Appendix A Programming The Watchdog Timer; Programming The Watchdog Timer - Advantech PCA-6145B Manual

Half-size 486 all-in-one cpu card with panel/crt and ethernet interface

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Appendix A Programming the Watchdog

A.1 Programming the watchdog timer

If you decide to program the watchdog timer, you must write a program

which reads I/O port address 443 (hex). The output data is a timer value.

You can write it from 01 (hex) to 3F (hex), and the related timer is 1 sec.

to 63 sec.

After date entry, your program must refresh the watchdog timer by

rewriting the I/O port 443 (hex) while simultaneously setting it.

The following program is a program for the watchdog timer:

Step 1out 443h, data REM Start and reset the

watchdog timer

Step 2your application program task #1

Step 3out 443h, date

Step

4your application program task #2

Step

5out 443h, data

Step

nin 43hREM Disable watchdog function

Date values

1 sec.

2 sec.

3 sec.

4 sec.

63 sec

PCA-6145 User's Manual

Timer

REM Reset the timer

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