HP Calulator Patents

Here is a partial list of patents relating to HP calculators. In the first column I've entered the number of pages. The short ones aren't too interesting. The following relate to specific machines although I'm not too sure about the 9805. US4437156 (334 pages) HP9825 Processor description (No firmware) US4180854 (575 pages) HP9845 Description (No firmware) US4158285 (149 pages) wristwatch calculator US4089059 (375 pages) HP9815 Processor description and firmware listing US4075679 (599 pages) HP9825 Processor description and firmware listing US4012725 (589 pages) HP9830 Processor description and firmware listing US3971925 (162 pages) HP9805 Processor description and firmware listing US3839630 (389 pages) Unknown Also US4172281 Microprogrammable Control Processor for a Minicomputor or the like (125 pages) gives a description and schematic for a 16 bit TTL machine. Uses 74S181s in the ALU and reference is made to the HP21XX in the opcode listing. Unfortunately the quality of the copy is poor and there is no microcode. Downloaded from http://gb.espacenet.com. Chris Pages Patent No Issued Title 011 US05530234 06/25/1996 Hand held calculator having a retractable cover 021 US04885714 12/05/1989 Calculator having a user-accessible object stack for the uniform application of mathematical functions and logical operations to a multiplicity of object types 030 US04821228 04/11/1989 Method and apparatus for computation stack recovery in a calculator 010 US04566072 01/21/1986 Programmable calculator including means for digitizing the position of an X-Y plotter pen 011 US04546448 10/08/1985 Programmable calculator including program variable initialization means and definition means array 031 US04480305 10/30/1984 Programmable calculator including editing capability 019 US04456964 06/26/1984 Calculator including means for displaying alphanumeric prompting messages to the operator 010 US04455618 06/19/1984 Programmable calculator 026 US04455607 06/19/1984 Programmable calculator having keys for performing angular measurement unit conversion 334 US04437156 03/13/1984 Programmable calculator 031 US04412300 10/25/1983 Programmable calculator including alphabetic output capability 026 US04384328 05/17/1983 Programmable calculator including magnetic reading and recording means 030 US04381554 04/26/1983 Calculator for storing source data and evaluating numerical answers to problems 007 US04330839 05/18/1982 Programmable calculator including means for automatically processing imformation stored on a magnetic record member 012 US04322816 03/30/1982 Programmable calculator having structure for controlling an x-y plotter 031 US04309761 01/05/1982 Calculator for evaluating numerical answers to problems 029 US04291385 09/22/1981 Calculator having merged key codes 018 US04281390 07/28/1981 Programmable calculator including means for performing computed and uncomputed relative branching during program execution 003 USD0256133 07/29/1980 Casing for an electronic calculator 031 US04203152 05/13/1980 Programmable calculator including key-log printing means 030 US04198684 04/15/1980 Electronic calculator with keyboard-controlled unary function capability 010 US04197586 04/08/1980 Electronic calculator assembly 019 US04187547 02/05/1980 Programmable calculator including means for controllably introducing blank lines on a printed record during program execution 007 US04181966 01/01/1980 Adaptable programmed calculator including a percent keyboard operator 019 US04181965 01/01/1980 Programmable calculator including program trace means ??? US04180854 12/25/1979 Programmable calculator having string variable editing capability 018 US04178633 12/11/1979 Programmable calculator including multifunction keys 012 US04177520 12/04/1979 Calculator apparatus having a single-step key for displaying and executing program steps and displaying the result 019 US04177518 12/04/1979 Programmable calculator including scrolling alphanumeric display means 018 US04164039 08/07/1979 Programmable calculator including a key for performing either a subtraction or a unary minus function 019 US04164019 08/07/1979 Programmable calculator including alphanumeric display means 019 US04162532 07/24/1979 Programmable calculator including data format display control means 019 US04161031 07/10/1979 Programmable calculator including boolean flag variable means 019 US04159525 06/26/1979 Programmable calculator employing computed memory addresses 149 US04158285 06/19/1979 Interactive wristwatch calculator 018 US04158233 06/12/1979 Programmable calculator including means for performing implied multiply operations 019 US04158231 06/12/1979 Programmable calculator including program listing means 019 US04158228 06/12/1979 Programmable calculator including alphanumeric error display means 006 US04156921 05/29/1979 Adaptable programmed calculator including automatic decimal point positioning 018 US04156918 05/29/1979 