Hewlett Packard HP15C

[sP1d3r]

Many thanks BigEd,
I'm working my way through the manual and whilst it's not an essential diagram I was interested to see it because it wasn't in the manuals I've downloaded.

[BigEd]

Take note, the recently franchised outfits which have taken over HP's calculator business have announced the imminent availability of a new, faster, HP15C which they have called "collector's edition" to distinguish it.

It's £100, on pre-order in the UK. (This site suggests it's a limited edition, but that's not clearly the case.)
https://www.studentcalculators.co.uk/ac ... ckard.html

See also
https://www.hpmuseum.org/forum/thread-19886.html

This new model credits a number of prominent people in the HP calculator enthusiast community and claims a number of bug fixes: it should be pretty good. (Edit: it's the fastest 15C and has more registers and program space too.)

[sP1d3r]

I understand that Atmel based HP Voyager series calculators can be flashed with HP15C firmware but require a keyboard overlay and stickers for the keys.

[BigEd]

There are some models which can be reflashed, and there are some approaches which need stickers - I'm OK with an overlay but I don't think stickers would do it for me. (I did buy a 30b because it can be reflashed as a full-featured scientific, instead of a semi-scientific business calculator, but I never did flash it.)

HP15C ... so popular that Hewlett Packard have released an Open Source emulator...

Are you sure? HP did release a free-of-charge emulator, with the usual restrictive click-through license, but I'm not aware of any source for it. You can download the Windows installer for each of several HP models here and more here. For me the HP15C emulator runs OK in WINE on Mac. I believe it's the same version as the Limited Edition.

Being HP's own, that emulator is 100% the same as the calculator. Others do vary... but one interesting thing is a tweaked firmware "HP15C_XE" for HP's emulator which increases the memory (forum login needed for the download.) This particular tweak may have problems with large matrix operations - see the readme within the download. Having said which, it passes this test of solving an 8x8 system of equations, which the actual 15C can't fit.

There is an excellent online emulator here

Nice! I was prompted by this to check out a few 15C emulators. I have two diagnostics:

• 3* (4/3 - 1) - 1 which won't be zero
• sin(3.141592653) in radians mode, which won't be zero (this is 10 typed digits of pi, not the pi button)

Actual HP-15C Limited Edition:

• -1E-9 and 5.9E-10

HP's windows/WINE emulator:

• ditto

Greg Hewgill's hp15c.com online and multi-platform emulator, open source:

• -2.220446049E-16 and 5.897932257E-10 (binary floats both!)

JPRN 15C by Bill Foote, online multiplatform and open source (but watch out there's a bug):

• -1E-9 (decimal!) and 5.897932257E-10 (binary!)

Torsten Manz' multiplatform open source:

• -2.220446049E-16 and 5.897932257E-10 (binary floats both!)

[sP1d3r]

HP15C ... so popular that Hewlett Packard have released an Open Source emulator...

Are you sure? HP did release a free-of-charge emulator, with the usual restrictive click-through license, but I'm not aware of any source for it.

I don't know where that came from, I may have misread a forum post that was wishful thinking/chagrin.

Sorry about that BigEd

[BigEd]

No worries, it's been an interesting adventure in emulations. I've now got emulators installed for Free42 (both binary and decimal versions) and a C47 née C43 (which is still a work in progress.) Mildly surprised to see that Free42 is the most accurate - I thought C47 was going to be the same.

[sP1d3r]

There are some models which can be reflashed, and there are some approaches which need stickers - I'm OK with an overlay but I don't think stickers would do it for me. (I did buy a 30b because it can be reflashed as a full-featured scientific, instead of a semi-scientific business calculator, but I never did flash it.)

I found this about 12C flashing, it seems to be JTAG dependant for copying the existing rom.
There's copyright issues involved with flashing also with 12C/16C you'd need a good memory without stickers for the keys and an overlay.

[sP1d3r]

My old Windowsphone has a calculator with various functions, including a programmers calculator:

Windows Phone calculator

Programmers calc

Useful if you haven't got a 16C!

[BigEd]

Left and right shifts too - very nice, and quite unusual. The HP-35s offers hex numbers but does it in quite a clumsy way. So clumsy I've never really experimented.

[sP1d3r]

Left and right shifts too - very nice, and quite unusual. The HP-35s offers hex numbers but does it in quite a clumsy way. So clumsy I've never really experimented.

It does rotate right and rotate left as well.
I've not got so far with my projects that I've used it!

[sP1d3r]

I wonder if anyone has an original copy of the HP15C owner's manual?

There's an illustration at the back of the manual, the inside cover I believe, that doesn't appear in any of the downloadable manuals that I've found online.
It's a diagram showing registers r0 to r9, r.0 to r.9 and the index register.
If anyone has a copy of the manual and the inclination to post a photo of the diagram, I'd appreciate it.

Subsequent to Big Ed's post with the diagram in question, I found that the picture of the registers, although not present on the inside cover where it was claimed to be, is actually on p.76 of the owner's handbook.
This may not be the particular diagram referred to but it's essentially similar, BTW.