Appendix D. Interrupt request and direct memory access channel assignments

The following tables list the IRQ and DMA channel assignments.

Table 4. IRQ channel assignments

IRQ

System resource

 

 

NMI

Critical system error

 

 

SMI

System-management interrupt for power management

 

 

0

Timer

 

 

1

Keyboard

 

 

2

Cascade interrupt from slave PIC

 

 

3

COM2 (some models only)

 

 

4

COM1

 

 

5

Available to user

 

 

6

Diskette controller

 

 

7

LPT1

 

 

8

Real-time clock

 

 

9

Video, ACPI

 

 

10

Available to user

 

 

11

Available to user

 

 

12

Mouse port

 

 

13

Math coprocessor

 

 

14

Primary IDE (if present)

 

 

15

Secondary IDE (if present)

 

 

Note: The default settings for COM 1 (IRQ 4), COM 2 (IRQ 3), and LPT 1 (IRQ 7) can be changed to another IRQ.

Table 5. 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

 

 

 

© Copyright IBM Corp. 2001

67

Page 79
Image 79
IBM Partner Pavilion 6825, 6343, 6793, 6349, 6791, 6790, 6792, 6795 Following tables list the IRQ and DMA channel assignments