- IBM Corp User Guide Desktop Computer 2292, 6343, 6349, 6350, 6790, 6791, 6792, 6793, 6794, 6795, 6823, 6825

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