Image Processing Reference
In-Depth Information
VNA is the top-level tool in the Volcano automotive groups tool chain for designing vehicle
network systems. he tool chain supports important aspects of systems engineering such as
•
Use of functional modeling tools
•
Partitioning of responsibilities
•
Abstracting away from hardware and protocol-specific details providing a signal-based
API for the application developer
•
Abstractingawayfromthenetworktopologythroughautomaticgatewayingbetween
different networks
•
Automatic frame compilation to ensure that all declared requirements are fulfilled (if
possible), that is, delivering correctness by design
•
Reconfiguration flexibility by supporting post-compile-time reconfiguration capability
The VNA tool supports network design and makes management and maintenance of distributed
network solutions more eicient. he tool support capturing of requirements and then takes the user
through all stages of network definition.
19.15.1 Car OEM Tool Chain: One Example
Increasing competition and complex electrical architectures demands enhanced processes. Function
modeling has proved to be a suitable tool to capture the functional needs in a vehicle. Tools such as
Rational Rose provide a good foundation to capture all different functions and other tools (Statemate,
Simulink) model them in order to allocate objects and functionality in the vehicle. Networking is
essential since the functionality is distributed among a number of ECUs in the vehicle. Substantial
parts of the outcome from the function modeling are highly suitable to use as input to a network
design tool such as VNA.
The amount of information required to properly define the networks are vast. To support input of
data, VNA provides an automated import from third party tools through an XML-based format.
It is the job of the signal database administrator/system integrator to ensure that all data entered
into the system are valid and internally consistent. VNA supports this task through a built-in
multilevel consistency checker that verifies all data.
In this particular approach the network is designed by the system integrator in close contact with
the different function owners in order to capture all necessary signaling requirements—functional
andnonfunctional(includingtiming).WhentherequirementsareagreedanddocumentedinVNA,
the system integrator uses VNA to pack all signals into frames, this can be done manually or
automatically. The algorithm used by VNA handles gatewaying by partitioning end-to-end timing
requirements into requirements per network segment.
All requirements are captured in the form of a Microsot Word document called software require-
ment specification (SWRS) that is generated by VNA and sent to the different node owners as a draft
copy to be signed off. When all SWRS has been signed off, VNA automatically creates all neces-
sary configuration files used in the vehicle along with a variety of files for third party analysis and
measurement tools.
The network level (global) configuration files are used as input to the Volcano configuration tool
and Volcano back-end tool in order to generate a set of downloadable binary configuration files for
each node. he use of reconfigurable nodes makes the system very flexible since the Volcano concept
separates application-dependent information and network-dependent information. A change in the
network by the system integrator can easily be applied to a vehicle without having to recompile the
application software in the nodes. The connection between function modeling and VNA provide
good support for iterative design. It verifies network consistency and timing up front, to ensure a
predictable and deterministic network.
