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General purpose keyboard for central processing unit with microprocessor and use of this keyboard with a microcomputer

  • US 4,879,557 A
  • Filed: 11/06/1987
  • Issued: 11/07/1989
  • Est. Priority Date: 03/10/1986
  • Status: Expired due to Fees
First Claim
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1. A multi-purpose keyboard assembly for a central processing unit with a microprocessor (9) comprising:

  • a housing having at least one set (300) of variable allocation keys, a booklet (2) removably fixed on the housing, said booklet comprising at least two pages (30), (21) indicating the allocation of the keys;

    a first remote means of detection comprising light emitting cells (E0,E1) and photoelectric receivers (R0,R1) mounted on the housing for detecting the position of the pages (20), (21) of the booklet (2);

    a means for providing codes to the central processing unit (9) in response to the detection of the position of the pages (20), (21) of the booklet (2) and in response to the actuation of a key (32) of the keyboard belonging to the one set (300) of keys, said means for providing codes comprising a scanning keyboard interface (45), (46), a keyboard processing unit (40) a data bus (401) and a programmable read only memory (431);

    said scanning keyboard interface (45) being connected through the data bus (401) to the processing unit (40);

    the programmable read only memory (43) containing tables (T1,T4) corresponding to the keys and the codes to be provided to the central processing unit (9) according to the position of the pages (20), (21) of the booklet detected by the first remote means.

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