Intel MB820 - Manual (Page 27)

INSTALLATIONS
MB820 User’s Manual 23
Watchdog Timer Configuration
The WDT is used to generate a variety of output signals after a user
programmable count. The WDT is suitable for use in the prevention of
system lock-up, such as when software becomes trapped in a deadlock.
Under these sort of circumstances, the timer will count to zero and the
selected outputs will be driven. Under normal circumstance, the user will
restart the WDT at regular intervals before the timer counts to zero.
SAMPLE CODE:
This code and information is provided "as is" without warranty of any
kind, either expressed or implied, including but not limited to the implied
warranties of merchantability and/or fitness for a particular purpose.
;[]================================================
; Name : Enable_And_Set_Watchdog
; IN
: AL - 1sec ~ 255sec
; OUT : None
;[]================================================
Enable_And_Set_Watchdog
Proc Near
push ax ;save time interval
call Unlock_Chip
mov cl, 2Bh
call Read_Reg
and al, NOT 10h
call Write_Reg ;set GP24 as WDTO
mov cl, 07h
mov al, 08h
call Write_Reg ;switch to LD8