AUTOMOTIVE ELECTRONICS
`Digital networks in the
`automotive vehicle
`
`by Gabriel Leen, Dona1 Heffernan and Alan Dunne
`
`Automotive electronic systems are piggybacking on the exponential
`growth of the computer industry. This article takes a look at the
`progressive innovations which have shaped the electrical architecture of
`today's vehicles and which will mould tomorrow's. It discusses: why
`networks are necessary in vehicles; special attributes of these networks;
`examples of automotive control network protocols; importance of
`software in modern vehicles; and future automotive system trends.
`
`to thc manuIacturers. lilcctronic systems provide the
`technology to enablc thc manufacturer to deliver new
`features and to meet the mandatory regulation require-
`ments in a cost-effective manner. Vehicle electronic
`systems arc now cnmmon place and are growing in terms
`of both quantity and complcxity. In this arlicle we take a
`glimpse under the h o ~ l of the modern vehicle to provide
`an insight into the world of automotive cleclrnnics, with
`special emphasis on lhe networking aspects ol these
`electronic systems.
`
`Developments in automotive networks
`Up until recently
`the
`in~vehiclc communication
`between simple devices such as switches and actuators
`was achieved using point~to-point wiring-resulting
`in
`bulky, expcnsivc and complicated wiring harnesses
`which were difficult to manufacture and install. With
`the expanding nuniber of features within the vehiclc the
`amount of wiring grew to a stage where the volume,
`rcliahilily and weight became a rcal problem. Vig. 1 shows
`
`Pig. 1 Growth of
`automotive
`wiring
`
`/'
`
`N
`
`othing stands still €or long in the world of
`eleclrnnics. The automotive industry is party
`to this phenomenon and is fast becoming a
`breeding gi-ound for binary electronic life
`forms. 'roday's vehicles include a complex symbiosis of
`intelligent elcclronic systems and inlegralcd mechanical
`structures. The rapid growth oi the computer industry
`has spawned a host oi modern solutions and oppor~
`tunitics for automotivc systems. It could he argued that
`the eleclronics revolution of lhc past two decades is the
`single biggcsl driving forcc behind the evolution of the
`motor car. Tooday, electronic components and systems
`account for over 20% of the cost of a high-end passenger
`car, and this percentage ligure is increasing rapidllr.
`Thc customer'is dcmanding inore and more sophisti-
`cated lealurcs at an affordable price. The autnmotive
`manulacturers we competing to mecl such customer
`demands within
`the mal-ket price envelope. New
`regulatory safety and fuel related standards (emissions,
`fuel efliciency etc.) are presenting further challenges
`
`E
`
`1400
`.g 1200
`t 1000
`
`Page 1 of 10
`
`Mercedes Exhibit 1015
`
`

`
`AUTOMOTIVE ELECTRONICS
`
`distributed network
`
`centralised network
`
`point to point
`
`electricel
`
`elwctri~ai
`
`4
`
`n
`5 c
`e<
`
` 2- C t
`
`0 -
`
`a
`
`Page 2 of 10
`
`

`
`AUTOMOTIVE ELECTRONICS
`
`the growth of vehicle wiring requirements
`for Volvo passengcr cars over nearly eight
`decades.' The problems associated with
`the vast amount of vehicle wiring can be
`summarised as follows:
`
`automotive
`
`industrial
`COnSUrnsl electrOnlCS
`communicatms
`aerospace
`
`r
`
`0
`
`7
`
`-
`
`5
`
`1
`
` ,
`
`i o
`%
`
`,
`15
`
`,
`20
`
`Fig. 3 Semiconductor consumption compound annual growth rate
`
`shrinking layout space
`manufacturing and assembly
`difficulties
`deterioration of serviceability
`the cosubcnefit ratio docs not improve
`when adding additional functions at
`the expense of extra wiring
`increased emphasis on fuel efficiency
`and performance (acceleration,
`deceleration) requires reduction in vehicle weight
`sensoriinput data being ineniciently distributed by
`multiple discrete signal channels
`the numerous connectors lead to unreliable operation,
`each link reducing the mean time between failure.
