
frame end sequence
FES
bit sequence that consists of two bits (01) and is sent at the end of each FlexRay data frame
NOTE The asymmetric delay budget is based on the end of a data frame:
in the worst case up to 10 consecutive identical bits can be seen.
BSS + 1 byte + FES = 10 00000000 01
3.1.27
functional class
grouping of various features that are implemented together
NOTE The BD/AS offers various technical features. To keep the resulting products testable and to offer them a good
chance on the market it is required to implement various features only together.
3.1.28
generic bus driver
simulation model which is derived from the specification directly
NOTE The knowledge about real implementations is taken into consideration. The generic BD supports a receiver
stage, a transmitter stage and optionally the AS routing behaviour.
3.1.29
idle
see "bus state".
Idle distinguishes 3 bus biasing states:
idle while all nodes are neither un-powered nor in a low power mode, thus all nodes are biasing the bus.
idle while all nodes are either un-powered or in a low power, thus none of the nodes is biasing the bus.
idle while some nodes are biasing the bus and others not.
3.1.30
leg
passive network that is involved in the calculation of timing budget
4 © ISO 2013 – All rights reserved

NOTE A topology is interpreted as a single path from a transmitter to a receiver that contains several passive
networks. Each of these passive networks is named leg.
3.1.31
linear passive bus
FlexRay bus that consists of 2 terminated FlexRay nodes with one cable between
NOTE Additionally some un-terminated FlexRay nodes are plugged to the cable by splices and short stubs.
3.1.32
monolithic
see: active star.
NOTE This term is used to characterize various implementations on an AS. If the AS is monolithic implemented all
specified components are included in a single device.
3.1.33
NoActivity
signal to the Central_Logic when this communication path is idle is detected (see also Activity)
3.1.34
non-monolithic
character of various implementations on an AS
NOTE This term is used to characterize various implementations on an AS. If the AS is non-monolithic implemented
all specified components are not included in a single device, two devices are used at least. See "active star".
3.1.35
NotReceiveActive
communication path signals NotReceiveActive to the Central_Logic when a state is entered at that the
communication path is idle or is actively transmitting data
3.1.36
parasitic capacity
capacity that appears although it is not technically necessary
EXAMPLE
pins of a device housing generate a capacity
3.1.37
parasitic resistance
resistance that appears although it is not technically necessary
3.1.38
passive net
all possible implementation of AS branches
NOTE This summarizes: point-to-point connections, linear busses and passive stars. They do not include BD/ASs.
3.1.39
passive star network
network consisting of passive stars
3.1.40
physical layer
component that includes all components between TP0 and TP5
3.1.41
ReceiveActive
communication path signals ReceiveActive to the Central_Logic when a state is entered at that the incoming
data stream is forwarded to other communication paths
3.1.42
receiver
device or entity that receives an information transfer originated by a transmitter
NOTE A term that is used in various ways based on the context.
EXAMPLE
BD´s input stage from the bus.
FlexRay communication element receiving node
3.1.43
receive enable not
RxEN
output pin at the BD to show the state of the bus
NOTE Two states are distinguished: idle or activity
3.1.44
serial peripheral interface
SPI
synchronously working hardware interface to exchange data among circuits mounted on a PCB
3.1.45
signal integrity
SI
procedures or requirements to differential bus signals to guarantee the faultless transmission of FlexRay
communication elements
3.1.46
signal integrity voting
SI voting
procedure to determine Sq based on measured bus signals
3.1.47
specific line delay
propagation of a FlexRay signal per meter of a transmission line in ns/m
3.1.48
splice
any implementation of a connection-point where 3 or more transmission lines are plugged together
NOTE A splice may contain passive components to damp radiation
EXAMPLE
A splice in a linear bus allows to connect a stub to a FlexRay node.
3.1.49
signal quality
Sq
parameter to describe whether the required signal integrity of FlexRay signals on the bus is met
NOTE Pass or fail are the possible results.
6 © ISO 2013 – All rights reserved

