embedded system123.doc

8/9/2019 EMBEDDED SYSTEM123.doc

http://slidepdf.com/reader/full/embedded-system123doc 1/13

TECHNICAL PAPER PRESENTATION ON

EMBEDDED SYSTEMS

Presented by

1



EMBEDDED SYSTEMS

CHAITANYA BHARATHI INSTITUTE OF

TECHNOLOGY,

HYDERABAD-500072.

JNTU UNIVERSITY

2



EMBEDDED SYSTEM

ABSTRACT:-An embedded system can be defined asthe computing device that has computer hardware, either with software

embedded in it as one of its mostimportant component. It may be anindependent system or a part of a larger system. The emergence of embeddedsystems is a recent development. As ascientific discipline it resembles the stateof microelectronics (and !"I design, in particular# around 1$%&. Today'schallenge is similar to bac then, e)ceptthat the staes are probably higher.*mbedded systems will appear in

virtually all devices, and intelligentdevices have the tendency to oust their +stupid+ counterparts from the maret place, ust lie - players have oustedgramophone players. Thans todevelopments in microelectronics, thecomputing power of the destopcomputers is now becoming available onthe palmtops. *mbedded systems areheterogeneous. "ince they are mi)turesof hardware and software, trade/off is

important design decisions0 do werealie a function in hardware or insoftware 3ut embedded systems aremore heterogeneous than ust combiningcomputer science 4 digital electronics.This paper presents an overview of e)isting modes of *mbedded "ystems,architecture 4 their application. A loo has also been given to future deploymentof *mbedded "ystems.

1. INTRODUCTION:-An embedded system can be defined asthe computing device that has computer hardware with software embedded in itas one of its most important component.It may be either an independent system

or a part of a larger system. As itssoftware usually embeds in 567 ,itdoes not need secondary memories as ina computer. 8early $$9 of the

processors manufactured end up inembedded systems. *mbedded systemsfind applications in every industrialsegment. *mbedded systems can becategoried as stand/alone systems, real/time systems, networed informationappliances 4 mobile devices. :ust in the1& years, such changes have occurredmore rapidly that they see morerevolutionaries than evolutionary. Asthese systems have brought about radical

changes in *lectronics and -omputer,they have also begun to impact other human activities.

INTRODUCTION

TO EMBEDDED SYSTEM:-An embedded system is somecombination of computer hardware 4software, either fi)ed in capability or programmable, that is specificallydesigned for a particular ind of

application device. ;ardware 4 software that forms acomponent of some larger system 4 ise)pected to function without humanintervention. Typically an embeddedsystem consists of a single/boardmicrocomputer with software in 567,which starts running a dedicatedapplication as soon as power is turned on4 does not stop until power is turnedoff. An embedded system is any device

controlled by instructions stored on achip. These devices are usuallycontrolled by a microprocessor thate)ecutes the instructions stored on a5ead 6nly 7emory (567# chip. ;erean e)ample of a chip <PI-= is shown

>



?ig. 1

An embedded system is pre/programmedto perform a dedicated or narrow rangeof functions as part of a larger system,usually with minimal end/user or operator intervention. The term@embedded@ implies that these chips are

an integral part of the system. 3roadlyspeaing, these programmable devicesor systems are generally used to perform, control or monitor processes,machinery, environments, euipmentand communications tass.*mbedded systems have several thingsto do at onceBrespond to several*vents at onceC cope with unusualconditions without human intervention,while being subected to a deadline. In

fact a general computer system is madeup of numerous embedded systems. If anembedded system is designed well, thee)istence of the processor 4 thesoftware could be completely unnoticed by a user of the device.

