Appendix A Programming The Watchdog Timer; Programming The Watchdog Timer - Advantech POS-761F User Manual

Appendix A Programming the Watchdog
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 inter-
val. The value range is from 01(hex) to 3E(hex), and the related time
interval is 1 sec. to 62 sec.
Data Time Interval
01
02
03
04
3E
After data entry, your program must refresh the watchdog timer by rewrit-
ing 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:
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 (&H443) REM Disable the watchdog timer
80 END
1000 REM Subroutine #1, your application task
POS-761 User's Manual
Timer
1 sec.
2 sec.
3 sec.
4 sec.
.
.
.
62 sec.
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