SS_OPTION_ASYNCHRONOUS

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

Description

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.