2-12
Chapter 2: Hardware information
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
PCI INTA
PCI INTB
PCI INTC
PCI INTD
PCI slot 1
1
12
13
14
PCI slot 2
4
15
16
17
PCI slot 3
5
18
19
20
PCI slot 4
8
21
22
23
PCI slot 5
9
24
6
7
PCI slot 6
10
27
28
29
Onboard 82551QM controller
2
—
—
—
Onboard 82544GC controller
3
—
—
—
Onboard SCSI controller
6
7
—
—
Onboard VGA controller
30
—
—
—
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.
