Personal Computer User Manual
Table Of Contents
- Contents
- Safety Information
- Overview
- Chapter 1. Installing options
- Features
- Specifications
- Available options
- Tools required
- Handling static-sensitive devices
- Installing external options
- Removing the cover
- Locating components
- Identifying parts on the system board
- Installing memory
- Installing adapters
- Installing internal drives
- Physical security
- Changing the battery
- Replacing the cover and connecting the cables
- Erasing a lost or forgotten password (clearing CMOS)
- Chapter 2. Using the IBM Setup Utility program
- Appendix A. Updating System Programs
- Appendix B. Manual modem commands
- Appendix C. System address maps
- Appendix D. Interrupt request and direct memory access channel assignments
- Appendix E. Notices
- Index
Appendix D. Interrupt request and direct memory access
channel assignments
The following tables list the IRQ and DMA 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.
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. 2002 41