WANTED MegaST 68881 copro board C103067 / SPF004

[SophieRose]

@ Guus

Let us know what price you're after shipped to the UK and I'll weigh up my options.

Cheers

Soph

[DoG]

It is Chinese New Year between 6feb-18feb so it will probably take a while longer. But maybe PCBway function anyway?

EDIT: Apparently 12feb-26feb. I was a bit off.

[frank.lukas]

The Layout with Eagle PCB is errorfree but it do not work. So there is something wrong with the design ...

The design is from Djordje Vukovic.

fertig_forum_klein.jpg

schaltplan.png

[exxos]

DSACK0 is floating ?

[frank.lukas]

DSACK0 is low active, should I put the pin with 4.7k high?

[frank.lukas]

czietz told me ...

DSACK0 is an output of the FPU and with regard to the 16-bit operation used here, see the manual of the MC68881: "it is not necessary to connect the DSACK0 pin since the FPCP never asserts it in this configuration."

[exxos]

How do you know it's not working ? You also need custom libs and code as the FPU io mapped isn't normally compatible with linef 030 instructions. Its why GB6 doesn't support io mapped as nobody ever uses io mapped.

[frank.lukas]

Can anyone make a schematics from a Atari SPF004 ... ?

[troed]

How do you know its not working ? You also need custom libs and code as the FPU io mapped isn't normally compatible with linef 030 instructions. Its why GB6 doesn't support io mapped as nobody ever uses io mapped.

I know I found a benchmark program that could do I/O mapped FPU when I added one to my MSTE - but now I can't figure out what it was. While looking for it, I see GFA v3.6 supports it though.

/Troed

[exxos]

I know I found a benchmark program that could do I/O mapped FPU when I added one to my MSTE - but now I can't figure out what it was. While looking for it, I see GFA v3.6 supports it though.

Never heard of one past GB4. DML wrote GB6's FPU code. We decided it wasn't worth adding io mapped for what few machines had it. Even so, I would assume the code overhead running in ram would be where most of the benchmark speed goes. So it would just end up like a slightly faster ram test kinda thing.