Browse Prior Art Database

PC-Program-Controlled Watchdog Timer for PCs

IP.com Disclosure Number: IPCOM000119373D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 1 page(s) / 31K

Publishing Venue

IBM

Related People

Immeyer, G: AUTHOR

Abstract

The arrangement described in this article uses the standard parallel interface of a PC without adversely affecting the remaining devices connected thereto.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

PC-Program-Controlled Watchdog Timer for PCs

      The arrangement described in this article uses the
standard parallel interface of a PC without adversely affecting the
remaining devices connected thereto.

      Hardware is linked to the PC parallel interface to which the
usual equipment, such as a printer, is connected.

      A task of a multi-task program running in the PC triggers a
timer circuit at regular intervals, so that a relay is always in the
"ON" state.

      If the processing of a program task for controlling the timer
circuit is prevented by, say, a program loop of another task or by
power failure of the entire arrangement, the relay will turn itself
off, activating an alarm, such as an automatic selector, connected to
the relay contact of the watchdog circuit.

      The circuit as such consists of known components. There is no
separate interface, as the parallel interface is used for the
described purpose without adversely affecting any of the remaining
users.  The watchdog circuit is also monitored, as the energized
state of the relay is the normal state, meaning that the relay would
be de-energized by a power failure.