Advantech PPC-103, Manual

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112 PPC-103 User's Manual
A.1 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 62 sec.
Data Time Interval
0 1 1 sec.
0 2 2 sec.
0 3 3 sec.
0 4 4 sec.
.
.
.
3 F 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 443 (hex).
The following example shows how you might program the watchdog
timer in BASIC:
1 0 REM Watchdog timer example program
2 0 OUT &H443, data REM Start and restart the
watchdog
3 0 GOSUB 1000 REM Your application task #1
4 0 OUT &H443, data REM Reset the timer
5 0 GOSUB 2000 REM Your application task #2
6 0 OUT &H443, data REM Reset the timer
7 0 X=INP (&H443) REM Disable the watchdog timer
8 0 E N D
1000 REM Subroutine #1, you application task
.
.
.
1070 RETURN
2000 REM Subroutine #2, you application task
.
.
.
2090 RETURN