Advantech PENTIUM PPC-150 - Manual (Page 158)

142 PPC-150 User's Manual
Programming the Watchdog Timer
To program the watchdog timer, you must write a program which writes
I/O port address 443 (hex). The output data is a time interval value. The
value range is from 01 (hex) to 3F (hex), and the related time interval is
from 1 sec. to 63 sec.
Data
Time Interval
01 1 sec.
02 2 sec.
03 3 sec.
04 4 sec.
• •
• •
• •
3F 63 sec.
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).