Hello there,
I know it is not a OSI hardware but it is running OS65D so may be some of you will be interested.
This my FPU unit for Junior Computer. It use an Intel C8231A at 4 Mhz. Its inspired from the Microcrunch of M. Hart.
Basically (with peek and poke) it works. Now I have to think how to use it in a more handy way.
If you are interested contact me by PM I freely share the design. I have also remaining pcb but they need some corrections before use.
Regards.
Philippe