ASUS tr-dlsr ユーザーズマニュアル

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 the motherboard has PCI
audio onboard, an additional IRQ will be used. If the motherboard also has MIDI
enabled, another IRQ will be used, leaving 4 IRQs free.

The following table lists the default IRQ assignments for standard PC devices. Use this
table when configuring your system and for resolving IRQ conflicts.

ISA Interrupt (IRQ) Assignments

ISA 00

1

System Timer

ISA 01

2

Keyboard Controller

ISA 02

N/A

Programmable Interrupt

ISA 03*

11

Communications Port (COM2)

ISA 04*

12

Communications Port (COM1)

ISA 05*

13

Sound Card (sometimes LPT2)

ISA 06

14

Floppy Disk Controller

ISA 07*

15

Printer Port (LPT1)

ISA 08

3

System CMOS/Real Time Clock

ISA 09*

4

ACPI Mode when used

ISA 10*

5

IRQ Holder for PCI Steering

ISA 11*

6

IRQ Holder for PCI Steering

ISA 12*

7

PS/2 Compatible Mouse Port

ISA 13

8

Numeric Data Processor

ISA 14*

9

Primary IDE Channel

ISA 15*

10

Secondary IDE Channel

*These IRQs are usually available for PCI devices.