IAR PowerPac RTOS User Guide

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OS_SetTimeSlice()DescriptionAssigns a specified timeslice value to a specified task.Prototypeunsigned char OS_SetTimeSlice (OS_TASK* pTask,unsigned char TimeSlice);ParameterDescriptionpTaskTimeSliceTable 12: OS_SetTimeSlice() parameter listReturn valuePrevious timeslice value of the task as unsigned char.Additional InformationCan be called at any time from any task or software timer. Setting the timeslice value only affects the tasks running inround-robin mode. This means another task with the same priority must exist.The new timeslice value is interpreted as reload value. It is used after the next activation of the task. It does not affectthe remaining timeslice of a running task.OS_Suspend()DescriptionSuspends the specified task.Prototypevoid OS_Suspend (OS_TASK* pTask);ParameterDescriptionAdditional InformationIf pTask is the NULL pointer, the current task suspends.If the function succeeds, execution of the specified task is suspended and the task's suspend count is incremented. Thespecified task will be suspended immediately. It can only be restarted by a call of OS_Resume().Every task has a suspend count with a maximum value of OS_MAX_SUSPEND_CNT. If the suspend count is greater thanzero, the task is suspended.In debug versions of IAR PowerPac RTOS, calling OS_Suspend() more often than OS_MAX_SUSPEND_CNT timeswithout calling OS_Resume(), the task's internal suspend count is not incremented and OS_Error() is called witherror OS_ERR_SUSPEND_TOO_OFTEN.OS_Resume()DescriptionDecrements the suspend count of the specified task and resumes it, if the suspend count reaches zero.Prototypevoid OS_Resume (OS_TASK* pTask);ParameterDescriptionPointer to a data structure of type OS_TASK.New timeslice value for the task. Must be within the following range:1
Task routinesAdditional InformationThe specified task's suspend count is decremented. If the resulting value is 0, the execution of the specified task isresumed.If the task is not blocked by other task blocking mechanisms, the task will be set back in ready state and continuesoperation according to the rules of the scheduler.In debug versions of IAR PowerPac RTOS, the OS_Resume() function checks the suspend count of the specified task.If the suspend count is 0 when OS_Resume() is called, the specified task is not currently suspended and OS_Error()is called with error OS_ERR_RESUME_BEFORE_SUSPEND.OS_GetSuspendCnt()DescriptionThe function returns the suspension count and thus suspension state of the specified task. This function may be usedfor examining whether a task is suspended by previous calls of OS_Suspend().Prototypeunsigned char OS_GetSuspendCnt (OS_TASK* pTask);ParameterDescriptionpTaskPointer to a data structure of type OS_TASK.Table 15: OS_GetSuspendCnt() parameter listReturn valueSuspension count of the specified task as unsigned character value.0: Task is not suspended.>0: Task is suspended by at least one call of OS_Suspend().Additional InformationIf pTask does not specify a valid task, the debug version of IAR PowerPac RTOS calls OS_Error(). The releaseversion of IAR PowerPac RTOS can not check the validity of pTask and may therefore return invalid values ifpTask does not specify a valid task. When tasks are created and terminated dynamically, OS_IsTask() may be calledprior calling OS_GetSuspendCnt() to examine whether the task is valid. The remturned value can be used for resuminga suspended task by calling OS_Resume() as often as indicated by the returned value.Example/* Demo-function to illustrate the use of OS_GetSuspendCnt() */void ResumeTask(OS_TASK* pTask) {unsigned char SuspendCnt;SuspendCnt = OS_GetSuspendCnt(pTask);while(SuspendCnt > 0) {OS_Resume(pTask); /* May cause a task switch */SuspendCnt--;}}OS_Terminate()DescriptionEnds (terminates) a task.Prototypevoid OS_Terminate (OS_TASK* pTask);ParameterDescriptionpTaskPointer to a data structure of type OS_TASK which is used as task control block (and reference)for this task.Table 16: OS_Terminate() parameter listAdditional InformationIf pTask is the NULL pointer, the current task terminates. The specified task will terminate immediately. The memoryused for stack and task control block can be reassigned.PPRTOS-233
Page 1 and 2: IAR PowerPac RTOSUser GuidePPRTOS-2
Page 3 and 4: PrefaceWelcome to the IAR PowerPac
Page 5 and 6: ContentsPreface ...................
