[Coco] usb floppy drives?

James Dessart dessart at istop.com
Thu May 27 12:29:24 EDT 2004

On 27-May-04, at 12:00 PM, <alsplace at pobox.com> wrote:

> Question:  Can a 1.44MB USB floppy drive read/write a 720K disk?  I 
> assume it can, and if so, electronically a 3.5" drive looked just like 
> a 5 1/4" drive -- you could swap them back and forth with the right 
> cables.  So, that makes me think it would be possible.

The problem is, most of those floppy drive units are made in very small 
casings, and probably use laptop drives, since they usually are bus 
powered. Which means even if there is a standard controller in there, 
the connectors would all be small and very hard to work with.

What would be easier would be setting up one of those 8051-core USB 
microcontrollers with UFI code, and a WDC1773, or whatever else is out 
there now, and hooking it up to the drives, using the standard CoCo 
drive cables.

> If there is a "standard" for things like USB keyboards, mice, floppy 
> drives, etc., a USB interface for the CoCo sure would be nice too.  
> But if they all require custom and different drivers...  Blah.  
> Threeor so years ago Steve Bjork was looking into the possibility of a 
> USB CoCo interface, but I don't know how far he got with it.  I 
> imagine chipsets have evolved quite a bit since then.

There are standard drivers for bulk-storage devices (digital cameras 
tend to use these, I think), for keyboard, mice, floppy drives, etc. 
However, I don't think there's a standard for connecting to something 
like a CoCo.

As for chipsets, something like these: 
http://www.silabs.com/products/microcontroller/usb.asp might be a good 
start. The problem is, if it's not a standard thing, writing the host 
OS drivers. I know in Mac OS X it's pretty straightforward to write a 
USB driver... but I'm not willing to. :) writing to a standard 
interface, like UFI, gives you the chance to exploit the OS's built-in 
drivers, and all you have to do is write the device code. The 
development kit for their stuff is $230 US. Not too shabby, since the 
controllers themselves are about $20 canadian from Digikey. If you 
could write the floppy interface code into the mcu, you wouldn't even 
need a floppy controller.

Actually, when I have a bit more money, that sounds really tempting! :)


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