2. CATEGORIES OF

EMBEDDED SYSTEM:-2.1 S!"#-!$%"& E'(&##&# S)*&'*:-

As the name implies, stand/alone

systems wor in stand/alone mode. Theytae inputs, process them 4 produce thedesired output. The input can beelectrical signal from transducers or commands from a human being such as pressing of a button. The output can beelectrical signals to drive another system, an !* or !- display for

displaying of information to the users.*mbedded "ystems used in processcontrol,automobiles,consumer electronicitems etc. fall into this category in a process control system, the inputs arefrom sensors that convert a physicalentity such as temperature or pressureinto its euivalent electrical signal.These electrical signals are processed bythe system and the appropriate electricalsignals are produced. ?ew *mbedded"ystems used at home are shown in fig0

?ig. 22.2. R&!$-+'& S)*&'*:-

*mbedded "ystems in which somespecific wor has to be done in specifictime period are called real/time systems.?or e)ample/ -onsider a system that has

to open a valve within >& millisecondswhen the humidity crosses a particular threshold. If the valve is not openedwithin >& milliseconds, a catastrophemay occur. "uch systems with strictdeadline are called hard real/timesystems. 6n the other hand, if weconsider a player and we givesome command from a remote control,4 there is a delay of a milliseconds ine)ecuting the command, but this delay

won't lead to a serious implication. "uchsystems are called as soft real/timesystems.2. N&%/ I"%'!+%" A$+!"&*:-

*mbedded systems that are providedwith networ interfaces 4 accessed bynetwors such as !ocal Area 8etwor or the Internet are called networed

D



information appliances. "uch embeddedsystems are connected to a networ,typically a networ running T-PEIP(Transmission -ontrol ProtocolEInternet protocol# protocol suite, such as theInternet or the -ompany's Intranet.These systems have emerged in recentyears.H&& !& *%'& &3!'$&* % *4

*)*&'*:-

A networed process control systemconsists of a number of embeddedsystems connected as a !A8. *achembedded system can send real/timedata to a central location from whereentire process control system can bemonitored. The monitoring can be doneusing a web browser such as the Internet

*)plorer.The door/loc of your home can be asmall/embedded system with T-PEIPand ;TTP server software running on it.Fhen your children stand in front of thedoor/loc after they return from school,the web camera in the door/loc willsend an alert to your destop over theInternet and then you can open the door/loc ust by clicing the mouse.

? ig > . 8etwor InformationAppliances

.OVERVIE6 OF EMBEDDED

SYSTEM ARCHITECTURE:-

*very embedded system consists of custom B built hardware built around a-entral Processing Gnit (-PG#. Thishardware also contains memory chipsonto which software is loaded. Thesoftware residing on the memory chip iscalled the firmware. The embeddedsystem architecture can be represented

as a layered architecture as shown infig/D. The operating system runs abovethe hardware and the applicationsoftware run above the operating system.It is not compulsory to have an operatingsystem in every embedded system. ?or small appliances such as remote controlunits, air conditioner, toys etc., there isno need for an operating system. ?or applications involving comple) processing, it is advisable to have anoperating system. In such a case, youneed to integrate the applicationsoftware with the operating system 4then transfer entire software into amemory chip. 6nce the software istransferred to the memory chip, thesoftware will continue to run for a long

time 4 you don't need to reload the newsoftware.

?ig.D

Architecture of an embedded system

.1 B4+$#+" B$%/ % !#!& % !"

E'(&##&# S)*&':-

?ig. H

H



C&"!$ P%&**+" U"+ 8CPU9:-

The -PG is a unit that centrally fetches4 processes a set of general/purposeinstructions. The -PG instruction setincludes instructions for data transfer operations, A!G operations, stac operations, input 4output operations 4 program control, seuencing 4supervising operations. The general/ purpose instruction set is always specificto a specific -PG. 6ne e)ample of anolder generation 7icroprocessor is Intel%&%H.It is an %/bit processor. Another isIntel %&% or %&%%, which is a 1/bit processor.The -PG can be of the following0/ 7icrocontroller, microprocessor or

igital "ignal Processor ("P#.A micro/controller is a low/cost processor. Its main attraction is that onthe chip itself, there will be many other components such as memory, A-etc. on the other hand, microprocessorsare more powerful, but you need to usemany e)ternal computers with them."P is mainly used for applications inwhich signal processing is involved.

