130
B
Watchdog Timer
Appendix B - Watchdog Timer
Watchdog Timer
The following parameters are references for setting the time interval of the
Watchdog Timer function. The system will regularly be “cleared” according to the
set time interval. If the system hangs or fails to function, it will also reset ac-
cording to the time interval so that your system will continue to operate.
;================ PROGRAM START ================
SIO_CON_PORT
EQU
2EH
SIO_DATA
EQU
2FH
begin:
MOV
DX,SIO_CON_PORT ;SUPERIO ENTER CONFIG
MOV
AL,87H
OUT
DX,AL
OUT
DX,AL
MOV
DX,SIO_CON_PORT
MOV
AL,2DH
;GPIO5 AND POWER CONTROL SIGNALS
MULTI-FUNCTION PIN SELECTION
OUT
DX,AL
;BIT 0 PIN77 SELECT (0= WDTO#, 1= GPIO50)
MOV
DX,SIO_DATA
IN
AL,DX
AND
AL,0FEH
;SELECT PIN TO WATCH DOG
OUT
DX,AL
MOV
DX,SIO_CON_PORT
MOV
AL,07H
;LOGIC DEVICE SLELCT
OUT
DX,AL
MOV
DX,SIO_DATA
MOV
AL,08H
;SELECT DEVICE 8 (WATCH DOG)
OUT
DX,AL
MOV
DX,SIO_CON_PORT
MOV
AL,030H
;ACTIVATE REGISTER
OUT
DX,AL
MOV
DX,SIO_DATA
OR
AL,01H
;0= INACTIVATE, 1=ACTIVATE
OUT
DX,AL
MOV
DX,SIO_CON_PORT
MOV
AL,0F5H
;WATCH DOG CONTROL REGISTER
OUT
DX,AL
