IBT Technologies IB881, User Manual

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APPENDIX
IB881 User’s Manual 53
C. 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
mov cl, 0F5h
call Read_Reg
and al, NOT 08h
call Write_Reg ;set count mode as second
pop ax
mov cl, 0F6h
call Write_Reg ;set watchdog timer
mov
al, 01h
mov cl, 30h
call Write_Reg ;watchdog enabled