IBM PC 300PL manual Appendix C. IRQ and DMA channel assignments, IRQ channel assignments

Appendix C. IRQ and DMA channel assignments

Appendix C. IRQ and DMA channel assignments

The following figures list the interrupt request (IRQ) and direct memory access (DMA) assignments.

Figure	38. IRQ channel assignments
IRQ		System	resource
NMI		Critical		system			error
SMI		System management interrupt — power management
0		Reserved			(interval			timer)
1		Reserved			(keyboard)
2		Reserved,			cascade			interrupt from slave PIC
3		COM2	3
4		COM1	3
5		LPT2/audio			(if		present)
6		Diskette			controller
7		LPT1	3
8		Real-time			clock
9		Video
10		Available			to	user
11		Available			to	user
12		Mouse	port
13		Reserved			(math		coprocessor)
14		Primary		IDE		(if present)
15		Secondary			IDE		(if	present)

Figure	39. DMA channel assignments
DMA channel		Data width		System resource
0		8	bits	Open
1		8	bits	Open
2		8	bits	Diskette	drive
3		8	bits	Parallel port (for ECP or EPP)
4		–		Reserved	(cascade channel)
5		16	bits	Open
6		16	bits	Open
7		16	bits	Open

3 Default, can be changed to another IRQ.

40  Copyright IBM Corp. September 1999