Intel SYS7180VE user manual Appendix Watch-Dog-Timer WDT Setting

CHAPTER 3 - BIOS SETUP

APPENDIX Watch-Dog-Timer (WDT) Setting

一． Definition for SYS7180VE watchdog

The watchdog timer can be adjusted by software setting from 1second to 239seconds or from 1 minute to 239 minutes. The I/O port is defined at address EFH. You can trigger/enable disable the timer by writing port EFH.

F0H: timer for minute

F1H: timer for second

0:disable the timer

二． Test procedure in DOS

Implement Debug order in MS-DOS:

o	ef	f1
o	ef	5
[ enter]
The system will reset after 5 seconds

三． Assembly language example
Timer for second:
mov	AL, f1
mov	dx, ef
out	dx, AL
mov	AL, 65 (time for 65 sec. decimal system )
mov	dx, ef
out	dx, AL
Timer for minute:
mov	AL, f0
mov	dx, ef
out	dx, AL
mov	AL, 75 (time for 75 min. decimal system )
mov	dx, ef
out	dx, AL
Disable the watchdog-timer:
mov	AL, 0
mov	dx, ef
out	dx, AL
SYS7180VE User’s Manual		59

CHAPTER 3 - BIOS SETUP

NOTE: Because WIN NT win2000 win2003	winXP are not effective by
writing the port directly, so we must make lib file	driver or DLL first.

60 SYS7180VE User’s Manual