At 1:49 PM -0400 6/2/02, Hauke Fath wrote:
>At 10:13 Uhr -0700 2.6.2002, Randy Beaudreault wrote:
>>I just read this on the OS X Unix list and thought this would be of
>>interest here with all the 68k floppies having no access and this
>>being a driver for the SWIM3 floppy chip.  Is the SWIM3 on 68k Macs
>>or just IWM?
>
>We have IWM in m68k Macintoshes (vanilla Macintosh II), SWIM (probably all
>DMA-less 680[23]0 Macintoshes and the Quadra 700), SWIM II (later 68040
>models), IOP based floppy controllers (IIfx, Quadra 9x0) and a DMA based
>controller (840AV).

The "NewAge" floppy controller in the AV is a NEC 72070, which I think is a
specialized version of another NEC floppy controller.

I've managed to extract the floppy driver from the ROMs when I was trying
to understand the AV's DMA controller. Looking at it, it must have been
written in assembly by a human because its pretty easy to read (unlike the
CIVIC video driver which must have been written by an optimizing C
compiler!). Its so easy to read, in fact, that I think if somebody had a
datasheet for the 72070, a NetBSD driver would soon follow.

The problem, of course, is that the datasheet seems impossible to get a
hold of. I think Ken Nakata tried a couple of years ago, and I recently
tried again. I was met with nothing but stoney silence from NEC. I think
that unless you are a paying corporation or your part is easily found on
their website, they couldn't give a hoot about your inquiry. Never mind the
fact that the datasheet is either in a long lost file cabinet somewhere or
propping up a table leg in a NEC lunch room. :-)

Still, I had some luck tracking down the specs for a National programmable
video clock chip used in the Quadras. With a lot of persistance I finally
got through to the right guy who cared enough to track down the ancient
part I wanted in his spare cycles. So with a little persistance, it might
be possible to get some info on this from NEC.

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 Michael Zucca - mrz5149@acm.org
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 "I'm too old to use Emacs." -- Rod MacDonald
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