--- In minimigtg68@yahoogroups.com, Mark McDougall <msmcdoug@...> wrote:
>
> requin_frederic2 wrote:
>
> > How is it going down under ?
>
> Well, Winter refuses to give way which is annoying, but otherwise OK!
>
> > I plan to use it on the boot menu of the MCC board (see:
> > www.arcaderetrogaming.com), on the Amiga core and as the sd-card/floppy
> > controller of the C64 core. It is a lot easier to manage FAT filesystem
> > with a 68000 than with a 6510 :-).
>
> I've been meaning to make a final decision on how to implement floppy media
> emulation (via FAT filesystem) on PACE projects in general. I've got the
> 1541 emulation for C64 and WD179X emulation for the TRS-80 (and perhaps a
> few other systems) waiting for a FAT filesystem back-end. Trouble is,
> there's a number of PACE targets with differing capabilities and I can't
> decide how best to implement floppy support. I'm leaning towards an ARM
> micro with SD via a SPI interface... though I would actually prefer the
> emulation to be on-chip!
>
> > Now, I am working on a unified cache implementation for TG68. I think I
> > can get a 8KB 4-way associative cache (21.5 MHz on the CPU side, 86 MHz
> > on the SDRAM side). I am wondering if I should keep the two clocks or if
> > I can clock enable the TG68 with the 86 MHz. What do you think ?
>
> I tried clock-enabling the TG68 at 12.5MHz with a 100MHz clock some time ago
> without success. In theory I shouldn't have had a problem but it simply
> didn't run correctly. I dropped it down to 50MHz and it seems good so far.
>
> Regards,
>
> --
> | Mark McDougall | "Electrical Engineers do it
> | <http://members.iinet.net.au/~msmcdoug> | with less resistance!"
>

Hello,

I have tried the NIOS II with FatFS, but I was quite disappointed by the code
density. I do not want to eat up all my block RAMs with a boot ROM.
I also thought about the AVR since there is an AVR soft core and a 1541 clone
that is AVR based.
But finally, the TG68 seems to be a good solution. Plus, I have a specific SPI
core that takes care of some of the particularities of the SPI protocol for
SD-Cards, like automatically sending of zeroes when I just want to read the
SD-Card.
For the boot ROM, I think I will use the cache with a pre-initialized tag and
data content at startup so it can act as a boot ROM.

Regards,

Frederic