Amiga USB Floppy

I have now dropped all previous hardware (i.e. Arduino, LoRaWAN, Raspberry Pi, etc.) projects. Few seem to be progressing, most have been surpassed and so decision made to drop them all. I am starting just one new one. There are a stack of old Amiga floppy disks that go with my trusty old Commodore Amiga 500 that I would like to read so the new project is to connect, via USB, to an external Amiga floppy drive.

Why I hear you ask?

Can’t you buy a Catweasel or use the ADF project? Well yes and no. Some of these solutions are expensive, require PCI, a parallel port, Windows, etc. I am on a Mac and have no PCI or parallel port and would like something universal.

The plan is to create an adapter to allow reading of Amiga double density floppy disks. There will be a USB on the Mac end and a 23 pin connector to plug into an external Amga floppy drive. In between there will be some logic to act as a floppy controller. I spoke to Keith over at Tech Travels to get some advice. Keith who did a similar project called the Amiga Floppy Project a few years back using a microcontroller and a second version by FPGA.

So the steps to achieve this, and yes each step I will report back on, are:

  1. Figure out control lines.
    • Using an Arduino work out how to use all the control lines.
    • Nothing special at this point other than to figure out use of the control lines.
    • Aim to have code complete to allow control of a floppy.
  2. Read data
    • Using Arduino see if it can read data.
    • My suspicion is it will not be fast enough so looking at alternatives such as a PIC32MX or Raspberry Pi.
  3. Save data to ADF format
    • Test by using the ADF in UAE.
  4. Create custom PCB to house all parts.

If this works then there are multiple ways in which it might be extended.

  • Allow writing to floppy.
  • Option to use internal drives so that any PC drive might be used.
  • Sniff data, that is to sit between the Amiga and external drive.
  • Investigate using a LS-120 drive. These use an IDE connector and can read, as is, standard PC floppy disks as well as the 120MB disk. I would like to see a list of commands, I assume ATAPI comes in somewhere, in the firmware or perhaps a copy of the firmware itself, might be possible to adapt it.

That is the plan, first though to get all hardware parts on order for step 1.

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