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Embedded computer



Introduction

Mainlyfromthreeaspectstounderstandtheconceptofembeddedsystem

Embeddedcomputer(17photos)

1.Fromthehardware.IntegrateCPU-basedperipheraldevicesintotheCPUchip.Forexample,intheearlycomputersbasedontheX86architecture,theCPUonlyhasthefunctionsofarithmeticunitandaccumulator,andallchipsneedtobeextendedbyexternalbridges,suchasserialports.Theyareallrealizedbytheexternal16C550/2serialcontrollerchip,andthecurrentserialcontrollerchiphasbeenintegratedintotheCPU,andPCshavegraphicscards,andmostembeddedprocessorshaveLCDcontrollers.Butinasenseitisequivalenttoagraphicscard.TheIXPnetworkprocessorCPUundertherelativelyhigh-endARM-likeIntelXscalearchitectureintegratesaPCIcontroller(whichcanbeconfiguredtosupport4PCIslavedevicesorconfigureitselfasaCPIslavedevice);italsointegrates3NPEnetworkprocessorengines,TwoofthemcorrespondtotwoMACaddresses,whichcanbeusedforgatewayswitching,andtheotherNPEnetworkprocessorenginesupportsDSL.AslongasaPHYchipisaddedoutside,DSLInternetaccesscanberealized.ThehighestfrequencyofIXPseriescanreach1.8G,support2Gmemory,1G×10or10G×1EthernetportorFebrechannelopticalchannel.TheIXPseriesshouldbethehighestprocessorbasedontheARMsystemarchitectureintegratedbyInteltobecometheXscalecore.

2.Fromthesoftwarepointofview,theapplicationisselectedinthecustomoperatingsystemkernel,andthekernelisdownloadedtotheROMaftercompilation.Theapplicationcomponentselectedwhencustomizingtheoperatingsystemkernelistocompletethe"embedding"ofthesoftware.Forexample,whenWinCEiscustomizingthekernel,therewillbecorrespondingchoices,amongwhichareWordpad,PDF,MediaPlayandsoon.Ifwechoose,AftertheCEisstarted,youcanfindthesethingsintheinterface.IfitisthewindowsoperatingsystemofthepreviousPC,mostofthethingsneedtobereinstalled.

3.BurnthesoftwarekernelorapplicationfilesystemintotheROMoftheembeddedsystemhardwareplatformtoachieveareal"embedding".

Theabovedefinitionismyself-explanatorydefinitionofembeddedsystems6or7yearsago.Therearemanydefinitionsinthebook,butinthisfield,noonedares.Isaythatmydefinitionisveryprecise,includingthoseexpertsandscholars,whohavealwaysconsideredembeddedsystemstobeacomprehensivedisciplineinthefieldofcomputers.

Layeredsituation

Theembeddedsystemisdividedinto4layers,hardwarelayer,driverlayer,operatingsystemlayerandapplicationlayer.

1.Thehardwarelayeristhefoundationoftheentireembeddedsystem.IfyouarefamiliarwiththemicrocontrollerandinterfaceandcanbeprogrammedinCandassemblylanguage,startfromthehardwarelayeroftheembeddedsystem.Itisrelativelyeasy.Thehardwarelayerisalsothefoundationofthedriverlayer.AnexcellentdriverengineermustbeabletounderstandthecircuitdiagramofthehardwareandcompletethelogicdesignoftheCPLDbyhimself.Atthesametime,hemustbequitefamiliarwiththeoperatingsystemkernelanditsscheduling.Butthehardwareplatformisthefoundation,andvalue-addeddependsonthesoftware.

Thehardwarelayerismoresuitableforpeoplewhospecializeinelectronics,communications,automation,mechatronics,andinformationengineering.Thebasicprofessionalknowledgethatneedstobemasteredincludestheprincipleandinterfacetechnologyofsingle-chipmicrocomputers,andtheprincipleandinterfacetechnologyofmicrocomputers.,Clanguage.

