HP-15C

Programmable scientific calculator produce by Hewlett-Packard

The HP-15C is a high-end scientific programmable calculator of Hewlett-Packard's Voyager series produced between 1982 and 1989.

Models

HP-15C

The HP-15C is a high-end scientific pocket calculator with a root-solver and numerical integration. A member of Hewlett-Packard Voyager series of programmable calculators, it was produced between 1982 and 1989. The calculator is able to handle complex numbers and matrix operations. Although out of production, its popularity has led to high prices on the used market. The HP-15C was a replacement for the HP-34C. The 15C used bulk CMOS technology for its processor, resulting in very low power consumption.

HP 15C Limited Edition

After showing a prototype labelled HP 15c+^[2] at the HHC 2010, HP announced the HP 15C Limited Edition (NW250AA) on 1 September 2011. It is based on a flashable controller utilizing the same ARM7TDMI core already used in the 2008 revision of the 12C but in a different package,^[3] an Atmel AT91SAM7L128-AU^[4][5][6][7] running an emulator written by Cyrille de Brébisson to execute the old HP Nut code much faster than on the original hardware. The calculator was released alongside the HP 12c 30th Anniversary Edition. This model is powered by two CR2032 batteries, and can easily be differentiated from the original model by the "Limited Edition" script below the company logo as well as the black text on brushed metal back label, as opposed to the white text on black of the original. The power consumption of the processor is greater than that of the original HP-15C, as HP did not use the same technology in any of the future models.

HP 15C Collector’s Edition

In May 2023, a HP 15C Collector's Edition was announced^[8] and was released in July 2023 by the HP Development Company, L.P.'s licensees Moravia Consulting spol. s r.o. and Royal Consumer Information Products, Inc.^[9][10] The calculator is manufactured in the Philippines. It supports up to 672 steps for programs and up to 99 registers. The initial firmware incorporates fixes for the known bugs from previous models (as shown below) and others;^[11] it is emulated on the same CPU^[12] as the 2015 and 2022 variants of the HP-12C, the Microchip ATSAM4LC2CA (ARM Cortex-M4).^[13] The calculator is also powered by two CR2032 batteries.

The test menu (Off, g+↵ Enter+ON) officially offers three choices. A fourth choice (4) is undocumented and permits to enter two hidden modes: "15.2" (more memory, but with some limitations like 8×8 inversion matrices and three-digit step number display) and "16" (emulating a HP-16C).

Bugs and problems

HP-15C:

• CHS stack lift bug (and fix)
• The non-responsive reset procedure documented in the 15C manual had the side effect of rotating the X register by 22 bits which could then be used to perform synthetic programming.^[14][15]

HP-15C Limited Edition:^[16]

• One of the more significant bugs in the released firmware version (dated 2011-04-15 in the self-test) is that PSE only works once in a program and subsequently blanks the display until the program stops or is stopped. Downgrading the firmware resolves the PSE bug,^[17] however, other bugs will also be reintroduced.
• The original HP-15C self-test keystrokes do not work with the HP-15C LE and can corrupt memory contents. Although a new functional self-test procedure was added, the original manual did not document it.^[18]

HP-15C Collector's Edition:

• No known bugs in the officially supported "15" mode yet; the bugs above and others have been fixed in the firmware, or in the case of the non-functional self-test procedure, instructions to switch to the new self-test are included in the accompanying documentation.^[11] There are a number of bugs and shortcomings in the undocumented "15.2" and "16" modes,^[19] most of which were fixed by a community member by October 2023.^[20][21][22]

Legacy

An official PC emulator for the 15C is available as freeware from Hewlett-Packard.^[23][24]

There are many calculators simulating software, imitating various HP calculators.^[25][26][27]

Gallery

• 
  HP-15C from the 1980s
• 
  The rear side of HP-15C
• 
  HP-15C Collector's Editon