P%&**% +" & S)*&':-An embedded system processor chip or -ore can be one of the following.1. Jeneral Purpose Processor (JPP#0/a# 7icroprocessor b# 7icrocontroller c# *mbedded processor d# igital signals processor ("P#e# 7edia Processor 2. Application "pecific "ystemProcessor

(A""P# As Additional Processor . 7ultiprocessor system using JeneralPurpose processors (JPP"# 4Application "pecific InstructionProcessors (A"IPs#. JPP core(s# or A"IP core (s#integrated into either an Application"pecific Integrated -ircuit

-ircuit (A"I-# or a ery !arge "caleIntegrated -ircuit (!"I# circuit or an?PJA core integrated with processor unit(s# in a !"I (A"I-# chip.

B$%/ #+!!' % C%'%"&" % &

E'(&##&# S)*&' H!#!&:-

?ig.

P%&**%:-

A processor is the heart of the embeddedsystem. ?or an embedded system

designer, nowledge of microprocessors4 7icrocontrollers is a prereuisite. A processor has two essential units01. Program flow -ontrol Gnit (-G#2. *)ecution Gnit (*G#The -G includes a fetch unit for fetchinginstruction from the memory. The *Ghas circuits that implement theinstructions pertaining to data transfer operation 4 data conversion from oneform to another. The *G includes the

Arithmetic and !ogical Gnit (A!G#4 also the circuits that e)ecuteinstructions for a program control tass,say, halt, interrupt, or ump to another setof instructions. It can also e)ecuteinstructions for a call or branch toanother program 4 for a call to afunction. Processors runs the cycle of



fetch 4 e)ecute the instruction definedin the processor instruction set aree)ecuting in the seuence that they arefetched from the memory. A processor is mostly in the form of an I- chipCalternatively it could be in core form inan A"I- or at a "oc. -ore means a partof the functional circuit on the !"Ichip.A Jeneral Purpose Processor is used because of the following0/1# Processing by the nown instructionsAvailable at redefined general/purposeinstruction set result in fast systemdevelopment.2# 6nce the board 4 inputEoutputinterfaces are designed for a JPP, these-an be used for a new system by ust

changing the embedded software in the3oard 567.># 5eady availability of a compiler ?acilitates embedded softwaredevelopment in high level language.D# 5eady availability of a well tested 4ebugged processor specific APIs 4 the-odes previously designed for other Applications results in fast developmentof new system.

M+%%&**%:-A microprocessor is a single !"I chipthat has a -PG 4may also have someother units (for eg0 floating/point processing arithmetic unit, pipelining4super/scaling units# that areadditionally present 4 that result infaster processing of instructions.

M&'%):-

The memory is categoried as 5andom

Access 7emory (5A7# and 5ead 6nly7emory (567#. The contents of 5A7will be erased if power is switched off."o, the firmware is stored in the 567.Fhen the power is switched on, the -PGreads the 567, the program istransferred to 5A7 and program ise)ecuted.

I"4 #&;+&*:-

Gnlie the destops, the IEP devices toan embedded system have very limitedcapability. There will be eyboard or amouse, 4 hence interacting with theembedded system is no easy tas. 7any

embedded systems will have a smalleypad/you press one ey to give aspecific command. A eypad may beused to IEP only the digits. 7anyembedded system uses in process controldo not have any IEP device for user interactionC they tae IEPs from sensorsor transducers 4 produce electricalsignals.

O44 #&;+&*:-

The output devices of the embeddedsystems also have very limitedcapability. "ome embedded systems willhave a few !ight *mitting iodes toindicate the health status of the systemmodules. A small !iuid -rystal isplay(!-#may also be used to display someimportant parameters.

C%''4"+!+%" +"&!&*:-

The embedded systems may need to

interact with other embedded systems or they may have to transmit data to adestop.

A$+!+%"-*&++ +4+):-

"ensors, transducers, special processing4 control circuitry may be reuired for an embedded system, depending on itsapplication. The circuitry interacts withthe processor to carry out the necessarywor.

. SPECIALITIES OF

EMBEDDED SYSTEMS:-Fhile designing the embedded systems,developers have to eep the belowspecialties in mind0 /.1 P&%'!"&:-

K



7any embedded systems have timeconstraints. ?or instance, in a processcontrol system, a constraint can be0 <if the temperature e)ceeds D& degrees,open a valve within 1& milliseconds.=The system meets such deadlines. If thedeadlines are missed, it may result in acatastrophe. Lou can imagine thedamage that can be done if suchdeadlines are not met in a safety systemof a nuclear plant.

