For demos, application examples, tutorials, user stories, and pricing:

• Visit www.mathworks.com

• Contact The MathWorks directly

US & Canada 508-647-7000

Benelux +31 (0)182 53 76 44France +33 (0)1 41 14 67 14Germany +49 (0)241 470 750Italy +39 (011) 2274 700Korea +82 (0)2 6006 5114Spain +34 93 362 13 00Sweden +46 (8)505 317 00Switzerland +41 (0)31 950 60 20UK +44 (0)1223 423 200

Visit www.mathworks.com to obtain contact information for authorized MathWorks representatives in countries throughout Asia Pacific, Latin America, the Middle East, Africa, and the rest of Europe.

Stateflow® is an interactive design and simulation

tool for event-driven systems. Stateflow pro-

vides the language elements required to describe

complex logic in a natural, readable, and under-

standable form. It is tightly integrated with

MATLAB® and Simulink®, providing an efficient

environment for designing embedded systems that

contain control, supervisory, and mode logic.

Stateflow charts enable the graphical representa-

tion of hierarchical and parallel states and the

event-driven transitions between them. Stateflow

augments traditional statecharts with the innova-

tive capabilities of control flow, MATLAB and

graphical functions, truth tables, temporal opera-

tors, directed-event broadcasting, and support for

integrating hand-written C code.

You can automatically generate C code from

Stateflow charts using Stateflow® Coder (available

separately).

Stateflow® 6Design and simulate event-driven systems

KEY FEATURES■ Provides language elements, hierarchy, parallelism, and deter-

ministic execution semantics for describing complex logic in a

natural and understandable form

■ Defines functions graphically, using flow diagrams; procedurally,

using the MATLAB language; and in tabular form, with truth tables

■ Schedules transitions and events using temporal operators

■ Incorporates custom and legacy C code with input and output

arguments

■ Supports vector, matrix, and fixed-point data types

■ Provides viewing and logging of states and data

■ Animates Stateflow charts to enhance understanding of the

system and facilitate debugging

■ Performs static checks, including checks for ill-specified truth tables

■ Performs run-time checks for transition conflicts, cyclic problems,

state inconsistencies, data-range violations, and overflow conditions

■ Includes an integrated debugger for setting graphical break-

points, stepping through models, and browsing data

The fault detection, isolation, and recovery system of an aircraft elevator. You can use Simulink and Stateflow to simulate and study the effects of switching modes on the control system and aircraft dynamics.

elev_pos pos_bus

Signal Conditioning

and

Fault Detection

modes

left positions

right positions

control points

Pilot Commands and Control

low_press

R_pos_fail

L_pos_fail

LDL_mode

Mode Logic

modes

control points

hydraulic pressures

elevator positions

Hyraulic Acutators

and Elevators

3

<low_press>

44

42

<R_pos_fail>

2

<L_pos_fail>

2

<Left positions>

{14}

{14}

{14}

{14}

2

<Right positions>

2

3

3

<hydraulic pressure>

2{2

2{2}elev_pos pos_bus

low_press

R_pos_fail

L_pos_fail

LDL_mode

3

<low_press>

42

<R_pos_fail><R_pos_fail>

2

<L_pos_fail>

{14} {14} {14} {14} {14}

{14} {14}

Working with StateflowStateflow is part of an integrated simulation

environment in which you can model, simu-

late, and analyze complex dynamic systems.

By using Stateflow with Simulink, you can

create models of your embedded software

that combine the logical behavior (such as

fault detection and mode switching) with

the algorithmic behavior (such as feedback

control and signal conditioning). You can

also create a model of the system and its

environment in Simulink and run hybrid

simulations to study the interactions

between the two.

Simulink model of the same system, incorporating the electric motor (modeled in SimPowerSystems) and the window mechanism (modeled in SimMechanics) to determine the load on the motor and enable the logic to detect obstacles in the window’s path.

Stateflow chart of the control logic for a power window system.

