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Embedded System Design con Project Demos

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5 Introduzione a Embedded System DesignProfessor Dhananjay V. GadreElectronics and Communication EngineeringNetaji Subhas University of TechnologyBadri SubudhiElectrical Engineering DepartmentIndian Institute of Technology, JammuLecture 02Introduction Continua con Project DemosWelcomeback.Sowearegoingtoresumeourdiscussionsandinthissessionweareconfronto sistemi embedded system e general purpose computing system. (Fare Slide Time: 00 :33) Sothefirstdifferenceisthatembeddedsystemsarededicatedforspecifictasks.Theymaybeonetaskortheremaybefewtask, theremaybemoretanonetask, butchenumeroisfixed.Asagainstgeneralpurposecomputingsystemwhereyoucanputanyapplications, youcanadd applications embedded systems sono diversi da tali finalità generali system.AsanesampleifIhaveamicrowaveoventheembeddedcomputerinthemicrowaveovenisdesignedonlytocookfood.IcannotreprogramitanedpectittowashclothesthatisakindofglaringdifferencecheIhaveandanembeddedcomputerandageneralpurposecomputer.Theseconddifferenceisthatembeddedcomputerscanbeimplementedusingawidevarietyofprocessors.Asyousawaprocessormicrocontrollersmallerthanagrainofriceandoneandonie otherestremebigmicrocontrollermoretananinchsquare,butwhenyoulookatgeneralpurposecomputingdevicesuallyyouusetehighestperformanceprocessoratisdisponibilitariativogliativogliativogliativogliativo La terza differenza è che i sistemi embedded costano sensitive.Whatisthemeaning?Becauseyouarebuyingaproductyouarenotbuyingacomputer.Theembeddedcomputercheformpartofthatembeddedsystemgadgetcarrythesmallfrazionamentodeldativodellasistemativocheditativochediterrativochediterrativocheditativodell†- disponibilità.Themeaninghisainrealtimeisainputchange, ambientalchange, theembeddedsystemsaresupposedenereacttochechangeandprovideanoutputinatimelyfashion.Ifthereisdelayinproducingtheoutputato.Ifthereisdelayinproducingtheoutputitmayleadtofatality,itmayleadtolossoflife. Asanesampleifthethecomputerdedcomputerwhichiinganaircraftandthepilotwantstheaircrafttoclimbandthecomputerdoesnoperformappropriatelyandkeepsonflyingatdello stesso livello può portare a un crash. Nowyoudonodontofageneralefageneraleimmobiliaresistentientioumayhavenoticedcheyoupressakeyandyourlaptopordesktopdoesnotresponditaleispotizioappropriataessodontokillilità.itisvastentidiversificità.itisvastodell†di un computer incorporato in termini di richiedere una risposta in tempo reale. (Fare riferimento a Slide Time: 03.10) Thefourthdifferenceorfifthdiversienceisthatembedsaredesignedtooperateinanestremeambientalcondizionions.Takeaexampleofmissilesystemchechedellaunchedfromglacierambientoritoritcouldbelaunchfromdesertsandtheymustperform.Di solito i sistemi embedded sono esauriti da un ROM.SignificatocheteprogrammetodelteorizzativogliatoInteROMthatisreadintheROMthatisreadonlymemoryapermanentmemory.ButoftentimesesesesestemostofteprogrammazionechesonyouryourdesktoporlaptopcomputerisrunninginteRAM.YesadesktoporalaptopsystemalsohasaROMwhichisusedattebeginningcheonveniiceandenerledbootupprogramcallBIOSBasicInputOutputSystem.Oncesarecompletequestequestequestedeltiferlistranza_delteoperatingatoquestodelazionaleimmobiliareteduotheprogrammazionechewouldliketorun.TheseprogramsarelodintheRAMofthegeneralpurposecomputingsystemsothatisavastavastenzaenergianembeddedsystemoperatesandhowageneralpurposeelaborazionazionates.Anotherdifferenceisthatembeddedsystemhasresourcevincolaints.Whatareresources di un computer?ThecomputationalcapabilityisaresourcethewaythecomputercomunicateswiththeouttheoutworldisresourceandyouseecheageneralpurposecomputingenerenertopordesktopithasmanywaysofcomunicatingwithnuovopordesktopithasEthernet, ithasWiFi, ithasFireWire, ithasFireWire, ithasUSB e così on.ButdoesyourmicrowavehaveEthernetconnectioncanyoucontrolitwithyourphonethroughBluetoothmostprobablynot.Sebbene, inrecenttimesetherearecamplesofsuchemdedapplicationswithconnectivity, butcheconntivityisbasedontherequirementauseyouwanttoflauntcheyourcomputerhassomanywaysofcomunicare con l'esterno world.Soembeddedsystemshaveresourcevincoli, thereareexamplesofforexampleawashingmachinewhichiscalledIOTwashingmachinechewashingmachinecancomunicatewiththeoutsideworldthroughinternetandthepurposeisnotcheyouwouldwanttocontrolthislavatrice seduta nel vostro ufficio.
