PRESENTED BY :BIREN KUMAR PRESENTED BY :BIREN KUMAR SAMALSAMAL

ADMISSION NO:22I&E/2000ADMISSION NO:22I&E/2000

Embedded System is a combination of hardware and software that forms the component of larger system.

DefinitionDefinition

Categories of Embedded Categories of Embedded systemsystem

Stand-alone embedded systemsStand-alone embedded systems Real-time embedded systemsReal-time embedded systems Embedded systems for Embedded systems for

Networked appliancesNetworked appliances Embedded system for Mobile Embedded system for Mobile

devicesdevices

Stand-alone embedded Stand-alone embedded systemssystems

As the name suggests, in a stand-alone As the name suggests, in a stand-alone mode work is taking input and producing mode work is taking input and producing output, which may be any thing. Also the output, which may be any thing. Also the deadlines to carry out a specific task may deadlines to carry out a specific task may not be strict; a few milliseconds variation not be strict; a few milliseconds variation not matter much. For example, an air not matter much. For example, an air conditioning unit can be set to turn on when conditioning unit can be set to turn on when the temperature is out of specified limit. the temperature is out of specified limit.

Real-time embedded Real-time embedded systemssystems

Some embedded systems are required to Some embedded systems are required to carry out specific tasks in a specified time carry out specific tasks in a specified time period. Such systems are called as Real time period. Such systems are called as Real time system. system.

Systems in which real-time constraints are Systems in which real-time constraints are to be strictly met are called to be strictly met are called hard real-time hard real-time embedded system. embedded system. Systems in which real-Systems in which real-time constraints are not so critical are time constraints are not so critical are called as called as soft real-time embedded system soft real-time embedded system ..

For example, opening a valve for say 30 For example, opening a valve for say 30 milliseconds when humidity crosses the milliseconds when humidity crosses the limitlimit

Embedded systems for Embedded systems for Networked appliancesNetworked appliances

Some embedded systems are connected to a network --typically, one based on a TCP/IP protocol suit, such as the Internet or companies Intranet. Even the Web server running HTTP can be embedded into the system. A typical example is to monitor some parameter in the system and sending information on internet for on-line monitoring. A camera for this can be incorporated here

Embedded system for Mobile Embedded system for Mobile devicesdevices

With advent of wireless networks that support high speed, mobile devices are capable of supporting high data rates services in addition to the voice services. Accessing Internet services such as e-mail, the World Wide Web, and so on can be done while the person is on move. So for downloading this all information, a power full processor is needed with high speed which can be an embedded processor .

Requirement issuesRequirement issues

ThroughputThroughput ResponseResponse TestabilityTestability Debug abilityDebug ability ReliabilityReliability Memory spaceMemory space Program installationProgram installation Power ConsumptionPower Consumption Processor hoggsProcessor hoggs CostCost

Hardware ApplicationHardware Application

ExternalRAM

Processor AddressLatch

ResetCircuitary

Application Specific controlCircuitary

ADC / DAC

Crystal

Chip select

LCD display

Latch for External Devicecontrol

LEDindicators

External ROM

Tri-stateBuffer

Communication interface

ProcessorProcessor

The processor used in the embedded system can of three types:

Micro-controller Microprocessor Digital signal processor Each of these processors is specified by

clock speed and data word-length. The higher the clock speed and bigger the word-length the better the processor.

The choice of the processor depends upon the application in use.

MemoryMemory

The memory used in an embedded The memory used in an embedded processor can be either internal or processor can be either internal or external. The internal memory is very external. The internal memory is very limited. For the small application if this limited. For the small application if this memory is sufficient then no need to memory is sufficient then no need to use external memory. Internal memory use external memory. Internal memory is faster than the external, also the cost is faster than the external, also the cost of memory increases with capacity and of memory increases with capacity and speed. Reprogrammable memories are speed. Reprogrammable memories are now availablenow available..

Latches and buffersLatches and buffers

Processor-based system need to drive Processor-based system need to drive external devices such as LED external devices such as LED displays, relays, etc. the processor displays, relays, etc. the processor does not interact directly with these does not interact directly with these devices. Flip-flop logic chips are devices. Flip-flop logic chips are used to drive external devices. used to drive external devices. These chips hold the processor These chips hold the processor output data to be sent to the output data to be sent to the external devices.external devices.

Application-specific control Application-specific control circuitrycircuitry

This is used for the control This is used for the control of the sensors and the of the sensors and the relays etc. used to relays etc. used to interface embedded interface embedded system to other system system to other system under test.under test.

Display unitsDisplay units

Some embedded system-for Some embedded system-for instance, those in an unnamed instance, those in an unnamed spacecraft or the process spacecraft or the process control system we do not need control system we do not need displays. But in system where displays. But in system where the user interaction is the user interaction is important, LCD or other important, LCD or other displays are used.displays are used.

