CONTENTS

Introduction

History

Applications of Embedded System

Embedded Operating System and Interfaces

Typical Embedded System Constraints

Conclusion

References

EMBEDDED SYSTEM

Picture of the internals of a Netgear ADSL modem/router. A modern example of an embedded system. Labeled parts include microprocessor (4), RAM (6) & flash memory (7).

INTRODUCTION:

An Embedded System is a special-purpose computer system designed to perform one or a few dedicated functions, often with real-time computing constraints.

It is usually embedded as part of a complete device including hardware and mechanical parts. In contrast, a general-purpose computer, such as a personal computer, can do many different tasks depending on programming. Embedded systems control many of the common devices in use today.

A computer (CPU) without conventional keyboard/screen interface. Frequently the embedded system interfaces with the world through sensors and actuators.

Complexity varies from low, with a single microcontroller chip, to very high with multiple units.

A specialized computer system that is part of a larger system or machine.

Typically, an embedded system is housed on a single microprocessor board with the programs stored in ROM.

Virtually all appliances that have a digital interface -- watches, microwaves, VCRs, cars -- utilize embedded systems. Eg. Mobile phones, digital watches, MP3 players,microwave oven, washing machines, toys, trains, planes, automobiles, space vehicles, robots, cameras, even in home appliances and many more to name

Some embedded systems include an operating system, but many are so specialized that the entire logic can be implemented as a single program.

Embedded systems that are programmable are provided with a programming interface, and embedded systems programming is a specialized occupation.

Certain operating systems or language platforms are tailored for the embedded market, such as Embedded Java and Windows XP Embedded. However, some low-end consumer products use very inexpensive microprocessors.

HISTORY:

In the earliest years of computers in the 1930-40s, computers were sometimes dedicated to a single task, but were far too large and expensive for most kinds of tasks performed by embedded computers of today.

One of the first recognizably modern embedded systems was the Apollo Guidance Computer, developed by Charles Stark Draper at the MIT Instrumentation Laboratory.

An early mass-produced embedded system was the Autonetics D-17 guidance computer for the Minuteman missile, released in 1961. It was built from transistor logic and had a hard disk for main memory.

Minuteman II went into production in 1966, the D-17 was replaced with a new computer that was the first high-volume use of integrated circuits.

Intel developed the Microcomputer chip (4004) in 1971 for the Busicom Desktop Calculator. It sold for $200, and ran at 92.5 KHz internally. Intel's initial strategy was to use this device to sell more memory chips. The 4004 was an unexpected hit and was quickly followed by a flurry of similarly enhanced devices from Intel, Motorola, Zilog, and Texas Instruments.

EXAMPLES OF EMBEDDED SYSTEM:

1. Telecommunications Systems

Telecommunications systems employ numerous embedded systems from telephone switches for the network to mobile phones at the end-user.

Cellular phones

2. Transportation Systems

Transportation systems from flight to automobiles increasingly use embedded systems.

New airplanes

Various electric motors —induction motors and DC motors — are using electric/electronic motor controllers.

Automobiles, electric vehicles, and hybrid vehicles are increasingly using embedded systems to maximize efficiency and reduce pollution.

Symbol Technologies' WS 5000 Wireless Switch

Other automotive safety systems such as anti-lock braking system (ABS), Electronic Stability Control (ESC/ESP), traction control (TCS) and automatic four-wheel drive.

3. Consumer Electronics

Personal digital assistants (PDAs),

Mp3 players,

Mobile phones,

Videogame consoles,

Digital cameras,

DVD players,

GPS receivers

Printers

4. Many Household Appliances, such as

Microwave ovens,

Washing machines

Dishwashers,

Are including embedded systems to provide flexibility, efficiency and features.

5.Medical Equipment

Medical equipment is continuing to advance with more embedded systems for vital signs monitoring, Electronic stethoscopes for amplifying sounds and various medical imaging (PET, SPECT, CT, MRI) for non-invasive internal inspections.

6. Robotics

Sony Robotic DOG – 64 bit RISC microprocessor

7. The Sonicare® Elite 7650 –

PRICE:

$ 159.95

The Toothbrush of Sonicare Elite's bristle tips move three times faster than all other leading power toothbrushes to create dynamic cleaning action.

EMBEDDED OPERATING SYSTEM AND INTERFACES:

The simplest form of embedded system is an on chip CPU with firmware. Embedded operating system provides more flexibility in use and so does the user interfaces. But both depend upon the requirement specifications.

1. Embedded operating system:

An embedded operating system is dedicated to a specific purpose in the embedded system. It is real time operating system. Its use depends upon the applications such as airline reservation systems.

Embedded operating systems are very efficient than others as they exclude non-embedded functionalities.

Almost meet the real-time constraints. Embedded operating system resides on ROM-read only memory, as its task never changes.

Commonly used operating systems such as windows XP or Linux are also used as Embedded windows XP, Embedded Linux, Embedded JAVA for some embedded systems.

2. Embedded System Interfaces:

The interfaces not only depend upon requirements but also the way designers handle it. For example use of touch screen instead of separate keypads and displays. But also keeping in mind the cost issue. Reducing the user actions simplifies the design.

One way to reduce user actions is to use a light indicator for any information. Most often designers use red color for danger indication, green for OK and yellow indicating may be there is an error.

TYPICAL EMBEDDED SYSTEM CONSTRAINTS:

As till now, we have discuss about embedded system. But now it’s time to come to focus on the constraints which should be followed before creating any embedded systems. They are:

1. Small Size, Low Weight : ES should be small in size, and having low weight. Hand-held electronic Transportation applications --weight costs money.

2. Extreme cost sensitivity : $.05 adds up over 1,000,000 units. So the embedded systems are cost sensitive.

3. Low Power: Battery power for 8+ hours (laptops often last only 2 hours) Limited cooling may limit power even if AC power available

4. Harsh environment: Power fluctuations, RF interference, lightning, Heat, vibration, shock, Water, corrosion, physical abuseOr in any other such type of harsh environment, our embedded system can work efficiently and properly.

5. Safety-critical operation: Must function correctly and Must not function incorrectly. If the embedded system not works properly then the complete embedding system in which the embedded system is place can’t work. So we have to check that our system always in safety condition.

CONCLUSION:

Embedded System = A computer which is integrated into another system, the embedding system. Embedded systems are part of a bigger system. Embedded System programming is programming with resource constraints.

An embedded system is based on specifications. Specific requirements are defined and based on these requirements an embedded system is developed.

In short an embedded system works for a predefined task. On the whole a hardware chip programmed for a dedicated task results in an embedded system.

As integrated circuits get continuously cheaper, more capable and power efficient, complexity of chip designs are constantly growing. This is illustrated by new design approaches such as multi-core technologies.

As there is no foreseeable end to this development of embedded system, higher abstractions for the design process need to be invented.

REFERENCES:

www.google.com

www.wikipedia.com

www.whatis.com

www.seminartopics.org