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Asynchronous Task Specification

Specify priority of asynchronous task represented by referenced model triggered by asynchronous interrupt

  • Asynchronous Task Specification block

Simulink Coder / Asynchronous


The Asynchronous Task Specification block specifies parameters, such as the task priority, of an asynchronous task represented by a function-call subsystem with a trigger from an asynchronous interrupt. Use this block to control scheduling of function-call subsystems with triggers from asynchronous events. You control the scheduling by assigning a priority to each function-call subsystem within a referenced model.

To use this block, follow the procedure in Convert Asynchronous Subsystem to a Referenced Model.

Observe in the figure:

  • The block must reside in a referenced model between a root-level Inport block and a function-call subsystem. The Asynchronous Task Specification block must immediately follow and connect directly to the Inport block. The combination of these two blocks constitutes the modeling style known as JMAAB-B.

  • The Inport block must receive an interrupt signal from an Async Interrupt block that is in the parent model.

  • The Inport block must be configured to receive and send function-call trigger signals.

How to use Asynchronous Task Specification block



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Interrupt input signal received from a root-level Inport block.


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Interrupt signal with specified task priority that triggers a function-call subsystem.


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Specify an integer or [] as the priority of the asynchronous task that calls the connected function-call subsystem. The priority must be a value that generates relevant rate transition behaviors.

  • If you specify an integer, it must match the priority value of the interrupt signal initiator in the parent model.

  • If you specify [], the priority does not have to match the priority of the interrupt signal initiator in the top model. The rate transition algorithm is conservative (not optimized). The priority is unknown but static.

Consider the following model.

The referenced model has the following content.

If the Task priority parameter is set to 10, the Async Interrupt block in the parent model must also have a priority of 10. If the parameter is set to [], the priority of the Async Interrupt block can be a value other than 10.

Version History

Introduced in R2011a