Programming the watchdog timer
Watchdog timer
The watchdog timer uses a EPLD (erasable programmable logical
device) to program the WatchDog function. The time range is from
1 second to 255 seconds. When timer times out, a system reset will
happen.
Configuration register
The watchdog timer of PCM-4898 is located in a IC on the board. If
you want to use it, you have to know how to reset the timer. The
procedure is as follows.
Use the debug (DOS command) under DOS
-O 443 5
==> set 5 seconds
-O 444 0
==> set watchdog reset function
It means that it will reset after it counts 5 seconds
-O 443 FF
==> set the maximum, 255 seconds
-O 443 2
==> it will occur IRQ15 pulse
It means that it will have a IRQ 15 pulse after 255 seconds
The IRQ (interrupt request) value is an assigned location where
the computer can expect a particular device to interrupt it when
the device sends the computer signals about its operation. For
example, when a printer has finished printing, it sends an
interrupt signal to the computer. The signal momentarily inter-
rupts the computer so that it can decide what processing to do
next. Since multiple signals to the computer on the same interrupt
line might not be understood by the computer, a unique value
must be specified for each device and its path to the computer.
