Chapter 14: Watchdog Timer And Hardware Reset; Description; Booting, Power Down, And Strobing The Watchdog Timer - Octagon Systems XE–700 Reference Manual

Chapter 14: Watchdog timer and hardware reset

Description

The watchdog timer is a fail-safe against program crashes or processor lockups. It
has programmable timeout periods of 1, 10 and 60 seconds. The watchdog timer
can be enabled or disabled in Setup. INT17 software calls (a DOS TSR) or an
operating system driver can be used to enable and set the timeout period, strobe
the watchdog, and disable the watchdog timer from your application. If the timer
expires, it performs a hardware reset.

Booting, power down, and strobing the watchdog timer

When the watchdog is enabled in Setup, it sets the timeout period for 60 seconds.
The BIOS will strobe the watchdog during the boot process and once more just
before booting is finished. The user's application must then begin strobing. The
watchdog will continue until it is disabled or power down occurs.
If the watchdog is enabled in Setup and your operating system cannot load up
before the timer expires, your system could reset. Also, if you do not disable the
watchdog and your strobing application ends before power down you could again
reset. If these watchdog situations should occur, set the "S" switch, Switch 4
position 1, to Off and reboot. This causes the XE–700 SBC to boot using Setup
defaults (watchdog disabled). Enter Setup, then change and save the watchdog
settings in Setup.
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