Re: updated

From: Ruud Baltissen (
Date: 2001-08-31 07:40:53

Hallo Nicolas,

> > If none, they cannot be used. A pro is that some people stated that they
> > replaced their 1571 drive with a HD (?) one.
> Who did this? Do you have any details?

None. I was not sure anymore if it they mentioned they used a HD one. The
reason why _I_ assumed it was a HD is that you tell a FD to change one track
by giving a pulse to a certain pin of the connector. So until recently I
thought "1 track = 1 step". The 1541 can handle half-tracks ie. "1 track = 2
steps". So 40 1541-tracks make 80 steps. A HD-FD has 80 tracks = 80 steps.
Knowing now that you used a former 360 KB drive means that for a 360 KB
floppy "1 track = 2 steps".

Hmmm, a weird idea just popped up. I only hope I'm not inventing the wheel
twice. You stated you used a 360 KB FDD. Would it be possible to attach a HD
FDD to your 1541 board in the same way? In this way one could use all 80
steps to save data on a floppy.
Remark 1: I don't know if the HD FDD uses 1 or 2 steps/track. 2 s/t would be
better as that means less SW to change.
Remark 2: is there an adjustment of the current or whatever needed?

A thought-avalange:
- And what about skipping the analogue part of the 1541 and connecting the
TTL-signals to the according shugartbus-pin?
- And to hook the diskcontroller/6522 directly to the shugartbus? (Remark:
requires SW change)

I even dare to dream a little bit further: what about the same trick(s) but
using a 3.5" DD- or even HD-drive? But that makes less sence as IMHO it may
be is easier to build a 1581 yourself.

I own a MicroPower 2000. Consider this roughly as a 4040-clone with an extra
IEC-interface. The most interesting thing is it uses two SS shugartbus
drives. We replaced these with normal 360 KB ones W/O any problem. Remark:
only one side could be used.
I intend to re-engineer it. This could give us the possibility to make a
Catweasle-clone of our own ie. using 1541-floppys in a PC.
Another idea is attaching a 3.5" DD-, maybe HD-, drive to this MP2000. But
same remark as above.
  / __|__
 / /  |_/     Groetjes, Ruud
 \ \__|_\

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