嵌入式LINUX-復(fù)習(xí)整理-2019

chplOverviewofembeddedsystemsDefinitionofembeddedsystem:TheSpecialpurposecomputersystemwhicharecenteredinapplication,basedoncomputertechnology,andtheirsoftwareandhardwarecanbecutout,theycanmeetthestrictrequirementsoftheapplicationsystemforfunction,reliability,cost,volume,andpower.Characteristicsofembeddedsystem:Forspecificapplications,therearegenerallyreal-timerequirements.It'saconstantlyinnovatingknowledgeintegrationsystemwhichintegratesadvaneedcomputertechnology,semiconductortechnology,electronictechnologyandcommunicationnetworktechnology.Embeddedsystemisorganicallyintegratedwiththespecificapplicationobject,soitsupgradeandreplacementisalsosynchronizedwiththespecificproducts.Thesoftwareandhardwaredesignofembeddedsystemfocusesonhighefficiency.Formeetingtheapplicationrequirementstothemaximumextent,reducingthecostisamajorproblemthatmustbeconsidered.Embeddedsystemsoftwareisgenerallysolidifiedinmemorychips,ratherthanstoredindisksandothercarriers.Thecompositionofembeddedsystem:Embeddedsystemisusuallycomposedofembeddedprocessor,embeddedperipherals,embeddedoperatingsystemandembeddedapplicationsoftware.Whatarethetypesofembeddedprocessors?EMPU(embeddedmicroprocessorunit)EMCU(embeddedmicrocontrollerunit)EDSP(embeddeddigitalsignalprocessor)ESOC(embeddedsystemonchip)Whatarethefunctionsofembeddedperipherals?Auxiliaryfunctions(輔助功能)suchasstorage,communication,protection,debugging,display,etc.Whatkindsofembeddedperipheralscanbedividedinto?Memory:RAM,SRAM,DRAM,ROM,EPROM,EEPROM,FLASH,etc.I/Ointerface:RS-232,IRDA（紅外線數(shù)據(jù)輸入輸出），I2C（現(xiàn)場總線）,SPI（串行外設(shè)接口）,USB,Ethernet,EPP,etc.InputandOutputEquipments:Keyboard,LCD,LED,CRT,Touchscreen,etc.Listsomekindsofembeddedoperatingsystem:WindowsCE,EmbeddedLinux,PalmOS,pSOS,DeltaOS,Android,MontaVistaReal-time:VxWorks,卩C/OS,卩C/OS1JQNX,Differenee betweenRTOS（Real-timeOperationSystem）andgeneralOS:1） Realtime:Fastresponsespeed:usExecutiontimeisdeterminedandpredictable.2） Smallsizecode:10~100KB3） Applicationprogramdevelopmentisdifficult4） Dedicateddevelopmenttools:Simulator,Compiler,Debugger…CharacteristicsofRTOS:1） Supportsynchronizationsynchronizationbetweenprocessescoordinateshareddata（協(xié)調(diào)共享數(shù)據(jù)）2） Prioritymechanism（ 優(yōu)先級(jí)機(jī)制）forinterruptandschedulingtasksSupportpreemptivescheduling（ 搶占式調(diào)度）3） DeterminedtaskswitchingandinterruptdelaytimeImportant!4） Supportforasynchronousevent（ 異步事件）responseResponsetoexternaleventswithinspecifiedtimeApplicationofembeddedsystem :1） Informationapplianeenetwork（ 信息家電網(wǎng)絡(luò)）2） MilitarydefenseTrafficelectronicequipmentsMedicalinstrumentsIndustrialcontrolChapter2.BasicConceptsmainstepstocreatingatargetLinuxsystem.Determinesystemcomponents..Configureandbuildthekernel..Buildtherootfilesystem..Setupbootsoftware