The HP-12c and platinum Kinpo story

[AnnoyedOne]

(12-02-2024 08:15 PM)dm319 Wrote:  It seems strange to me that we're still making modern equipment that runs on such an old 8 bit design.

I know I've said this before. Cost, cost, cost.

Simpler 8-bit CPUs means less silicon means lower cost. That's why many put 8-bit 8051/6502 CPU's in "modern" SoCs. Increase the clock speed, up the memory, and "Bob's your aunty" Many Microchip PICs fall into the same category IMHO.

By contrast ARMs are a 32-bit architecture. Some variants use the reduced-cost "THUMB" instruction set which is a 16/32-bit hybrid as I recall. FYI ARM (a UK company) sells CPU designs and not chips. Chip manufacturers purchase designs from ARM, put stuff around them, and sell those (SoC = System on Chip). So "ARM" is a CPU architecture not a specific chip.

The 68020 is a true 32-bit CPU made by Motorola (now Freescale). Probably a bit slower than newer ARM based designs but comparable.

The Zilog Z80 is a 8-bit CPU. A super Intel 8080 in effect. I'm not a fan but again it is cheap. I've written a lot of Z80 assembler and some PASCAL code (but not cross-compiled 'C').

The 68000 is 32-bit internally with a 16-bit data and 24-bit address bus. I've written assembler and 'C' code for a 68000 system (on a Motorola multi-user 68010 VMEbus based computer).

Insofar as calculators go the end-user probably doesn't care much. Sure an ARM-based HP-12C+ is faster than a 6502-based HP-12C Platinum but who cares? Since you're often selling them in large quantities every penny saved counts. Ask any accountant (who, ironically, probably uses a 12C to count those "beans").

The general "rule" in engineering is that you can build something fast/cheap/good. Pick two

A1