Instance Parameters Tab (View Menu) (Qsys)

You can use instance parameters to modify a Qsys system when you use the system as a subcomponent in another Qsys system. The higher-level Qsys system can assign values to these instance parameters. You create a Tcl instance script to apply these parameters to subcomponents in the system.

When you click the Preview Instance button, Qsys creates a preview of the current Qsys system with the specified parameters and instance script, and opens the Parameter Editor for the instance. In the editor, you can see how the instance of your system appears when you use it as a subcomponent in other Qsys systems. The instance preview does not affect the saved system.

• Instance Parameters—Allows you to define parameters for instances of your Qsys system. Each column in the table allows you to configure a property of the parameter.
• Name—The name of the parameter.
• Display Name—The name that appears in the parameter editor.
• Type—The parameter type, either integer or string.
• Default Value—The integer or string default value.
• Allowed Range—The range of valid values for the parameter. The following formats are allowed for integer and string parameters:

• Description—Description of the parameter.
• Add Parameter—Allows you to add a new instance parameter.
• Remove Parameter—Removes the selected parameter(s).
• Instance Script—Allows you to enter your parameterization Tcl script. The script allows you to query the parameters defined for the system, and sets the parameter values for subcomponent instances in the system. For example, the following script sets the parameter DATA_WIDTH in the subcomponent named "child0" to the value of the SYSTEM_DATA_WIDTH parameter:

package require -exact qsys <version number> set_module_property COMPOSITION_CALLBACK compose proc compose {}
{
set x [ get_parameter_value SYSTEM_DATA_WIDTH ] set_instance_parameter_value child0 DATA_WIDTH $x
}

}

• Preview Instance—Allows you to preview an instance with your parameter declarations, and the instance script.

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