Hello there,

Anybody have a schematics for add a AM9511 or Intel 8231 FPU to a 6502 bus ?

Ideally a schematic with a separate clock for the FPU so asynchronous operations will be possible...

Many thanks.

Regards.
Philippe

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Hello there,

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

if you want to share the project freely, why not just upload the schematics and everything to github? it's much easier and convenient than individually sending each person that asks the files.

anyways that's a neat little board! though personally the downsides of the chip are that it's pretty slow at 4MHz and requires 12V to function.
looking at the cycle times in the datasheet (page 8) i wonder if it's actually that much faster than a 65c02 doing the same operations in software, especially since the 65c02 can run 5x faster than the FPU.
but even if it was just as fast as the CPU doing it in software, you would still save yourself the program space and of course the CPU can do other things while the FPU is working. parallelization is always nice.
also I'm not sure what most logic on that board is doing since interfacing could likely just be done through a VIA by bit banging the control signals and data bus.
but besides that, the 12V requirement is probably a bit of deal breaking for a lot of existing SBCs.

now i'm wondering what other FPUs might be out there that only need 5V to function. the "uM-FPU" would be nice, modern, small, no external clock, SPI/I2C interface... but sadly it's no longer in production and basically impossible to buy anywhere online.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Nice job!

I also like to interface older chips to faster CPUs.. It's all in good fun and I mostly don't do a whole lot with them except personal experiments that will never see the light of day.

I'd be interested in the schematic. You could just post it to this thread, but if you prefer not to then please PM it to me.

_________________
Bill

Hello,

Schematics (I apologize... I works with paper, pencil and eraser so the look is not terrible) and gerbers with all the corrections further to statup are in the zip hereunder.

You could use also an AM9511 but then use 2 MHz clock (jumper)

Refer to viewtopic.php?f=1&t=7187 about usage and design details.

Regards.
Philippe