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Example assembly program:
TIMER_PORT = 443H
TIMER_START = 443H
TIMER_STOP = 843H
;;INITIAL TIMER COUNTER
MOV DX, TIMER_PORT
MOV AL, 8
;;8 seconds
OUT DX, AL
MOV DX, TIMER_START
IN AL, DX
.
;;START COUNTER
W_LOOP:
MOV DX, TIMER_STOP
IN AL, DX
MOV DX, TIMER_START
IN AL, DX
;;RESTART COUNTER
;;ADD YOUR APPLICATION HERE
CMP EXIT_AP, 0
JNE W_LOOP
MOV DX, TIMER_STOP
IN AL, DX
;;EXIT AP
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Appendix B. I/O Address Map
•
I/O Address Map
I/O Address
Map
Description
000-01F
DMA Controller #1
020-021
Interrupt Controller # 1, Master
040-05F System
Timer
060-06F Standard
101/102
keyboard
Controller
070-07F
Real time Clock, NMI Controller
080-0BF
DMA Page Register
0A0-0BF
Interrupt Controller # 2
0C0-0DF
DMA Controller # 2
0F0-0F0
Clear Math Coprocessor Busy
0F1-0F1
Reset Math Coprocessor
0F8-OFF Math
Coprocessor
170-1F7
BUS Master PCI IDE Controller
278-27F
Parallel Printer Port 2
2F8-2FF
Serial Port 2
376-376
BUS Master PCI IDE Controller
378-37F
Parallel Printer Port 1
3B0-3DF
Standard AGP Graphic Adapter
3F0-3F7
Floppy Disk Controller
3F8-3FF
Serial Port 1
443
Watch dog timer enable
480-48F PCI
BUS
843/043
Watch dog timer disable
