Advantech PPC-L126 Manual de usuario descargar pdf (Pagina 104)

PPC-L126 User Manual 92

Appendix A Programming the Watchdog

Timer

To use the watchdog timer, your program must write a time interval value

to I/O port 443 (hex). The value range is from 01 (hex) to 3E (hex), and

the related time interval is from 1 sec. to 62 sec.

Data Time Interval

01 1 sec.

02 2 sec.

03 3 sec.

04 4 sec.

••

3E 62 sec.

After data entry, your program must refresh the watchdog timer by writ-

ing to I/O port 443 (hex) while simultaneously setting it. To disable the

watchdog timer, your program should read I/O port 443 (hex).

The following BASIC program shows how to use the watchdog timer.

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

••

1070 RETURN

2000 REM Subroutine #2, your application task

••

2090 RETURN

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Advantech PPC-L126 Manual de usuario Pagina 104