1. STATE MACHINE AND CONCURRENT
PROCESS MODEL

2. INTRODUCTION
MODELS vs LANGUAGES
FINITE STATE MACHINE WITH DATA PATH MODEL
USING STATE MACHINES
PROGRAM STATE MACHINE MODEL
CONCURRENT PROCESS MODEL
CONCURRENT PROCESSES
COMMUNICATION AMONG PROCESSES
IMPLEMENTATION
DATA FLOW MODEL
REAL TIME SYSTEMS

3. Describing the processing behavior Assembly Language
Implementation
Processor
Describing the processing behavior
Assembly Language
High level languages
Uses sequential computational model
Increasing the complexity of ES
Needs advanced computational models

4. Common method of describing the system
Uses English language
computation model assists the designer
understand and describe the behavior by providing means to compose the behavior from simpler objects.

5. 1. Sequential program model
MODELS COMMONLY USED FOR DESCRIBING THE EMBEDDED SYSTEMS
1. Sequential program model
It provides a set of statements, rules for putting statements one after other, semantics stating how statements are executed one at a time.
2. Communication process model
it supports description of multiple sequential programs running concurrently
3. State machine model
it is used commonly for control dominated systems. Control dominated system is the one whose behavior consists mostly of monitoring control inputs and reacting by setting control outputs.

6. Data flow model
It is used for data dominated systems. The system behavior consists of transforming streams of input data into streams of output data
Object oriented model
which provides an elegant means for breaking complex software into simpler and well defined pieces
State
Machine
Seq.
Program
Data
Flow
Poetry
Recipe
Story
English
Spanish
Japanese C
C++
JAVA
Sequential program / c
Model vs English

7. Models vs languages
A computation model describes the desired system behavior while language captures models
A model is a conceptual notion while a language captures that concept in the concrete form.
A sequential program is a model, a conceptual notion consisting of a set of program instructions for computing something , and a notion of how to sequence among those instructions.
Sequential program can be captured in any of the following languages like C, C++ or java .
Particular language can capture many different models other than sequential programs such as state machines or data flow models.
other languages such as C and assembly languages are more suited in some applications.

8. Recipes Vs English
Poetry
Recipe
Story
English
Spanish
Japanese

9. Sequential program vs C
State Machine
Sequential Program
Data flow C
C ++
Java

10. TEXTUAL LANGUAGES vs. GRAPHICAL LANGUAGES
Methods to capture models
Text and graphs
State machine model
Captured in textual language
Captured in graphical language

11. TEXTUAL LANGUAGES vs. GRAPHICAL LANGUAGES
Languages may use variety of methods to capture models such as Text or Graphics.
The choice of textual language vs. graphical language is entirely independent of the computational model used.
Thee graphical language uses icons of objects, and icons for tasks.
Graphical sequential languages were commonly proposed in 1980’s but have not become very popular.
The state machine model is often captured in textual languages but it is also commonly captured in graphical languages

12. Button inside the elevatorUp
Down
Open
Floor
Unit control
req
Request resolver B2 B3 Bn
Button inside the elevator
Up1
Up2
Dn2
Up3
Dn3
Dn N
Up, Down Buttons on each floor

13. Void unitcontrol () {
up = down = 0; open = 1;
while(1)
while(req == floor) ;
Open = 0;
If( req > floor ) { up =1;}
Else { down = 1; }
While( req != floor)
up = down =0;
open = 1 ;
delay (1); }
Void response resolver () {
While (1)
Req = ; }
Void main()
Unitcontrol();
and
Responseresolver();

14. A BASIC STATE MACHINE MODEL : FINITE STATE MACHINE
A finite state machine model:
The system behavior can be described as a set of possible states.
System can also be described possible transitions from one state to another state depending on the input values.
Describe the actions that occur when in a state or transitioning between states.

15. THE FINITE STATE MACHINE CAN BE EXPRESSED AS 6 TUPLE
REQ > FLOOR
!( REQ > FLOOR)
GOING UP
U, D, O, T =
TIMER < 10
REQ > FLOOR
!(TIMER < 10)
IDLE
DOOR OPEN
U, D, O, T =
REQ = FLOOR
REQ < FLOOR
U, D, O, T =
GOING DN
U, D, O, T =
REQ < FLOOR
THE FINITE STATE MACHINE CAN BE EXPRESSED AS 6 TUPLE
F < ( S, I, O, F, H, so) S is the set of states, I is the set of inputs, O is the set of outputs, F is the next state function ( S x I -> S ), H is an output function S-> O maping current state to outputs. so is the initial state.

16. S is the set os states {so, s1, s2, ………}
I is the set of inputs { i0, i1, i2, …….,im}
O is the set of out put states { o0,o1, o2, ………,on}
Often FSM is used to describe the single purpose processor
The hardware is synchronous reg. updates are synchronized to clock pulse.
The FSM every transition condition and with clock.

17. Finite state machine with data path model
In an embedded system the inputs and outputs are Boolean type.
This is sufficient for many control system applications.ne as set states
For more complex data type the FSM is extended with data path model.
The possible FSMD model is a
F<S , I, O, V, F, H, So>
Describe the machine behavior as a state machine and
List all possible steps giving each descriptive name.
Declare all variables
For each state list the possible transitions, list the associated conditions.
For each state or transition list the associated actions
For each stat ensure that existing transition conditions are exclusive

18. COMPARING THE STATE MACHINE AND PROGRAMMING LANGUAGE
The state machine model is appropriative over sequential program model for describing control based system.
It encourages the designer to think of all possible states of the system and to think of all possible transition among the states based on the possible input conditions.
It provides the more natural means of computing for each case.
In the sequential program model the system is designed to transform the data through a series of instructions that may be initiated or conditionally executed.
It encourages a different way of
thinking the behavior of the system.

