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If you decide to program the watchdog timer, you must write data
to I/O port 443 (hex). The output data is a value timer. You can
write from 80 (hex) to FF (hex) for input minute data plus from
00 (hex) to 7F (hex) for input second data, and the related timer is
0 second to 127 minutes plus 127 seconds sec.
After data entry, your program must refresh the watchdog timer
by rewriting the I/O port 443 (hex) while simultaneously setting
it. When you want to disable the watchdog timer, your program
should write I/O port 80 (hex) a Hex value.
The following procedure is a sample program for the watchdog
timer:
•
Type C:\DOS\Debug <ENTER>
•
To start watchdog timer and set function "Reset" type;
o 444 0 <Enter>; out 444h data 0
•
To input watchdog timers time-out interval of 3 minutes type;
o 443 83 <Enter>; o 443 0 <ENTER>; out 443h data 83
•
To input Watchdog timers time-out interval of 5 seconds type;
o 443 05 <Enter>; out 443h data 05
•
To disable the watchdog timer type;
o 80 x <Enter>; out 080h data x (x can be any Hex value)
The time interval data of the watchdog timer is shown in binary
code (8 bits).
If bit 8 is "1" = To input "minute"
If bit 8 is "0" = To input "second"
Sample 1: 3 minutes
Sample 2: 5 seconds
8
7
6
5
x
1
0
0
0
0
0
0
0
4
3
2
1
0
0
1
1
0
1
0
1
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