Yeah, I've been finding out that commercial dual-****ted RAMs are pricy. In
the environment in which my first two projects will live -- ISA bus
boards -- there's a fairly leisurely speed requirement (an 8 MHz clock)
that
will allow me to construct a dual ****ted memory by time-sharing the memory
by the phase of the clock. 60 ns static RAM is fairly easy to get so that
won't be a problem.
It still leaves open the issue of what to do with a fast co-processor in
this environment. I've discovered an obsolete (but still available) part,
74F573, which is an asynchronous access arbitrator which has been used in
at
least one commercial design I've seen. Another viable suggestion is to
treat ISA or PCI bus access to the card as a DMA-request and let the
on-board processor arbitrate it.
Norm
"dwight elvey" <dkelvey@[EMAIL PROTECTED]
> wrote in message
news:cah_0004373314@[EMAIL PROTECTED]
> "Norm Dresner" <ndrez@[EMAIL PROTECTED]
> wrote in message
news:<cah_0004370024@[EMAIL PROTECTED]
>...
> > For a project that will reside on an ISA bus card, I need some dual
****ted
> > memory. Not much, a few hundred K to a megabyte or two.
> >
> > Are there any commercially available memory controllers that I can
just
> > "incor****ate"?
> >
> > Any available dual-****ted (preferably static) RAM ICs?
> >
> > Any URL's to circuits that can be created?
> >
> > TIA
> > Norm
>
> Hi
> I think the name is Cyprus Electronics. They make
> static dual ****t RAMs. They make both parallel-parallel
> and parallel-serial type. They are not cheap though.
> If you don't have speed requirements, it would be better
> to build your own from standard parts.
> Dwight
>