`
`networked electronic subsystems arc a vital element in
`all classes of vehicle as can be seen from Fig. 3? This
`electronics presence in vehicles is growing rapidly.
`In the USA the SAL? (Society of Automotive Ihginecrs)
`has published a scries of di~cumcnls describing recoin-
`mended practices for vehicle networking. The SAli has
`also formally classiiicd vehicle networks bascd on their
`bit transfer rates, 'bble 1 illustrates these categories.
`Specific standards exist for Class A, Class E and Class C
`networks, but the SAE has not yet defined specik
`I) networks. Ibwevel; natworlis
`which exceed a data rate o l 1 Mhitk arc often referred to
`as Class D networks.
`A typical motor vchiclc reprcsents an i:xtremely liostilc
`environment fur eleclronic equipment, subjecting this
`equipment to adverse conditions such as: nicchanical
`vibration; temperature swings from 4 0 ° C to +8o"C;
`splashes from oil, petrol and water; ice; sirong electro-
`magnetic iiclds (automotivc field strengths can be
`is around 3 Vim and industrial
`>ZOO Vim-domestic
`10 Vim); electrical spikesitransients oi both polarities
`(; il00 V); load dumps; jump starts; high humidity; dust;
`sand storms; and poiential mis-wiring ol electrical
`systems (e.g. short cii-cuits to ground or positive, reverse
`battery etc.).
`
`Table 1 Classification of automotive networks
`speed
`
`application
`
`The need to reduce the vehicle wiring content and to
`improve the distribution of control and monitoring
`[unctions within the vehicle has become apparent over
`the years and solutions for vchiclc networking started
`to emerge during the 1980s. Fig. 2 charts this historical
`progression and shows many of the early and curl-cnt
`vchiclr networking solution.' Many of the technical
`concepts for vehicle networking were borrowed fi-om
`developments in the area of computer data networks,
`but vehicle communication requirements are driven hy
`control strategies rather than by classical data transfer
`strategies.
`In the early days ol vchiclc networking devclnpment
`there was little interest in devising common networking
`standards. Many of the early networks made me of
`custom circuits and generic UART (universal asynchron-
`ous receivcritransmitter) devices to provide simple serial
`communication links. This approach was acceptable at
`the time, as then most manuiacturers were vertically
`integrated and not as highly dependent on external
`suppliers as they are today. As confidence grew and
`the benefits of adopting a standardised networking
`approach bccamc more appal-ent, external suppliers
`were commissioned
`lo develop increasingly more
`sophisticated modnlcs which finally resulted in a move
`away from proprietary interlaces in Iavour ol indnstry~
`wide standardised protocols. The standardisation of
`protocols helped Pdcilitate the integration of systems
`developed by different suppliers, leading to a type of
`'open architecture', and added a degree of coinposability
`to the system design process. In-vehicle netwoi-king was
`initially introduced in high-end luxury class models (as
`with all leading-edgc technology), but the standard-
`isation efforts which followed helped to support the
`economies of scale necessary for its introduction into
`the midrange and standard class vehicle. Today
`
`network
`classlflcatlon
`Class A
`
`4 0 kbitls
`low speed
`
`Class
`
`tO-i25 kbiffs
`medium speed
`
`Class D
`
`>I Mbiffs
`
`convenience features.
`e.g. trunk release, electric
`mirror adjustment
`general information
`transfer, e.g. instruments.
`power windows
`Class C 125 kbitis-1 Mbiffs real-time control. e.o.
`high speed
`power train. vehbe-
`dynamics
`multimedia applications,
`e.g. Internet, digital TV
`hard real-time critical
`functions, e.g. X-by-wire
`applications
`
`Page 3 of 10
`
`

`
`AUTOMOTIVE ELECTRONICS
`
`Along with the environmental considerations, aulo-
`motive network solulions require some special design
`considerations, such as:
`
`High integrity: The probahility of an undetected
`error must he negligible for the life span 01 the vehicle.
`Bounded determinism: A guaranteed upper
`threshold on message
`latency
`time for control
`problems.
