United States Patent 4,099,246
Calculator having Merged Key Codes
Jul. 4, 1978
Inventors:
- Thomas E. Osborne, San Francisco, Calif.
- Richard Kent Stockwell, Palo Alto, Calif.
Assignee: Hewlett-Packard Company, Palo Alto, Calif.
Appl. No.: 425,341
Filed: Dec. 17, 1973
Abstract:
A hand-held, programmable, electronic calculator is capable of performing a
larger number of functions than the number of keys on its keyboard and has one
or more prefix keys to allow one function key to initiate more than one
function. Each key generates a unique key code when it is depressed, and the
calculator may be programmed by storing a series of the key codes in a memory.
Memory space can be saved by generating unique merged codes to represent the
combination of a prefix key and a function key, and storing this single merged
code rather than the two key codes.
8 Claims, 3 Drawing Figures
An image of first page of this patent is
available (approximately 49 Kbytes).
It is a TIFF class F file at 300 DPI resolution using ITU-T Group 4 Facsimile
(T.6) coding.
Eric's notes:
This patent describes the HP-65, and contains a listing of the first half of
the microcode ROM.
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Last updated July 17, 1995
Copyright 1995 Eric Smith
eric@brouhaha.com
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