Programmable calculator including means for performing computed jumps during program execution 020 US04156917 05/29/1979 Programmable calculator including separate user program and data memory areas 018 US04156285 05/22/1979 Programmable calculator including keyboard functions whose argument may be a numeric constant, a storage register, or an arithmetic expression 018 US04156282 05/22/1979 Programmable calculator including relational operator means 020 US04152774 05/01/1979 Programmable calculator including keyboard function means for raising the number ten to any designated power 018 US04152773 05/01/1979 Programmable calculator including means for establishing a priority for executing algebraic operations 019 US04152771 05/01/1979 Programmable calculator including display means for signalling the user to indicate the exhaustion of a printer paper supply 020 US04152770 05/01/1979 Programmable calculator including means for programmably controlling magnetic storage units 019 US04152769 05/01/1979 Programmable calculator including means for permitting data entry during program execution 022 US04145752 03/20/1979 Programmable calculator including separate line numbering means for user-definable functions 025 US04145742 03/20/1979 Programmable calculator including user-definable keys 012 US04127897 11/28/1978 Programmable calculator having extended input/output capability 012 US04126898 11/21/1978 Programmable calculator including terminal control means 002 USD0249243 09/05/1978 Wristwatch calculator 002 USD0249090 08/22/1978 Casing for an electronic calculator 011 US04109315 08/22/1978 Wristwatch calculator with selectively scanned keyboard 028 US04099246 07/04/1978 Calculator having merged key codes 015 US04091270 05/23/1978 Electronic calculator with optical input means 375 US04089059 05/09/1978 Programmable calculator employing a read-write memory having a movable boundary between program and data storage sections thereof 014 US04078257 03/07/1978 Calculator apparatus with electronically alterable key symbols 599 US04075679 02/21/1978 Programmable calculator 021 US04063221 12/13/1977 Programmable calculator 005 US04059750 11/22/1977 General purpose calculator having selective data storage, data conversion and time-keeping capabilities 009 US04055757 10/25/1977 Calculator apparatus with annuity switch for performing begin-and end-period annuity calculations 002 USD0245810 09/13/1977 Casing for an electronic calculator 005 US04047012 09/06/1977 General purpose calculator having factorial capability 002 USD0245107 07/19/1977 Electronic calculator 007 US04037092 07/19/1977 Calculator having preprogrammed user-definable functions 009 US04035627 07/12/1977 Scientific calculator 002 USD0244862 06/28/1977 Casing for an electronic calculator 013 US04028538 06/07/1977 Programmable calculator employing algebraic language 589 US04012725 03/15/1977 Programmable calculator 055 US04009379 02/22/1977 Portable programmable calculator displaying absolute line number addresses and key codes and automatically altering display formats 092 US04001569 01/04/1977 General purpose calculator having selective data storage, data conversion and time-keeping capabilities 032 US03996562 12/07/1976 Programmable electronic calculator for evaluating mathematical problems 009 US03987290 10/19/1976 Calculator apparatus for displaying data in engineering notation 162 US03971925 07/27/1976 Adaptable programmed calculator having provision for plug-in keyboard and memory modules 004 US03955074 05/04/1976 General purpose calculator having keys with more than one function assigned thereto 005 US03946218 03/23/1976 General purpose calculator with capability for performing yield-to-maturity of a bond calculation 007 US03893173 07/01/1975 Miniaturized magnetic card reader/recorder for use in hand-held calculator 073 US03863060 01/28/1975 GENERAL PURPOSE CALCULATOR WITH CAPABILITY FOR PERFORMING INTERDISCIPLINARY BUSINESS CALCULATIONS 007 US03855461 12/17/1974 CALCULATOR WITH KEY CODE ASSOCIATION AND DISPLAY FEATURES 389 US03839630 10/01/1974 PROGRAMMABLE CALCULATOR EMPLOYING ALGEBRAIC LANGUAGE 058 US03825736 07/23/1974 CALCULATOR WITH PROVISION FOR EFFICIENTLY MANIPULATING FACTORS AND TERMS ??? US03781820 12/25/1973 PORTABLE ELECTRONIC CALCULATOR ??? US03769621 10/30/1973 CALCULATOR WITH PROVISION FOR AUTOMATICALLY INTERPOSING MEMORY ACCESS CYCLES BETWEEN OTHERWISE REGULARLY ??? US03711690 01/16/1973 CALCULATOR AND TESTER FOR USE THEREWITH ??? US03678466 07/18/1972 ELECTRONIC CALCULATOR ??? US03675213 07/04/1972 STORED DATA RECALL MEANS FOR AN ELECTRONIC CALCULATOR ??? US03668461 06/06/1972 OUTPUT DISPLAY FOR USE WITH A CALCULATOR ??? US03641328 02/08/1972 KEYBOARD ENTRY MEANS AND POWER CONTROL MEANS FOR CALCULATOR ??? US03623156 11/23/1971 CALCULATOR EMPLOYING MULTIPLE REGISTERS AND FEEDBACK PATHS FOR FLEXIBLE SUBROUTINE CONTROL ??? US03576983 05/04/1971 DIGITAL CALCULATOR SYSTEM FOR COMPUTING SQUARE ROOTS