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