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

[coco at yourdvd.net]

could i see a copy of your circuit? are you latching on the falling
edges of ras and cas?

> -------- Original Message --------
> Subject: [Coco] Re : FREE Services For Members Of The CoCoList at
> Malted Media
> From: Sylvain Rousseau <surtoutnombliepas at yahoo.ca>
> Date: Fri, April 20, 2007 9:41 am
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> 
> I tried to made one myself (512k static ram for CoCo3) last winter but
> it don't works. I got an oscilloscope last week. I expect to
> investigate it soon. I hope it will works because I don't have a 512k
> CoCo3, only 128k so I can't try the new Sockmaster port of DonkeyKong
> :( I use a Lattice CPLD (isplsi1016e) to demux the Gime address bus.
> Sylvain ----- Message initial ---- De : "coco at yourdvd.net"  À :
> CoCoList for Color Computer Enthusiasts  Envoyé le : vendredi 20 avril
> 2007, 11 h 24 min 24 s Objet : Re: [Coco] FREE Services For Members Of
> The CoCoList at Malted Media 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  > Date: Fri, April 20, 2007 8:08 am > To:
> CoCoList for Color Computer Enthusiasts  > > 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 >
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