F7 (hex) | read/write | Bit 6: Write 1 to enable key- |
|
| board 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 watch- |
|
| dog timer, 1 means timer is |
|
| ""time out""." |
|
|
|
AA (hex) | Write this address to I/O | |
|
| port 2E (hex) to lock the |
|
| watchdog timer.2 |
|
|
|
Table A.1: Watchdog timer registers
A.1.4 Example Program
1.Enable watchdog timer and set 10 sec. as timeout interval
Mov dx,2eh | ; Unlock W83627HF | |
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 |
|
Mov | al,01h |
|
Out | dx,al |
|
71 | AppendixA |
