has anyone built the unreleased Casio fx-702p memory expansion module?

[blackjetrock]

(06-13-2023 11:49 AM)dmh Wrote:  Just curious if anyone has attempted or successfully built the Casio fx-702p expansion memory module that there was a slot for but Casio never released?

Wondering how difficult it would be or if it just needs a memory chip wired to an appropriate connector.

The 702p has such limited memory that an expansion module would be useful.

If you look at the service manual schematic it is labelled as a ROM PCB, and someone found a ROM keyword in the code, apparently.
The pinout is there as well, but the instruction set isn't known as far as I'm aware, so what you'd put in the ROM is difficult to say. The pinout suggests some form of Casio 4 bit bus like on the 502P and 602P family.

Andrew