> >I have a question regarding how the VME Interrupts map to the PC's 16
> >hardware IRQs. My device is properly setting IRQ level 6, for example,
> >yet I don't understand how to register for this interrupt on my
> >machine. Does this truly just map to hardware interrupt 6? If someone
> >could explain anything regarding this topic, maybe it will hit me.

> This can of course be implimented in various ways. The VME interrupt
> structure maps naturally to the type of interrupt structure used by
> Motorola processors. The PC interrupt structure is a lot less
> flexible. The VME interrupts are probably handled by totally seperate
> hardware, which can be programmed for one or more interrupts, and for
> which a priority and vector can be assigned. This hardware would then
> have one or more interrupt signals which would be connected to one or
> more of the normal PC interrupt controller.  So to enable interrupts
> you would probablt have to set up the "VME" interrupt hardware as
> well as the PC interrupt hardware. If the VME interrupts maps to one
> PC IRQ, then your interrupt routine would read the VME interrupt
> vector address, and use this information to jump to the correct
> handler.  The details vary, but this "double" set of interrupt
> hardware is fairly common on VME CPU boards.

> Hope this helps

> Regards
>   Anton Erasmus