Window_Switches

Window_Mechanics

Visulization

Driver Up

Driver Down

Passenger Up

Passenger Down

Obstacle

Test Cases

DOC

Requirements

obstacle

position

velocity

force

Obstacle_Effects

Motor_and_Electronics

Convert(SI) IaADC

driver_up

driver_down

passenger_up

passenger_down

moveUp

moveDown

Control

Logicon tick: switches();

Remain in Stop state until a NEUTRALevent triggers Stop.Mode to be Ready. go()

function switches()

truthtable

Fail safe time out after continuousmovement of more than five secondsStop /

go.neutral();

EmergencyDown /go.down();

Moveentry: obstacles.init();on tick: obstacles.detect();

EndStopAtTop /go.down();

Position 2 Direction 1

Error

Mode 1

AtBottom /go.up();

obstacles() function

Mode 2

ErrorNearBottom Up /go.up();

NearTop

Down /go.down();

NotSureYet

Ready

Auto

Waiting

NotSureWhere

Manual

NEUTRALafter(FAILSAFE_TIMEOUT,tick)

UP | DOWN DOWN[~in(Down)]

DOWN[in(AtTop)]

after(_70ms,tick)

UP [in(Ready)] UP[~in(Up)]

NEUTRAL[in(Manual)]

[after(_1s,tick)] en(Direction.Up) | ...en(Direction.Down)

NEUTRALOBSTACLE NEUTRAL

[after(_200ms,tick) ...& before(_1s,tick)]

after(_1s,tick)[in(Direction.Down)] ENDSTOP

4x4 Switch

Packet Contents:1) 92) Total length (>=5)3) Destination4) Source5) Data (Integer):Length-1) Data (Integer)Length) 0

1/z

0

0

0

Dummy Event

Dummy Event

Dummy Event

Dummy Event

Clock

Fifos

Selector

Fifo

Start_Popping

SchedulerPacket Generator

Packet Generator

Packet Generator

Packet Generator Vert Cat

[Fifo_Select]

[Start_Popping_1]

[Fifo_Out_2]

[Fifo_Out_1]

[Input_3]

[Dest1]

[Start_Popping_4]

[Input_2]

[Dest4]

[Tick_Out4]

[Tick_In4]

[Input_4] [Status_4]

[Fifo_Out_4]

[Tick_Out3][Tick_Out2][Tick_Out1]

[Tick][Tick_In1]

[Start_Popping_3]

[Dest3]

[Dest2]

[Tick_In3][Tick_In2]

[Status_3]

[Status_2]

[Start_Popping_2]

[Status_1]

[Fifo_Out_3]

[Input_1]

GlobalCloc

Fifo_Select]

rt_Popping_

[Tick_In2]

Fifo_Select]

[Input_2]

[Dest1]

[Dest4]

[Input_4]

[Tick_Out4][Dest4]

Fifo_Out_4]

Fifo_Select]

[Tick_In1]

[Tick_In4]

rt_Popping_

[Tick_Out3[Dest3]

[Tick_Out2[Dest2]

[Tick_Out1][Dest1]

[Dest3][Dest2]

Fifo_Out_3]

Fifo_Out_2]

Fifo_Out_1]

art_Popping_2

Fifo_Select]

[Tick_In3]

[Input_3]

rt_Popping_

[Input_1]

Clock

In

Pop

Fifo

Out

Status

FIFOManager

#4

Fifo

Out

Status

FIFOManager

#3

Out

Status

FIFOManager

#2

ClockOut

Status

FIFOManager

#1

Clock

In

Pop

Fifo

Out

Status

FIFOManager

#4

Clock

In

Pop

Fifo

Out

Status

FIFOManager

#3

Clock

In

Pop

Fifo

Out

Status

FIFOManager

#2

Clock

In

Pop

Fifo

Out

Status

FIFOManager

#1

emu

emu

U

E1

U(E)

Crossbar

Packet_In

[4x1]

[5x1]

4

4

Input 1Input 2Input 3

Output 3

Output 1Output 2

[3x4]

3

3

3

4

4

3{3}

3{3}

3{3}

3 3{3}

Output 4

Input 4

1/z

0

0

0

Dummy Event

Dummy Event

Dummy Event

Dummy Event

Clock

Fifos

Selector

Fifo

Start_Popping

Scheduler

Vert Cat

[Fifo_Select[Fifo_Select]

[Start_Popping_1][Start_Popping_1]

[Dest1]

[Start_Popping_4][Start_Popping_4]

[Dest4]

[Tick_Out4[Tick_Out4]

[Tick_In4]

[Tick_Out3[Tick_Out3][Tick_Out2[Tick_Out2][Tick_Out1[Tick_Out1]

[Tick][Tick_In1]

[Start_Popping_3][Start_Popping_3]

[Dest3]

[Dest2]

[Tick_In3][Tick_In2]

[Start_Popping_2][Start_Popping_2]

GlobalCloc

[Tick_Out4[Tick_Out4]][Dest4][Dest4]

Fifo_Out_4]Fifo_Out_4]Fifo_Out_4]

[Tick_Out3[Tick_Out3[Dest3][Dest3]

