I have written Nonpareil, a microcode-level simulator for many older HP calculators. Nonpareil uses the GTK+ toolkit and runs on Linux/Posix/Unix platforms and Windows.
I've found several United States Patents relating to HP calculators. I've typed in the abstracts of some of them, and I have PDF files of many.
I also have a bibliography of Hewlett-Packard Journal articles regarding HP calculators.
There has always been much speculation on Usenet about future HP calculators. In 1995 there were threads comparing the then-new TI-92 with the HP-48. I posted a short article expressing my opinion of the technology issues that I expected to shape future HP calculators.
In late 2003, HP introduced the HP-49G+, which uses an ARM processor core and runs Saturn code in simulation. Low-level portions of the calculator software have been migrated to native ARM code, and more may be migrated in future releases.
Other HP calculators introduced in the recent years have used off-the-shelf hardware designs. Many of these, particularly at the low end, have apparently been designed by other companies for OEM use by HP. Some of them have used GeneralPlus (formerly SunPlus) microcontrollers with a 6502-compatible processor core.
In 2008, HP introduced the 20b and a soft roll of the 12C. These are their first models to use the Atmel AT91SAM7L128 microcontroller, which has an ARM 7 core, 128KB of flash memory, and 6KB of RAM (2KB battery backed). It is expected that most future HP midrange calculators will use this microcontroller. At the very low end, HP will continue to use OEM products designed by other vendors, and at the high end HP will most likely use more powerful ARM SoC chips.
Although I have at least one of each of the HP 38G, 39G, 40G, 48S/SX/G/GX and 49G models, other people have already provided much more information and software for these models on the Web than I could ever hope to. I recommend starting with hpcalc.org.
For HP 38G/39G/40G/48S/SX/G/GX/49G emulation, look at:
The following are links to information about other HP calculators:
Last updated 17 Sep 2009
Copyright 1995-2001, 2003-2005, 2007, 2009 Eric Smith