3.1.50
stochastic jitter
jitter of data stream edges in the time domain due to e.g. radiation
NOTE The EPL-specification passes its appropriate consideration to the responsible system designer.
3.1.51
stub
component within passive nets
NOTE A stub consists of a single FlexRay cable connected to the centre of a passive star or to a linear bus (short:
plugged to a splice).
The stub ends at the BD pins BP and BM within a FlexRay node.
3.1.52
termination
set-up of components between a BD and a transmission line
NOTE Mainly they are used to ensure SI and EMC requirements.
EXAMPLE
Resistors, capacitances, chokes etc.
3.1.53
termination area (of the cables)
assembly of FlexRay cables to ECU-connectors that require several procedures which disturb the geometric
integrity of the FlexRay cable:
untwisted, unshielded and unsheathed cable segment.
twisted but unshielded or unsheathed cable segment.
Both segments together represent the termination area.
3.1.54
test plane
virtual or real places to get electrical signals and to determine their properties
NOTE The test planes are located on the path from a transmitter to a receiver.
3.1.55
topology
non-hierarchical flat geometric structure of the FlexRay system
NOTE A distributed FlexRay system consists of several components like nodes, busses, active and passive stars etc.
3.1.56
test plane 0
TP0
virtual time reference point that represents the digital output from the protocol machine with a perfect timing
according the data link layer specification
3.1.57
test plane 1 flip flop (virtual)
TP1_FFi
transmitting CC’s virtual test plane to visualize PLL jitter, clock skew and propagation delay of the flip flop
3.1.58
test plane 1 flip flop
TP1_FF
transmitting CC’s internal test plane at ‘Q’ pin of last flip flop before output buffer
3.1.59
test plane 1 communication controller
TP1_CC
transmitting CC’s output pin (TxD)
3.1.60
test plane 1 bus driver input
TP1_BD
test plane located at the transmitting BD’s input pin TxD directly
3.1.61
test plane 1 bus driver (virtual)
TP1_BDi
virtual test plane hidden in the transmitting BD’s output of its TxD logical state detection stage
3.1.62
test plane 1
TP1
test plane located at the transmitting BD’s output pins BP and BM
3.1.63
test plane 2
TP2
test plane located at the transmitting ECU connector’s terminals to the wiring harness
3.1.64
test plane 3
TP3
test plane located at the receiving ECU connector’s terminals from the wiring harness
3.1.65
test plane 4
TP4
test plane located at the receiving BD’s input pins BP and BM
3.1.66
test plane 4 bus driver (virtual)
TP4_BDi
virtual test plane hidden in the receiving BD’s output of its differential bus signal logical level detection stage
3.1.67
test plane 4 bus driver
TP4_BD
receiving BD’s output pin (RxD)
3.1.68
test plane 4 communication controller
TP4_CC
test plane located at the receiving CC’s input pin RxD
3.1.69
test plane 4 communication controller (virtual)
TP4_CCi
virtual test plane hidden in the receiving CC’s output of its RxD logical state detection stage
3.1.70
test plane 4 flip flop
TP4_FF
receiving CC’s internal test plane at ‘D’ pin of first flip flop after input buffer
8 © ISO 2013 – All rights reserved

3.1.71
test plane 4 flip flop (virtual)
TP4_FFi
receiving CC’s virtual test plane to visualize PLL jitter, clock skew and propagation delay of the flip flop
3.1.72
test plane 5 communication controller
TP5_CC
clock input to CC
3.1.73
test plane 5
TP5
virtual test plane that represents the input of the decoding algorithm with a perfect timing according the data
link layer specification
3.1.74
test plane 11
TP11
test plane located at the transmitting AS device’s output pins BP and BM
3.1.75
test plane 12
TP12
test plane located at the transmitting AS ECU connector’s terminals to the wiring harness
3.1.76
test plane 13
TP13
test plane located at the receiving AS ECU connector’s terminals from the wiring harness
3.1.77
test plane 14
TP14
test plane located at the receiving AS device’s input pins BP and BM
3.1.78
transmission line
FlexRay cable or a line on a PCB when their properties to transmit electrical signals are focused
3.1.79
transmission start sequence
TSS
bit sequence that is sent in front of each FlexRay data frame or CAS/MTS symbol. The TSS is necessary for a
BD and an AS to detect activity on the bus. A BD and an AS is allowed to shorten or lengthen the TSS.
3.1.80
transmitter
term that is used in various ways based on the context
EXAMPLE
BD´s output stage to the bus.
FlexRay traffic transmitting node
3.1.81
wiring harness
all components inside the component "vehicle wiring harness" to transmit FlexRay communication elements
NOTE This includes connectors to plug ECUs, in-line connectors, cables, splices etc.
3.2 Abbreviated terms
AC alternating current
APM autonomous power moding
AS active star
AS_BGI active star – bus guardian interface
AS_IVR active star – internal voltage regulator
AS_VRC active star – voltage regulator control
ASP abstract service primitive
BD bus driver
BD_VRC bus driver – voltage regulator control
BD_BGCI bus driver – bus guardian control interface
BD_IVR bus driver – internal voltage regulator
BD_LLA bus driver – logic level adaptation
BG bus guardian
BGE bus guardian enable
BM bus minus
BP bus plus
C capacitor
CC communication controller
CE communication element
CHI controller host interface
CMC common mode choke
DUT device under test
ECU electronic control unit
EMC electromagnetic compatibility
EN optional/product specific mode control signals of the bus driver
ERRN error not output pin of the BD/AS
This pin allows the BD/AS signalling error events or/and errors.
I/R interruption
Idle_LP bus state in case all nodes (and active stars) are in a low power mode
10 © ISO 2013 – All rights reserved

