FabiaTech FB2402, User Manual

Page: 63 / 77

FabiaTech Corporation
57
Watchdog Timer Trigger
After you enable the watchdog timer, your program must write the same factor as
enabling to the watchdog register at least once every time-out period to its
previous setting. You can change the time-out period by writing another timer
factor to the watchdog register at any time, and you must trigger the watchdog
before the new time-out period in next trigger.
;--------------------------------
; Timer Counter
;--------------------------------
Mov al,02h
Mov dx,3bh ;Index 3bh set 02h =4 sec
Out dx,al
;------------------------------------------------
; System Reset or Interrupt
;------------------------------------------------
Mov al,38h
Mov dx,22h
Out dx,al
;Mov al,50h ;Trigger IRQ7
Mov al,d0h ;System Reset
Mov dx,23h
Out dx,al
;------------------------------------------------
; Trigger (Reset) Watchdog Timer
;------------------------------------------------
Mov
al,3ch
Mov dx,22h
In dx,al
Or al,40h ;Trigger Watchdog
Mov dx,23h
Out dx,al
Watchdog Timer Disabled
To disable the watchdog timer, simply write a 00H to the watchdog register.
;-----------------------------------
; Disabled Watchdog
;-----------------------------------
Mov al,37h
Mov dx,22h
Out dx,al
Mov al,00h ;Index 37 Bit 6 set 0
Mov dx,23h
Out dx,al