`EMC compliance: Both emitted radiation levels and
`the tolerated absorption levels ninsl bc met.
`Low
`intercbnnection coun1: Each additional
`connector increases the probability of a potentially Me
`endangering fault.
`Compact connectors: The conneclor is iiften
`the largest cornponeti1 on an automotive cleclronic
`module.
`Low cost: Costs are critical. A saving of a iew pennies
`on a component is substmtial in high volume priiduc~
`tion.
`Network composability: Variations across models
`and after market exlras require a network which is
`easily expanded aiid modified.
`Fault tolerance: Communicaliiin must be restored
`when iaults arc removed and redundancy is beaiming
`importanl.
`
`The typical vehicle will have more
`than one network system
`Electronic equipment is distributed throughout a
`modern vehicle supporting a host o l functions, as
`illustrated in Vig. 4. The Iunctionality for a given
`automotive systcni is often distributed to span more than
`one network system. For example, the interplay between
`an engine management system network and the traction
`control system network needs to be carefully defined
`where, lor instance, a reduction in engine torque is
`necessary to reduce drive wheel slippage, through fuel
`and engine timing adjuslnienl. Another example is an
`intelligcnt anto~routing function, which might require
`informalion from a nninbci- of systems, gathering
`variables such as ABS whecl position data, steering
`whecl angle, GPS salellite data, and the radio RDS-TMC
`(radio data system-traffic message channel) information.
`
`Automotive network solutions
`Table 2 shows a seleclion of aulomotivc network
`solutions. Thew is a wide range of autoiiiolivc networks
`reflecting defined functional and economic niches. High-
`Bandwidth networks are used for vehicle multimedia
`applications, where cost is not excessively critical.
`Reliable, responsive networks are required for critical
`real-time control applications such as powertrain control
`
`Icip. 4 Electronic equipment in a modern motor car
`
`*,.-
`
`Page 4 of 10
`
`

`
`AUTOMOTIVE ELECTRONICS
`
`Table 2 A selection of aulomotive networks
`
`protocol
`
`affiliation
`
`application
`
`medla
`
`vw
`ABUS
`Ford
`APC
`AUTOLAN General Inst.
`BEAN
`Toyota
`CAN
`Bosch
`
`control
`audio
`control
`control
`control
`
`single wire
`twisted pair
`twisted pair
`single wire
`twisted pair
`
`Chrysier
`Chrysler
`
`sensor mux.
`sensor mux.
`
`twisted pair
`twisted pair
`
`bit
`encoding
`NRZ
`NRZ
`API
`NRZ
`NRZ &
`stuffing
`NRZ
`voltage
`
`media
`access
`contention
`CSMNCA
`masterlslave
`CSMNCD
`contention
`
`error
`detection
`bit only
`checksum
`CRC
`CRC
`CRC
`
`data field
`length
`16 bit
`64 bit
`0-64 bit
`6-88 bit
`0-64 bit
`
`may.
`bit rate
`500 kbiffs
`9.6 kbiffs
`4 Mbiffs
`10 kbiffs
`1 Mbitls
`
`CSMNCR
`polling1
`addressing
`contention
`
`masterlslave
`rnasterlslave
`
`polling
`CSMNCR
`CSMNCR
`contention
`
`masterlslave
`masterlslave
`contention
`TDMA
`
`CRC -
`
`unlimited
`1 bit
`
`-7.6 kbitis
`-1 kbiffs
`
`nia
`
`CRC
`CRC
`
`parity
`CRC
`CRC
`CRC
`
`nla
`nla
`CRC
`CRC
`
`CRC
`
`nla
`
`12 MbiVs
`
`8 bit
`16 bit
`
`9.6 kbitls
`>5 kbiffs
`
`16 bit
`8-64 bit
`8.64 bit
`0-64 bit
`
`-27.6 kbiffs
`41.6 kbitis
`10.4 kbiffs
`1 Mbitls
`
`s2046 bit 10 Mbiffs
`nla
`25 Mbiffs
`32 or 64 bit
`1 Mbiffs
`2 MbiVs
`128 bit
`
`0-64 bit
`
`1 MbiVs
`
`CCD
`csc
`
`D2B
`
`DAN
`DSi
`
`Optical Chip audiolvideo
`Consonium
`Alfa Romeo
`Motorola
`
`dashboard
`sensor mux.
