Chapter 4 – Programming
4-7
VMEbus Interrupt Generation
The XVME-655 can generate VMEbus interrupts on all seven levels. There is a unique
STATUS/ID associated with each level. Upper bits are programmed in the STATUS/ID
register. The lowest bit is cleared if the source of the interrupt is a software interrupt, and
set for all other interrupt sources. Consult the Universe User’s Manual for a more in-
depth explanation.
VMEbus Reset Options
The XVME-655 resets the VMEbus according to the following conditions:
1.
Power on always causes the Universe chip to assert the VMEbus reset signal.
2.
The Universe chip may reset the VMEbus by asserting a software bit.
3.
The Toggle reset switch can reset the VMEbus when SW1-position 2 is closed.
Note
If SW1-position 1 is closed, the entire XVME-655 is reset.
You can also use the XVME-655 toggle switch to reset only the local XVME-655.
Note
SW1-position 2 must be open. SW1-position 5 must be closed.
PCI BIOS Functions
Special PCI BIOS functions provide a software interface to the Universe chip, providing
the PCI-to-VMEbus interface. You can invoke these PCI BIOS functions using a
function and subfunction code. You set up the host processor’s registers for the function
and subfunction desired and call the PCI BIOS software. The PCI BIOS function code is
B1h. Status is returned using the Carry flag ([CF]) and registers specific to the
subfunction invoked.
Interrupt 1Ah provides access to the PCI BIOS special functions for 16-bit callers.
Calling through a 32-bit protect mode entry point provides 32-bit (i.e., protect mode)
access.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com