To Next Page

To Previous Page

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 LPT2/audio (if present)

6 Diskette controller

7 LPT1

8 Real-time clock

9 Video, ACPI

10 MIDI/joystick (some models only)

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

IBM 6339 User Manual

Other manuals for IBM 6339