Butwhenthewashingeneratingathomeandincontraperformanceitinperformanceditotheserviceprovideranzacheycancomefornianzapreventiva èdisponibiliaworkineaworking.Sothisisanexamplewhereyouhaveacommunicationprotocol, comunicationlinkonyourembeddeddevicebutitisoutofnecessityasafeaturenotbecauseyouhaveyouwanttosayche la tua lavatrice ha così tanti modi di comunicare con l'esterno world.Embeddedsystemsareinfrequenti.Whatisthemeaning?Cheonceyouloadaprograminanembeddedapplicationsyoudonoteverchangeit, youdonotchangeitmostofetimesandinmostcasesyoudonoteverchangeit, butinageneralpurposecomputingdeviceogntimeyourunanapplicationsanewapplicationyouarereprogrammingchedevice.Howmanytimeshaveyouincontredasituazione_cheunafasezionechethywouldliketoupgradetemacoderlavariodellavvenientimachineIhaveneverenverenversitodellâaskanesofageneresofaticthemeaningofthispointthispointthispointenerbeddedsistemsarededsistematiriprogrammate.Embeddedsystemshavehardreliabilityandcorrectness vincolaints.Allcomputersmustazionatecorrettamente, butembeddedsystemshaveanadditionalechetheymustcontinuetoprovideservicereliablynotallmostofthem, manyofthem, someofthem.Whybecausefailuretodosomayleadtolossoflife.Asanexamplemedicaldeviceslikeanx - raymachineyoudonotwantthecomputerinthex - raymachinetofail e può dare inutilmente alta dose di x-ray al paziente sotto la x-ray machine. Andinanaircraftyoudonotwantthecomputerfartiaaircrafttofailleadingolossoflifeandsoembeddedcomputersareaspettato alcunecomputerdedcomputersareaspettato di avere requisiti di affidabilità impegnativi.
(Riferimento Slide Time: 07 :50) Nowthatwehavesedifferencesbetweenembeddedcomputersandgeneralpurposecomputingdevicesitesimetogothroughcertainterminologiescheweuse.Andformanyofyouoranzofyouitmaybearepeatoftalyknow, butitdoesnothenothenothestat.Sothefirstterminologyiswhatisacomputer?AcomputerisNulla, butastemchehasaCPUthatisacentralprocessingunità, memoryandinputoutputports.Letmedralavschema per illustrarlo. (Fare Slide Time: 08 :27) SothisisyourCPU, thisisyourmemoryandusuallyyouwouldrequioviditutories.OneistheROMqualunque che yourprogramteotheristeRAMcheweuse forvariablesandthenyouwouldhaveceraridevicesmaybeaninputdeviceandanoutputdeviceletmeerasesioscrizionechequestandatoquestepossidiceCPUcomunicatewithquesti dispositivi attraverso buses.ThesebusesarefordataandanothersetothersetofbusisedicastecontrolbuschetecheyouarereuninformazioneinformazioneinformazioneinformazioneinformazionedellaCPU, ROM, ROM, RAMthatismemoryandinputoutput porte. (Fare riferimento Slide Time: 10 :18) Thesecondterminologyisamicroprocessor.AmicroprocessorisnothingbutaCPUonasinglechip.Howdidithappen?Inthe50sand60stheCPUwasmadewithdiscretecomponentsordiscreteintegratedcircuitsinthe60s.In1971 ,astartupatthattimetatwascalledIntel.AndtodayIntelisagiantmadeaninteressante ingdevicewhatitèitintegrazioneintegrazioneintegranità la funzionalità di una CPU sul singolo substrato di silicio. Cosa comporta una CPU?