INH inhibit output pin of the BD/AS
INH signals on one hand the BD/AS state and allows on the other hand to control the states of a
voltage regulator.
INH1 inhibit 1 output signal of the bus driver / active star
INTN interrupt not
IUT implementation under test
LWU local wakeup
PCO point of control and observation
PDU protocol data unit
PL physical layer
PS passive star
RWU remote wakeup
RxD receive data signal from the bus driver
RxEN receive data enable not signal from the bus driver
S/C short-circuit
SCSN SPI chip select not input
SI signal integrity
SOVS system operating variable space
SPI serial peripheral interface
Sq signal quality
STBN standby not
Input pin at the BD to control its power modes
SUT system under test
SV supervisor
TCP test coordination procedure
TP test plane
TSS transmission start sequence
TxD transmit data signal to the bus driver
TxEN transmit data enable not signal
Output pin at the CC and input pin at the BD. The pin allows the CC to control the states which
are generated by the BD. Two states are distinguished: idle or activity.
U ground shift voltage
GS
WAKE local wakeup input signal of the bus driver
WU wakeup
3.3 Symbols
R Resistor to terminate a transmission line
T
X don’t care. This term is used when the state of a signal is not relevant.
supply voltage (battery)
V
BAT
Voltage of the vehicle battery measurable at BD´s pins.
V supply voltage (+5 V)
CC
supply voltage for the digital I/O ports
V This term is used in two ways, BD´s pin to connect the logical 1 reference voltage and voltage
DIG
value of the logical 1 reference voltage.
supply voltage for the digital I/O ports
V This term is used in two ways, BD´s pin to connect the logical 1 reference voltage and voltage
IO
value of the logical 1 reference voltage.
supply voltage of the active star
V
StarSupply
Can be derived from V and/or V
BAT CC
12 © ISO 2013 – All rights reserved

4 Document reference according to OSI model
Figure 1 depicts the FlexRay document reference according to OSI model.
ISO 17458-1
FlexRay communications
system - General
information and
use case definition
Vehicle Manufacturer
Enhanced Diagnostics
specific
ISO 14229-1 UDS Vehicle
ISO 14229-4
Specification and subset manufacturer
OSI Layer 7
UDSonFR
requirements specific
Application
Vehicle Vehicle
manufacturer manufacturer
OSI Layer 6
specific specific
Presentation
ISO 14229-2 UDS ISO 14229-2 UDS Vehicle
1 : 1
Session layer Session layer manufacturer
OSI Layer 5
services services specific
Session
Standardized Service Primitive Interface
FlexRay communications system
Vehicle
manufacturer
OSI Layer 4
specific
Transport
ISO 10681-2
Communication on
FlexRay –
Communication
layer services
Vehicle
manufacturer
OSI Layer 3
specific
Network
ISO 17458-3
ISO 17458-2
FlexRay
FlexRay
communications system
OSI Layer 2 communications system
– Data link layer
Data Link – Data link layer
conformance test
specification
specification
ISO 17458-5
ISO 17458-4
FlexRay
FlexRay
communications system
communications system
OSI Layer 1
- Electrical physical
- Electrical physical
Physical
layer conformance test
layer specification
specification
Figure 1 — FlexRay document reference according to OSI model
5 Conventions
5.1 General
ISO 17458, ISO 10681 and ISO 14229-4 are based on the conventions specified in the OSI Service
Conventions (ISO/IEC 10731) as they apply for physical layer, protocol, network & transport protocol and
diagnostic services.
5.2 Notational and parameter prefix conventions
Each FlexRay parameter is prefaced by two prefixes. The prefixes are applied in the following way:
 ::= Name
::= a | c | v | g | p | z
::= d | l | n | s | u
Table 2 defines the values for prefix 1.
Table 2 — Prefix 1
Naming Information
Description
Convention Type
Auxiliary Auxiliary parameter used in the definition or derivation of other parameters or in
a
Parameter the derivation of constraints.
Protocol Values used to define characteristics or limits of the protocol. These values are
c
Constant fixed for the protocol and cannot be changed.
Node
v Values that vary depending on time, events, etc.
Variable
Parameter that shall have the same value in all nodes in a cluster, is initialized in
Cluster
g the POC:default config state, and can only be changed while in the POC:config
Parameter
state.
Parameter that may have different values in different nodes in the cluster, is
Node
initialized i
...