CCS 7811 Math Coprocessor

["mdj" <mdj.mdj@gmail.com>]

Greetings,

A kindly gentleman enriched my Apple II collection recently with (yet
another) Apple II+ and a collection of expansion cards including a CCS
A/D Converter and a 7811 Math Copro, complete with original
documentation :-D

Unfortunately I don't have the software for the card, and from the
docs it seems it would only work in software mode on a Apple II, not a
II+, due to the requirement of a patched Applesoft.

A cursory glance of the schematic in the manual also indicates that
the board asserts /RDY, presumably to halt the 6502 during a
calculation so that the next instruction can fetch the result. This
would render the device useless on an accelerated Apple II :-(

However, the manual also indicates that the board has a pair of
jumpers for rigging up /IRQ, which leads me to believe the board can
be operated in 'asynchronous' mode, which might make it compatible.

The benchmarks listed in the manual indicate the performance gain on
DIV and MUL ops are pretty modest, and probably worse than an
accelerated Apple II doing soft DIV/MUL. However, the trig/exp/log
operations show an impressive 5 (and sometimes 6) orders of magnitude
improvement, which would probably smoke my accelerated IIe :-)

Anyway, just thought I ask here if anyone else has experience with
such a board, before I run off on some wild goose chase. Modifying the
Pascal p-machine to use this board would provide a spritely boost in
performance, and make for a fun weekend project.

Matt