2,thedriverlayer,thispartismoredifficult,thedriverengineermustnotonlyunderstandthecircuitdiagram,butalsobeveryproficientintheoperatingsystemkernel,sothatthedriverwrittenbyitwillnotbeusedwhenthesystemiscalled.Occupytheoperatingsystemtimeslicealone,andcauseothertaskstobeinoperable,donotunderstandtheoperatingsystemkernelarchitectureandreal-timescheduling,anddonothaveagooddriverwritingstyle.Accordingtothemethodofaddingdriversmentionedinmostbooks,manypeoplecanItcanbedone,butitmaynotevenreachthelevelofajuniordriverengineer.Whentheapplicationiscalled,thedriverwrittenisjustlikewhenweopenaprogramandrunitunderwindows,andthenopenaprogram,oritwillinterruptthepreviousone.Program,orwaitforawhiletoruntheprogramopenedlater.Ifyouwanttobeagooddriver,youdon'thavethreeorfouryearsofknowledge.Itisnoteasytosucceedifyoudon'tstudythekerneloftheoperatingsystem.However,thesalaryisthehighestamongthefourlayersofembeddedsystems.

Thedriverlayerismoresuitableforpeoplewithmajorsinelectronics,communications,automation,mechatronics,andinformationengineering,especiallycomputer-biasedarchitecture.Inadditiontothebasicdisciplinesofthehardwarelayer,italsorequiresMustbeveryproficientindatastructuresandalgorithms,operatingsystemprinciples,andcompilationprinciples.

3.Theoperatingsystemlayer,theoperatingsystemlayermayonlybeasimpletransplantatpresent,andfewpeoplecomefromtheoperatingsystemthathasbeenwritten,ortheoperatingsystemthatlacksarmsandlegs.Partoftheworkismostlydonebydriveengineers.Theoperatingsystemisresponsibleforsystemtaskdebugging,diskandfilemanagement,andthereal-timenatureoftheembeddedsystemisveryimportant.ItissaidthatMicrosoftinvested300peopleintheXPoperatingsystemintwoyears.Thetotalhoursare600man-years.ItisestimatedthattheNuwaHopenoperatingsystemoftheChineseAcademyofSciencesSoftwareInstitutewilltakehundredsofman-yearstocomplete.Therefore,thispartoftheworkisrelativelymeaningless.

4.Theapplicationlayerisrelativelyeasy.Ifyouknowhowtocalltheprogramminginterfacefunctionunderwindows,itwillonlychangethecompilationanddevelopmentenvironmentundertheoperatingsystem.ThisisalsotrueifprogramminginJavaisinvolved.Thealgorithminvolvedintheembeddedsystemishandledbytheprofessionalalgorithmperson,anditdoesnotneedtobeattributedtotheembeddedsystemcategory.Butifitinvolvesembeddeddatabasesunderembeddedsystems,networkprogrammingbasedonembeddedsystems,andprotocolapplicationdevelopmentbasedonacertainapplicationlevel(forexample,basedonSIP,H.323,Astrisk),itismorecomplicatedanddifficult.

Detailedsystemexplanation

1.Whatisanembeddedsystem?

Anembeddedsystemgenerallyreferstoanon-pcsystem,whichhascomputerfunctionsbutisnotcalledacomputerEquipmentorequipment.Itisadedicatedcomputersystemthatisapplication-centric,softwareandhardwarecanbecut,andadaptedtotheapplicationsystem'scomprehensiveandstrictrequirementsonfunction,reliability,cost,volume,andpowerconsumption.Simplyput,theembeddedsystemintegratestheapplicationsoftwareandhardwareofthesystem,whichissimilartotheworkingmodeofbiosinpc.Ithasthecharacteristicsofsmallsoftwarecode,highautomation,andfastresponsespeed.Itisespeciallysuitableforsystemsthatrequirereal-timeandmulti-tasking..Embeddedsystemismainlycomposedofembeddedprocessor,relatedsupportinghardware,embeddedoperatingsystemandapplicationsoftwaresystem.Itisa"device"thatcanworkindependently.

