IAR PowerPac RTOS User Guide

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For interrupt-driven sending, the task places the character(s) in the mailbox using OS_PutMail() orOS_PutMailCond(); the interrupt handler that is activated when a new character can be sent retrieves this characterwith OS_GetMailCond().For interrupt-driven receiving, the interrupt handler that is activated when a new character is received puts it in themailbox using OS_PutMailCond(); the task receives it using OS_GetMail() or OS_GetMailCond().A buffer for commands sent to a taskAssume you have one task controlling a motor, as you might have in applications that control a machine. A simple wayto give commands to this task would be to define a structure for commands. The message size would then be the sizeof this structure.Single-byte mailbox functionsIn many (if not the most) situations, mailboxes are used simply to hold and transfer single-byte messages. This is thecase, for example, with a mailbox that takes the character received or sent via serial interface, or normally with amailbox used as keyboard buffer. In some of these cases, time is very critical, especially if a lot of data is transferredin short periods of time.To minimize the overhead caused by the mailbox management of IAR PowerPac RTOS, variations on some mailboxfunctions are available for single-byte mailboxes. The general functions OS_PutMail(), OS_PutMailCond(),OS_GetMail(), and OS_GetMailCond() can transfer messages of sizes between 1 and 127 bytes each. Their singlebyteequivalents OS_PutMail1(), OS_PutMailCond1(), OS_GetMail1(), and OS_GetMailCond1() work thesame way with the exception that they execute much faster because management is simpler. It is recommended to usethe single-byte versions if you transfer a lot of single byte-data via mailboxes.The routines OS_PutMail1(), OS_PutMailCond1(), OS_GetMail1(), and OS_GetMailCond1() work exactlythe same way as their more universal equivalents and are therefore not described separately. The only difference is thatthey can only be used for single-byte mailboxes.62IAR PowerPac RTOSfor ARM CoresPPRTOS-2
MailboxesMailboxes API function overviewRoutineOS_CREATEMB()OS_PutMail()OS_PutMail1()OS_PutMailCond()OS_PutMailCond1()OS_PutMailFront()OS_PutMailFront1()OS_PutMailFrontCond()OS_PutMailFrontCond1()OS_GetMail()OS_GetMail1()OS_GetMailCond()OS_GetMailCond1()OS_GetMailTimed()OS_WaitMail()OS_ClearMB()OS_GetMessageCnt()OS_DeleteMB()Table 59: Mailboxes API overviewOS_CREATEMB()DescriptionMacro that creates a new mailbox.PrototypeExplanationMacro that creates a new mailbox.void OS_CREATEMB (OS_MAILBOX* pMB,unsigned char sizeofMsg,unsigned int maxnofMsg,void*pMsg);)ParameterDescriptionStores a new message of a predefined size in a mailbox.Stores a new single-byte message in a mailbox.Stores a new message of a predefined size in a mailbox, if the mailbox is able to acceptone more message.Stores a new single-byte message in a mailbox, if the mailbox is able to accept onemore message.Stores a new message of a predefined size into a mailbox in front of all othermessages. This new message will be retrieved first.Stores a new single-byte message into a mailbox in front of all other messages. Thisnew message will be retrieved first.Stores a new message of a predefined size into a mailbox in front of all othermessages, if the mailbox is able to accept one more message.Stores a new single-byte message into a mailbox in front of all other messages, if themailbox is able to accept one more message.Retrieves a new message of a predefined size from a mailbox.Retrieves a new single-byte message from a mailbox.Retrieves a new message of a predefined size from a mailbox, if a message is available.Retrieves a new single-byte message from a mailbox, if a message is available.Retrieves a new message of a predefined size from a mailbox, if a message is availablewithin a given time.Waits until a mail is available, but does not retrieve the message from the mailbox.Clears all messages in a specified mailbox.Returns number of messages currently in a specified mailbox.Deletes a specified mailbox.pMBPointer to a data structure of type OS_MAILBOX reserved for managing the mailbox.sizeofMsg Size of a message in bytes. ( 1
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IAR PowerPac RTOSUser GuidePPRTOS-2
Page 3 and 4:
PrefaceWelcome to the IAR PowerPac
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ContentsPreface ...................
Page 7 and 8:
ContentsOS_WaitCSema() ............
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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 and 32: Task routinesExampleint sec,min;voi
Page 33 and 34: Task routinesAdditional Information
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: MailboxesWhy mailboxes?In the prece
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
Page 87 and 88: Event objectsExampleOS_EVENT_Reset(
Page 89 and 90: 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
Page 101 and 102: InterruptsRules for interrupt handl
Page 103 and 104: InterruptsOS_LeaveInterruptNoSwitch
Page 105 and 106: InterruptsNesting interrupt routine
Page 107 and 108: Critical RegionsIntroductionCritica
Page 109 and 110: System variablesIntroductionThe sys
Page 111 and 112: Configuration for your targetsystem
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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
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RTOS-aware debuggingTimersA softwar
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DebuggingRuntime errorsSome error c
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DebuggingValue Define Description17
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Performance and resource usageThis
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Performance and resource usageThe c
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Performance and resource usage*/sta
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ReentranceAll routines that can be
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LimitationsThe following limitation
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Source code of kernel and libraryIn
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Additional modulesKeyboard manager:
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FAQ (frequently asked questions)Q:
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GlossaryActive TaskCooperativemulti
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IndexIndexAAdditional modules . . .
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IndexOS_WaitSingleEventTimed(). . .
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IAR PowerPac RTOS User Guide

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