`
`IVMS
`J1850PWM
`J1850VPW
`J1939
`
`Nissan
`SAE
`SAE
`SAE
`
`control
`control
`control
`control
`
`MML
`MOST
`PALMNET
`TTP
`
`VAN
`
`multimedia
`Delphi
`MOST Co-op multimedia
`Mazda
`control
`TTTech
`real-time
`controi
`control
`
`Renault &
`PSA
`
`fibre optic
`
`PWM
`
`twisted pair
`2 wire
`
`twisted pair
`2 wire
`1 wire
`twisted pair
`
`fibre optic
`fibre optic
`twisted pair
`2 channel
`
`NRZ
`voltage 8.
`current
`PWM
`PWM
`VPW
`NRZ &
`stuffing
`NRZ
`nla
`NRZ
`MFM
`
`twisted pair
`
`Manchester
`
`contention
`
`and vehicle dynamics. In such demanding control
`applications the functional needs dominate over the
`economic ones aud it is sometimes necessary to
`implement networks incoi-porating fail-saie redundancy.
`Comfort electronic systcms such as power windows,
`adjustable seats and some instrumentation require only
`modest response times which only just surpass human
`perception times. Comfort systems are far more cost
`sensitive and the associated networks and modules are
`highly tuned to be cost effective. Certain vehicle functions
`may be implemented on a very minimalist network,
`supporting simple features such as trunk release and
`central locking, where delays in the order of a second
`are acceptable. Often single wii-e networks running at
`10 Itbitis are suitable here.
`Gateways and bridges are devices employed to iuter-
`connect multi-network architectures. Gateway devices
`can connect dissimilar networks whcreas bridges are
`used to coiincct networks which havc common data link
`layer protocols. Gateways and bridges can filter data
`passing between iunctionally independent network
`segments, allowing ouly the messages required by a
`modulc on another network segment to pass through. For
`example, if the trip computer requires the fuel tank lcvel
`data in order to determine the optimum refuelling point,
`it can receive data, which may have originated on a Class
`A network node. This data may have travelled via a
`
`bridge to a Class 1% network and then via a gateway to
`a Class D network. Often diagnostic interfaces are
`optimally placed on gateway orbridge nodes for sti-ategic
`traffic monitoring.
`
`Automotive control networks
`Conventional automotive control networks are widely
`used in control systems loi- applications such as engine
`management, door control etc. These networks operate
`at moderate data rates (WE Class U or Class C). 'The
`automotive system design engineer must consider the
`functional requirements in terms of inlormation ilow,
`network bandwidth and I-csponse times. The following
`issues will require specitic consideration:
`
`9 worst case network traffic load which includes: intcr-
`network trauic; diagnosis data; etc.
`9 individual message priority assignment
`physical and logical distribution of data sinks and
`sources
`network expansion capacity for an cntirc range of
`vehicle models
`error probability and its effects oii traffic latency
`system level lM?A (iailure mode and effect analyses)
`and fault tree analyscs rcsults
`physical length constraints for network segments
`fault tolcraucc behaviour and possihlc redundancy
`
`Page 5 of 10
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`

`
`AUTOMOTIVE ELECTRONICS
`
`Fig. 5 1
`)rive by
`wire
`
`n
`
`optimum placement of bridges and gateways
`network management control schemes and associated
`traffic.
`
`the automotive industry has created and
`I'ortunately,
`is adopting market-wide standards for vehicle conlrol
`netwoi-ks in order to minimise production costs through
`mass production. A global consensus on methods and
`implementations enhances the total product development
`cycle, ullitnately inipactiiig on the filial cost to the
`consumer. CAN and 51850 arc currciitly two of the most
`successful standards for vehicle control networks.