Theembeddedsystemincludesalmostallelectricalequipmentinlife,suchaspalmpda,calculator,electronicwatch,telephone,radio,recorder,DVDplayer,mobilephone,telephonewatch,tabletcomputer,TVset-topbox,Routers,digitalTVs,multimediaplaybackequipment,cars,trains,subways,airplanes,microwaveovens,ovens,cameras,cameras,cardreaders,POSmachines,washingmachines,waterheaters,inductioncookers,homeautomationsystems,elevators,airconditioning,securitysystems,Navigationsystems,vendingmachines,cellularphones,consumerelectronics,industrialautomationinstruments,medicalequipment,interactivegameconsoles,VR,robots,videolearningmachines,pointreadingmachines,etc.

Thehardwarepartoftheembeddedsystem,includingthemicroprocessor,memoryandperipheraldevices,i/oports,graphicscontrollers,etc.Theembeddedsystemisdifferentfromthegeneralcomputerprocessingsystem.Itdoesnothaveastoragemediumwithalargecapacitylikeaharddisk,butmostlyuseseprom,eepromorflashmemory(flashmemory)asthestoragemedium.Thesoftwarepartincludesoperatingsystemsoftware(requiresreal-timeandmulti-taskoperation)andapplicationprogramming.Theapplicationprogramcontrolstheoperationandbehaviorofthesystem;andtheoperatingsystemcontrolstheinteractionbetweenapplicationprogrammingandhardware.

Second,whatisanembeddedmicroprocessor?

Thecoreofanembeddedsystemisanembeddedmicroprocessor.Embeddedmicroprocessorsgenerallyhavefourcharacteristics:(1)Ithasstrongsupportforreal-timeandmulti-tasking,cancompletemulti-taskingandhasashortinterruptresponsetime,sothattheinternalcodeandreal-timeoperatingsystemexecutiontimeReducetoaminimum;(2)Ithasapowerfulstorageareaprotectionfunction,whichisbecausethesoftwarestructureoftheembeddedsystemhasbeenmodularized,andinordertoavoidthewrongcross-actionbetweenthesoftwaremodules,itisnecessarytodesignapowerfulstorageZoneprotectionfunction,butalsoconducivetosoftwarediagnosis;(3)Scalableprocessorstructure,canquicklyexpandtomeettheapplicationofhigh-performanceembeddedmicroprocessor;(4)ThepowerconsumptionoftheembeddedmicroprocessormustbeveryhighLow,especiallyforbattery-poweredembeddedsystemsusedinportablewirelessandmobilecomputingandcommunicationdevices.Thepowerconsumptioncanonlybemworevenμw.

3.Whatisanembeddedoperatingsystem?

Embeddedoperatingsystemisanoperatingsystemsoftwarethatsupportsembeddedsystemapplications.Itisanembeddedsystem(includinghardwareandsoftwaresystems).)Averyimportantcomponent,usuallyincludingtheunderlyinghardware-relateddriversoftware,systemkernel,devicedriverinterface,communicationprotocol,graphicalinterface,standardizedbrowser,etc.Browser.Theembeddedoperatingsystemhasthebasiccharacteristicsofageneraloperatingsystem,suchasbeingabletoeffectivelymanageincreasinglycomplexsystemresources;beingabletovirtualizehardware,freeingdevelopersfrombusydriverportingandmaintenance;beingabletoprovidelibraryfunctions,Drivers,toolsets,andapplications.Comparedwithgeneraloperatingsystems,embeddedoperatingsystemshavemoreprominentfeaturesintermsofsystemreal-timeefficiency,hardwaredependency,softwaresolidification,andapplicationspecificity.

