StarTech.com TUEP2-M 3.7.2Assigning IRQs for Expansion Cards, Standard Interrupt Assignments, Interrupt Request Table for this Motherboard, H/W, 3Expansion

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 motherboard 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.

Interrupt Request Table for this Motherboard

Interrupt requests are shared as shown by the following table:

	A	B	C	D	E	F	G	H
PCI slot 1	—	—	—	—	—	not shared	—	—
PCI slot 2	—	—	—	—	—	— not shared		—
PCI slot 3	—	—	—	—	—	—	—	shared
Onboard USB controller HC0	—	—	— not shared		—	—	—	—
Onboard USB controller HC1	—	—	—	—	—	—	—	shared
AGP	shared	—	—	—	—	—	—	—
CNR LAN	—	—	—	— not shared —			—	—
CNR Audio/Modem	—	not shared —		—	—	—	—	—
Onboard LAN	—	—	not shared	—	—	—	—	—

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 will arise between the two PCI groups that will make the system unstable or cards inoperable.

28 ASUS TUEP2-M User’s Manual