Microcalculator model-85

Hardware
1

This is a board that serves as a calculator accessible via a parallel 8 bit port, e.g. from a KIM-1. Send commands and read the calculated results.
Made by Artisan Electronics in 1977.
A very early floating point processor! Aimed at the KIM-1, usable from any computer with a 8 bit bidirectional port.

Acquired August 2026, as built in a KIM-1 with KIMSI system.
Found the manual as luck has and now a documented piece of very rare KIM-1 history!

Scanned, KIM-1 program typed in and photos made:
Microcalculator Model-85 – Retro Computing

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manual microcalculator
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2

Any clue as to what the “Artisan Electronics ICD-85” chip really is? I’ve seen computers that used the National Semiconductor MM57109 calculator chip as a (slow) RPN number cruncher, but they require fiddly +5 / -4 V power supplies.

3

I do like that the brochure gives timings - nearly 3 seconds for yᕽ!

4

SWTPC sold a board based on the MM57109.

I never used one. There was never any support built into any of the BASIC interpreters available for the system.

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5

In the manual the IC is given the brand Artisan Electronics. I think it is an IC especially made for them, not a generic one.

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