[Tick_Out2[Tick_Out2[Dest2][Dest2]

[Tick_Out1[Tick_Out1][Dest1][Dest1]

Fifo_Out_3]Fifo_Out_3]Fifo_Out_3]

Fifo_Out_2]Fifo_Out_2]Fifo_Out_2]

Fifo_Out_1]Fifo_Out_1]Fifo_Out_1]

Clock

In

Pop

Fifo

Out

Status

FIFOManager

#4

Fifo

Out

Status

FIFOManager

#3

Out

Status

FIFOManager

#2

ClockOut

Status

FIFOManager

#1

emememu

emememu

U

E1

U(E)

Crossbar

[4x1]

[5x1]

4

4

[3x4] 4

4

3{3}

3{3}

3{3}

3{3}

AutoPush 1 Queue 2

PacketState 4

AutoPop 3

Idle

DeQueue function

NonEmpty

PacketInen:Queue.Push;

EnQueue function

Tempen:Queue.Push;

Full

Idle

Empty

Nees gap of 2 between packets

Empty

PacketReadyLenOut=Fifo[LenLoc];Dst=Fifo[DstLoc];

PacketNotReadyPacketInen:Queue.Pop;

[strt==End]PacketStart

Pop[!in(Queue.Empty)]{DeQueue();}

after(LenIn41,Tick)...{PacketState.PacketPushed;}

Tick{LenIn=DataIn;}

Tick{Queue.Push;} Push[!in(Queue.Full)]{EnQueue();}

[strt==End]

after(LenOut,Tick){PacketState.PacketPopped;}

StartPopping[WhichFifo==My_Number]{UsingSwitch=1;PacketState.PacketNotReady;} PacketPushed

{NumPackets++;} [NumPackets==0]

PacketPopped{NumPackets44;UsingSwitch=0;}

PacketPushed{NumPackets++;}

PacketNotReadyPacketPushed{NumPackets++;}

Tick/Queue.Pop;

Simulink model of a packet switch used in data network-ing applications. Stateflow defines the queue and control logic for the FIFO Manager.

Creating Stateflow ChartsA Stateflow chart is a graphical representation

of a finite state machine where states and tran-

sitions form the building blocks of the system.

You create a Stateflow chart by dragging states,

junctions, and functions from the toolbar into

the drawing window. You can then create

transitions and flow by connecting states and

junctions together. You can reduce a complex

chart to a set of simpler, hierarchically

organized diagrams by using subcharts.

Stateflow features several interactive tools for

creating and modifying charts. These include:

A Stateflow diagram editor that provides

shortcut menus, navigation and command

toolbars, zoom controls, and other produc-

tivity enhancers

A Symbol Autocreation Wizard that lets you

define nongraphical objects

A debugger that controls animation of your

Stateflow charts and provides extensive capa-

bilities for examining simulation results and

locating and diagnosing unexpected behavior

in your Stateflow chart

Stateflow uses the Model Explorer in

Simulink to create data, events, and targets

and to navigate, search, and configure the

attributes of all Stateflow objects.

Adding FunctionsStateflow lets you include functions within

your statechart. You can define and use

three types of functions:

Graphical functions let you graphi-

cally program an algorithm and track its

behavior during simulation.

Embedded MATLAB functions let you call

MATLAB functions for data analysis and

visualization. You can also use an embedded

subset of the MATLAB language to define

embedded, matrix-oriented algorithms.

Truth tables let you specify functions with

combinational logic in a concise, tabular

form without drawing flow diagrams.

You can control the execution of Simulink

function-call subsystems from Stateflow,

letting you call Simulink subsystems like a

function. You can also incorporate existing

hand-written C code functions into your

Stateflow chart.

A truth table is used to implement the logic to select a valid sensor reading in a fault-detection algorithm.

Stateflow chart defining the logic for a boiler temperature control system that uses temporal logic to ensure that the boiler does not overheat. An embedded MATLAB function (above) and graphical functions (right side of chart) implement utility algorithms called by the heater system (left side of chart).

b = cold() function

turn_boiler(mode) eM

flash_LED() function

Heater

On

Offentry: turn_boiler(OFF)on every(5,sec): flash_LED()

after(20,sec) after(40,sec)[cold()]

{LED=OFF}

[Heater.On.warm()]

{LED=color}

[LED==OFF]

{ b = temp<=reference}

Specifying Temporal Logic ConditionsStateflow employs an event-scheduling

mechanism that generates accurate and effi-

cient code for event-driven systems. You can

use temporal operators (“before”, “after”, “at”,

and “every”) to specify scheduling logic for

transition and state activities. These tempo-

ral logic conditions operate on occurrence

counts of Stateflow events, freeing you from

the error-prone event-scheduling tasks of

handling timers and counters.

