HP-15C
| Industry | Electronics, Computer hardware |
|---|---|
| Founded | January 1, 1939 |
| Headquarters | Palo Alto , United States |
| Products | Calculators, Computers, Printers |
The HP-15C represents a top-tier scientific programmable calculator from Hewlett-Packard's HP Voyager series, manufactured between 1982 and 1989. The suffix "C" signifies its continuous memory feature, which preserves the calculator’s state even when powered down.
HP-15C
As a high-performance scientific pocket calculator, the HP-15C includes capabilities such as a root-solving function and numerical integration. It belongs to the Hewlett-Packard Voyager series and offers support for complex number calculations and matrix operations. Although production ceased years ago, its sustained demand has maintained strong resale prices. This model followed the HP-34C and incorporated bulk CMOS technology, resulting in exceptionally low energy consumption.
HP 15C Limited Edition
After presenting a prototype at HHC 2010, HP officially released the HP 15C Limited Edition (NW250AA) on September 1, 2011. This iteration employs a flash-programmable controller based on the ARM7TDMI core—the same processor utilized in the 2008 revision of the HP 12C—and is built around an Atmel AT91SAM7L128-AU microcontroller in a different casing. It runs an emulator created by Cyrille de Brébisson, which executes original HP Nut firmware more efficiently than the legacy hardware. Launched concurrently with the HP 12c 30th Anniversary Edition, it draws power from two CR2032 batteries. Visually distinct, it displays "Limited Edition" beneath the logo and uses black text on a brushed metal rear label, contrasting with the original’s white lettering on black. Due to architectural differences, its processor consumes more power compared to the original HP-15C.
HP 15C Collector’s Edition
In May 2023, HP Development Company, L.P.’s licensees Moravia Consulting spol. s r.o. and Royal Consumer Information Products, Inc. announced the HP 15C Collector’s Edition, which became available in July 2023. Manufactured in the Philippines, this model supports up to 672 program steps alongside 99 registers. Its initial firmware resolves known issues from earlier versions and runs on the same Microchip ATSAM4LC2CA (ARM Cortex-M4) processor found in the 2015 and 2022 HP-12C models. Power is supplied by two CR2032 batteries.
The official test menu provides three options, with an undocumented fourth selection unlocking two hidden modes: "15.2," offering expanded memory with certain restrictions, and "16," which emulates an HP-16C calculator. Unlike previous editions, this Collector’s Edition omits the "Hewlett-Packard" branding on the front panel and features a slightly deeper brown coloration.
Bugs and problems
HP-15C:
- A CHS stack lift flaw existed but was subsequently corrected.
- The documented reset method caused a 22-bit rotation of the X register, facilitating synthetic programming techniques.
HP-15C Limited Edition:
- Firmware dated April 15, 2011 contains a PSE-related defect that leads to display blanking after initial program execution; reverting to earlier firmware versions removes this issue but reintroduces other errors.
- The original HP-15C self-test key sequence is incompatible, risking memory corruption; an updated self-test procedure was introduced but not included in official documentation.
HP-15C Collector's Edition:
- Firmware updates address prior bugs and revise self-test procedures.
- The concealed "15.2" and "16" modes exhibit multiple bugs that have largely been resolved through community-developed firmware patches as of October 2023.
- Key press behaviors after GSB commands or in user mode differ from those of the original HP-15C model.
Legacy
Hewlett-Packard provides an official PC emulator for the 15C model as free software, enabling users to continue utilizing the calculator’s capabilities in a virtual environment.
A variety of software-based calculators emulate HP models, serving both enthusiasts and professionals who need HP calculator functionalities on contemporary platforms.
See also
Further reading
External links
- HP 10C Series Technology and Packaging – Museum of HP Calculators, David G. Hicks
- Hewlett-Packard Calculators – Eric Smith
- HP-15C – MyCalcDB
- HP-15 Limited Edition (photo) – Flickr
- HP 15c CE Firmware Update (fixing the hidden 16c mod) – hpcalc.org