`
`CAN
`In Europe the domiiiant vehicle control network is
`CAN (Controller Area Network). This protocol was
`developed by Robert Bosch GmbH in the inid 1980s and
`was lirst implcniented in a Mercecles Benz S-class car iii
`1991. CAN has since been adopted by inost major
`European antomotive manufacturers and a growing
`number of US ciimpanies arc now using CAN. In the
`USA in 1994 the SAE lruck and Bus Control and
`Communications subcommittee selected CAN as the
`basis lor the 51939 standard (a Class C network for
`truck and bus applicatims). The IS0 standardised CAN
`as an automolive networking protocol: IS0 11898 and
`IS0 11519~2.
`Many of the world's major scniiconductor companies
`now offer CAN implementations. It is estimated that
`tlwe are already over 140 million CAN nodes installed
`worldwide. (Although CAN was developed as a vehicle
`uetwork standard, it is interesting to note that, currently,
`the majority of CAN applications exist outside of the
`automotive industry, employed in numerous other appli~
`cations ranging irom larm machinery to photocopiers,)
`CAN may he iniplcmented as a Class A, Class B or Class
`C network
`
`J1 X50
`In the USA, the SA& adopted JlSSO as the recom~
`mended protocol for Class A and Class B networks. This
`protocol was the 1-esult of a co~opcrativc effort among
`the 'big tlirce' car companies: GM, Ford, aud Chryslcr.
`The protocol specification is a ci~mbination of GMs
`Class 2 protocol and Ford's SCI' (Standard Corporate
`Protocol). Emissions legislatioii was highly influential
`in the standardisation of J1850. The OBD-ll (On
`Board Diagnostics ll), created by CARB (California
`Air Resources Board), requires the implcnient;ition of
`diagnostic tools for emission-related systems. It specifies
`that stored fault codes should be available through a
`diagnostic port via a standard protocol, namelyJ1850 and
`thc European standard IS0 9141.
`
`High bandwidth automotive networks
`Formula One competitions are not the oiily races in the
`automotive arena. The race to introduce an automotive
`multimedia network standard is well under way. It is just
`a matter ol time before networked in-car PCs will become
`options or standard features in motor cars. Such PCs will
`provide a host ol additional lunctionality for entertaiii-
`nicnt, navigation and business applications. A number ol
`companies such as Microsoft, Saab, Mecel, Intel, Clarion
`and others arc working on their vision of the street
`computer for in-vehicle use, and have clcrnonstrated their
`work in the Personal Productivity Vehicle. Meanwhile,
`IRM, Delco, Netscape and Sun Microsystems are
`developing the Network Vehicle which uses Java as its
`operating eiivironment. The developnient of such in-car
`personal computess will support leatures such as:
`
`voice activated control cor many functions
`Internet iiccess from the car
`text to speech IS~mail reading while you 'di-ive and
`listen'
`
`Page 6 of 10
`
`

`
`AUTOMOTIVE ELECTRONICS
`
`voicemail
`auto-1-outc planner with real-time updates using the
`traffic reports from your radio's IDS or the Wcb
`advanced interactive digital audio and video features
`computer games and in-car entertainment systems for
`the back seat passengers.
`
`intertaces for vehicle systems, connectors and network
`implementations. Critical
`to
`this architecture arc
`gateways and Iirewalls, preventing I'C soltware (viruses
`etc.) or maliunctions from interfcriiig with the vehicle's
`other control and data networks. There is a clear
`incentive for companies to have their technologies
`incorporated into the vehicle multimedia standai-ds and
`Microsoft is making a significant effort with the
`The emerging technology will allow the vehicle to
`Windows CE based Auto IC, unveiled
`become a true mobile oflice or a
`in 1998. However, the automotivc
`sophisticated ramina arcade, at lhe
`-
`-
`
`press of a button. Ihwever, the
`giants arc determined to remain in the
`The emerging
`driving scat, and it is uiilikcly thit
`question of driver dislraction and the
`technology will
`they will uncharacteristically
`lie
`associated effects on safcty has yct to
`themselves to a single supplier h m
`be resolved.