Designprocess

1.Requirementanalysis

Determinethedesigntasksandgoals,andformulatespecificationdocumentsastheguidanceandacceptancecriteriaforthenextdesign.Demandanalysisoftenrequiresrepeatedexchangeswithuserstoclarifysystemfunctionalrequirements,performancerequirements,environment,reliability,cost,powerconsumption,resourcesandotherrequirements.

2.Architecturedesign

Architecturedesignistheoveralldesignoftheembeddedsystem.Itneedstodeterminetheoverallarchitectureoftheembeddedsystemanddividethesoftwareandhardwarefunctionally.Onthisbasis,determinethehardwareselectionoftheembeddedsystem(mainlytheprocessorselection),theselectionoftheoperatingsystemandtheselectionofthedevelopmentenvironment.

3.Hardwaredesign,productionandtesting

Atthisstage,itisnecessarytodeterminethefunctionalmodulesofthehardwarepartandtherelationshipbetweenthemodules,andcompletethecomponentsonthisbasisSelection,schematicdrawing,printedcircuitboard(PCB)design,hardwareassemblyandtesting,finaldeterminationandtestingoftargethardware.

4.Softwaredesign,implementationandtesting

Thispartofworkiscarriedoutinparallelandinteractivelywithhardwaredevelopment.Thesoftwaredesignmainlycompletesthepreparationofthebootprogram,thetransplantationoftheoperatingsystem,thedevelopmentofthedriver,andthewritingoftheapplicationsoftware.Afterthedesigniscompleted,thesoftwaredevelopmententerstherealizationstage.Thisstageismainlyaboutthegenerationofembeddedsoftware(compiling,linking),debuggingandcuringoperation,andfinallycompletingthesoftwaretest.

5.Systemintegration

Loadthecompletedsoftwaresystemintothemanufacturedhardwaresystem,andconductacomprehensivesystemtesttoverifywhetherthesystemfunctionscanbeimplementedcorrectly.Finally,Thecorrectsoftwareissolidifiedinthetargethardware.Theworkatthisstageisthemostcomplexandtime-consumingintheentiredevelopmentprocess,anditrequiresthesupportofcorrespondingauxiliarytoolsinparticular.

6.Systemperformancetestandreliabilitytest

Testwhetherthefinalsystemperformancemeetstheperformanceindicatorsandrequirementsofthedesignspecification.Ifitissatisfied,thecorrectsoftwarecanbesolidifiedinthetargethardware;ifitisnotsatisfied,intheworstcase,itisnecessarytoreturntotheinitialstageofthedesigntore-formulatethedesignplan.

Applicationfield

EmbeddedIndustrialComputerisaruggedizedandenhancedindustrialcomputer,whichcanbeusedasanindustrialcontrollertorunreliablyinanindustrialenvironment.Inlayman'sterms,anembeddedindustrialcomputerisacompactcomputerdesignedspecificallyforindustrialsites.

Embeddedindustrialcomputerscanbeflexiblyusedinharshenvironmentssuchastemperatureandusespace,includingautomotive,retail,surveillance,electronicbillboards,factorycontrolandotherapplicationmarketsthatrequirelow-powersystems.

Futureimpact

1:Embeddedsystempromotestheshapeandperformanceofthecomputertobemoreminiaturized,multi-functional,andlowpowerconsumption.

2:EmbeddedsystemThecomputerhasdevelopedfromthepreviousNormanystructuretomulti-processorparallelcomputing,greatlyimprovingoperatingefficiencyandstability!

3:Embeddedsystemshavebecomeamajorbranchofcomputertechnology!

4:Thedevelopmentofembeddedsystemshasbecomeanimportantsymbolofthedevelopmentofcomputertechnologytoday!

5:Changetheconceptoftraditionalminicomputersandmicrocomputers,sothatembeddedsystemsnolongerbecomecomputerhardwarecontrolSynonymouswithtechnology.Theperformanceofsomeembeddedsystemscansurpassthatofmicrocomputers!

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