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 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.

IRQ assignments for this motherboard

 

A

B

C

D

E

F

 

G

H

PCI slot 1

—

—

—

—

 

—

shared

—

 

—

 

PCI slot 2

—

—

—

—

 

—

—

shared

—

 

PCI slot 3

—

—

—

—

 

—

—

—

shared

 

PCI slot 4

—

—

—

—

shared

—

—

 

—

 

PCI slot 5

—

—

—

—

 

—

shared

—

 

—

 

PCI slot 6

—

—

shared

—

 

—

—

—

 

—

 

AGP

shared

—

—

—

 

—

—

—

 

—

 

Onboard USB controller HC0

shared

—

—

—

 

—

—

—

 

—

 

Onboard USB controller HC1

—

—

—

shared

 

—

—

—

 

—

 

Onboard USB controller HC2

—

—

shared

—

 

—

—

—

 

—

 

RAID controller

—

—

—

—

 

—

—

shared

—

 

LAN controller

—

—

—

—

shared

—

—

 

—

 

Onboard audio

—

—

—

—

 

—

shared

—

 

—

 

Onboard 1394

—

—

—

shared

 

—

—

—

 

—

 

USB 2.0 controller

—

—

—

—

 

—

—

—

shared

 

When using PCI cards on shared slots, ensure that the drivers support “Share IRQ” or that the cards do not need IRQ assignments. Otherwise, conflicts will arise between the two PCI groups, making the system unstable and the card inoperable.

2-14

Chapter 2: Hardware information