Learn more about Stateflow

How Events Work in Stateflow Charts

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What Is an Event? When to Use Events Types of Events Where You Can Use Events

What Is an Event?

An event is a Stateflow object that can trigger actions in one of these objects:

• A Simulink triggered subsystem

• A Simulink function-call subsystem

• A Stateflow chart

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When to Use Events

Use events when you want to do one of the following:

• Activate a Simulink triggered subsystem (see Using Edge Triggers to Activate a Simulink Block)

• Activate a Simulink function-call subsystem (see Using Function Calls to Activate a Simulink Block)

• Trigger actions in parallel states of a Stateflow chart (see Broadcasting Events in Actions)

Although Stateflow software does not limit the number of events you can use in a chart, the underlying C compiler enforces a theoretical limit of (2^31)-1 events for the generated code.

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Types of Events

An explicit event is an event that you define and can have one of the following scopes.

Scope	Description
Local	Event that can occur anywhere in a Stateflow machine but is visible only in the parent object (and descendants of the parent). See Directed Event Broadcasting.
Input from Simulink	Event that occurs in a Simulink block but is broadcast to a Stateflow chart. See Using Input Events to Activate a Stateflow Chart.
Output to Simulink	Event that occurs in a Stateflow chart but is broadcast to a Simulink block. See Using Output Events to Activate a Simulink Block.

An implicit event is a built-in event that broadcasts automatically during chart execution (see Using Implicit Events).

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Where You Can Use Events

You can define explicit events at these levels of the Stateflow hierarchy.

An event you define in a...	Is visible to...
Chart	The chart and all states and substates
Subchart	The subchart and all states and substates
State	The state and all substates

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Defining Events

How to Define Events

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