19. #define IDLE 0
#define UP 1
#define DN 2
#define OPEN 3
void unitcontrol() {
int stae=IDLE;
While(1) {
IDLE:
up=0; down=0; open = 1;staRT =0;
if(req==floor) { state = IDLE;}
if(req > floor) { state = UP;}
if(req < floor) {state = DN;}
break;
UP:
up=1; down=0; open = 0; timerstart=0;
if(!(req > floor)) {state = OPEN;}
DN:
up=1; down=0; open = 0; timerstart=0;
if(req < floor) { state = DN;}
if(!(req < floor)) {state = OPEN;}
break;
OPEN:
up=0; down=0; open =1; timerstart=1;
if(timer < 10) { state = OPEN;}
if(!(timer < 10)) {state = IDLE;} }

20. HCFSM and the state charts language
Hierarchy extension in HCFSM allows to decompose the state machine into another state machine or a group of states into a new hierarchical states.
Going up
Idle
Door open
Hierarrc hy
Going dn
Fire Going dn
Fire door open
With out hierarchy

21. Going up Idle Door open Going dn Fire mode Fire Going dn
Fire door open

22. Using concurrency in HCFSM
! Fire Fire
Unit control
Request resolver
Normal mode
Fire Mode
Using concurrency in HCFSM

23. If(req>floor){up=1;}
PROGRAM STATE MACHINE MODEL
Elevator control
It allows the programmer to use sequential code to define state actions, including extensions for the complex data types and variables.
It includes hierarchy and concurrency.
A SPM having only one state is called program state terminology.
A PSM having many states whose actions are just assignment statements is equivalent to HCFSM.
Unit control
Normal mode
Up=dn=0; open =1
While(1){
While(req==floor){
Open =0;
If(req>floor){up=1;}
Else {dn=1;}
While(req !=floor)
Open=1;
Delay(10);
Req. resolver
req
fire
!fire
Fire mode
Up=0; dn=1; open=0
While(floor >1) ;
Up=0;down=0; open =1

24. ROLE OF APPROPRIATE MODEL AND LANGUAGE
PSM INCLUDES TWO TYPES OF TRANSITIONS.
Transition takes immediately if the condition is true.
Transition immediately
Transition on completion
Transition takes ones the requested task is completed.
ROLE OF APPROPRIATE MODEL AND LANGUAGE
Model represent the system while the language captures the model.
Language have constructs which captures the model.

25. CONCURRENT PROCESS MODEL
A systems functionality is described using multiple computation models
It allows to describe the functionality of a system in terms of two or more concurrently executing sub tasks.
It uses the multitasking scheme.
State machine
Seq. program
Data flow
Concurrent process
Pascal
C/C++
Java
VHDL
Implementation A
implementation B
Implementation C

26. The choice of the computation model is based on the designer to describe the system.
The choice of the language is to capture the computation model used by the designer
The choice of implementation is based on whether it meets power and size and cost requirements.

27. Heart beat monitoring system
Task :1
Read pulse
If pulse is lo then
Activate siren
If pulse > hi
Sleep 1 sec
repeat
Task :2
If B1/B2 pressed then
Lo = Lo+/- 1
If B3/B4 pressed then
Hi = Hi+/- 1
Sleep 500 ms
Set top box system
Task :1
Read signal
Separate audio/video
Send audio to task :2
Send video to task :3
repeat
Task :2
Wait on task 1
Decode/output audio
Task :3
Wait on task 2
Decode/output video
repeat

28. Process create and terminate. Process suspend and resume. Process join
BASIC OPERATIONS DEFINED BY THE CONCURRENT PROCESS MODEL
Process create and terminate.
Process suspend and resume.
Process join
COMMUNICATION AMONG PROCESSES
Shared memory.
Message passing.

29. SYNCHRONIZATION AMONG PROCESSES
One process must wait for another process to compute a value reach a point in execution, or signal some condition before it proceeds.
Synchronization among concurrently executing processes is to use a construct : condition variables such as signal and wait..
One method to achieve synchronization is to monitor:
It is nothing but collection of data and methods that operate on this data similar to an object in oop

30. X terminated and y is allowed Y waits and x is allowed
X waits and y is allowed
X is allowed y waits
Monitor
Data
Code
Process - X
Process - Y
Waiting
Monitor
Data
Code
Process - X
Process - Y
Waiting
X terminated and y is allowed
Y waits and x is allowed

31. IMPLEMENTATION Process-1 Process-2 Process-3 Process-4 Process-1
Processor - A
Processor - B
Processor - C
Processor - D
General purpose processor
Process-1
Process-2
Process-3
Process-4
Communication bus
Process-1
Process-2
Process-3
Process-4
Communication bus
Processor-A
Process-1
Process-2
Process-3
Process-4
General purpose processor

32. Creating and terminating processes.
One way to implement multiple processors is to implement multitasking
Often we encounter with multiple processes to be implemented with a single processor.
To achieve the above is to share the processor to many processes .
During the process of sharing the processor leads the concept of suspending and resuming the processes.
In order to implement the above we need Operating System.
The task of the OS is:
Creating and terminating processes.
Suspending and resuming the processes
Joining processes.
Scheduling the processes.