User guide

IMBA-9454G Motherboard
Page 167
BL: Time-out value (Its unit-second is dependent on the item “Watchdog
Timer unit select” in CMOS setup).
Table B-1: AH-6FH Sub-function
Call sub-function 2 to set the time-out period of Watchdog Timer first. If the time-out value
is not zero, the Watchdog Timer starts counting down. When the timer value reaches zero,
the system resets. To ensure that this reset condition does not occur, calling sub-function
2 must periodically refresh the Watchdog Timer. However, the watchdog timer is disabled
if the time-out value is set to zero.
A tolerance of at least 10% must be maintained to avoid unknown routines within the
operating system (DOS), such as disk I/O that can be very time-consuming.
NOTE:
When exiting a program it is necessary to disable the Watchdog Timer,
otherwise the system resets.
Example program:
; INITIAL TIMER PERIOD COUNTER
;
W_LOOP:
MOV AX, 6F02H ;setting the time-out value
MOV BL, 30 ;time-out value is 48 seconds
INT 15H
;
; ADD THE APPLICATION PROGRAM HERE
;
CMP EXIT_AP, 1 ;is the application over?
JNE W_LOOP ;No, restart the application