Re: Commodore 2031LP and Zoomfloppy

On Tue, May 29, 2018 at 4:18 PM,  <afachat@gmx.de> wrote:
> Hi there,
>
> I was finally able to do some tests using my zoomfloppy and a real 2031LP, a
> 1541 converted to IEEE488 using the 64er schematics and ROM, and a 1001.
>

> The converted 1541 would give, after reset, a correct status, but a detect
> command would result in a message like
>
>   8: *unknown*, footprint=<F@NJ>
>
> however the footprint number is actually changing from detect to detect. I
> also got values NIDJ, GNBI, NJNJ, DOB@ ....
> In the end it also hangs, but that can be resolved by resetting the drive
> (with the reset button I conveniently added when I converted it :-)

With my 2031LP, I also noticed a pattern of what appeared to be status
text (lots of '0' and some ',' and parts of the ASCII of DOS status
messages) intertwined with the footprint.  I posted some examples a
couple of weeks ago from my tests.

> The 2031LP also was giving strange errors on detection. After drive power up,
> status gives the correct message, but detect also returns a similar message to
> the one above.
>
> Both, the 2031 and the 1541par fail reading their ROMs at all.

That looks just like my experience with my ZF and my 2031LP.  I got
zero file-size on attempting to download the ROMs.

> Interesting. It seems either the 2031 has a problem with the IEEE488 protocol
> of the zoomfloppy, or something is different with I guess M-R with which the
> ROM is read (and the drive type detected?)

Could be a problem with M-R I suppose.

I don't know the 1001 drive but the 2031LP happens to use 75160/75161
IEEE drivers and I'm wondering if there's a subtle difference in
handshaking or a delay in turning around the interface on the drive
compared with drives with the 3x 3446 buffers.  I used to do some IEEE
hacking in the PET days but I don't know how the 6502 has to change to
use the newer line drivers.

-ethan