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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Operators

Change Detection

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

Edge Detection

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

Message Activity

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

State Activity

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

Data Type Conversion

cast	Convert numeric value to different numeric data type
`boolean`	Convert numeric value to Boolean value
`ascii2str`	Convert array of type `uint8` to string
`str2ascii`	Convert string to array of type `uint8`
`str2double`	Convert string to double-precision value in Stateflow chart
`string`	Convert value to string in Stateflow chart
`tostring`	Convert value to string
`type`	Type of Stateflow data object

String Creation and Concatenation

`blanks`	Character array of spaces
`plus`	Concatenate strings in Stateflow chart
`strcpy`	Assign string value
`strcat`	Concatenate strings

Properties of String Data

`isletter`	Determine which characters are letters in Stateflow chart
`isspace`	Determine which characters are spaces in Stateflow chart
`isstring`	Determine if input is string in Stateflow chart
`strlen`	Determine length of string
`strlength`	Determine length of string in Stateflow chart

Find and Replace Substrings

`contains`	Determine if string contains substring in Stateflow chart
`startsWith`	Determine if string starts with substring in Stateflow chart
`endsWith`	Determine if string ends with substring in Stateflow chart
`strfind`	Find substring within a string in Stateflow chart
`extractAfter`	Extract substring after position in Stateflow chart
`extractBefore`	Extract substring before position in Stateflow chart
`substr`	Extract substring from string
`replace`	Find and replace substrings in Stateflow chart
`replaceBetween`	Replace substrings between start and end points in Stateflow chart
`strrep`	Find and replace substrings in Stateflow chart
`erase`	Delete substrings within strings in Stateflow chart
`eraseBetween`	Delete substring between start and end points in Stateflow chart
`insertAfter`	Insert string after substring in Stateflow chart
`insertBefore`	Insert string before substring in Stateflow chart

Edit String Data

`lower`	Convert string to lowercase in Stateflow chart
`upper`	Convert a string to uppercase in Stateflow chart
`reverse`	Reverse order of characters in strings in Stateflow chart
`strip`	Remove leading and trailing characters from string in Stateflow chart
`strtrim`	Remove leading and trailing white space from string in Stateflow chart

Compare String Data

`matches`	Determine if two strings match in Stateflow chart
`strcmp`	Compare strings in Stateflow chart (case sensitive)
`strcmpi`	Compare strings in Stateflow chart (case insensitive)
`strncmp`	Compare first N characters of strings in Stateflow chart (case sensitive)
`strncmpi`	Compare first N characters of strings in Stateflow chart (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
`every`	Execute chart at regular intervals
`duration`	Time during which condition is valid in Stateflow chart
`elapsed`	Time since state became active
`count`	Number of chart executions during which condition is valid
`temporalCount`	Number of events, chart executions, or time since state became active

Interface with MATLAB Code

this Access chart data during simulation

Topics

Differences Between MATLAB and C as Action Language Syntax

Compare the functionality of the chart action languages.
- Operations for Stateflow Data
- Supported Symbols in Actions
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.
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.
Reduce Transient Signals by Using Debouncing Logic
Design state machines that are resilient to rapidly changing signals.
Control Oscillations by Using the duration Operator
Simplify debouncing logic in charts that have transient signals.

Featured Examples

Model Bang-Bang Temperature Control System

Model a bang-bang control system that regulates the temperature of a boiler.

Open Model

Implement an Automatic Transmission Gear System that Controls Transient Signals

Use debouncing logic to filter out transient signals that do not represent a true change of state.

Open Model

Simulate a Media Player

Use enumerated data and strings to define the behavior of a media player.

Open Model

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:

Open Model

Model an Automatic Transmission Controller

Model an automotive drivetrain by using Simulink^® and Stateflow.

Open Model

Count Events by Using the temporalCount Operator

Count occurrences of explicit and implicit events.

Open Model