Creating Chart LibrariesBy creating a chart library in Stateflow, you

facilitate chart reuse. For example, when you

update a chart in a library, all instances of the

chart are automatically updated.

Interfacing with Simulink You can exchange events and data with

Simulink by simply:

• Adding and defining input and output

events and data for your Stateflow chart in

the Model Explorer

• Connecting the Stateflow input and output

ports to Simulink blocks

• Defining simulation parameters in Simulink

You can also define an interface between a

Stateflow block and code sources external to

the Stateflow block and Simulink model.

The Model Explorer lets you navigate, create, configure, and search all data, events, and attributes of your Stateflow chart, as well as create an interface with Simulink.

The logic for a fault-tolerant fuel system, defined using several key Stateflow elements.

[in(O2_normal)]

enter(MultiFail)

[in(FL1)]

[in(FL1)]

[in(FL0)]

DEC

[ speed > max_speed ]

INCINC INCINC

DECDECDEC

[!in(MultiFail)]

exit(MultiFail)

Warmup

Rich_Mixtureentry: fuel_mode = RICH

Single_Failure

Low_Emissionsentry: fuel_mode = LOW

Normal

Running

FL0

Fuel_Disabled

Fueling_Mode 2

FL1 FL2

Sens_Failure_Counter 1MultiFail

FL3 FL4

H

H

ParallelismState

Transition

History

Action

Junction

Hierarchy

Condition

Subchart

Supertransition

Using the floating scope from Simulink, you can view state transitions as the simulation runs.

Executing Stateflow ChartsAfter modeling your logic in Stateflow, you

can simulate and view its behavior live to test

and validate your design. A graphical debug-

ger helps you resolve simulation run-time

errors and diagnose unexpected behavior in

your design.

Visualizing ResultsYou can visualize the Stateflow chart during

simulation by:

• Highlighting the active states and the

transition paths taken

• Viewing states and data with the displays

and scopes provided in Simulink

• Building your own custom displays using

MATLAB visualization and graphical user

interface development tools

You can also log states and data for post-

processing.

Debugging a SimulationThe Stateflow debugger lets you set break-

points, control the simulation execution,

and display model information. It can be

run from a graphical user interface (GUI) or

from the MATLAB command line. The GUI

provides clear information about the chart’s

execution status. You can display information

on breakpoints, current data values, active

states, and the call stack.

Run-time errors can also be detected with the

debugger. These include state inconsistencies,

transition conflicts, data range, potential infi-

nite loops, and ill-specified truth tables.

For demos, application examples, tutorials, user stories, and pricing:

• Visit www.mathworks.com

• Contact The MathWorks directly

US & Canada 508-647-7000

Benelux +31 (0)182 53 76 44France +33 (0)1 41 14 67 14Germany +49 (0)241 470 750Italy +39 (011) 2274 700Korea +82 (0)2 6006 5114Spain +34 93 362 13 00Sweden +46 (8)505 317 00Switzerland +41 (0)31 950 60 20UK +44 (0)1223 423 200

Visit www.mathworks.com to obtain contact information for authorized MathWorks representatives in countries throughout Asia Pacific, Latin America, the Middle East, Africa, and the rest of Europe.

Validating your DesignYou can map requirements directly to

Stateflow objects and collect model cover-

age metrics using Simulink Verification and

Validation (available separately).

Generating CodeStateflow charts can be deployed to many

applications using Stateflow Coder (available

separately).

Required ProductsMATLABSimulink

Related ProductsReal-Time Workshop. Generate optimized,

portable, and customizable C code from

Simulink models

Simulink® Verification and Validation. Develop designs and test cases mapped to

requirements and measure test coverage

Stateflow Coder. Generate C code for

Stateflow charts

For more information on related products,

visit www.mathworks.com/products/stateflow

Platform and System RequirementsFor platform and system requirements, visit

www.mathworks.com/products/stateflow ■

Tel: 508.647.7000 info@mathworks.com www.mathworks.com 9397v05 05/04

© 2004 by The MathWorks, Inc. MATLAB, Simulink, Stateflow, Handle Graphics, and Real-Time Workshop are registered trademarks, and TargetBox is a trademark of The MathWorks, Inc. Other product or brand names are trademarks or registered trademarks of their respective holders.

The Stateflow debugger can set breakpoints, start and stop simulations, evaluate run-time errors, and perform dynamic error checking.