2-24
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
—
Re-direct to IRQ#9
3
11
Communications Port (COM2)*
4
12
Communications Port (COM1)*
5
13
IRQ holder for PCI steering*
6
14
Floppy Disk Controller
7
15
Printer Port (LPT1)*
8
3
System CMOS/Real Time Clock
9
4
IRQ holder for PCI steering*
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.
