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Regarding Location monitors and MVME5100.What exactly is a "LOCATION MONITOR?"

Discussion in 'Embedded' started by ssubbarayan, Jun 28, 2005.

  1. ssubbarayan

    ssubbarayan Guest

    Dear all,
    Can some one explain me what exactly is meant by "LOCATION
    MONITORS?"I have come across this term often when ever theres a
    reference to the Motorola processors and MVME5100.Whats the purpose of
    this location monitors?While working with Vxworks also in the BSP I
    have come across LOCATION MONITORS but never got an oppurtunity to work
    in it.Is this available on our normal X86 processors?
    It would be helpful if someone could throw some light and point me to
    some links to understand abt LOCATION MONITORS...

    ssubbarayan, Jun 28, 2005
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  2. ssubbarayan

    Martin Raabe Guest

    Hello s.subbarayan,
    a location monitor is an entity of the VMEbus. So if you have a
    VMEbus-based x86 board, yes, there is a good chance, you have access to
    such a location monitor.
    A location monitor is a address comparator, which triggers an IRQ when
    the address to compare with is seen on the address bus, usually the
    external, here the VMEbus. The comparison may be parameterized according
    to the implementation of the VMEbus interface, it could be a 4kb address
    range or like.
    There also is a chance that the comparator triggers, when this address
    is used from inside the borad it self, so this could be a method to
    request an hardwar interrupt via software!
    There are also other busses where location monitoring is implemented or
    could be implemented e.g. Compact PCI. But it is not bound to a
    processor family, bus architecture or such. It just is a commonly seen
    implementation in the VMEbus world.

    Hope it helps.

    Best Regards
    Martin Raabe, Jun 28, 2005
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  3. ssubbarayan

    Toby Guest

    The problem is though - it is not well documented in a single place. In
    particular how the memory location is configured. (The location within
    the 4Kb block can be configured - just don't know the magic needed to
    map / locate the 4Kb in the address space.

    Any help ?
    Toby, Jun 28, 2005
  4. ssubbarayan

    Martin Raabe Guest

    Hello Toby,
    Since this is a board specific hardware feature, you need to take a look
    into the board and VMEbus Interfaace Chip specification.
    There is no way around. :-(
    Martin Raabe, Jun 28, 2005
  5. ssubbarayan

    Doug Guest

    We (Toby and myself) have had a good hunt through all the Tundra II
    documentation but still don't seem to be able to find out how to
    specifiy the actual location of the window to be monitored by the
    location monitor :-(

    Does anyone know what exactly the LM_BS register specifies ? we are a
    little unsure as to whether this is the offset within the 4kb window
    .... or the actual base address of the window its self in our target
    address space (e.g. in this case, A24) ?
    Doug, Jun 28, 2005
  6. Well, why don't you simply write some code to test which is true?
    Colonel Forbin, Jul 11, 2005
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