2-16
Chapter 2: Hardware information
2.5.3 Interrupt assignments
Standard Interrupt Assignments
IRQ Priority Standard Function
0 1 System Timer
1 2 Keyboard Controller
2 N/A Programmable Interrupt
3* 11 IRQ Holder for PCI Steering
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 Express x1 — — — — — — — shared
PCI Express x16 — — — — — — — shared
Gigabit LAN — — — — — — — shared
Marvell 6121 SATA — — — — — — — shared
SATA — shared — — — — — —
USB1 shared — — — — — — —
USB2 — shared — — — — — —
USB3 — — shared — — — — —
USB4 — — — shared — — — —
HD audio — 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, conicts will arise between the two PCI groups, making the
system unstable and the card inoperable.