that HP42sx thing again


Reading old literature and journals, i've found out that there was some form of HP42sx prototype actaully present and publicly used by a Corvallis engineer. The I/O functionality had been burned to a larger ROM and a hole cut in the case to take the hand wired socket. But it worked, and was there!

A fully disassambled ROM image from a 42S would make building an IO/extended functions ROM this much easier. I'd also vote for strictly Infrared IO due to power and space.

A disassembled 17Bii ROM would also add the ability to get the code for some of the financial and statistics functionality into a second ROM.

I'm sure that it would be easy to get submissions sifficient to fill any ROM package that was made. (to preserve the 'pioneer-ness' of the calc, it would have ot be a small surface mount item.

Periodically, steps are taken by various people to try and get closer to this Holy Grail of Pioneer calcs.

So here I am, starting the next cycle :)

Maybe I can get a disassembler running on a 48 to handle this.

and- for anyone building an emulator, go for it! a good 42 emulator would make final builds of a ROM much easier


I'm actually building a emulator in hardware (with microcontrollers) in my spare time, and I'm planning to emulate the coconut processor (HP41CX, 11C, 12C, 15C). I can add later the ability to emulate the Saturn processor, it isn't so different. The part I'm thinking about is the graphical LCD of the 42S, it is 131x16... I may use a larger graphic LCD and use some part to display the status of the emulator and the annunciators.




We *do* have an extremely good HP-42S emulator for this purpose (Emu42 by Christoph Giesselink). And we also have a very suitable mechanism for it in the additional ROM (as used for the mulilanguage 17BII)...


Yes, I have this emulator, and it is great! My hobby project is to build a mainboard replacement for some Spices, and using a matrix LED display (5x7, 12 char.) it is possible to run a HP-41cx emulation. I'm working to get the ROM of my HP-15C, as it uses the same CPU as the 41. I'm thinking of make a "blended" calculator using the most interesting functions from several others... (not a pure emulator; a CPU emulator running a new ROM image compiled from several sources). As I said, it is a hobby project. I have some microcontrollers and some non-working calculators, and why not?




I purchased an HP 42S in 1991 from the now defunct Educalc (not related to the current I like it very much. A few years back I read in a Chip Chapter newsletter that HP was working on a prototype for an expandable HP 42S (what is here referred to as an HP 42sx). The newsletter stated that the HP 48SX put the HP 42sx idea on hold. If enough persons expressed an interest, could HP market an HP 42sx? I know some persons are skeptical, but with HP introducing several new models of calculators this year (the HP 49G+ of which I am eagerly waiting) it might happen. I am open to comments/feedback.


As long as we are discussing 'dream' calculators, this is my take on it...

Introducing the hp 48c. Basicly a hp 48 in a pocket (pioneer) sized case with a smaller screen (131x32 ?) and perhaps ditching the serial IO, but keeping IR IO. Using IRDA would allow direct comunication with PC:s anyway...


Unfortunately, I don't think HP will do it. At least, not to a degree that would make anyone here happy.

it is *possible* that something in a 10bii case (ugh) with some of the capabilities of a 42, and maybe even IO, could happen.

i'm a bit skeptical about their actual *ability*, let alone willingness, to provide something of the hardware and software capability of the 42S. Look at the obvious and silly bug with program entry limits in the 12CP, the case durability of the 10bii.

Hence my desire to add on to my 42S further :)


Maybe the HP 42sx will never become a calculator available to the general public. The next best thing might be HP 42sx (i.e., compatibility with HP 42S, HP 41C/CV/CX) emulation for the soon to be released HP 49G+. I remember that there was an HP 41CV emulation package for the HP 48SX about 10 or more years ago. After a while I no longer saw this package. The huge amount of programs written for the HP 41C/CV/CX and HP 42S could run on a much faster platform with the ability to add additional memory with the Secure Digital (SD) card that can be inserted. I do not know if applications can actually to burned to the SD cards as applications could for the HP 48SX/GX plug-in cards, as well as the HP 41C/CV/CX plug-in modules.



[Christof wrote: ]
i'm a bit skeptical about their actual ability*,
let alone willingness, to provide something of
the hardware and software capability of the 42S.
look at the obvious and silly bug with program
entry limits in the 12CP, the case durability of
the 10bii.
Hence my desire to add on to my 42S further :)

I agree about the 42S :) Dream calc.

HP/Kinpo failed on the 12CP because they had a small time & cost budget and decided to do a rewrite from scratch. In situations like this it would've been faster & more reliable to write a 'Nut CPU emulation layer - poss w/a few 'hotspot' areas optimized - that runs on the 6502. Even if written in assembly code, this wouldn't take too long; not that hard to emulate a 'Nut in C or assembly macros.

Instead of a "code interpreter" the emulation could also be done as a machine translation (i.e, at "compile time") via macros/pseudoops & subroutine calls, taking into account ROM space use.

Since I/O setups would be different, you'd jump in & out of emulation for KB, display I/O.

Then the 12C code could could run in 100% conformity to a regular 12C. Once this is done, minor changes (# of program steps, etc) could be done incrementally.

Building a new-old calculator is not difficult these days software-wise if you can change/replace/reflash a ROM with your choice of firmware. The new ARM-based 49 would be WAY cool for this. (Linux on a 49 anyone? :) The hard part for small runs on consumerish widgets like calculators is finding/manufacturing keytops w/appropriate legends and keyboard overlays w/legends. This takes at least (guesstimating) $25K-$40K for even small runs because setup costs are the big thing.

Bill Wiese
San Jose, CA


"The new ARM-based 49 would be WAY cool for this. (Linux on a 49 anyone? :)"

I think it just might have a miniature Linux underlying there...


This is exactly what I hoped to see among the new calculators released this autumn: A HP42S compatible calculator with 32K (or more) memory, a faster CPU and *most* important - I/O. In a way the HP33S is a step in the right direction, at least HP are producing a keystroke programmable RPN calculator again! (Only future will tell if we are waiting in vain for the dream calculator I describe above...) However, in the meantime - I/O for the HP-42S!? - well, I would be delighted! :-)

Best regards,
Erik Ehrling (Sweden)

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