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AST RESEARCH, INC.            TECHNICAL BULLETIN # 1033               12-14-94

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                   PLUG-N-PLAY SYSTEMS AND ISACU IRQ 2 CONFLICT


PROBLEM:        The AST ISACU does not allow the use of IRQ 2(9) on
                Plug-n-Play systems. The system returns a resource conflict
                error message.

CAUSE:          IRQ2 is used by the interrupt controller on the system board
                and it is not available.

SYSTEMS
AFFECTED:       All Plug-n-Play systems.

SOLUTION:       When installing a non-Legacy ISA adapter board in a
                Plug-n-Play system that requires IRQ 2(9), select IRQ 9(2) in
                the ICU program.  (Legacy refers to any ISA board which is not
                designed to support Plug-n-Play.)  Follow the steps below:

                1) Add in a VGA adapter to the system to disable the integrated
                   VGA adapter.

                2) Run the ICU utility.  Since the integrated VGA is no longer
                   installed, IRQ2 (shown as 9(2) in the ICU utility) is now
                   available.  (Because IRQ 2 is used as a cascade to IRQ 9,
                   the system board will always show 2(9) in use.  The same
                   interrupt will be available to the user as 9(2).)  Configure
                   the  desired legacy board for IRQ2 (the Token Ring adapter
                   configuration file will display interrupts as IRQx while
                   the resources list will display it as 9(2))and save the
                   configuration.

                3) Remove the add-in VGA card and restart the system.  Since
                   IRQ2 is now configured for another board, the integrated
                   VGA adapter will select another IRQ.  (If it is desired
                   that the VGA use a specific IRQ, the user can install
                   phantom ISA adapters which use all interrupts except the
                   one desired for the VGA adapter.  When the system is
                   restarted, the integrated VGA adapter will then select from
                   among the remaining interrupts to configure itself.)

                4) Run ICU again.  Inspect the new settings.  If the same
                   setting will be required for multiple systems, save the
                   current configuration under the Advanced menu item to a
                   file.  Save the configuration and quit the utility.  (This
                   file can be used by copying it to other systems and reading
                   it in directly through the Advanced menu item, rather than
                   using the first 3 steps listed above.)