To define the values that control variation points in an AUTOSAR software component, components use the following AUTOSAR elements:
SwSystemconst — Defines a system constant that
serves as an input to control a variation point.
SwSystemconstantValueSet — Specifies a set of system
constant values to apply to an AUTOSAR software component.
PredefinedVariant — Describes a combination of
system constant values, among potentially multiple valid combinations, to apply
to an AUTOSAR software component.
For example, in ARXML code, you can define
SwSystemconsts for automobile features, such as
Transmission, Headlight,
Sunroof, and Turbocharge. Then a
PredefinedVariant can map feature combinations to automobile
model variants, such as Basic, Economy,
Senior, Sportive, and
Junior.
Suppose that you have an ARXML specification of an AUTOSAR software
component. If the ARXML files also define a
PredefinedVariant or SwSystemconstantValueSets
for controlling variation points in the component, you can resolve the variation points
at model creation time. Specify a PredefinedVariant or
SwSystemconstantValueSets with which the importer can initialize
SwSystemconst data.
Typical steps include:
Get a list of the PredefinedVariants or
SwSystemconstantValueSets defined in the
ARXML file.
>> obj = arxml.importer('mySWC.arxml');
>> find(obj,'/','PredefinedVariant','PathType','FullyQualified');
ans =
'/pkg/body/Variants/Basic'
'/pkg/body/Variants/Economy'
'/pkg/body/Variants/Senior'
'/pkg/body/Variants/Sportive'
'/pkg/body/Variants/Junior'>> obj = arxml.importer('mySWC.arxml');
>> find(obj,'/','SystemConstValueSet','PathType','FullyQualified')
ans =
'/pkg/body/SystemConstantValues/A'
'/pkg/body/SystemConstantValues/B'
'/pkg/body/SystemConstantValues/C'
'/pkg/body/SystemConstantValues/D'Create a model from the ARXML file, and specify a
PredefinedVariant or one or more
SwSystemconstantValueSets.
This example specifies PredefinedVariant Senior, which
describes a combination of values for Transmission,
Headlight, Sunroof, and
Turbocharge.
>> createComponentAsModel(obj,compNames{1},'ModelPeriodicRunnablesAs','AtomicSubsystem',...
'PredefinedVariant','/pkg/body/Variants/Senior');This example specifies SwSystemconstantValueSets A and B,
which together provide values for SwSystemconsts in the
AUTOSAR software component.
>> createComponentAsModel(obj,compNames{1},'ModelPeriodicRunnablesAs','AtomicSubsystem',...
'SystemConstValueSets',{'/pkg/body/SystemConstantValues/A','/pkg/body/SystemConstantValues/B'});During model creation, the ARXML importer creates
AUTOSAR.Parameter data objects, with Storage
class set to SystemConstant. The
importer initializes the system constant data with values based on the specified
PredefinedVariant or
SwSystemconstantValueSets.
After model creation, you can run simulations and generate code based on the combination of variation point input values that you specified.
In Simulink®, you can redefine the SwSystemconst data that controls
variation points without recreating the model. Call the AUTOSAR property function
createSystemConstants, and specify a different imported
PredefinedVariant or a different cell array of
SwSystemconstantValueSets. The function creates a set of system
constant data objects with the same names as the original objects. You can run
simulations and generate code based on the revised combination of variation point input
values.
This example creates a set of system constant data objects with names and values based
on imported PredefinedVariant
'/pkg/body/Variants/Economy'.
arProps = autosar.api.getAUTOSARProperties(hModel); createSystemConstants(arProps,'/pkg/body/Variants/Economy');
Building the model exports previously imported PredefinedVariants
and SwSystemconstantValueSets to ARXML
code.