USR quad modems... (ontopic - really!)

[Roger Merchberger]

Rumor has it that Tony Duell may have mentioned these words:

>Hmm.. Both the SAM (CoCo 1 and 2) and GIME (CoCo 3) chips are pretty much
>designed to use DRAM. They output the multiplexed addresses and all the
>right timing signals.

Yup.

>  Surely 41256 DRAMs are not that rare yet?

Nope.

>   It would be a lot easier to stick 16 of those into a CoCo 3 to get it 
> up to 512K.

But the *boards* to stick 'em in aren't exactly easy to find, and Cloud 9 
(http://www.cloud9tech.com/) aren't building/shipping any more hardware 
(including their 512K upgrade boards) until they get the SuperBoard done; 
which might be quite a while yet.

Besides - I have bigger fish to fry. This is part of my evil, twisted plot 
for world domination!!!

OK, just kidding, but - to venture into where my brain & dynamic memory 
part understanding, the 41256 uses a particular refresh[1]
which newer memory doesn't deal with well[2], so going *beyond* 512K is 
problematic.[3] *If* I can figure out how to get 512K of SRAM to work in a 
CoCo3, going *beyond* 512K might become a bit easier.

Not to mention - going from SRAM to FRAM would be a pretty easy jump. A 
CoCo3 with a "Suspend" switch could be *neat*. ;-)

Or, I might be full of condensed milk, as my father-in-law used to say.

Just my random thoughts for the day...

Laterz,
Roger "Merch" Merchberger

[1] 256 cycle / 8-bit counter / something like that. Did I mention that my 
brain doesn't grok DRAM well??? ;-)

[2] 512/1024 cycle / 9-10 bit counter / something like that. Just in case 
you didn't catch it, I have DRAMophobia. ;-)

[3] Now we're getting into the world of PAL/GAL/PEEL/CPLD - which is *way* 
beyond anything comprehensible to my grey matter.

--
Roger "Merch" Merchberger   | "Bugs of a feather flock together."
sysadmin, Iceberg Computers |           Russell Nelson
zmerch at 30below.com          |