Intel MB893 user manual Watchdog Timer Configuration, Sample Code

INSTALLATIONS

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 sorts 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

pushax		;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
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