Sample program – Axiomtek PICO841 User Manual
Page 76

PICO841 Intel
®
Atom
TM
Processor E3845/E3827 Pico-ITX Board
70
Watchdog Timer
Sample Program
Assembly sample code :
;Enable WDT:
mov
dx,2Eh
mov
al,87
;Un-lock super I/O
out
dx,al
out
dx,al
;Select Logic device:
mov
dx,2Eh
mov
al,07h
out
dx,al
mov
dx,2Fh
mov
al,07h
out
dx,al
;Enable WDT base address:
mov
dx,2Eh
mov
al,30h
out
dx,al
mov
dx,2Fh
mov
al,01h
out
dx,al
;Activate WDT:
mov
dx,2Eh
mov
al,0F0h
out
dx,al
mov
dx,2Fh
mov
al,80h
out
dx,al
;Set base timer :
mov
dx,2Eh
mov
al,0F6h
out
dx,al
mov
dx,2Fh
mov
al,Mh
;M=00h,01h,...FFh (hex),Value=0 to 255
out
dx,al
;(see below
Note
)
;Set Second or Minute :
mov
dx,2Eh
mov
al,0F5h
out
dx,al
mov
dx,2Fh
mov
al,Nh
;N=71h or 79h(see below
Note
)
out
dx,al
Note:
If N=71h, the time base is set to second.
M = time value
00: Time-out Disable
01: Time-out occurs after 1 second
02: Time-out occurs after 2 seconds
03: Time-out occurs after 3 seconds
.
.
FFh: Time-out occurs after 255 seconds