.2 P%& C%"*4'+%":-

7ost of the embedded systems operatethrough a battery. To reduce the batterydrain 4 avoid freuent recharging of the battery, the power consumption of anembedded system has to be very low.

. C%*:-

?or an embedded system used in safetyapplications of a nuclear plant or in aspacecraft, cost may not be a veryimportant factor. ;owever, for anembedded system used in consumer electronics or office automation, the costis of utmost importance. "uppose youhave designed a toy in which theelectronics will cost G"M2&. 3y a careful

analysis design, if you can telecomoperator will change the algorithm for the calculation of the bill amount. This isvery cumbersome, considering that amemory chip will have to replace inthousands of P-6.

. S+<&:-

"ie is certainly a factor for manyembedded systems. Fe do not lie amobile phone that has to be carried on

our bacs. The sie and the weight(ie.compactness# are the important parameters in embedded systems used inaircraft, missiles etc. because in suchcases, every inch 4 every grain matters.

.5 S%!& U !#!+%" !!(+$+):-

*mbedded systems are meant for a veryspecific tas. "o, once the software istransferred to the embedded system, thesame software will run throughout itslife. ;owever, in some cases, it may benecessary its upgrade the software.-onsider the e)ample of a Public -all6ffice (P-6#. At the P-6, an embeddedsystem is used which displays theamount to be paid by a telephone user.The amount is calculated by a firmware, based on the calling number 4 theduration of the call from time to time,the broadband 4 wireless networ, 4consumer electronic products.

5. RECENT TRENDS

IN EMBEDDED SYSTEMS:-In old good days, developing embeddedsystems was confined to very specialists.7ost of the embedded systems arewritten only in assembly language 4hence writing, debugging 4 maintainingthe code were very difficult 4 timeconsuming. Fith the availability of powerful processors 4 advanceddevelopment tools, embedded softwaredevelopment is no longer Nrocet

science'.

5.1 P%&**% P%&:-

The growing importance of embeddedsystems can be gauged by theavailability of processors about 1H&varieties of processors are available fromaround H& semiconductor vendors.Powerful %/bit, 1/ bit, >2/bit and D/bitmicro controllers, 4 microprocessors areavailable to cater to the different maretsegments the cloc speed 4 memoryaddressing capability of these processorsare also increasing. ery powerful digitalsignal processors are also available for real time analyses of audio and videosignals. As a result, the power of destopcomputers is now available on palmtops.

%



5.2 M%(+$& D&;+&*:-

7obile devices such as mobile phones,Personal igital Assistants, smart phones etc. are a special category of anembedded system. Though the PA doesmany general/purpose tass, they needto be designed ust lie the conventionalembedded systems. The limitations of the mobile devices/memory constraints,small sie, display etc. are same as thosefound in the embedded systems. ;encemobile devices are considered asembedded systems.

5. O&!+" S)*&'*:-

Gnli & the destop on which the optionsfor an operating system are limited, avery of operating systems are available

which can be ported on to the embeddedsystem. The advantage of embedding anoperating system is that the softwaredevelopment will be very fast 4marinating the code is very easy. Thesoftware can be developed in a highlevel language such as <-=. "o time tomaret the system gets reduced. If realtime performance is reuire a real timeoperating system can be used. Inaddition too many commercial

embedded operating system open sourcesoftware campaigned let to developmentof many open source operating system.The attraction of open source software isthat it is free 4 also the complete sourcecode is available to customie thesoftware as per your application needs.

5. C%''4"+!+%" I"&!&* !"#

N&%/+" C!!(+$+):-

Fith the availability of low/cost chips,

embedded systems can be providednetworing capability throughcommunication interfaces such as*thernet, %&2.11b wireless !A8 4infrared. 8etwor enabling of anembedded system has many advantages0it can be accessed over a networ for remote control or monitoring.

