3Expansion
H/W .

SETUPCards

3.HARDWARE SETUP

3.7.2Assigning 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 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.

26

ASUS TUWE-M User’s Manual