United States Patent 3,863,060
General Purpose Calculator with Capability for Performing Interdisciplinary Business Calculations
Jan. 28, 1975
Inventors:
- France Rode, Los Altos, Calif.
- William L. Crowley, Jr., Cupertino, Calif.
- Alexander D. R. Walker, San Francisco, Calif.
- David S. Cochran, Palo Alto, Calif.
Assignee: Hewlett-Packard Company, Palo Alto, Calif.
Filed: Oct. 30, 1972
Appl. No.: 302,371
Abstract:
A battery-powered, hand-held, calculator employs MOS/LSI calculator circuits to
perform arithmetic and financial calculations. Data and commands are input to
the calculator fram a keyboard having a prefix key to double the functions of
selected keys. A 15-digit, seven-segment light emitter diode (LED) display
serves as the output for the calculator. The calculator circuits include a
read-only memory circuit in which the algorithms for performing the arithmetic
and financial calculations are stored; a control and timing circuit for
scanning the keyboard, retaining status information about the condition of the
calculator or of an algorithm, and generating the next read-only memory
address; and an arithmetic and register circuit containing an adder, a group
of working registers, a group of data storage registers forming a stack for
roll down operation, and a constant storage register. These circuits are
interconnected by a multiple line buss system.
34 Claims, 36 Drawing Figures
Eric's notes:
This patent mainly describes the HP-80, although it contains detailed
technical information concerning the circuitry and instruction set which is
used in the entire Classic series. It contains the entire microcode ROM
listing of the HP-80.
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Copyright 1995 Eric Smith
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