5.5 P%!''+" L!"4!&*:-

?ig.

evelopment of embedded system wasdone mostly in assembly languages.;owever, due to the availability of cross/compilers, most of thedevelopment is now done in high/levellanguages such as -. the obect/oriented

languages lie -OO 4 :ava are nowcatching up.

5.= D&;&$%'&" T%%$*:-

Availability of a number of tools for development, debugging 4 testing aswell as for modeling the embeddedsystems is now paving way for the fastdevelopment of robust 4 reliablesystems. evelopment tools such as35*F (3inary 5outine *nvironment for wireless#, Fireless Application Protocol(FAP# development tools facilitate easydevelopment of applications for mobiledevices

5.7 P%!''!($& H!#!&:-

P!s4 ?PJA pave the way for reducingthe components on an embedded system,leading to small, low/cost systems. After developing the prototype of anembedded system, for mass production,?PJA can be developed having all the

functionality of the processors, peripherals 4 application/specificcircuitry.

=. APPLICATION AREAS:- In today's world the electronic deviceshave been dominated. The children need

$



embedded systems to play smart videogames 4 to operate automatic chocolateending machines Loung people needembedded systems to borrow smartcards from parents to see movies;ousewives need embedded system for smart Internet B compliant homeappliances, such as, microwave,television, music system, 4 so on. 8early $$9of the processorsmanufactured end up in embeddedsystems. The embedded system maretis one of the highest growth areas asthese systems are used in very maretsegment/ consumer electronics, officeautomation, biomedical engineering,wireless communication,4 datacommunication, military and so on.

=.1 C%"*4'& !$+!"&*:-

At home we use a number of embeddedsystems that include digital camera,digital diary, player, electronic toy,microwave oven, remote controls for T4 air conditioner etc. Today's high/techcar has about 2& embedded systems for transmission control, spar control,navigation etc. *ven wristwatches arenow becoming embedded systems.

=.2 I"#4*+!$ !4%'!+%":-

Today a lot of industries use embeddedsystems for process control. Theseinclude pharmaceutical, cement, sugar,oil e)ploration, nuclear energy,electricity generation 4 transmission.The embedded systems for industrial useare designed to carry out the specifictas such as monitoring the temperature,

pressure, humidity, voltage, current etc.4 then tae appropriate action based onmonitored levels to control other devices.

=. M&#+!$ &$&%"+*:-

Almost every medical euipment in thehospital is an embedded system. This

euipment's include diagnostic aids suchas *-J, **J, blood pressure measuringdevices 4 Q/ray scanners etc.

=. C%'4& N&%/+":-

-omputer networing products such as bridges, routers, Integrated "ervices

igital 8etwors (I"8#, AsynchronousTransfer 7ode 4 relay switches are theembedded systems that implement thenecessary data communication protocols.

=.5 6+&$&** &"%$%+&*:-

Advances in mobile communications are paving way for many interestingapplications using embedded systems.The mobile phone is one of the marvelsof the last decade of the 2&th century. It

is very powerful embedded system that provides voice communication while weare on the move.

=.= I"*4'&"!+%":-

Testing 4 measurement are thefundamental reuirements in allscientific and engineering activities. Themeasuring euipment we use inlaboratories to measure parameters suchas weight, temperature, voltage, current

etc. are all embedded systems. Testeuipment such as oscilloscope, logicanalyer, protocol analyer, radiocommunication test set etc, areembedded systems built around powerful processors

=.7 S&4+):-

Security of persons and information hasalways been a maor issue. Fe need to proect our homes and offices, 4 also the

information we transmit 4 store.eveloping embedded systems for security applications is one of the mostlucrative businesses nowadays.

=.> F+"!"&:-

?inancial dealing through cash 4cheues are now slowly paving way for

1&



transactions using smart cards and AT7(Automatic Teller 7achine, alsoe)panded as Any Time 7oney# machine."mart card, of the sie of a credit card,has a small micro/controller andmemoryC 4 it interacts with the smartcard reader E AT7 machine 4 acts as anelectronic wallet.

