HP35s Internal Investigations - new processor? - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: HP35s Internal Investigations - new processor? (/thread-213654.html) |
HP35s Internal Investigations - new processor? - stefan - 03-07-2012 Hi, I have just purchased a new HP35S and surfing on internet I go through the following thread contained in this forum:
"HP35s Internal Investigations re: Creation of the PH35sx I was really curios to read it (I'm an HP vintage calculator fan). I read that there was the idea to modify the HP35S (PH35S) and I wanted just to flag this link: http://ex6502.altervista.org/ It is regarding a 32bit version of the 6502 processor (the one used into the HP35S). This site was just mentioning the HP35S as a possible system where to use this processor. I don't know if it could be interesting for some of you. It seems to fit well in the idea explained by Jeff O.
Cheers Re: HP35s Internal Investigations - new processor? - Eric Smith - 03-07-2012 As a long time 6502 programmer, I find that interesting. There have been other attempts at 32-bit extensions of the 6502, including the WDC65832/WDC65T32 "Terbium" from Western Design Center, the company that developed the first CMOS 6502 and the 65816, as well as independent projects such as the 65020. There even was one group trying to define a 64-bit extension. However, I see a few problems with using such a thing in a calculator design. 1. It isn't actually available as a commercial product. 2. If it was available, it would probably use more power than is desirable for a handheld calculator processor.
3. The 6502 architecture, even extended to 16 or 32 bits, isn't really competitive with modern architectures such as the ARM Cortex-M3. The only reason it made sense for HP to use a microcontroller with a 6502 core in some of their calculators is that the masked-ROM version of those microcontrollers is cheaper than dirt. For a hobbyist or small company to develop a calculator, it is much more important to have a part that is readily available and uses flash memory.
Re: HP35s Internal Investigations - new processor? - uhmgawa - 03-08-2012 Quote:
The publicized efforts were post MOS Technology after it had
There was a little known original internal engineering effort at
Anyway the "merger" with Commodore terminally sunk that project.
Re: HP35s Internal Investigations - new processor? - Eric Smith - 03-08-2012 The part that was pin-compatible with the Motorola MC6800 was the MCS6501. I've got a computer using an MCS6501 from the late but not much lamented company "the Digital Group". The part number for a plastic-packaged part would have used the prefix "MPS", but I haven't seen any evidence that it actually shipped. The more well-known part was originally designated the MCS6502 or MPS6502. The original second-source vendors, Synertek and Rockwell, used different prefixes and suffixes. Synertek used "SYC", "SYD", and "SYP" for ceramic, CERDIP, and pastic, respectively. Rockwell used an "R" prefix, with a "C" suffix for ceramic and "P" for plastic. Both Synertek and Rockwell often omitted the letter denoting the package variant from the actual labelling printed on the part.
The more interesting story about the MC6809 (IMHO) concerns Hitachi's CMOS version. Hitachi was a licensed second-source for many Motorola parts, and developed CMOS versions of some of them, generally replacing the "68" with "63" to designate CMOS. In the case of the MC6809, they also decided to extend the architecture, adding more registers, and even a few 32-bit operations. Reportedly Motorola was very unhappy about that, and somehow brought pressure to bear on Hitachi which resulted in the architectural extensions of the HD6309 not being described in the public documentation. It was only years later that the details were leaked to a Japanese magazine.
Re: HP35s Internal Investigations - new processor? - uhmgawa - 03-08-2012 Quote:
I've always claimed the 6809 was one of the most under
IIRC the falling out over the 6809 soured the cross-licensing
Years later when encountering the Hitachi SH it was obvious from
Re: HP35s Internal Investigations - new processor? - Paul Dale - 03-08-2012 The 68k is alive and well in the ColdFire range. Lovely processors. The SH4 is an interesting processor, although the R0 register becomes a serious bottleneck and the dual issue interactions are difficult to handle well. The only CPU I know of that has a 4x4 matrix times 4x1 vector instruction that is fully pipelines -- if you can massage your problem into this form, it flies along at an absurd rate for its clock.
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