Alternative Hardware Design for Floppy Interface

Chuck Guzis cclist at sydex.com
Mon Oct 22 12:55:58 CDT 2007


On 22 Oct 2007 at 18:11, Jules Richardson wrote:

> Hmm, I thought all modern machines emulate a parallel port connected via an 
> ISA bus - i.e. it's still slow compared to the rest of the machine, and a 
> modern xGHz system won't drive the port any quicker than a syatem of ten years 
> ago...

If it's an IEEE 1284-conforming port, then it can execute at least 2M 
transfers/second, which should be sufficient for most 5.25" DD and SD 
floppies.  If you want to get more exotic, add some RAM (like the 
Catweasel) or a FIFO.  Still no big deal.
 
> > At least on the CW MK I and MK III, most of the board is taken up by 
> > Amiga-realted nonsense like joystick ports and SID sockets.
> 
> That's another thing putting me off a CW... I just want a floppy-access 
> device, not half an Amiga thrown into the mix.

Then get a CW MK4 - Jens has left all of the Amiga stuff off of it.  
The MK3 was interesting in that it was a "flippy" card--you could 
plug it into a PCI bus or whatever the Amiga used for a bus.

As I said, it's not rocket science and even a USB catweasel reader 
can probably be constructed easily with off-the-shelf components.  If 
a standard is needed, the only things I can really think of are the 
meaning of the high-order bit (in the CW, it's the presence of the 
index signal) and the clock frequency used (the CW, depending on 
model, uses two or three fairly odd ones--probably related to the SID 
accommodation).

Cheers,
Chuck




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