floppy

  • Thread starter Thread starter Ed
  • Start date Start date
Much useful information Arno.
My problem seems to begin with finding how to synchronize the 1mhz clock
with the data.
I dont have much experience with analog circuits or frequence synthesis.
I am mainly a microcontroller/digital engineer.
Any information you can give as to doint this part?
 
Previously Ed said:
Much useful information Arno.
My problem seems to begin with finding how to synchronize the 1mhz clock
with the data.
I dont have much experience with analog circuits or frequence synthesis.
I am mainly a microcontroller/digital engineer.
Any information you can give as to doint this part?
Click to expand...

Hmm. I feel you have a fundamental information deficit here.
In analog circuits this is done with something called a "PLL".
In software it is done differently. Basically you measure the
phase difference between the clock and the signal and then shift
the clock phase. In order fot hei to be stable, you shift only a
little per observed signal ''flank'', e.g. 1/16. For this you need
a base clock running at 16 times the signal.

The singal you sunchronise to is the MFM-embedded clock.
I think this is actually described in the WD-1772 datasheet
somewhere. What the wd1772 does in hardware, you have to do
in software.

Some info on MFM is here

http://en.wikipedia.org/wiki/Modified_Frequency_Modulation

Other than that, I would recommend some text in communication
technology or the like. I learned this a long time ago
in a telematics lecture.

Arno
 
Ed said:
Looking for a way to connect 2 pc's via floppy ports?
Any suggestions would be helpfull.
Please do not suggest the obvious as using floppy diskettes.
I want to try to connect 2 pc's using the floppy's 34 pin cables.
Thanks.
Click to expand...

Perhaps they can help here....

http://www.torlus.com/floppy/

Selected quote..

"...the floppy drive has been replaced by some piece of hardware. This piece
of hardware features an USB connection to a PC."
 
Perhaps they can help here....

Selected quote..
Click to expand...
"...the floppy drive has been replaced by some piece of hardware. This piece
of hardware features an USB connection to a PC."
Click to expand...

Yes, I believe that is the idea. This one is for Amiga and ATARI
filesystems. And the MAmiga special mode of reading/writing,
since it does not uses MFM, as I recall.

Arno
 
Yes, I believe that is the idea. This one is for Amiga and ATARI
filesystems. And the MAmiga special mode of reading/writing,
since it does not uses MFM, as I recall.
Click to expand...

Also it seems this does not support writing to floppies at all,
but just offers the right pre-digitized track to the attached
device. For that it does not need to understand the filesystem
or modulation. In fact this is pretty close to the
device I build almost 2 decades ago.

Arno
 
I spoke with them already and was told it wouldnt be ready for several
months yet.
I found another floppy emulator for the amiga system but have gotten no
response from them.
What exactly did you build 2 decades ago??
What information do you still have? Schematics?, Code?
 
Previously Ed said:
I spoke with them already and was told it wouldnt be ready for several
months yet.
I found another floppy emulator for the amiga system but have gotten no
response from them.
What exactly did you build 2 decades ago??
What information do you still have? Schematics?, Code?
Click to expand...

A floppy copier that just digitized the data with a
constant sampling rate and replayed it.

I have the impression that is what they do. Nos useful for what
you want to do, I think.

Arno
 
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