7. SPECIFIC APPLICATIONS:-

7.1 AUTOMATIC TELLER

MACHINE 8ATM9:-

AT7 is an electronic device that allowsa ban@s customers to mae cashwithdrawals and chec their account balances without the need for a humanteller. 7any AT7s also allow people todeposit cash or cheues, transfer money between their ban accounts or even buy postage stamps. The world@s first AT7was developed by e la 5ue 4 installedin *nfield Town in 8orth !ondon on:une 2K, 1$K by 3arclays 3an. Theidea of a personal identification number (PI8# stored on a physical card beingcompared with the PI8 entered whenretrieving the money was developed bythe 3ritish engineer :ames Jood fellow

in 1$H.In modern AT7s, customersidentify themselves by using a plasticcard with a magnetic stripe, whichencodes the customer@s account number,4 by entering a four/digit pass code(PI8#. If the PI8 is entered incorrectlyfor several times in row then the AT7retains the card for a security purpose toavoid the use of card by an unauthorieduser. There are AT7s that are accessibleto blind and visually impaired peoples.

This is one of the great inventions. Theseare types of AT7s whose eypads areeuipped with 3raille system.

?ig. % AT7

7.2 EMBEDDED SYSTEM IN A

SHOE:-

The microprocessor embedded in thisA#+#!* running shoe calculates the pressure between the runner@s foot 4 theground five million times per second 4continuously changes the cushioning tomatch an adustable comfort level. Thecomputer controls a motor that lengthens4 shortens a cable attached to a plasticcushioning element.

?ig. $

<*mbedded "ystem in a "hoe=

11



7. BRAILLE INTERFACE TO

MICROCONTROLLER:-

In today's world mobile phone has become the most simplest and effectiveway of communication .Fhat to do if wewant to send a message to our friend."imple, we write a sms and send it to our friend. That's very cool and handy for us. 3ut, what if one of our friends isB$+"#. 3eing blind does not mean heshould be deprived of the simplestfacility available on mobile phone. Thereshould be some way that blind peoplecan also read messages, isn't it "o basically our aim is to enable blind person to read sms.

8e)t uestion how is it possibleThis is possible through B!+$$&. 3railleis a matri) of engraved dots. There is acoding for each *nglish character. 3lind person can read the te)t ust by touching

it. This comes through training. And3raille's are used in almost all blindschool nowadays. 3lind person are usingit e)tensively to communicate withmobiles, typewriters and evencomputers.The message can be transferred to the3raille structure. This is done byinterfacing a microcontroller to themobile through a cable. This uses serialcommunication. The mobile

communicates microcontroller throughAT commands .The microcontroller outputs signal to the relay drive circuit.The message is also displayed on the!- connected to the microcontroller.There are si) relays which drive themechanical structure, consisting of si)thic wires. There is encoding for each

*nglish alphabet and character. Thewires corresponding to the particular alphabet or character is raised up and the blind person can feel it through their fingers.

10. CONCLUSION:-An embedded system is closelyintegrated with the main systemIt may not interact directly with theenvironment.Thus embedded systems contain programmed instruction running via processor chips. They perform control, protection 4 monitoring tass. In broadterms embedded systems are programmable devices or systems whichare generally used to control or monitor things lie processes machinery,environmental euipment 4communications. The range of embedded system is vast 4 includes allindustrial 4 commercial sectors.*mbedded systems are rapidly becominga catalyst for change in the computing,data communication,telecommunications, industrial control 4entertainment sector. The obective of this study is to enlighten readers aboutthe application of embedded systemsCthe embedded systems technologyC 4 theimpact of the technology on variousmarets.

11. REFERENCES:-

*mbedded "ystems Architecture,esigning and Programming

B 3y 5aamal.

*mbedded "ystem Programming andesigning B 3y 7ichael 3arr.esigning 6f *mbedded ;ardware B 3y :ohn Reysouisi.*mbedded "ystem esign

B 3y ?ran ahid.

www.embedded.com

12

http://www.embedded.com/

http://www.embedded.com/



www.nptel.iitm.ac.in

1>

http://www.nptel.iitm.ac.in/

http://www.nptel.iitm.ac.in/

embedded system123.doc

Documents