Assigning Dma Channels For Isa Cards - Asus P I-P65UP8 CP6ND User Manual

III. INSTALLATION
Some expansion cards need to use an IRQ to operate. Generally an IRQ must be
exclusively assigned to one use. In a standard design there are 16 IRQs available but
most of them are already in use, leaving 6 IRQs free for expansion cards.
Both ISA and PCI expansion cards may require to use IRQs. System IRQs are avail-
able to cards installed in the ISA expansion bus first, then any remaining IRQs are
available to PCI cards. Currently, there are two types of ISA cards. The original ISA
expansion card design, now referred to as legacy ISA cards, requires that you con-
figure the card's jumpers manually and then install it in any available slot on the ISA
bus. You may use Microsoft Diagnostics (MSD.EXE) utility located in the Win-
dows directory to see a map of your used and free IRQs. If you use Windows 95, the
Resources tab under Device Manager displays the resource settings being used by
a particular device (to gain access, double-click the System icon under the Control
Panel program). Ensure that no two devices share the same IRQs or your computer
will experience problems when those two devices are in use at the same time.
To simplify this process, the baseboard complies with the Plug and Play (PnP) speci-
fication, which was developed to allow automatic system configuration whenever a
PnP-compliant card is added to the system. For PnP cards, IRQs are assigned auto-
matically from those available.
If the system has both legacy and PnP ISA cards installed, IRQs are assigned to PnP
cards from those not used by legacy cards. The PCI and PNP configuration section
of the BIOS setup utility can be used to assign which IRQs are being used by legacy
cards. For older legacy cards that do not work with the BIOS, you may contact your
vendor for an ISA Configuration Utility.
An IRQ number is automatically assigned to PCI expansion cards after those used
by legacy and PnP ISA cards. In the PCI bus design, the BIOS automatically assigns
an IRQ to a PCI slot that contains a card requiring an IRQ. To install a PCI card, you
need to set the INT (interrupt) assignment. Since all the PCI slots on this baseboard
use an INTA #, set the jumpers on your PCI cards to INT A.

Assigning DMA Channels for ISA Cards

Some ISA cards, both legacy and PnP, may also need to use a DMA (Direct Memory
Access) channel. DMA assignments for this baseboard are handled the same way as
the IRQ assignment process described earlier. You can select a DMA channel in the
PCI and PnP configuration section of the BIOS Setup utility.
IMPORTANT: To avoid conflicts, reserve the necessary IRQs and DMAs for legacy
ISA cards (under PNP AND PCI SETUP of the BIOS SOFTWARE, choose Yes in
IRQ xx Used By ISA and DMA x Used By ISA for those IRQs and DMAs you want to
reserve).
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