USB Universal Floppy Disk controller

Jules Richardson julesrichardsonuk at
Sat Mar 12 14:02:46 CST 2005

On Sat, 2005-03-12 at 01:20 +0000, Philip Pemberton wrote:
> In message <1110586962.6194.110.camel at weka.localdomain>
>           Jules Richardson <julesrichardsonuk at> wrote:
> > > Why not stuff it all in a CPLD? Maybe create a logic-only version too...
> > 
> > Well personally I prefer logic-only because I know I'll have the parts
> > here, plus I don't have any sort of programmer for making more exotic
> > things (ok, so I do have an ancient PAL/EPROM programmer, but without
> > manuals I've only ever figured out the EPROM side of it :)
> The Altera ByteBlaster and Xilinx Parallel Download Cables are literally
> three-component devices - a DB25 connector, a 74LS244 and an IDC header. Plug
> the cable into the target board, apply power, run the downloader, hit
> "Program", then wait a few seconds for the fuse data to download.

Forget all I said then - that's nice and easy ;-)

> > I still like the idea of SRAM from old PC motherboards; didn't they
> > normally have 64 or even 128KBytes? Free then; with other parts costs
> > it'd probably make the whole thing do-able for a fiver or so (more with
> > a few frills like a case, PSU etc.)
> I've got a TAG RAM here from a Pentium board and it's only 16k. I'm still
> trying to find a few more of them...

Hmm, just grabbing a random 486 board from the pile here; it's got 8
61256 chips on it which is presumably 256KB in total. I suppose by the
Pentium era the cache was all in the CPU or something though...

> I did have a SCSI card in my RiscPC, but I replaced it with a 100BaseT LAN
> card, seeing as I wasn't using the SCSI (no SCSI devices to use with the
> card).

I unearthed about ten Acorn SCSI cards the other day :-)



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