Advantech PCA-6763, Руководство пользователя

Страница: 71 / 94

PCA-6763 User Manual 60
A.1.3 Example program
1. Enable watchdog timer and set 10 sec. as timeout interval
;-----------------------------------------------------------
Mov dx,2eh
; Unlock NCT6776D
Mov al,87h
Out dx,al
Out dx,al
;-----------------------------------------------------------
Mov al,07h
; Select registers of watchdog timer
Out dx,al
Inc dx
Mov al,08h
Out dx,al
;-----------------------------------------------------------
Dec dx
; Enable the function of watchdog timer
Mov al,30h
Out dx,al
Inc dx
In al,dx
Or al,01h
Out dx,al
;-----------------------------------------------------------
Dec dx
; Set second as counting unit
Mov al,0f5h
Out dx,al
Inc dx
In al,dx
And al,not 08h
Out
dx,al
;-----------------------------------------------------------
Dec dx
; Set timeout interval as 10 seconds and start counting
Mov al,0f6h
F6 (hex) write
0: stop timer [default]
01~FF (hex): The amount of the count, in seconds or
minutes, depends on the value set in register F5 (hex).
This number decides how long the watchdog timer waits
for strobe before generating an interrupt or reset signal.
Writing a new value to this register can reset the timer to
count with the new value.
F7 (hex) read/write
Bit 6: Write 1 to enable keyboard to reset the timer, 0 to
disable.[default]
Bit 5: Write 1 to generate a timeout signal immediately
and automatically return to 0. [default=0]
Bit 4: Read status of watchdog timer, 1 means timer is
“timeout”.
AA (hex) -----
Write this address to I/O port 2E (hex) to lock the
NCT6776D.