vxworks嵌入式操作系统

嵌入式软件VxWorks编程介绍

邹昕光哈尔滨工业大学自动化测控所联系电话：86413531-609

E-mail：xgzou@vxworks嵌入式操作系统共93页，您现在浏览的是第1页!AgendaTaskIntertaskmunicationISRvxworks嵌入式操作系统共93页，您现在浏览的是第2页!TaskEachtaskhasitsowncontext,whichistheCPUenvironmentandsystemresourcesthatthetaskseeseachtimeitisscheduledtorunbythekernel.Atask’scontextissavedinthetaskcontrolblock(TCB).vxworks嵌入式操作系统共93页，您现在浏览的是第3页!TaskAtask’scontextincludes:-athreadofexecution;thatis,thetask’sprogramcounter-theCPUregistersand(optionally)floating-pointregisters-I/Oassignmentsforstandardinput,output,anderror-adelaytimer-atime-slicetimer-kernelcontrolstructures-signalhandlers-debuggingandperformancemonitoringvaluesvxworks嵌入式操作系统共93页，您现在浏览的是第4页!TaskSchedulerControlRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第5页!TaskControlRoutinevxworks嵌入式操作系统共93页，您现在浏览的是第6页!TaskSpawnvxworks嵌入式操作系统共93页，您现在浏览的是第7页!TaskInformationRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第8页!TaskDeletingRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第9页!TaskControlRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第10页!SharedCodeandReentrancyAsinglecopyofcodeexecutedbymultipletasksiscalledsharedcode.Asubroutineisreentrantifasinglecopyoftheroutinecanbecalledfromseveraltaskcontextssimultaneouslywithoutconflict.Modifyglobalorstaticvariables.vxworks嵌入式操作系统共93页，您现在浏览的是第11页!DynamicStackVariablesvxworks嵌入式操作系统共93页，您现在浏览的是第12页!TaskVariablesvxworks嵌入式操作系统共93页，您现在浏览的是第13页!SharedDataStructuresGlobalvariablesLinearbuffersRingbuffersLinkedlistsPointersvxworks嵌入式操作系统共93页，您现在浏览的是第14页!MutualExclusionDisableinterruptsDisablepreemptionResourcelockingwithsemaphoresvxworks嵌入式操作系统共93页，您现在浏览的是第15页!PreemptivelocksLessrestrictiveformofmutualexclusion.Noothertaskisallowedtopreemptivethecurrentexecutingtask,ISRareabletoexecute.Tasksofhigherpriorityareunabletoexecuteuntilthelockingtaskleavesthecriticalregion.vxworks嵌入式操作系统共93页，您现在浏览的是第16页!SemaphoreControlRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第17页!BinarySemaphorevxworks嵌入式操作系统共93页，您现在浏览的是第18页!BinarySemaphore-MutualExclusionvxworks嵌入式操作系统共93页，您现在浏览的是第19页!BinarySemaphore-Synchronizationvxworks嵌入式操作系统共93页，您现在浏览的是第20页!MutualSemaphore-RecursiveResourceAccessvxworks嵌入式操作系统共93页，您现在浏览的是第21页!CountingSemaphoresvxworks嵌入式操作系统共93页，您现在浏览的是第22页!MessageQueuesvxworks嵌入式操作系统共93页，您现在浏览的是第23页!MessageQueueExamplevxworks嵌入式操作系统共93页，您现在浏览的是第24页!MessageQueueExamplevxworks嵌入式操作系统共93页，您现在浏览的是第25页!PipesPipesprovideanalternativeinterfacetothemessagequeuefacilitythatgoesthroughtheVxWorksI/Osystem.vxworks嵌入式操作系统共93页，您现在浏览的是第26页!RPCRemoteProcedureCalls(RPC)isafacilitythatallowsaprocessonamachinetocallaprocedurethatisexecutedbyanotherprocessoneitherthesamemachineoraremotemachine.vxworks嵌入式操作系统共93页，您现在浏览的是第27页!SignalSignalsasynchronouslyalterthecontrolflowofatask.AnytaskorISRcanraiseasignalforaparticulartask.Thetaskbeingsignaledimmediatelysuspendsitscurrentthreadofexecutionandexecutesthetask-specifiedsignalhandlerroutine.vxworks嵌入式操作系统共93页，您现在浏览的是第28页!EventSendingandReceivingEvents