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Actions take place as part of Stateflow chart execution. The action can be executed as part of a transition from one state to another, or depending on the activity status of a state. Transitions can have condition actions and transition actions as shown.
Action language defines the categories of actions you can specify and their associated notations. For example, states can have entry, during, exit, and on event_name actions as shown.
An action can be a function call, a broadcast event, a variable assignment, and so on. For more information on actions and action language, see Using Actions in Stateflow Charts.
Format you can use to access and communicate with an application program from a programming or script environment.
Graphical object that groups together other graphical objects in your chart. For details about how a box affects chart execution, see Using Boxes to Extend Charts.
| Name | Icon in the Stateflow Editor | Description |
| Box |
 | Graphically organizes states, transitions, and other graphical objects in your chart. |
Link from a Stateflow model to a chart stored in a Simulink library. A chart in a library can have many chart instances. Updating the chart in the library automatically updates all the instances of that chart.
Boolean expression to specify that a transition occurs if the specified expression is true. For example,
In the preceding example, assume that the state second is active. If an event occurs and the value for the data speed is greater than the value of the data threshold, the transition between states second and third is taken, and the state third becomes active.
Illustrates decision points in the system. A connective junction is a graphical object that simplifies Stateflow chart representations and facilitates generation of efficient code. Connective junctions provide different ways to represent desired system behavior.
This example shows how connective junctions (displayed as small circles) represent the decision flow of an if code structure.
| Name | Icon in the Stateflow Editor | Description |
| Connective junction |
 | Handles situations where transitions out of one state into two or more states can occur based on the same event, but different conditions guard the transitions. |
See Connective Junctions for more information.
Data objects store numerical values for reference in the Stateflow chart.
See Adding Data for more information on representing data objects.
See Stateflow Debugger.
A state has a decomposition when it consists of one or more substates. A Stateflow chart that contains at least one state also has decomposition. Rules govern how you can group states in the hierarchy. A superstate has either parallel (AND) or exclusive (OR) decomposition. All substates at a particular level in the hierarchy must be of the same decomposition.
Parallel (AND) State Decomposition
Parallel (AND) state decomposition applies when states have dashed borders. This decomposition describes states at that same level in the hierarchy that can be active at the same time. The activity within parallel states is essentially independent.
Exclusive (OR) State Decomposition
Exclusive (OR) state decomposition applies when states have solid borders. This decomposition describes states that are mutually exclusive. Only one state at the same level in the hierarchy can be active at a time.
Primarily used to specify which exclusive (OR) state is to be entered when there is ambiguity among two or more neighboring exclusive (OR) states. For example, default transitions specify which substate of a superstate with exclusive (OR) decomposition the system enters by default in the absence of any other information. Default transitions are also used to specify that a junction should be entered by default. A default transition is represented by selecting the default transition object from the Stateflow Editor toolbar and then dropping it to attach to a destination object. The default transition object is a transition with a destination but no source object.
| Name | Icon in the Stateflow Editor | Description |
|---|---|---|
| Default transition |
 | Indicates, when entering this level in the hierarchy, which state becomes active by default. |
See Default Transitions for more information.
A function that works with a rich subset of the MATLAB programming language. You can use an Embedded MATLAB function to call MATLAB functions in a Stateflow chart.
| Name | Icon in the Stateflow Editor | Description |
| Embedded MATLAB function |
 | Calls MATLAB functions in a Stateflow chart. |
See Using Embedded MATLAB Functions in Stateflow Charts for more information.
Events drive the Stateflow chart execution. All events that affect the Stateflow chart must be defined. The occurrence of an event causes the status of the states in the Stateflow chart to be evaluated. The broadcast of an event can trigger a transition to occur and/or can trigger an action to be executed. Events are broadcast in a top-down manner starting from the event's parent in the hierarchy.
Events are added, removed, and edited through the Model Explorer. See How Events Work in Stateflow Charts for more information.
Tool to search for objects in Stateflow charts on platforms that do not support the Simulink Find tool. See Stateflow Finder.
Representation of an event-driven system. FSMs are also used to describe reactive systems. In an event-driven or reactive system, the system transitions from one mode or state to another prescribed mode or state, provided that the condition defining the change is true.
Set of decision flow paths that start from a transition segment that, in turn, starts from a state or a default transition segment.
Ordered sequence of transition segments and junctions where each succeeding segment starts on the junction that terminated the previous segment.
Set of decision flow paths that start on the same transition segment.
Function whose logic is defined by a flow graph. See Using Graphical Functions to Extend Actions.
Hierarchy enables you to organize complex systems by placing states within other higher-level states. A hierarchical design usually reduces the number of transitions and produces neat, more manageable charts. See Stateflow Hierarchy of Objects for more information.
Specifies the destination substate of a transition based on historical information. If a superstate has a history junction, the transition to the destination substate is defined to be the substate that was most recently visited. The history junction applies to the level of the hierarchy in which it appears.
| Name | Icon in the Stateflow Editor | Description |
|---|---|---|
| History junction |
 | Indicates, when entering this level in the hierarchy, that the last state that was active becomes the next state to be active. |
See these sections for more information:
Transition that does not exit the source state. Inner transitions are most powerful when defined for superstates with exclusive (OR) decomposition. Use of inner transitions can greatly simplify a Stateflow chart.
See Inner Transitions and Inner Transition to a History Junction Example for more information.
Link to a chart that is stored in a library model in a Simulink block library.
Stateflow model that is stored in a Simulink library. You can include charts from a library in your model by copying them. When you copy a chart from a library into your model, you create only a link to the library chart. You can create multiple links to a single chart. Each link is called a chart instance. When you include a chart from a library in your model, you also include its Stateflow machine. Thus, a Stateflow model that includes links to library charts has multiple Stateflow machines.
