Task: Specify Top-Level Functional Design Architecture |
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This task defines the top-level functions, and their interfaces, of the functional design architecture to be implemented in software. |
Disciplines: Core Tasks |
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Purpose
The purpose of this task is to define the functions of the functional design
architecture, which are identified for implementation in software, and to define their interfaces.
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Relationships
Roles | Primary Performer:
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Inputs | Mandatory:
| Optional:
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Outputs |
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Process Usage |
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Main Description
The realization of the FAA on design level relies on the FDA. The Functions and the LocalDeviceManagers of the FDA
represent the functionality that will eventually be application software in ECUs. The Functional Design Architecture
contains Functions and LocalDeviceManagers and their connections. This task specifies the top-level structure of such
Functions and their interfaces.
The top-level structure may be based on functionality, responsibility, legacy, etc. depending on engineering decisions.
To define the Functional Design Architecture, type definitions of Functions and LocalDeviceManagers necessary to realize
the FAA are either defined or existing types are identified. FunctionPrototypes for each of these are then defined, and
their ports are connected with Connectors.
The top-level definition of the FDA involves an adaptation of the ”ideal” abstract solution in the FAA. Adaptations are
necessary to realize the same solution in the presence of resource constraints, allocation concerns, communication,
hardware interfacing, sourcing, dependability, etc.
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Steps
Specify top-level design functions
Specify design functions from analysis functions in the FAA that have been identified for implementation in software,
according to the HW/SW assignment. The resulting specification shall after this step include top-level design functions,
their external interfaces and a textual description of their behaviour and intent. The specification process involves
structuring and decomposition of analysis functions to meet needs on allocation, sourcing, re-use, criticality,
performance, etc. |
Specify top-level local device managers
Specify local device managers to interface sensors and actuators. These participate in realizing the FunctionalDevices of
the FAA. |
Specify top-level hardware functions
Specify hardware functions to provide the overall behaviour of sensors, actuators and other functions to be implemented in
hardware, according to the HW/SW assignment. |
Specify top-level BSW functions
Specify the BSW functions needed for assessing the feasibility of the design at the design level. Implementation-specific
BSW that have no impact on design level need not be defined. |
Connect Function Prototypes
This step adds Connectors between ports of the interfaces of the functions in the
FDA. After this step, the functional design architecture is ideally fully connected.
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Identify design constraints
Design constraints that need to be posed on the overall architecture, and particularly on specific functions, are
identified, assessed and documented in the dedicated work product. Such constraints could, for instance, relate to
performance and limited hardware resources. |
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