The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 11, 1990
Filed:
Dec. 16, 1983
Akio Hosaka, Kanagawa, JP;
Akito Yamamoto, Yokohama, JP;
Nissan Motor Company, Limited, Yokohama, JP;
Abstract
A watchdog timer works in concert with special computer program features to monitor program execution and reset the computer in case of malfunction. The computer CPU is programmed to periodically output one of an alternating pair of values to a register which holds the value for a comparator. The output value is compared to a predetermined value equal to one of the alternating output value. When the compared values are equal, the comparator outputs a reset signal to a counter. The counter counts clock pulses and if it counts to its full capacity before being reset by the comparator output, it outputs a reset signal which causes the computer to restart program execution. A second comparator may be provided to compare the alternating values to a reference value equal to the other values. Thus the comparators check for proper output of both signals and reset the counter only in response to receipt of both values. In addition a second counting system may be provided so that the computer will be reset whether the period of alternating value output increases or decreases.