KeypadsKeypads

Every embedded systems offer Every embedded systems offer different capabilities for different capabilities for providing user input. For providing user input. For example, for PDA’s key pads example, for PDA’s key pads are used for entering data are used for entering data and sensors in industries and sensors in industries (machine). (machine).

Communication devicesCommunication devices

In order for the embedded In order for the embedded system to interact with the system to interact with the external devices, they need external devices, they need communication interface. communication interface. Mostly it is serial. But in case Mostly it is serial. But in case of mobile embedded system of mobile embedded system it may be serial or parallel.it may be serial or parallel.

Developing Embedded Developing Embedded systemsystem

In developing the embedded systems, steps In developing the embedded systems, steps are are

Determine the requirements of the embedded Determine the requirements of the embedded system.system.

Design the system architecture.Design the system architecture. Select the operating system.Select the operating system. Choose the processor & associated peripherals.Choose the processor & associated peripherals. Choose the development platform.Choose the development platform. Code the application & optimize the code; Code the application & optimize the code;

follow optimization guidelines.follow optimization guidelines. Verify the software on the host system.Verify the software on the host system. Verify the software on the target system.Verify the software on the target system.

Embedded system Embedded system development Toolsdevelopment Tools

Hardware development tools Hardware development tools Software development toolsSoftware development tools

Hardware development Hardware development toolstools

PCB making.PCB making. Emulators.Emulators. Logic analyzers.Logic analyzers.

Software development toolsSoftware development tools

Embedded software development is typically done Embedded software development is typically done on a host machine, different from a target machine on a host machine, different from a target machine on which the software will eventually be shipped to on which the software will eventually be shipped to customers.customers.

A tool for developing embedded software typically A tool for developing embedded software typically contains a cross-compiler, a cross-assembler, a contains a cross-compiler, a cross-assembler, a linker/locator, and a method for loading the software linker/locator, and a method for loading the software into the target machine.into the target machine.

The cross-compiler understands the same C The cross-compiler understands the same C languages a native compiler (with a few languages a native compiler (with a few exemptions), but its output uses the instruction set exemptions), but its output uses the instruction set of the target microprocessor.of the target microprocessor.

A cross-assembler understands an assembly A cross-assembler understands an assembly language that is specific to your target language that is specific to your target microprocessor and outputs instructions for that microprocessor and outputs instructions for that microprocessor.microprocessor.

Advantages Advantages

The overall cost of system is reduced.The overall cost of system is reduced. Even if hardware is not re-usable the Even if hardware is not re-usable the time-to-markettime-to-market

advantage is clear and importantadvantage is clear and important Other systems (machine tools, telephone Other systems (machine tools, telephone

switchgear...) can have software upgrades but utilise switchgear...) can have software upgrades but utilise existing embedded hardwareexisting embedded hardware

Any systems which would have required expensive Any systems which would have required expensive hardware upgrades in the past now need only hardware upgrades in the past now need only software changes this can sometimes be done software changes this can sometimes be done remotely, using communication links .remotely, using communication links .

Mechanical systems can be more effectively controlled Mechanical systems can be more effectively controlled by microprocessorby microprocessor

Development time is reduced because of use of Development time is reduced because of use of software on host system.software on host system.

More complex system can be developed in a simple More complex system can be developed in a simple way.way.

PitfallsPitfalls

The pitfalls or problems with The pitfalls or problems with development in embedded system development in embedded system is that hardware fabricated no is that hardware fabricated no chip can never be changed. Also chip can never be changed. Also embedded software programmers embedded software programmers need to be aware of diversity of need to be aware of diversity of application areas and specific application areas and specific requirement for eachrequirement for each

Application of Embedded Application of Embedded systemsystem

It is used in Consumer electronics such as It is used in Consumer electronics such as toys,air conditioners,CD toys,air conditioners,CD player,refrigerators,T.V sets etc.player,refrigerators,T.V sets etc.

It is used in control system & industrial It is used in control system & industrial automation .automation .

It can also be used in biomedical systems It can also be used in biomedical systems e.g. X-ray control unit,ECG & EEE units etc.e.g. X-ray control unit,ECG & EEE units etc.

It is also used in data It is also used in data communication,telecommunication,wirelescommunication,telecommunication,wireless communication .s communication .

ConclusionConclusion Embedded system is rapidly becoming a Embedded system is rapidly becoming a

catalyst for change in computing, data catalyst for change in computing, data communication, telecommunications, communication, telecommunications, industrial control etc. New innovative industrial control etc. New innovative application in these areas will roll out in application in these areas will roll out in near future.near future.

The global market size for embedded The global market size for embedded software development alone was $7 billion software development alone was $7 billion in 2001, which is expected to reach $31 in 2001, which is expected to reach $31 billion by 2005. As per Nasscom-McKinsey billion by 2005. As per Nasscom-McKinsey survey, Indian R& D in embedded system survey, Indian R& D in embedded system was worth $1.1 billion in 2001, which would was worth $1.1 billion in 2001, which would grow to $8 billion by 2008.grow to $8 billion by 2008.