Mounting BBC Micro disc images over USB
Channel: Chris McClelland
Date: 2012-01-10

See https://github.com/makestuff/udfs

The BBC Micro turned 30 in December 2011. I celebrated by buying a BBC Micro from eBay for £25. Unfortunately it did not come with a disc drive, so I built a cable to connect the BBC Micro to a USB port on a modern computer (Windows, MacOSX or Linux).

* The cable uses a Minimus AVR-USB development kit, costing £5. The AVR uses Dean Camera's LUFA library.

* A libusb-based fileserver program runs on the PC side, and accepts a BBC disc image on startup.

* A patched Acorn DFS ROM is installed in the BBC Micro. The code for this is based heavily on Martin Mathers' Beeb-MMC code.

* When the BBC tries to read a file, rather than sending commands to an attached disc drive, the commands are sent over USB to the PC, which returns the appropriate bytes from the "mounted" disc image.

* I've tried about fifty disc images downloaded from emulator sites; all appear to work fine.

* Total cost of ribbon cable + Minimus + ROM chip is about £6.

* All code and wiring info will be uploaded to github.com/makestuff soon!