ASUS CUVL-VM Manual Do Utilizador

3. HARDWARE SETUP

Expansion Cards

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

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 used

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

PCI slot 1

shared

—

—

—

PCI slot 2

—

shared

—

—

PCI slot 3

—

—

shared

—

Onboard audio controller

—

—

—

shared

Onboard USB controller

—

—

—

shared