Installation guide

A-64 PCM-4894 User Manual
Watchdog timer demo program
How to program the WATCHDOG TIMER
1. To enable the time-out interval of watchdog timer:
-- output the desired value to port 0x443. The resolution of
watchdog timer is 1 sec. Since the data is of 1 byte, the time-
out interval will be 1 sec ~ 255 sec.
Whenever the value of timer is not zero, the timer will
automatically count down
e.g. outportb(0x443, 30); // set interval to 30 sec and
count down
2. To set the time-out event:
-- output data to port 0x444. The default setting is “reset
system”.
· 0: reset system (default)
· 1, 2, 3: IRQ 10, 15, 11 respectively
· 4: NMI
e.g. outportb(0x444, 0); // set time-out event to
reset-system
3. To disable watchdog timer:
-- output value “0” to port 0x443.
e.g. outportb(0x443, 0); // disable watchdog timer