Watch dog timer functionality - VxWorks

This is a discussion on Watch dog timer functionality - VxWorks ; Hi, I am not aware of watch dog timer functionality in vxworks application.What is the watch dog timer task priority in particular vxworks application?Is this depends on application or it remains constant to all the applications?Please explain me in detail ...

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Thread: Watch dog timer functionality

  1. Watch dog timer functionality

    Hi,

    I am not aware of watch dog timer functionality in vxworks
    application.What is the watch dog timer task priority in particular
    vxworks application?Is this depends on application or it remains
    constant to all the applications?Please explain me in detail regarding
    watch dog timer task execution in vxworks application.


    Regards,
    JS


  2. Re: Watch dog timer functionality

    "santy321@gmail.com" wrote:

    > Hi,
    >
    > I am not aware of watch dog timer functionality in vxworks
    >application.


    From the wdLib entry in the VxWorks OS Libraries API Reference manual.

    ---
    This library provides a general watchdog timer facility. Any task may
    create a watchdog timer and use it to run a specified routine in the
    context of the system-clock ISR, after a specified delay.

    Once a timer has been created with wdCreate( ), it can be started with
    wdStart( ). The wdStart( ) routine specifies what routine to run, a
    parameter for that routine, and the amount of time (in ticks) before the
    routine is to be called. (The timeout value is in ticks as determined by
    the system clock; see sysClkRateSet( ) for more information.) After the
    specified delay ticks have elapsed (unless wdCancel( ) is called first
    to cancel the timer) the timeout routine is invoked with the parameter
    specified in the wdStart( ) call. The timeout routine is invoked whether
    the task which started the watchdog is running, suspended, or deleted.

    The timeout routine executes only once per wdStart( ) invocation; there
    is no need to cancel a timer with wdCancel( ) after it has expired, or
    in the expiration callback itself. Note that the timeout routine is
    invoked at interrupt level, rather than in the context of the task. Thus,
    there are restrictions on what the routine may do. Watchdog routines are
    constrained to the same rules as interrupt service routines. For example,
    they may not take semaphores, issue other calls that may block, or use
    I/O system routines like printf( ).
    ---

    > What is the watch dog timer task priority in particular
    >vxworks application?Is this depends on application or it remains
    >constant to all the applications?Please explain me in detail regarding
    >watch dog timer task execution in vxworks application.


    There is no watchdog timer task. Instead, the hardware timer that drives
    the watch dog timers generates interrupts at a programmable rate and the
    associated interrupt service routine scans each timer, decrements counters
    associated with running timers, and calls the timeout routine associated
    with any watchdog timers that are found to have expited.

    --
    ================================================== ======================
    Michael Kesti | "And like, one and one don't make
    | two, one and one make one."
    mrkesti at comcast dot net | - The Who, Bargain

  3. Re: Watch dog timer functionality

    "santy321@gmail.com" wrote:

    > Hi,
    >
    > I am not aware of watch dog timer functionality in vxworks
    >application.


    From the wdLib entry in the VxWorks OS Libraries API Reference manual.

    ---
    This library provides a general watchdog timer facility. Any task may
    create a watchdog timer and use it to run a specified routine in the
    context of the system-clock ISR, after a specified delay.

    Once a timer has been created with wdCreate( ), it can be started with
    wdStart( ). The wdStart( ) routine specifies what routine to run, a
    parameter for that routine, and the amount of time (in ticks) before the
    routine is to be called. (The timeout value is in ticks as determined by
    the system clock; see sysClkRateSet( ) for more information.) After the
    specified delay ticks have elapsed (unless wdCancel( ) is called first
    to cancel the timer) the timeout routine is invoked with the parameter
    specified in the wdStart( ) call. The timeout routine is invoked whether
    the task which started the watchdog is running, suspended, or deleted.

    The timeout routine executes only once per wdStart( ) invocation; there
    is no need to cancel a timer with wdCancel( ) after it has expired, or
    in the expiration callback itself. Note that the timeout routine is
    invoked at interrupt level, rather than in the context of the task. Thus,
    there are restrictions on what the routine may do. Watchdog routines are
    constrained to the same rules as interrupt service routines. For example,
    they may not take semaphores, issue other calls that may block, or use
    I/O system routines like printf( ).
    ---

    > What is the watch dog timer task priority in particular
    >vxworks application?Is this depends on application or it remains
    >constant to all the applications?Please explain me in detail regarding
    >watch dog timer task execution in vxworks application.


    There is no watchdog timer task. Instead, the hardware timer that drives
    the watch dog timers generates interrupts at a programmable rate and the
    associated interrupt service routine scans each timer, decrements counters
    associated with running timers, and calls the timeout routine associated
    with any watchdog timers that are found to have expited.

    --
    ================================================== ======================
    Michael Kesti | "And like, one and one don't make
    | two, one and one make one."
    mrkesti at comcast dot net | - The Who, Bargain

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