Assigning Irqs For Expansion Cards - Asus CUV266-DLS User Manual

3. HARDWARE SETUP

3.7.2 Assigning IRQs for Expansion Cards

Some expansion cards need 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. If your motherboard
has PCI audio onboard, an additional IRQ will be used. If your motherboard also
has MIDI enabled, another IRQ will be used, leaving 4 IRQs free.
IMPORTANT: If using PCI cards on shared slots, make sure that the drivers support
"Share IRQ" or that the cards do not need IRQ assignments. Conflicts arise between
the two PCI groups that will make the system unstable or cards inoperable.
The following table lists the default IRQ assignments for standard PC devices. Use
this table when configuring your system and for resolving IRQ conflicts.
Standard Interrupt Assignments
IRQ Priority
0
1
2 N/A
3*
4*
5*
6
7*
8
9*
10*
11*
12*
13
14*
15*
*These IRQs are usually available for ISA or PCI devices.
NOTE: IRQ settings vary with different operating systems. Refer to the actual
condition of your system when changing the settings.
Interrupt Request Table for this Motherboard
PCI slot 1
PCI slot 2
PCI slot 3
PCI slot 4
PCI slot 5
AGPPro slot
Onboard USB controller
Onboard SCSI controller
Onboard LAN controller
28
Standard Function
1 System Timer
2 Keyboard Controller
Programmable Interrupt
11 Communications Port (COM2)
12 Communications Port (COM1)
13 AIC7899 (sometimes LPT2)
14 Floppy Disk Controller
15 Printer Port (LPT1)
3 System CMOS/Real Time Clock
4 ACPI Mode when used (LAN Intel 82559)
5 IRQ Holder for PCI Steering
6 IRQ Holder for PCI Steering
7 PS/2 Compatible Mouse Port
8 Numeric Data Processor
9 Primary IDE Channel
10 Secondary IDE Channel
INT-A
—
shared
—
—
—
shared
—
—
—
ASUS CUV266-DLS User's Manual
INT-B INT-C
— —
— —
shared —
— shared
— —
— —
— —
shared shared
— —
INT-D
shared
—
—
—
shared
—
shared
—
shared