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92 SBC-596/599 User's Manual
Programming the Watchdog Timer
In order to program the watchdog timer, you must write a program
which writes I/O port address 443 (hex). The output data is a
value of time interval. The value range is from 01(hex) to 3F(hex),
and the related time interval is 1 sec. to 63 sec.
Data Time Interval
01 1 sec.
02 2 sec.
03 3 sec.
04 4 sec.
.
.
.
3F 63 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 read I/O port 043 (hex).
The following example shows how you might program the
watchdog timer in BASIC:
10 REM Watchdog timer example program
20 OUT &H443, data REM Start and restart the
watchdog
30 GOSUB 1000 REM Your application task #1
40 OUT &H443, data REM Reset the timer
50 GOSUB 2000 REM Your application task #2
60 OUT &H443, data REM Reset the timer
70 X=INP (&H043) REM Disable the watchdog
timer
80 END
1000 REM Subroutine #1, you application task
.
.
.
1070 RETURN
2000 REM Subroutine #2, you application task
.
.
.
2090 RETURN