EMBEDDED SYSTEMS

By

PANKAJ UPADHYAY (08D61A0487)

INTRODUCTION• An embedded system can be defined as a control system or computer system designed to perform a specific task. Common examples of embedded systems include MP3 players, navigation systems on aircraft and intruder alarm systems. An embedded system can also be defined as a single purpose computer.

• Embedded systems are more limited in hardware and/or software functionality than a personal computer (PC).

oAn employs a combination of hardware & software (a“computational engine”) to perform a specific function.

WHERE DO WE USE EMBEDDED SYSTEMS?

•· At Home: Washing Machines, dishwashers, ovens, central heating system,burglars alarms, etc.

•· In Motor Vehicle: Engine management, security (locking or antitheft devices), air conditioning, brakes, radio etc.

•· In Industry & Commerce: Machine control, factory automation, robotics,electronic commerce office equipments.

CHARACTERISTICS OF EMBEDDED SYSTEM

Embedded Systems are designed to do some specific task i.e., it is not a general purpose kind of a system.

Software for Embedded Systems are stored in ROM or flash memory.

Knowledge about behavior at design time can be used to minimize resources and to maximize robustness.

Embedded Systems provide low power consumption in many situations.

CLASSIFICATION OF EMBEDDED SYSTEM

Stand alone Embedded system.

Real time Embedded system.

Network appliance.

Mobile Embedded system.

EMBEDDED SYSTEM CAN BE CLASSIFIED : Stand alone Embedded System:

It is built using a specialized communication processor, memory a number of network access interfaces (known as networkports), and special software that implements logic for sending information from one device to another device.

Real Time Embedded System: A realtime embedded system usually monitors the environment where the embedded system is installed. This kind of system isrequired to respond in time to a request. Examples of realtimeembedded systems are aircraft engine control systems, nuclear monitoring systems and medical monitoring equipment.

CONTINUED…… · Network Appliances:

Network appliances are a new class of embedded systems that in addition to traditional realtime processing must support a broad and changing array of network protocols.

· Mobile Embedded System:Mobile Embedded Systems usually are simple,

batterypowered systems with resource limitations. In some situations, their batteries lifetime becomes a prim issue.

WHAT IS THE DIFFERENCE BETWEEN AN EMBEDDED SYSTEM AND A PERSONAL PC?General Purpose Systems:

A general purpose computer system is what you think of when someone says the word "computer." The defining feature of a general purpose computer is that it can be reconfigured for a new purpose. In the early days of digital computers, this involved actually rewiring the entire system. Today, most end users aren't even aware that this is happening, as the process has become completely transparent.

Embedded Systems:

An embedded system has a self-contained operating system on a "chip" thus embedded into the system and does not rely on having a hard disk with the operating system on it. Not to mention that is will be much faster because the access time of the OS on a chip.An embedded system has historically been defined as a single function product where the intelligence is embedded in the system. It could be anything from a dishwasher to a hearing aid, if that product includes a microprocessor and software.

PRE-REQUISITION FOR EMBEDDED SYSTEM

Microprocessor.

Microcontroller.

Assembly language.

C language.

OS

WHAT IS MICROCONTROLLER ?

A Microcontroller is basically a computer on a chip. It differs form normal desktop or laptop computers in that a microcontroller is an application specific computer that usually runs a single program performing dedicated task(s) while the the later two are general purpose computers that can run numerous programs depending on a users needs. A microcontroller contains on chip CPU, input/output interface, memory, clock, timer, and an assortment of of other peripherals.

WHAT IS MICROPROCESSOR?

A microprocessor incorporates the functions of a computer's central processing unit(CPU) on a single integrated circuit (IC) or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic, as it has internal memory.

ASSEMBLY LANGUAGEAssembly language is a low level language which we use for microcontroller and microprosseser.Assembly language is much harder to program than high level languages.The programmer needs to have a good understanding of the hardware being used.It used less memory and program can run much faster.Assembly language allows the programmer to use symbolic representation for machine operation codes (usually called mnemonics), memory locations, registers and other parts of an instruction.

WHY USE C? It is a „mid-level‟, with „high-level‟ features (such as

support for functions and modules), and „low-level‟ features (such as good access to hardware via pointers);

It is very efficient; It is popular and well understood; Even desktop developers who have used only Java or

C++ can soon understand C syntax; Good, well-proven compilers are available for every

embedded processor (8-bit to 32-bit or more);

CLASSIFICATION OF AN EMBEDDED OPERATING SYSTEM Non real time operating system:NonReal Time Operating Systems do not guarantee definedresponse times. Those systems are mostly used if multiple applications are needed. Eg: window os.

Real time operating system:Real Time Operating Systems are operating systems which guarantee responses to each event within a defined amount of time. Some commonly used RTOS for embedded systems are:VxWorks, OS9,Symbian, and RTLinux etc

LINUX OPERATING SYSTEM ADVANTAGE

Multiple choices vs. sole sourceSource code freely availableRobust and reliableModular, configurable, scalableSuperb support for networking and InternetNo runtime licensesLarge pool of skilled developers

EMBEDDED SYSTEM DESIGN PROCESS

•Creating the artitechure.

•Implementing artitechure.

•Testing the system.

•Maintaining the system.

APPLICATION AREA APPLICATION

Aerospace Navigation Systems, Automatic landing systems, Flight altitude controls.

Industrial Elevator Controls, Robots, Engine Control

Medical Imaging system,pateint monitor,heart pacers

Office automation FAX machines, Telephones, Cash Registers

Computer Peripherals

Printers,scanners,keyboards,displays,modems,Hard Disk Drives,CDROMdrives

Home

Oven,washing machine.

ADVANTAGE-They are designed to do a specific task and have real time performance constraints which must be met.

- They allow the system hardware to be simplified so costs are reduced.

- They are usually in the form of small computerized parts in larger devices which serve a general purpose.

- The program instructions for embedded systems run with limited computer hardware resources, little memory and small or even non-existent keyboard or screen.

REFERENCEwww.wikipedia.com

Designing Embedded Hardware John Catsoulis, O'Reilly, May 2005, ISBN 0-596-00755-8.

Michael Barr; Anthony J. Massa (2006). "Introduction". Programming embedded systems: with C .