Syntax for States and Transitions

Express chart behavior by using actions and conditions

Control the execution of your Stateflow^® chart by specifying when transitions between states occur and when actions are executed. Synchronize state execution by broadcasting events. Detect changes in data values and check which states are active during chart execution.

Blocks

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Stateflow Blocks

Chart	Implement control logic with finite state machine
State Transition Table	Represent modal logic in tabular format
Truth Table	Represent logical decision-making behavior with conditions, decisions, and actions

Stateflow Syntax

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Graphical Objects

Self-Loop Transitions

History Junctions

Operators

Change Detection

change	Generate implicit event when data changes value
hasChanged	Detect change in data since last time step
hasChangedFrom	Detect change in data from specified value
hasChangedTo	Detect change in data to specified value

Edge Detection

crossing	Detect rising or falling edge in data since last time step
falling	Detect falling edge in data since last time step
rising	Detect rising edge in data since last time step

Message Activity

discard	Discard message
forward	Forward message
isvalid	Determine if message is valid
length	Determine length of message queue
receive	Extract message from queue
send	Broadcast message or event

State Activity

enter	Generate implicit event when state becomes active
exit	Generate implicit event when state becomes inactive
in	Check state activity in Stateflow

Create, Concatenate, and Convert String Data

ascii2str	Convert array of type `uint8` to string
blanks	Create a character array of blanks
double	Convert string to double precision value
isletter	Determine which characters are letters
isspace	Determine which characters are space characters
str2ascii	Convert string to array of type `uint8`
str2double	Convert string to double-precision value
strcat	Concatenate strings
strcmp	Compare strings
string	Create a string
tostring	Convert numeric value to string

Determine Types and Properties String Data

isletter	Determine which characters are letters
isspace	Determine which characters are space characters
isstring	Determine if input is string
strlen	Determine length of string
strlength	Length of string

Find and Replace String Data

contains	Determine if pattern is in a string
endsWith	Determine if strings end with pattern
matches	Determine if pattern matches string
replace	Find and replace one or more substring
replaceBetween	Replace substrings between start and end points
startsWith	Determine if strings start with pattern
strfind	Find strings within other strings
strrep	Find and replace substrings

Edit String Data

erase	Delete substrings within strings
eraseBetween	Delete substring between start and end points
extractAfter	Extract substring after specified positions
extractBefore	Extract substring before specified positions
insertAfter	Insert string after specified substring
insertBefore	Insert string before specified substring
lower	Convert string to lowercase
plus	Append strings
reverse	Reverse order of characters in strings
strcpy	Assign string value
strip	Remove leading and trailing characters from string
strtrim	Remove leading and trailing white space from a string
substr	Extract substring from string
upper	Convert a string to uppercase

Compare String Data

matches	Determine if pattern matches string
strcmp	Compare strings
strcmpi	Compare strings (case insensitive)
strncmp	Compare first `n` characters of strings (case sensitive)
strncmpi	Compare first `n` characters of strings (case insensitive)

Temporal Logic

after	Execute chart after event broadcast or specified time
at	Execute chart at event broadcast or specified time
before	Execute chart before event broadcast or specified time
count	Chart executions during which condition is valid
duration	Time during which condition is valid
elapsed	Time since state became active
every	Execute chart at regular intervals
temporalCount	Number of events, chart executions, or time since state became active

Topics

Guidelines for Naming Stateflow Objects

Reserved keywords, name length restrictions, and naming limitations.

Eliminate Redundant Code by Combining State Actions

Combine entry, during, and exit actions in a state.

Control Function-Call Subsystems by Using bind Actions

Bind a function-call output event to the activity of a state.

Combine Transitions and Junctions to Create Branching Paths

Create decision points in transition paths.

Supported Operations for Chart Data

Perform mathematical computations in Stateflow charts.

Supported Symbols in Actions

Special symbols available for state and transition actions.

Call Extrinsic MATLAB Functions in Stateflow Charts

Access MATLAB^® functions that are not supported for code generation.

Access MATLAB Functions and Workspace Data in C Charts

Call built-in MATLAB functions by using the ml operator.

Call C Library Functions in C Charts

Access C functions in state and transition labels.

Check State Activity by Using the in Operator

Determine if a state is active during chart execution.

Detect Changes in Data and Expression Values

Define chart behavior when data and expressions change value between time steps.

Control Chart Execution by Using Temporal Logic

Use event-based and absolute-time temporal logic operators.

Control Chart Behavior by Using Implicit Events

Trigger chart actions by changes in data values and state activity.

Control Oscillations by Using the duration Operator

Simplify debouncing logic in charts that have transient signals.

Related Information

MATLAB as the Action Language

Featured Examples

Model Bang-Bang Temperature Control System

Model a bang-bang control system that regulates the temperature of a boiler. The model has two components: Boiler Plant Model is a Simulink® subsystem the models the boiler dynamics.

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Implement an Automatic Transmission Gear System by Using the duration Operator

Models an automotive transmission system by using the Stateflow® temporal logic operator duration to automatically shift gears based on the vehicle's throttle requirements and speed. For more information, see Control Chart Execution by Using Temporal Logic.

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Simulate a Media Player

Use string data to define the behavior of a media player.

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Design a Game by Using Stateflow

Implement the game of Tetris by using a Stateflow® chart. This model is a redesigned version of the classic Stateflow demo sf_tetris. The new design incorporates these programming paradigms: Parallel decomposition to separate pre- and post-processing tasks from the main game control logic.

Open Model

Modeling an Automatic Transmission Controller

Model an automotive drivetrain with Simulink®. Stateflow® enhances the Simulink model with its representation of the transmission control logic. Simulink provides a powerful environment for the modeling and simulation of dynamic systems and processes. In many systems, though, supervisory functions like changing modes or invoking new gain schedules must respond to events that may occur and conditions that develop over time. As a result, the environment requires a language capable of managing these multiple modes and developing conditions. In the following example, Stateflow shows its strength in this capacity by performing the function of gear selection in an automatic transmission. This function is combined with the drivetrain dynamics in a natural and intuitive manner by incorporating a Stateflow block in the Simulink block diagram.

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