`A new class of vehicle network is allow the vehicle
`the onset. From a iictwork pmpective
`it is probable that an IDB-C (Intelligcnt
`emerging to connect the forthcoming
`to become a
`in-car personal computcrs and their
`Data Bus-CAN) solution will become
`one of the adopted standards. IDlLC is
`peripherals. The Optical Chip Con-
`sortium has specilied a network called mobile Office Or a based on CANS physical and data link
`D2l3 (domestic digital bus) which is a gaming arcade at layers, but will be complemented by a
`fibre~outic based solution oiierina
`higher speed multimedia bus, almost
`the press O f a
`approximately 12 Mbilis of bancc
`certainly based on fibre-optic media,
`the MOST or MMI,
`similar
`to
`width. This network is currently used
`button
`solutions. The in-car PC is expected to
`in the new Merccdes S-Class. Oasis
`have a USB coiinection and a standard
`Silicon Systems has developed the
`MOST (media oricnted systems trans-
`IrllA (InlraRed Data Association)
`port) solution, again with a fibre-optic physical layer,
`port, leaving ample room €or peripheral expansion and
`giving a transfer rate of 25 Mbitis. Delphi Automotive
`after market upgrades.
`Systems provide a solution in the iorm of MML (mobile
`media link). Fibre-optic based MML has an impressive
`Control by wire networks
`transfer rate of 110 Mbitis.
`Networked electionic modules ai-c replacing the
`Toyota, GM, Ford, Daimler, Chrysler and Renault
`equivalent tncchanical systems! Electrical and electronic
`systems are eliminating power slecring pumps, hoses,
`founded AMIC
`(Automotive Multimedia Interface
`hydraulic fluid, drivc belts, pulleys and brake servos.
`Collahoration) in October 1998.' AMIC represents a
`Systems like E-steer (steer-by-wire) from I)elphi Auto-
`global project to standardise the vehicle multimedia
`architecture for the 21st century. The plug-and~play motive Systems will be seen in high~volume European
`vehicles in late 1999."
`'infotainment' specification will encompass software
`
`I
`
`Fig. 6 Softwerc development cycle
`
`263
`
`Page 7 of 10
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`

`
`AUTOMOTIVE ELECTRONICS
`
`X-&Wire is an EU-funded LIKITE-EURAM research
`project (contract nuinbcs BRl'RCT95-0032), which has
`rcsultcd in the design o l a novel coinputer architecture,
`TTA (time~triggered architecture), which is based on
`time~triggered tcchnology for fault-tolerant distributed
`to this
`embedded real~timc systems. Fundamental
`strategy is the communications protocol n'PG (titne-
`triggered protocol), where channel acccss control i s based
`on a 'TDMA (time division multiple acccss) scheme,
`derived isom a fault~tolerant corninon time base. I'soI.
`Hermann Kopetz at Vienna University of 'rcchnologp is
`the authority on this extremely wcll designed protocol,
`which has a bright future, not only in the automobile
`but also in the aerospace and rail industries. TTl' i s
`extremely reliable and deterministic but somewhat less
`flexible than most other automotive control networks.
`TTA has defined a network architecture to seplace the
`aiorementioned mechanical systems, Fig, 5 illustrates the
`concept. The replacement of mcchanical systems with
`elcctronic solutions potentially offcrs sevcral advantages:
`
`less expensive in volumc production
`
`simplifies manuIacturing or left~hand~drive and right-
`hand-drive vehicles
`simplifies the general assembly of vehicles
`intelligent self diagnosing systems, offering enhanced
`reliability and dependability
`less mass, thus enhancing vehicle performance
`enviroiirnentally compatible, no fluid necessary
`inore compact
`simplifies integration of auxiliary systems like active
`collision avoidance and cruise control systems.
`
`The drive-by~wirc concept is perhaps a little daunting at
`first, however, when one considers that we have been
`travelling in fly-by-wire controlled aircraft for many
`years now, drive-by-wire does not seem to be such a big
`step.