Eventscanbesentfromaresourcetoatask,fromanISRtoatask,ordirectlybetweentwotasks.WaitingforEvents Ataskcanwaitformultipleeventsfromoneormoreresources.Eachsourcecansendmultipleevents,andataskcanalsowaittoreceiveonlyoneevent,orallevents.vxworks嵌入式操作系统共93页，您现在浏览的是第29页!EventFreeResourceDefinitionMutexSemaphore -Amutexsemaphoreisconsideredfreewhenitnolongerhasanownerandnooneispendingonit.BinarySemaphore -Abinarysemaphoreisconsideredfreewhennotaskownsitandnooneiswaitingforit.vxworks嵌入式操作系统共93页，您现在浏览的是第30页!EventSendingandReceivingEvents Eventscanbesentfromaresourcetoatask,fromanISRtoatask,ordirectlybetweentwotasks.WaitingforEvents Ataskcanwaitformultipleeventsfromoneormoreresources.Eachsourcecansendmultipleevents,andataskcanalsowaittoreceiveonlyoneevent,orallevents.vxworks嵌入式操作系统共93页，您现在浏览的是第31页!WatchdogTimersCallsvxworks嵌入式操作系统共93页，您现在浏览的是第32页!EventRegisterRoutinevxworks嵌入式操作系统共93页，您现在浏览的是第33页!intConnectRoutinevxworks嵌入式操作系统共93页，您现在浏览的是第34页!Runashellvxworks嵌入式操作系统共93页，您现在浏览的是第35页!Cmandsinshellvxworks嵌入式操作系统共93页，您现在浏览的是第36页!ShellCommands:tdvxworks嵌入式操作系统共93页，您现在浏览的是第37页!ShellCommands:tivxworks嵌入式操作系统共93页，您现在浏览的是第38页!ShellCommands:twvxworks嵌入式操作系统共93页，您现在浏览的是第39页!ShellCommands:dvxworks嵌入式操作系统共93页，您现在浏览的是第40页!ShellCommands:dvxworks嵌入式操作系统共93页，您现在浏览的是第41页!ShellCommands:pwd&cdvxworks嵌入式操作系统共93页，您现在浏览的是第42页!ShellCommands:rebootvxworks嵌入式操作系统共93页，您现在浏览的是第43页!ShellCommands:semaphorevxworks嵌入式操作系统共93页，您现在浏览的是第44页!ShellCommands:semaphorevxworks嵌入式操作系统共93页，您现在浏览的是第45页!ShellCommands:MessageQueuevxworks嵌入式操作系统共93页，您现在浏览的是第46页!ShellCommands:MessageQueuevxworks嵌入式操作系统共93页，您现在浏览的是第47页!ShellCommands:MessageQueuevxworks嵌入式操作系统共93页，您现在浏览的是第48页!TaskThedefaulttaskschedulingalgorithminwindispriority-basedpreemptivescheduling.RoundRobinisanoptionalalgorithm.Thewindkernelhas256prioritylevels,numbered0through255.Priority0isthehighestandpriority255isthelowest.vxworks嵌入式操作系统共93页，您现在浏览的是第49页!TaskTaskLock WhenataskdisablestheschedulerbycallingtaskLock(),nopriority-basedpreemptioncantakeplacewhilethattaskisrunning. Ifthetaskexplicitlyblocksorsuspends,theschedulerselectsthenexthighest-priorityeligibletasktoexecute. Whenthepreemption-lockedtaskunblocksandbeginsrunningagain,preemptionisagaindisabled. ThetaskLock()preventtaskcontextswitching,butdonotlockoutinterrupthandling.vxworks嵌入式操作系统共93页，您现在浏览的是第50页!TasktaskSpawnTaskNameandIDRoutinesTaskInformationRoutinesTaskDeletingRoutinesTaskControlRoutinesTaskHookRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第51页!TaskNameandIDRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第52页!TaskInformationRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第53页!TaskDeletingRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第54页!TaskHookRoutinesvxworks嵌入式操作系统共93页，您现在浏览的是第55页!CodeReentrancySolutionsDynamicStackVariablesGuardedGlobalandStaticVariablesTaskVariablesvxworks嵌入式操作系统共93页，您现在浏览的是第56页!GuardedGlobalandStaticVariablesProvidingamutual-exclusionmechanismtoprohibittasksfromsimultaneouslyexecutingcriticalsectionsofcode.vxworks嵌入式操作系统共93页，您现在浏览的是第57页!IntertaskCommunicationSharedDataStructureMutualExclusionSemaphoresMessageQueuesPipesNetworkIntertaskCommunicationSignalsvxworks嵌入式操作系统共93页，您现在浏览的是第58页!SharedDataStructuresvxworks嵌入式操作系统共93页，您现在浏览的是第59页!DisableInterruptsThemostpowerfulmethodItpreventsthesystemfromrespondingtoexternaleventsforthedurationoftheselocks.Keepthedurationofinterruptlockoutsshort.vxworks嵌入式操作系统共93页，您现在浏览的是第60页!SemaphoresHighlyoptimizedandprovidethefastestintertaskmunicationmechanisminVxWorks.ThreetypesofWindsemaphores: -Binary -Mutualexclusion -Countingvxworks嵌入式操作系统共93页，您现在浏览的是第61页!BinarySemaphorevxworks嵌入式操作系统共93页，您现在浏览的是第62页!BinarySemaphore-MutualExclusionvxworks嵌入式操作系统共93页，您现在浏览的是第63页!BinarySemaphore-Synchronizationvxworks嵌入式操作系统共93页，您现在浏览的是第64页!BinarySemaphore-Synchronizationvxworks嵌入式操作系统共93页，您现在浏览的是第65页!MutualSemaphore-RecursiveResourceAccessvxworks嵌入式操作系统共93页，您现在浏览的是第66页!MessageQueueMessagequeuesallowavariablenumberofmessages,eachofvariablelength,tobequeued.TasksandISRscansendmessagestoamessagequeue,andtaskscanreceivemessageformamessagequeue.Multipletaskscansendtoandreceivefromthesamemessagequeue.Full-duplexmunicationbetweentwotasksgenerallyrequirestwomessagequeues,oneforeachdirection.vxworks嵌入式操作系统共93页，您现在浏览的是第67页!WindMessageQueueControlvxworks嵌入式操作系统共93页，您现在浏览的是第68页!MessageQueueExamplevxworks嵌入式操作系统共93页，您现在浏览的是第69页!MessageQueuesvxworks嵌入式操作系统共93页，您现在浏览的是第70页!SocketsInVxWorks,thebasisofintertaskmunicationacrossthenetworkissockets.VxWorkssupportstheInternetprotocolsTCPandUDP.TCPprovidesreliable,guaranteed,two-waytransmissionofdatawithstreamsockets.UDPprovidesasimplebutlessrobustformofmunication.vxworks嵌入式操作系统共93页，您现在浏览的是第71页!SignalSignalsasynchronouslyalterthecontrolflowofatask.AnytaskorISRcanraiseasignalforaparticulartask.Thetaskbeingsignaledimmediatelysuspendsitscurrentthreadofexecutionandexecutesthetask-specifiedsignalhandlerroutine.vxworks嵌入式操作系统共93页，您现在浏览的是第72页!EventVxWorkseventsaremeansofmunicationbetweentasksandinterruptroutine,betweentasksandothertasks,orbetweentasksandVxWorksobjects.VxWorksobjectsarereferredtoasresourcessuchassemaphoresandmessagequeue.vxworks嵌入式操作系统共93页，您现在浏览的是第73页!EventRegisteringforEvents Onlyonetaskcanregisteritselftoreceiveeventsfromaresource.Ifanothertasksubsequentlyregisterswiththesameresource,thepreviouslyregisteredtaskisautomaticallyunregistered.FreeingResource Whenaresourcesendstoatasktoindicatethatitisfree,itdoesnotmeanthatresourceisreserved.vxworks嵌入式操作系统共93页，您现在浏览的是第74页!EventFreeResourceDefinitionCountingSemaphore -Acountingsemaphoreisconsideredfreewhenitscountsisnonzeroandnooneispendingonit.MessageQueue -Amessagequeueisconsideredfreewhenamessagequeueispresentinthequeueandnooneispendingforthearrivalofamessageinthatqueue.vxworks嵌入式操作系统共93页，您现在浏览的是第75页!WatchdogTimersVxWorksincludesawatchdog-timermechanismthatallowsanyCfunctiontobeconnecttoaspecifiedtimedelay.Functioninvokedbywatchdogtimersexecuteasinterruptservicecodea