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:
Nov. 12, 1991
Filed:
Dec. 19, 1988
Applicant:
Inventor:
Robert B Puckette, Corvallis, OR (US);
Assignee:
Hewlett-Packard Company, Palo Alto, CA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
395800 ; 3649256 ; 3649278 ; 364928 ; 364D / ;
Abstract
The present invention describes a method and apparatus for interconnecting keyboard lines and memory lines to the same pins of a microprocessor or calculator chip. Resistors are placed in series with each keyboard line before interconnection to the memory lines and microprocessor pins to prevent disruption or degradation of the memory signal in the event a key on keyboard is depressed during a memory operation cycle. Means are provided to prevent memory operations during keyboard scan routines and means are provided to prevent keyboard scan routines from operating during memory operation cycles.