`Distributed software development for
`automotiue systems
`l'he development of distributed real-time control solt-
`ware is a challenge fot- any eiigincering design team. The
`combined hardware and software solution needs to be
`
`application
`
`OSEWCOM
`standard API
`
`/ I
`
`OSEWCOM
`standard protocols
`
`interaction
`
`management
`
`network
`
`A
`
`I
`
`ISO/OSI iayers
`
`application
`
`presentafion
`
`SeSSlO"
`rranspon
`
`network
`
`OSEWCOM
`device driver
`interface
`
`bus frame
`
`
`
`!
`t - 4
`
`1
`
`-
`
`data link layer
`
`bus 110 driver
`
`bus communication hardware
`
`I
`
`physical
`
`1
`
`network media
`
`b
`
`Fig. 7 OSEWVDX structural overvicw
`
`9HA
`
`..,..... ~, "
`
`~ - " " ~
`
`-
`
`Page 8 of 10
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`

`
`AUTOMOTIVE ELECTRONICS
`
`Fig. 8 OSEIZNDX
`independence of the
`nctwork, hardware and
`applications
`
`VDX
`
`P
`hardware
`
`platform
`
`variety ol development plaiforms such as a VME
`arrived ai in a cnst~cffective manner, which requires a
`hardwire rack, Power I'C platforms, ICs, or thc actual
`iormalised apprimch to design, prntotyping and tcsting.
`To this end rapid prototyping meihods are now hciiig
`targct hardware. Coufigurable and scaleable operaling
`introduced into the dcvelopmciit cycle for vehicle
`tbc hardware requirements
`to be
`systems alkiw
`rapid
`accurately assessed and quantified
`clectronics. The
`cmerging
`prototypingbised devclopmeiit cycle is Software testing early
`in t11c design cycle. In fact,
`sollware dcvelopmcnt can bc completed
`initialed with
`the generation of a
`automated before the final hardware is completely
`requirement aiialysis specification for
`test sequences
`system. A CASE
`+signed. I-IiL(hardware in the loop)
`the proposed
`(computer-aided software engineering)
`iniplemeiitations are possible wherc the
`dramatically
`rail-time siinulation is comprised of one
`tool assists in this analysis and leads
`-
`or more components which exist as real
`into a computer-aided design phase.
`cuts down on
`The soltware design approach
`hardware, while othcr components arc
`is
`the othervuise
`towards aii object-oriented
`moving
`simulated 21s mathematical rnodels
`model and the challenges of creating
`such as Matlab or
`using
`tools
`large-scale distributed applications caii repetitive testing Simulink.
`Soltwarc testing of the prototype
`he approached by using visual
`modclling tools such as UMI, (unified which Illay have implementation, using automated test
`modelling
`language). The ouiput
`sequciices, dramatically cuts down on
`required
`of such tools can be cross-linked to the
`lhc otherwise repetitive testing which
`engineering documentation activity so trials. in the car
`hitherto iray have rccquired actual trials
`in the car. Based on the cvaluaiion ol the
`that both cncle imolcmentalkin. textual
`implementation pcrlormaiicc the loop iterates until ready
`spccilications and system diagrams are combiiicd as
`lo proceed directly io early target rcsiclent cxecutable
`different views of the same system.
`As Vig. 6 illustrates thc conventional appinach of path
`code.
`necausc software has now been assigned such an
`U is being replaced by the interactive method, path A.
`important role in automotive systems, standardised
`Automatic code generation
`irom
`the specification
`soltware layers arc being delined for vehicle networks.
`rcpresentations of the system is now possible, oltcn
`leading to pre-production quality soltwarc code. The
`Such layers ollcr iunctioiiality such as ~iperatiiigsystcms,
`communicatioii interlace systems and network manage-
`resuliing code must be tested in a hardware ciivirnnment.
`ment systems. The recent developments in the area of
`Here perhaps the most powerful advances are being
`made. Thc prototype soltwarc can bc executed on a
`OSBI</VI)X provide a good examplc ol such an approach.
`
`Page 9 of 10
`
`

`
`AUTOMOTIVE ELECTRONICS
`
`QSEKfVDX
`In May 1993, OSEK was iniliated as a joint project by
`a number of companics within the German automotive
`industry OSb;K aims to achieve a standard open-ended
`architecture for distributed control units within vehicles.
