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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 is automatically assigned an IRQ to a PCI slot that has a card in it which requires an IRQ.
To install a PCI card, you need to set the correct "ADSEL" and "INT" (interrupt) assignment. Please refer to "Chapter
2-5" Installing a Riser Card for detail assignments.
IRQ Status Assignment
0 Used Timer
1 Used Keyboard
2 Used Second 8259
3 Used COM2
4 Used COM1
5 Used COM3
6 Used Floppy Disk
7 Used LPT1
8 Used RTC
9 Used LPT2 or Audio
10 Used COM4
11 Used LAN Adapter (on board)
12 Used PS/2 Mouse
13 Used Coprocessor
14 Used Hard Disk (IDE 1)
15 Used Reserved (IDE 2)
2-8. Assigning DMA Channels for ISA Cards
Since ISA cards, both Legacy and PnP may also need to use a DMA (direct memory access) channel, DMA
assignments for this motherboard are handled the same way as the IRQ assignment process described above. You
can select a DMA channel in the PCI and PnP configuration section of the BIOS setup utility. In the BIOS setup, you
should choose "Yes" for those IRQ's and DMA's you wish to reserve for Legacy cards.