See also

• List of Hewlett-Packard products: Pocket calculators
• HP calculators

References

1. "HP Voyager Calculator Variants". Brouhaha.com. Retrieved 2017-12-10.
2. "HP-15C+ Prototype?". Hpmuseum.org. Retrieved 2017-12-10.
3. "Filter News Results - HP Newsroom HP Press Releases". Hp.com. Retrieved 2017-12-10.
4. "HP 15C Limited Edition". Finetune.co.jp. Retrieved 2017-12-10.
5. "Product End-of-Life (EOL) Notification" (PDF). Media.digikey.com. Retrieved 2017-12-10.
6. "Product End-of-Life (EOL) Notification" (PDF). Media.digikey.com. Retrieved 2017-12-10.
7. "Product End-of-Life (EOL) Notification" (PDF). Media.digikey.com. Retrieved 2017-12-10.
8. Kuperus, Klaas (2023-05-02). "New: HP 15C Collectors Edition". Archived from the original on 2023-08-09. Retrieved 2023-08-10.
9. "HP Calculator Division". Retrieved 2023-07-05.
10. "Eduwinkel". Retrieved 2023-07-05.
11. "The Museum of HP Calculators, post from contributing developer". Retrieved 2023-08-03.
12. "The Museum of HP Calculators, vendor's post". Retrieved 2023-08-03.
13. "HP Voyager Calculator Variants". Brouhaha.com. Retrieved 2023-08-03.
14. Smith, Eric L. "Brouhaha" (2023-01-30) [2004]. "HP-15C Synthetics". Archived from the original on 2023-09-25. Retrieved 2023-09-25.
15. "HP 15C Synthetics and Synthetic Programming". YouTube. 2022-03-07. Retrieved 2022-08-10.
16. Wasserman, Katie (2011-12-26) [2011-09-16]. "HP-15C LE (Limited Edition) Bug Reports". Archived from the original on 2017-12-20. Retrieved 2017-12-20.
17. HP 15C LE PSE / Pause Bug Fix, 2022-07-04, retrieved 2022-08-05
18. HP 15C Limited Edition LE Scientific Calculator Self-tests, 2021-11-05, retrieved 2022-08-05
19. https://www.hpmuseum.org/forum/thread-19886-page-16.html
20. "NEW: HP 15C Collectors Edition".
21. "WIP: 16C firmware hack for more memory".
22. "Modifying firmware to fix the DEC bug - TheCalculatorStore". www.thecalculatorstore.com. Retrieved 2024-09-07.
23. "Emulateurs" (in French). 2014. Archived from the original on 2017-09-17. Retrieved 2017-09-17.
24. "HP 15C Virtual Calculator". Hewlett-Packard. 2012-11-29. Archived from the original on 2016-06-08. Retrieved 2017-09-17.
25. "HP Calculator Simulations". www.hpmuseum.org. Retrieved 2024-09-06.
26. "OTHER Files". www.hpcalc.org. Retrieved 2024-09-06.
27. "RPN Tutorial". hansklav.home.xs4all.nl. Retrieved 2024-09-06.

Further reading

• Hewlett-Packard HP-15C Owner's Handbook (PDF). 2.4. Hewlett-Packard Development Company, LP. September 2011. 00015-90001. Archived (PDF) from the original on 2017-09-17. Retrieved 2015-12-05.
• Hewlett-Packard HP-15C Advanced Functions Handbook (PDF). Hewlett-Packard Company, Corvallis Division. August 1982. 00015-90011. Archived (PDF) from the original on 2017-09-17. Retrieved 2015-12-05.
• Hewlett-Packard HP-15C Advanced Functions Handbook (PDF). Hewlett-Packard Development Company, LP. 2012 [1982]. 00015-90011. Archived (PDF) from the original on 2017-09-17. Retrieved 2015-12-05.
• HP 15c Collector's Edition - Scientific Calculator - Owner's Handbook (PDF) (3 ed.). MORAVIA Consulting spol. s r.o. February 2023. Archived (PDF) from the original on 2023-08-10. Retrieved 2023-08-10. (1+xi+293+2+1 pages)
• HP 15c Collector's Edition - Scientific Calculator - Advanced Functions Handbook (PDF) (3 ed.). MORAVIA Consulting spol. s r.o. July 2023. Archived (PDF) from the original on 2023-08-11. Retrieved 2023-08-11. (2+2+222+2 pages)
• Markstein, Howard W. (March 1982). "A look inside Hewlett-Packard's HP-11C". Electronic Packaging and Production Magazine. Archived from the original on 2017-09-17. Retrieved 2023-08-12.
• Evett, Eric A.; McClellan, Paul J.; Tanzini, Joseph "Joe" P. (May 1983). "Scientific Pocket Calculator Extends Range of Built-in Functions Matrix operations, complex number functions, integration, and equation solving are only some of the numerous preprogrammed capabilities of HP's latest scientific calculator, the HP-15C" (PDF). Hewlett-Packard Journal. 34 (5). Palo Alto, California, USA: Hewlett-Packard Company: 25–35. ISSN 0018-1153. Archived (PDF) from the original on 2023-09-21. Retrieved 2023-09-21. (11 pages)

External links

• Hicks, David G. "HP 10C Series Technology and Packaging". Museum of HP Calculators.
• Smith, Eric. "Hewlett-Packard Calculators".
• "HP-15C". MyCalcDB.
• HP-15 Limited Edition (photo) on Flickr
• HP 15c CE Firmware Update (fixing the hidden 16c mod)