`OSEK is an abbreviation for the German term 'Offene
`Systeme und deren Schnittstellen lur die Eleklronic im
`Ihftiahrzcug'. The Engish equivalent is: 'open systems
`and the corresponding interfaces [or automotive elcc-
`tronics'. The Ft-ench car manufaclurers I'SA and Renault
`were working on a similar project, the VDX-approach
`(Vehicle Distributed executive), and they joined OSEK
`in 1994, giving rise to the OSEKNDX standard.
`OSEKIVDX aims to specily a standardised interface lo
`allow the gelling together of hardware modules, network
`soflware in a co-ordinated and
`protocols and applic&n
`intelligent fashion.
`OSEWVDX specifics a series of interlaces, which
`allows for the development of soflware components,
`which are portableand reusable. Pig. 7 shows a structural
`overview of OSEKNIlX.7 The soltware application
`interface specification is abstracted from thc harcluwe
`and the network involved. This concept is illustratcd in
`Fig. 8. Functionality is both configurahle and scaleable,
`enabling optimum tuning ol architecture and application.
`The specification facilitates functional verification and
`validation. Because the API (application programming
`inteiiace) is standardised, development on various
`platforms without the need to learn a new too1 set is
`possible, resulting in a clear saving on development time.
`Software from different suppliers can now co-hahitate
`within a single microcontroller.
`Itor the first time the potential for real co-operation
`between the various system suppliers is made possible,
`where traditionally products were developed indcpen-
`denlly, and rivalry rather than co-operation was the order
`of the day. Now those who hold the purse strings are
`changing the rules somewhat.
`OSEWDX realises a distributed operating environ~
`ment wilhin the vehicle, based on the same principles used
`to implement distributed operating environments within
`large data networks. OSEKNDXs ultimale goal is to
`reduce costs by enabling theueationofre-usablcembcdded
`application sohare. The PC industry has shown that once
`an adopted operating system standard is in place, producls
`become far mot-e commercially competitive.
`However, it is worth noting that the flexibility offered
`by the OSE1WI)X approach has some cost implications
`in terms of additional ROM, RAM and processor over-
`head. If OSEK compliant software implementations
`demand higher specification processors, then cost saving,
`in terms of soltware reuse, in thc short term may be more
`than oUset by additional hardware costs accrued over
`millions of units! Nevertheless, future silicon prices will
`decrease, and the benefits cif reusable, mature and
`validaled software, in the long term, is probably worth
`the initial investment.
`
`It is interesting to note that thc aerospace induslry
`has expressed considerable interest in the OSEKNDX
`developments, viewing it as a potential solution to lheir
`similar problem set.
`
`Conclusions
`Vehicle nelworks were invented by necessity to resolve
`the problems associated with bulk wiring harnesses.
`However, thc coming of aulomotive networks has opened
`up new opporlunities for the industry. Control networks
`are now well eshblished in high~end vehicles and are
`quickly liltering down to all vehicle classes.
`Whereas control networks operate behind lhe scenes,
`as far as lhe driver and passeugei-s are concerned, it is the
`high-bandwidth multiinedia networks, which will have
`the biggest impact (in customer perceptions, offcring new
`concepts in in-vehicle work and entertainment features.
`Control-bywire solutions will provide new engineering
`solutions and challenges, where car users will need lo
`trust electronics to guarantee their safety in the absencc
`of the tricd and tested mechanical systems. The service
`and maintenance industry and the average car enthusiast
`will have to find room in their toolboxes €or a PC!
`Software development is becoming as important as
`engine design or chassis design in lhe automotive design
`process. Soon we should expect to see the emcsgence of
`aulomotive specific software suppliers and a possiblc
`redirection of emphases within existing supplier
`companies.
`Automotive related industries should benefit from the
`standardisation of vehicle network architectures and
`software environmcnls. At thc end of the day the ultimate
`winner will be the consumer.
`
`Acknowledgment
`The assistance of PE1 'rechnologies, University of
`Limerick, is greatly appreciated.
`
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`3 'Making il right bcfnre you Piit it on boat#, Su~ge Neiu.sicller 1st
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`Ire