[Coco] FREE Services For Members Of The CoCoList at Malted Media

coco at yourdvd.net coco at yourdvd.net
Fri Apr 20 11:24:24 EDT 2007

You could actually modify the refresh (i think it has something to do
with a cas before ras type refresh, but i can't remember) and make them
work if you wanted to add some extra circuitry. I'll get into my box of
simms and sort out all of the 256's. I was thinking about attempting to
demultiplex the gime address bus so it could support 512k fully static
rams (about 17 bucks each), but i haven't looked into it enough to see
if it is a possibility. the gime is designed for dual 256k banks using
a 256 cycle refresh. One bank is for even addresses, the other odd
addresses. The banks are accessed by the two we signals. I though
perhaps i could use cas and ras to latch the addresses and use the we
signals to generate the upper address bit and make it work, but again,
i haven't looked into it fully. -r

> -------- Original Message --------
> Subject: Re: [Coco] FREE Services For Members Of The CoCoList at Malted
> Media
> From: Roger Merchberger <zmerch-coco at 30below.com>
> Date: Fri, April 20, 2007 8:08 am
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Rumor has it that coco at yourdvd.net may have mentioned these words:
> >i've got the 3 8 and 9 chip versions. My question is, do i need to
> >verify that they are 256k or if i send larger simms (they're all 30
> >pin), as long as they are 8/9 chip, will they work as 256k simms in
> >your card? i can plug up and old 486 and verify them if i need to. I
> >bought a lot of them because i thought i might need them one day.
> >Bought all i could find regardless of mem size, but i want to make
> sure >i send useable simms. -r Only the 8 or 9 chip 256K Simms (the
> 9th chip is parity, which is ignored) will work on a CoCo - Mark
> already educamated me on that fact in the past. It all has to do with
> DRAM timing issues, and the 1Mbit chips just aren't refreshed the same
> as the 256kbit chips. I have 80 1Meg 9-chip 30-pin Simms available
> from an old DEC 3-processor 486 server, it rather sucks that I can't
> use any of them for any of my CoCo (or other classic) equipment. I
> wish I had enough knowledge to make 'em into a nice 80Meg Solid State
> Drive ... IMHO that would be kewl beyond belief! Laterz, Roger "Merch"
> Merchberger -- Roger "Merch" Merchberger | Anarchy doesn't scale well.
> -- Me zmerch at 30below.com. | SysAdmin, Iceberg Computers -- Coco
> mailing list Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco

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