Create Data Dependent State Behavior

Data dependent state behavior allows you to design Stateflow charts that respond to changes in data values. By connecting state transitions and actions to data conditions, you can create systems that adapt to input signals and internal variables.

Design States That Respond to Data Changes

States can respond to data in several ways:

1. Transition between states based on data conditions

2. Execute different actions based on data values

3. Use data to control timing and sequencing

To implement data dependent behavior:

1. Define data objects in your chart

2. Create conditions that use these data objects

3. Associate conditions with transitions or state actions

4. Implement detection mechanisms for data changes

Implement Conditional State Actions

State actions can execute conditionally based on data values.

For charts that use C as the action language, use transitions and junctions to implement conditional logic instead of control statements.

Use with Local State Data

Each state can maintain local data to track its internal conditions:

1. Define local data in the Stateflow chart

2. Use entry actions to initialize data

3. Use during actions to update data

4. Use exit actions to save final data values

Detect Data Changes

Stateflow provides operators to detect when data changes:

1. hasChanged(data) - Detects any change in value

2. hasChangedTo(data, value) - Detects change to a specific value

3. hasChangedFrom(data, value) - Detects change from a specific value

Monitor Signal Edges

For analog signals, edge detection operators identify when values cross thresholds:

1. rising(expression) - Detects when expression changes from negative to positive

2. falling(expression) - Detects when expression changes from positive to negative

3. crossing(expression) - Detects any zero crossing

Create Robust Data Processing

To handle data reliably:

1. Initialize all data before use

2. Consider the effects of data type conversion

3. Handle boundary conditions and invalid values

4. Use temporal logic to reduce sensitivity to noise

5. Document data dependencies for maintenance

By implementing data dependent state behavior, you can create responsive systems that adapt to changing conditions while maintaining the structure and clarity of state machine design.