Re: Transwarp IIe revisited

[mdj <mdj.mdj@gmail.com>]

On Dec 9, 11:43 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> mdj wrote:
> > On Dec 8, 11:50 pm, Linards Ticmanis <ticma...@gmx.de> wrote:
>
> >>David Wilson wrote:
>
> >>>On Dec 8, 7:51 pm, mdj <mdj....@gmail.com> wrote:
>
> >>>>FWIW, my card has 80ns RAM on it. I imagine someone has swapped the
> >>>>RAM at some earlier point, 150 is way to slow
>
> >>>I just took a look at mine and it has 8x HM50256-15 NMOS DRAM chips
> >>>(week 50 of 1985).
>
> >>Hmmm... I have HM50256P-15 from WK13/86. Then speed is maybe not the
> >>issue after all.
>
> > Unless one or more of them is faulty...
>
> > I didn't do the math, but I would have thought 150ns was marginal at
> > 3.6Mhz considering the Apple II refresh scheme.
>
> The Apple II "interleaved access" scheme will not apply to
> DRAM on the Transwarp card.  It will have its own, more conventional
> refresh method.

I had suspected that it would, since it still uses its own CPU in
'slow' mode so would need to mimic the timing of the Apple II...

But then I suppose it could have different refresh schemes for
different speeds, but that seems unlikely...

Matt