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

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

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 ?

Hello Toby, Toby schrieb:

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. :-(

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) ?

Well, why don't you simply write some code to test which is true?