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:
Apr. 04, 1989
Filed:
Aug. 05, 1987
James E Hamilton, Hoffman Estates, IL (US);
Gregory A Peterson, South Barrington, IL (US);
Digital Appliance Controls, Inc., Hoffman Estates, IL (US);
Abstract
A microcomputer of a household appliance, such as a microwave oven, receives input data from the user for operating the various functions of the appliance. The data is stored in the volatile memory of the microcomputer. The data is compressed into a bit pattern which is representative of all the bits in the volatile memory in the event of a power interruption. The compressed bit pattern is stored in the volatile memory of the microcomputer to be later verified. The operations of the microcomputer is continued for those functions which do not affect volatile memory until the power source is restored or the microcomputer is reset. In either case the volatile memory is verified by generating a compressed bit pattern for current data. The current bit pattern is then compared to an initial bit pattern. If the bit patterns are identical then the volatile memory has not been corrupted by an interruption of power exceeding a preselected 'data vaild time'. Also the fixed bit pattern is verified against a fixed bit pattern in nonvolatile memory to determine if any corrpution has occurred. If no corruption has occurred the normal operations continue. If it has been determined that the volatile memory has been corrupted, then the microcomputer is reinitialized with default data copies from nonvolatile memory to volatile memory.