Advantech PCA-6751 series Manual page 71

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:
10 REM Watchdog timer example program
20 OUT &H443, data REM
30 GOSUB 1000 REM
40 OUT &H443, data REM
50 GOSUB 2000 REM
60 OUT &H443, data REM
70 X=INP (&H443) REM, Disable the watchdog timer
80 END
1000 REM Subroutine #1, your application task
• •
• •
• •
1070 RETURN
2000 REM Subroutine #2, your application task
• •
• •
• •
2090 RETURN
Start and restart the watchdog
Your application task #1,
Reset the timer
Your application task #2,
Reset the timer
Appendix A Programming the Watchdog Timer 61