When you simulate a model that includes charts from a library model, you include all charts from the library model even if links exist only for some of its models. However, when you generate an embedded or standalone custom target, you include only those charts for which there are links. You can simulate a model that includes links to a library model only if all charts in the library model are free of parse and compile errors.
Collection of all Stateflow blocks defined by a Simulink model. This excludes chart instances from library links. If a model includes any library links, it also includes the Stateflow machines defined by the models from which the links originate.
An industry-standard paradigm for modeling finite-state machines, where output is a function of both inputs and state. See Building Mealy and Moore Charts for more information.
Use to add, remove, and modify data, event, and target objects in the Stateflow hierarchy. See Using the Model Explorer with Stateflow Objects for more information.
An industry-standard paradigm for modeling finite-state machines, where output is a function only of state. See Building Mealy and Moore Charts for more information.
Defines a set of objects and the rules that govern the relationships between those objects. Stateflow chart notation provides a way to communicate the design information in a Stateflow chart.
Stateflow chart notation consists of
A set of graphical objects
A set of nongraphical text-based objects
Defined relationships between those objects
A system with parallelism can have two or more states that can be active at the same time. The activity of parallel states is essentially independent. Parallelism is represented with a parallel (AND) state decomposition.
See State Decomposition for more information.
When you simulate a Simulink model containing Stateflow charts, you generate an S-function (MEX-file) for each Stateflow machine. This generated code is a simulation target.
For more information, see S-Function MEX-Files.
Semantics describe how the notation is interpreted and implemented behind the scenes. A completed Stateflow chart communicates how the system will behave. A Stateflow chart contains actions associated with transitions and states. The semantics describe in what sequence these actions take place during Stateflow chart execution.
Graphical object in a Stateflow chart that you fill with Simulink blocks and call in the actions of states and transitions. This function provides an efficient model design and improves readability by minimizing the graphical and nongraphical objects required in a model. In a Stateflow chart, this function acts like a function-call subsystem block of a Simulink model.
See Using Simulink Functions in Stateflow Charts for more information.
A state describes a mode of a reactive system. A reactive system has many possible states. States in a Stateflow chart represent these modes. The activity or inactivity of the states dynamically changes based on transitions among events and conditions.
Every state has hierarchy. In a Stateflow chart consisting of a single state, the parent of that state is the Stateflow chart itself. A state also has history that applies to its level of hierarchy in the Stateflow chart. States can have actions that execute in a sequence based upon action type. The action types are entry, during, exit, or on event_name actions.
| Name | Icon in the Stateflow Editor | Description |
|---|---|---|
| State |
 | Depicts a mode of the system. |
Masked Simulink model that is equivalent to an empty, untitled Stateflow chart. Use the Stateflow block to include a Stateflow chart in a Simulink model.
The control behavior modeled by a Stateflow block complements the algorithmic behavior modeled in Simulink block diagrams. By incorporating Stateflow blocks into Simulink models, you can add complex event-driven behavior to Simulink simulations. You create models that represent both data and decision flow by combining Stateflow blocks with the standard Simulink and toolbox block libraries.
A Stateflow chart is a graphical representation of a finite state machine where states and transitions form the basic building blocks of the system. See Stateflow Charts and Simulink Models for more information on Stateflow charts.
Use to debug and animate your Stateflow charts. Each state in the Stateflow chart simulation is evaluated for overall code coverage. This coverage analysis is done automatically when the target is compiled and built with the debug options. The Debugger can also be used to perform dynamic checking. The Debugger operates on the Stateflow machine.
Use this interface to create, modify, or delete states, transitions, and other graphical objects in your Stateflow chart. The toolbar icons represent objects that you can drag and drop into your chart.
Use to display a list of objects based on search criteria you specify. You can directly access the properties dialog box of any object in the search output display by clicking that object. See Finding Stateflow Objects for more information.
Chart contained by another chart. See Using Subcharts to Extend Charts.
A state is a substate if it is contained by a superstate.
A state is a superstate if it contains other states, called substates.
Transition between objects residing in different subcharts. See Using Supertransitions to Extend Transitions for more information.
A container object for the generated code from the Stateflow charts in a model. The collection of all Stateflow charts for a model appears as a Stateflow machine. Therefore, target objects belong to the Stateflow machine.
The code generation process can produce these target types: simulation, embeddable, and custom. See Building Targets for more information.
The circumstances under which the system moves from one state to another. Either end of a transition can be attached to a source and a destination object. The source is where the transition begins and the destination is where the transition ends. It is often the occurrence of some event that causes a transition to take place.
Flow path that starts and ends on a state.
A state-to-junction, junction-to-junction, or junction-to-state part of a complete state-to-state transition. Transition segments are sometimes loosely referred to as transitions.
Function that specifies logical behavior with conditions, decisions, and actions. Truth tables are easier to program and maintain than graphical functions.
| Name | Icon in the Stateflow Editor | Description |
| Truth table |
 | Tabular method of specifying logical behavior with conditions, decisions, and actions. |
See Truth Table Functions for instructions on how to use truth tables in Stateflow charts.
Use this option to set a value by scrolling through a list of choices. When you move the mouse over a menu item with a virtual scrollbar, the cursor changes to a line with a double arrowhead. Virtual scrollbars are either vertical or horizontal. The direction is indicated by the positioning of the arrowheads. Drag the mouse either horizontally or vertically to change the value.
 | Directed Event Broadcasting Examples |
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