Strobing scheme and keyboard sensing circuit for a one chip calculator
CA 1057402 A · Owner: Rockwell International Corporation · Inventors: Spence, John R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Circuitry having a unique strobing scheme to effectively drive both a light-emitting diode display and an associated keyboard directly from a single semiconductor chip. The circuitry accurately senses which of the keyboard keys is in a depressed condition in order that a suitable representation thereof may be displayed at an appropriate time.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted June 26, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 26, 1996.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.