intro sept 1 introduction to embedded systems and realtime systems

7/28/2019 Intro Sept 1 Introduction to embedded systems and realtime systems

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n ro uc on o em e e

systems and realtime

systemsB. RamamurthyCSE321

This course is partially supported National Science

Foundation NSF DUE Grant: 0737243

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Introduction to Realtime

Systems & Embedded SystemsB. RamamurthyCSE321

This course is partially supported National Science

Foundation NSF DUE Grant: 0737243

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The course will enable you to:

Understand and design embeddedsystems and real-time systems

For real-time systems:

Identify the unique characteristics of real-timesystems

Explain the general structure of a real-timesystem

Define the unique design problems andchallenges of real-time systems

Apply real-time systems design techniques tovarious software programs.

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Course overview

For embedded systems it will enableyou to : Understand the basics of an embedded

system

Program an embedded system

Design, implement and test an embeddedsystem.

Ex: realtime + embedded : games on aGameboy or arcade games

Ex: realtime: Spore on a laptop

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Example real-time and embedded

systems

Domain Application

Avionics Navigation; displays

Multimedia Games; simulators

Medicine Robot surgery; remote surgery;

medical imaging

Industrial systems Robot assembly lines;automated inspection

Civilian Elevator control

Automotive system; Global

positioning system (GPS)7/16/2013 5


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Lets discuss some realtime system

(RTS) characteristics

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Realtime Characteristics

RTS have to respond to events in acertain pre-detemined amount of time. The time constraints have to be considered

during planning, design, implementation and

testing phases.

Internal failures due to software andhardware fault have be handledsatisfactorily.

You cannot simply pop-up a dialog error boxthat says send report or dont send report.

Also external failures due to outside sourcesneed to be handled.

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Realtime Characteristics

(contd.) Typical interaction in an RTS is

asynchronous. Thus an RTS should

have features to handle asynchronous

events such as interrupt handlers anddispatcher and associated resources.

Potential for race condition: when

state of resources are timingdependent race condition may occur.

Periodic tasks are common.

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Embedded System

Is a special purpose system designedto perform a few dedicated functions.

Small foot prints (in memory)

Highly optimized code

Cell phones, mp3 players are

examples.

The components in an mp3 player are

highly optimized for storage

operations. (For example, no need to

have a floating point operation on an7/16/2013 9


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Real-time system concepts

A system is a mapping of a set of input into a set ofoutputs.

A digital camera is an example of a realtime

system: set of input including sensors and imaging

devices producing control signals and displayinformation.

Realtime system can be viewed as a sequence of

job to be scheduled.

Time between presentation of a set of inputs to asystem and the realization of the required behavior,

including availability of all associated outputs, is

called the response time of the system.

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Real-time system concepts

(contd.) Real-time system is the one in which logical

correctness is based on both the correctness of theoutput as well as their timeliness.

A soft real-time system is one in which performance

is degraded by failure to meet response-timeconstraints.

A hard real-time system is one in which failure tomeet a single deadline may lead to complete andcatastrophic failure.

More examples: Automatic teller: soft

Robot vacuum cleaner: firm

Missile delivery system: hard

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Regular Computer System

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From Minimalist:

STIR-FRIED CHICKEN WITH CREAMED CORNTime: 20 minutes

1 pound boneless chicken (breasts or thighs), in 1/2-inch chunks

2 tablespoons soy sauce

1 teaspoon sesame oil

1 tablespoon sherry, rice wine, sake or white wine

2 tablespoons peanut oil or another neutral oil, like corn or grape

seed

1 tablespoon minced garlic

1 tablespoon minced ginger

1 small chili, seeds and stems removed, minced (or dried red chili

flakes to taste)

1 15-ounce can creamed corn

1 cup corn kernels (fresh, frozen or canned)

Chopped cilantro leaves for garnish.

1. In a small bowl, mix the chicken with the soy sauce, the sesame oiland the wine. Put the peanut oil into a deep skillet or wok, preferably

nonstick, and turn heat to high. Drain chicken. When oil is hot, add

chicken to skillet, and cook, undisturbed, until bottom browns, about 2

minutes. Stir once or twice, and cook 2 minutes longer. Turn the heat

down to medium-low.

2. Add the garlic, the ginger and the chili to the skillet, and stir; 15

seconds later, add the creamed corn and the corn kernels. Cook,

stirring occasionally, until heated through, 3 or 4 minutes. Garnish,

and serve over white rice.

Data

Algorithm

Program


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Embedded Systems

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The Number Game (1)

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The Number Game (2)

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The Number Game (4)

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The Number Game (8)

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The Number Game (16)

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Analysis

What is theory /concept behind this game? How did I arrive at the number you guessed?

How can I automate this process?

What is the data and what is the algorithm?

How can we convey these to a computingmachine?

While a computer talks binary, we humans writeprograms in languages such as Java, C#, C++,Basic etc.

Binary numbers (1s and 0s) is the number systemused by the computer systems.

We humans use decimal number system that has 10distinct symbols (0,1,2,3,4,5,6,7,8,9)

Your task: Write a C program to computerize this7/16/2013 19


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Summary

We examined the course objectivesfor embedded and realtime systems

We looked at sample systems

Homework: Write a program that automates the

number game

Logo for NEXOS

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intro sept 1 introduction to embedded systems and realtime systems

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