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ASUS TUSL2 User’s Manual 29
3. HARDWARE SETUP
Expansion Cards
3. H/W SETUP
3.7.2 Assigning IRQs for Expansion Cards
Some expansion cards need an IRQ to operate. Generally, an IRQ must be exclu-
sively 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. If your
motherboard has PCI audio onboard, an additional IRQ will be used. If your moth-
erboard also has MIDI enabled, another IRQ will be used, leaving 4 IRQs free.
Standard Interrupt Assignments
IRQ Priority Standard Function
0 1 System Timer
1 2 Keyboard Controller
2 N/A Programmable Interrupt
3* 11 Communications Port (COM2)
4* 12 Communications Port (COM1)
5* 13 Sound Card (sometimes LPT2)
6 14 Floppy Disk Controller
7* 15 Printer Port (LPT1)
8 3 System CMOS/Real Time Clock
9* 4 ACPI Mode when enabled
10* 5 IRQ Holder for PCI Steering
11* 6 IRQ Holder for PCI Steering
12* 7 PS/2 Compatible Mouse Port
13 8 Numeric Data Processor
14* 9 Primary IDE Channel
15* 10 Secondary IDE Channel
*These IRQs are usually available for ISA or PCI devices.
Interrupt Request Table for this Motherboard
Interrupt requests are shared as shown by the following table:
ABCDEFGH
PCI slot 1 —————shared ——
PCI slot 2 ——————shared —
PCI slot 3 ———————shared
PCI slot 4 ————shared ———
PCI slot 5 —————shared ——
PCI slot 6 ——used —————
Onboard VGA shared ———————
Onboard USB controller HC0 ———used ————
Onboard USB controller HC1 ———————shared
AGP Pro shared ———————
CNR LAN ————shared ———
CNR Audio/Modem — used ——————
Onboard Promise ——————shared —
Onboard Audio —————shared ——
IMPORTANT: If using PCI cards on shared slots, make sure that the drivers sup-
port “Share IRQ” or that the cards do not need IRQ assignments. Conflicts will arise
between the two PCI groups that will make the system unstable or cards inoperable.