[Coco] SAMx4 - CPLD-based SAM replacement

[Bruce Borer]

Your SAM can use the crystal on the CoCo board and make everything
synchronized.
That should allow double speed or as fast as the other chips (memory
and PIA's) will allow.

Bruce Borer

On Fri, Dec 1, 2023 at 11:06 AM Ciaran Anscomb via Coco
<coco at maltedmedia.com> wrote:
>
> David Ladd via Coco wrote:
> > On Fri, Dec 1, 2023 at 7:43 AM Ciaran Anscomb via Coco <coco at maltedmedia.com>
> > wrote:
> > >
> > > http://www.6809.org.uk/dragon/samx4/
> > >
> > > Schematic, PCB layout, VHDL source.
> >
> > Does it work with the SAM accelerator? Or can it replace the SAM and SAM
> > accelerator?
>
> The only fancy thing this design (optionally) does speed-wise is feed
> video addresses _if possible_ in fast mode.  So in 32K mode you get noisy
> video and (enough) refresh, so long as you're mostly hitting the ROM.
> Much less use in 64K mode.
>
> This one also has an oscillator on-board, as I didn't want to bother
> figuring out how to interface to a crystal, so...  maybe?  As long as
> the accelerator didn't require replacing a crystal?  I don't have one :)
>
> ..ciaran
>
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