Stateflow®

Default Transition Examples

Default Transition in Exclusive (OR) Decomposition Example

This example shows a transition from an OR state to a superstate with exclusive (OR) decomposition, where a default transition to a substate is defined.

Initially, the Stateflow^® chart is asleep. State A is active. Event E_one occurs and awakens the chart. Event E_one is processed from the root of the chart down through the hierarchy of the chart:

1. The Stateflow chart root checks to see if there is a valid transition as a result of E_one. There is a valid transition from state A to superstate B.

2. State A exit actions (exitA()) execute and complete.

3. State A is marked inactive.

4. The transition action, A, is executed and completed.

5. State B is marked active.

6. State B entry actions (entB()) execute and complete.

7. State B detects a valid default transition to state B.B1.

8. State B.B1 is marked active.

9. State B.B1 entry actions (entB1()) execute and complete.

10. The chart goes back to sleep.

This sequence completes the execution of this Stateflow chart associated with event E_one when state A is initially active.

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Default Transition to a Junction Example

The following example shows the behavior of a default transition to a connective junction.

Initially, the Stateflow chart is asleep. State B.B1 is active. An event occurs and awakens the chart. Condition [C_two] is true. The event is processed from the root of the chart down through the hierarchy of the chart:

1. State B checks to see if there is a valid transition as a result of any event. There is none.

2. State B1 during actions (durB1()) execute and complete.

This sequence completes the execution of this Stateflow chart associated with the occurrence of any event.

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Default Transition and a History Junction Example

This example shows the behavior of a superstate with a default transition and a history junction.

Initially, the Stateflow chart is asleep. State A is active. There is a history junction and state B4 was the last active substate of superstate B. Event E_one occurs and awakens the chart. Event E_one is processed from the root of the chart down through the hierarchy of the chart:

1. The Stateflow chart root checks to see if there is a valid transition as a result of E_one.

   There is a valid transition from state A to superstate B.

2. State A exit actions (exitA()) execute and complete.

3. State A is marked inactive.

4. State B is marked active.

5. State B entry actions (entB()) execute and complete.

6. State B uses the history junction to determine the substate destination of the transition into the superstate.

   The history junction indicates that substate B.B4 was the last active substate, which becomes the destination of the transition.

7. State B.B4 is marked active.

8. State B.B4 entry actions (entB4()) execute and complete.

9. The chart goes back to sleep.

This sequence completes the execution of this Stateflow chart associated with event E_one.

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Labeled Default Transitions Example

This example shows the use of a default transition with a label.

Initially, the Stateflow chart is asleep. State A is active. Event E_one occurs, awakening the chart. Event E_one is processed from the root of the chart down through the hierarchy of the chart with the following steps:

1. The Stateflow chart root checks to see if there is a valid transition as a result of E_one.

   There is a valid transition from state A to superstate B. The transition is valid if event E_one or E_two occurs.

2. State A exit actions execute and complete (exitA()).

3. State A is marked inactive.

4. State B is marked active.

5. State B entry actions execute and complete (entB()).

6. State B detects a valid default transition to state B.B1. The default transition is valid as a result of E_one.

7. State B.B1 is marked active.

8. State B.B1 entry actions execute and complete (entB1()).

9. The chart goes back to sleep.

This sequence completes the execution of this Stateflow chart associated with event E_one when state A is initially active.

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Condition Action Examples

Inner Transition Examples