Casio Pocket Calculator CPU Question

[Steve Simpkin]

It should be noted that the first calculator-on-a-chip, the Mostek MK6010, used for a four-function calculator was purely logic-based and did not have any embedded software/firmware on it. This was quickly followed by the Texas Instruments TMS1802 single chip calculator which was a small embedded processor (CPU) with RAM and software to implement a four function calculator all on one IC.

The story behind the race to develop the single chip calculator is fascinating reading.
http://www.vintagecalculators.com/html/t...-chip.html

TI went on to develop more complex custom embedded processors for their increasingly complex calculators. When they developed their first graphing calculator, the TI-81, they switched to a Z80 CPU which was used in a number of microcomputers including the TRS-80, Sinclair and many CP/M computers.
http://www.datamath.org/Graphing/TI-81.htm

When TI developed the TI-92 CAS calculator, they choose the Motorola 68000 CPU which was used in the original Macintosh computers.
http://www.datamath.org/Graphing/TI-92.htm

It is very fair to say that the race to develop large scale integrated circuits for the booming calculator market led directly to the development of the various microprocessors used in
microcomputers.
http://www.vintagecalculators.com/html/b..._4004.html