Info on UM8397 floppy disk IC?

From: Jules Richardson <julesrichardsonuk_at_yahoo.co.uk>
Date: Fri Dec 26 06:27:54 2003

Hi,

has anyone got any data on the UM8297 floppy disk controller IC?

I found one on a tiny ISA board in the loft the other day (labelled
"FDC-III"). I was hoping it might provide a little more flexibility in
reading non-PC floppies on a PC machine (specifically Acorn BBC - none
of the spare PC motherboards I have kicking around happen to have floppy
controller ICs that do this)

Using the ISA board in a PC with the on-board floppy disk controller
disabled, the drives seek on startup as expected but I can't get any
data from floppies put into them (known-good MSDOS-format disks,
known-good drives, and a known-good data cable). Tried using both DOS
and Linux.

A few thoughts:

1) The controller IC might be broken; I don't know its history. The fact
that it's doing a seek on startup makes me think it's at least
semi-alive though.

2) The motherboard fdc IC might somehow get in the way for data
transfers, despite being disabled in the BIOS (bad design if so!)

3) The chip might need some specific setup from DOS before it'll work
correctly.

4) The chip might be expecting a specific floppy drive type or types to
be attached, or set up in a certain way. I've only tried known-good high
density 5.25" and 3.5" drives so far.

5) Maybe the IC doesn't emulate any kind of standard PC floppy
controller chip, and needs a whole complex driver to function. Yuck.

I'm hoping on 3) or 4) at the moment, with 3) being more useful to me!

If I fit a 5.25" drive say, and set it up as a 3.5" drive in the
motherboard BIOS, then the system halts on startup with a floppy disk
failure as expected - so it does look like the BIOS is trying to talk to
the ISA board with the IC on it and knows that it's there.

There's very little on the ISA board itself - the IC itself, a pair of
7406 chips, and some clock circuitry. No configuration on the board
whatsoever.

As I say, maybe the board isn't strictly DOS-compatible without a
driver, or designed to do some oddball task.

cheers

Jules
(waiting for hangover to go and eyes to start working correctly...)
Received on Fri Dec 26 2003 - 06:27:54 GMT