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Specify this S-function drives a function-call subsystem attached to interrupt service routines


Specifies that the S-function is driving function-call subsystems attached to interrupt service routines. This option applies only to S-functions that have no input ports during code generation and 1 output port. During simulation, the S-function may have an input port to provide a condition on which to execute. The output port must be configured to perform function calls on every element. If any of these requirements is not met, the SS_OPTION_ASYNCHRONOUS option is ignored. Specifying this option

  • Informs the Simulink® engine that there is no implied data dependency involving the data sources or destinations of the function-call subsystem called by the S-function.

  • Causes the function-call subsystem attached to the S-function to be colored purple, indicating that it does not execute at a periodic rate.

  • Enables additional checks to verify that the model is constructed correctly.

    1. The engine validates that the appropriate asynchronous rate transition blocks reside between the purple function-call subsystem. The engine also checks that period tasks exists. You can directly read and write from the function-call subsystem by using a block that has no computational overhead. To ensure safe task transitions between period and asynchronous tasks, use the SS_OPTION_ASYNC_RATE_TRANSITION option.

    2. For data transfers between two asynchronously executed (purple) function-call subsystem, the engine validates that the appropriate asynchronous task transition blocks exits.

Introduced in R2007b

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