xum1541 firmware for the ZoomFloppy

The xum1541 is firmware for USB device(s), such as the ZoomFloppy, which connect Commodore 15x1 or PET floppy drives to your PC. It is based on the Atmel AT90USB family of microcontrollers and is provided under the GPL license. It was developed by Nate Lawson, with testing and assistance from Wolfgang Moser, Spiro Trikaliotis, and Christian Vogelgsang. It uses code from the xu1541 by Till Harbaum and the LUFA USB library by Dean Camera.

A commercial version called the ZoomFloppy is now available from Jim Brain. It is quite nice and only slightly more expensive than a bare Atmel developer board, so I no longer recommend building your own hardware. The ZoomFloppy has connectors for IEC serial, parallel, IEEE-488, and 40-pin expansion connector. The latter has all signals from the microcontroller, so you can debug or build new devices from it as well.

Manual and installation package

2011/9/25: v2.0 released


If you're having problems with the initial setup or have questions about the ZoomFloppy product, please contact the ZoomFloppy users mailing list.

If you're having problems with using the software after installation succeeded, please see the OpenCBM-users mailing list.


Developer docs

ZoomFloppy board

The ZoomFloppy is a simpler version of the original design, intended for low-cost manufacturing with high-speed performance. It is now available commercially, which should make it the best choice for nearly all users. It is very inexpensive, costing only slightly more than the Atmel USBKEY board, so in almost all cases, you don't need to build it yourself.

If you do want to build it yourself, it can also be based on the Bumble-B daughterboard. However, the easiest option for DIY is the USBKEY board (below) since that only requires soldering a single connector (DB25) to the development board.

This device uses an ATmega32U2 microcontroller (AT90USB162 if you use the original Bumble-B). It has a 7406N hex inverter for better control of the pins. It runs at 5V with the board supplying power for the inverter.

For build info, see the included schematic, zoomfloppy-schem-*.png.

This is a perfboard build of the ZoomFloppy design. It has the parallel connector on a header with a custom cable to connect to the D-SUB 15 pin plug.

Here's a pic of the original breadboard version of the ZoomFloppy. The 7406 is on the left of the Bumble-B cpu board. The IEC serial port is on the far left. The parallel connections for the 1541 go off the bottom.

xum1541 AT90USBKEY board

This is the first generation board and is based on the Atmel AT90USBKEY developer's kit. The firmware was designed to be modular so there will be other boards some day. See the xum1541 README for pinouts and build info.

Here are some pics of the xum1541-AT90USBKEY model. As you can see, the devel board is connected directly to an XAP1541 adapter via a DB25 port. The "S" and "P" mean IEC serial and parallel connections.

Copyright © 2005-2011 Nate Lawson nate // root.org