Page 7 and 8: ContentsOS_WaitCSema() ............
Page 9 and 10: ContentsOS_LeaveInterrupt() .......
Page 11 and 12: Introduction to IAR PowerPacRTOSWha
Page 13 and 14: Basic conceptsTasksIn this context,
Page 15 and 16: Basic conceptsPREEMPTIVES MULTITASK
Page 17 and 18: Basic conceptsMAILBOXES AND QUEUESA
Page 19 and 20: Basic conceptsThe active task may b
Page 21 and 22: Basic conceptsThe flowchart below i
Page 23 and 24: Basic conceptsLIST OF LIBRARIESIn y
Page 25 and 26: Task routinesIntroductionA task tha
Page 27 and 28: Task routinesOS_CREATETASK() can be
Page 29 and 30: Task routinesExampleThe following e
Page 31: Task routinesExampleint sec,min;voi
Page 35 and 36: Task routinesReturn valueOS_TASKID:
Page 37 and 38: Software timersSoftware timerA soft
Page 39 and 40: Software timers#define OS_CREATETIM
Page 41 and 42: Software timersOS_SetTimerPeriod()D
Page 43 and 44: Software timersAdditional Informati
Page 45 and 46: Software timersAdditional Informati
Page 47 and 48: Software timersExampleOS_TIMER TIME
Page 49 and 50: Resource semaphoresIntroductionReso
Page 51 and 52: Resource semaphoresResource semapho
Page 53 and 54: Resource semaphoresOS_Request()Desc
Page 55 and 56: Counting SemaphoresIntroductionCoun
Page 57 and 58: Counting SemaphoresPrototypevoid OS
Page 59 and 60: Counting SemaphoresReturn value0: I
Page 61 and 62: MailboxesWhy mailboxes?In the prece
Page 63 and 64: MailboxesMailboxes API function ove
Page 65 and 66: MailboxesExampleSingle-byte mailbox
Page 67 and 68: MailboxesPrototypevoid OS_GetMail (
Page 69 and 70: MailboxesOS_WaitMail()DescriptionWa
Page 71 and 72: QueuesWhy queues?In the preceding c
Page 73 and 74: QueuesReturn valueThe size of the r
Page 75 and 76: QueuesExamplestatic void MemoryTask
Page 77 and 78: Task eventsIntroductionTask events
Page 79 and 80: Task eventsExampleOS_WaitEventTimed
Page 81 and 82: Task eventsPrototypechar OS_ClearEv
Page 83 and 84:
Event objectsIntroductionEvent obje
Page 85 and 86:
Event objectsExampleif (OS_EVENT_Wa
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Event objectsExampleOS_EVENT_Reset(
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Heap type memory managementANSI C o
Page 91 and 92:
Fixed block size memory poolsIntrod
Page 93 and 94:
Fixed block size memory poolsProtot
Page 95 and 96:
Fixed block size memory poolsProtot
Page 97 and 98:
StacksIntroductionThe stack is the
Page 99 and 100:
InterruptsIntroductionIn this chapt
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InterruptsRules for interrupt handl
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InterruptsOS_LeaveInterruptNoSwitch
Page 105 and 106:
InterruptsNesting interrupt routine
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Critical RegionsIntroductionCritica
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System variablesIntroductionThe sys
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Configuration for your targetsystem
Page 113 and 114:
Time measurementIntroductionIAR Pow
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Time measurementPrototypeU32 OS_Get
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Time measurementPrototypeOS_U32 OS_
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RTOS-aware debuggingThis chapter de
Page 121 and 122:
RTOS-aware debuggingTimersA softwar
Page 123 and 124:
DebuggingRuntime errorsSome error c
Page 125 and 126:
DebuggingValue Define Description17
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Performance and resource usageThis
Page 129 and 130:
Performance and resource usageThe c
Page 131 and 132:
Performance and resource usage*/sta
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ReentranceAll routines that can be
Page 135 and 136:
LimitationsThe following limitation
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Source code of kernel and libraryIn
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Additional modulesKeyboard manager:
Page 141 and 142:
FAQ (frequently asked questions)Q:
Page 143 and 144:
GlossaryActive TaskCooperativemulti
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IndexIndexAAdditional modules . . .
Page 147:
IndexOS_WaitSingleEventTimed(). . .
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IAR PowerPac RTOS User Guide

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