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DrawBridge aka Arduino Powered Floppy Disk Reader and Writer

...with 3rd party interfaces for Amiga, ATARI ST and DOS/PC Disk formats and designed to work with WinUAE and Amiberry!

Created by Robert Smith @RobSmithDev

What is it?

This project uses an Arduino to interface with a floppy disk drive and communicate with a PC in order to recover the data from any formatted disks. This includes Windows software to copy from and to ADF files.

This project is what is behind getting real floppy disks loading in real time into emulators like WinUAE and Amiberry


The Arduino firmware allows to read the raw MFM data from each track of the floppy. Decoding of the sector data is done on the PC. Usually a floppy image file is created (ADF for AMIGA, .img for ATARI ST and PC/DOS).

The 'firmware' can read MFM data from SD, DD and HD disks, although HD is untested. This would therefore be able to read data from AMIGA, ATARI ST, PC DOS, COMMODORE C64 etc.


This Visual Studio 2019 and Linux project contains two applications, a command line, and a Windows dialog based application allow reading and writing of Amiga formatted DD floppy disks. Using the supplied makefile you should be able to compile this on Linux. It has been tested with Raspberry Pi OS (Raspbian - Debian-based)


This is the Arduino source code/sketch for all Floppy formats.

  • Detect disk density (SD/DD or HD)
  • Motor ON/OFF
  • Seek to Track 0
  • Seek to any track (up to 82 - be careful, this can damage some drives!)
  • read write protection status
  • Read index pulse
  • read raw track data (its RAW, so FM, MFM; SD, DD or HD)
  • write track data (in DD with precompensation and HD)
  • Evaulate drive quality

Help and Instructions

For further details including how to wire this up please visit [] or join the discussion on discord at []

Whats changed?

  • v2.8.8 Added support for reading and writing track 82 and 83 (firmware update needed too, not all drives support this anyway) Fixed a mistake in diagnostics suggesting pin A0 was write protect, it's A1! Now hides any CH340 com ports from the list as they're incompatible anyway Fixed compiling under Linux
  • v2.8.7 Improved support for long track disks and general compatability improvements mainly for UAE! - Make sure you update the firmware
  • v2.8.6 Better extraction of disk revolutions and a few bugs fixed Accurate flux extraction available but experimental so you can choose to use it or not (can't handle some long-track disks) Modification of older flux reading method for more better compatability New firmware 1.9.23 includes basic PLL support for UAE to provide better support for games using Weak/Flaky bits Improved IPF & SCP writing by changing some of the parameters Console application now has an icon and version information Tidied up some of the assembly language in the Arduino Sketch Improvements and testing with the help of Dimitris Panokostas aka MiDWaN (Amiberry)
  • v2.8.5 Improved IPF support for non-index aligned images (SCP and IPF writing needs 1.9.21 firmware) Added warning if known applications are running that may be using the serial port
  • v2.8.4 Support for forcing Index Alignment of all writes, even in emulators (only for use if you know what you are doing) Added a timeout when connecting and syncing with the port
  • v2.8.3 Better handling with the 'gap' or 'splice' within IPF files
  • v2.8.2 Fixed a few more issues with SCP Added experimental support for writing IPF files
  • v2.8.1 Fixed and improved some of the SCP support
  • v2.8 Firmware 1.9.18 (see sketch notes) Added support for writing SCP files back to disk. If more than one revolution exists in the file, the software will pick the second one.
  • v2.7 Firmware 1.9.15 (see sketch notes) Added support for reading and writing HD Amiga floppy disks Added 'auto-detect' HD floppy disk inserted Fixed race condition with aborting reading Overhalled the UI to make it much cleaner Automatic update check (this is done in a way that is 100% private, there is no way I will ever know you checked for update) Slightly updated logo New EEPROM options to control how DrawBridge behaves Massively improved diagnostics: Can now detect DrawBridge vs DrawBridge Plus Fixed issue with read diagnostics Can detect the RPM of the drive for faults Will perform diagnostics for DD and HD Lists enabled and supported features of your DrawBridge setup Added optional support for direct access via the FTDI driver instead of COM ports Added ability to perform erase cycles before writing to a disk Added option for ADFs to be written index aligned Improved accuracy for *UAE disk reading and writing
  • v2.6 (firmware 1.8a) - Add support for 'noclick' Fixed issue with SCP/ADF file extension being incorrect if you change the type after choosing the filename Added some more tests during diagnostics
  • v2.5 A whole load of changes including: Fixed an encoding issue which prevented disks being read under Kickstart 1.3 or lower. Added support for read "streaming" with index sync support
    Changed read timings slightly which means more disks can now be recovered! Added support for PRECOMP disk writing to improve readability as you go past track 40 Added some new functions which allow for more direct control of the drive
  • v2.4 Improved support for Usb to Serial devices based on findings from GitHub user "prickle" - firmware is now V1.7
  • v2.33 Merged with Pull Request #9 (Detect and read out HD floppy disks 1.44M by kollokollo) - firmware is now V1.6
  • v2.32 Merged with Pull Request #6 (Modified the behavior of the current track location on Arduino boot - paulofduarte) which also addresses issues with some drives and updated firmware to 1.4 Made a small change to the diagnostics code to also erase the track before writing it
  • v2.31 Upgraded the PC code side to work with Visual Studio 2019 resolving issue #11 (ourIThome) and merging pull request #13 (bassclefstudio) Fixed a few typos in ArduinoInterface.cpp from pull request #12 (Crkk)
  • V2.2 Fixed 99% of checksum errors when writing by erasing the track first
  • V2.1 Diagnostics and potential write bug fixed
  • V2.0 Disk reading has been vastly improved and you can now also write disks!
  • V1.0 Initial release, can read disks fairly well

Scripts for linux

The above application apparently works under WINE, however, Github user "kollokollo" made some scripts for reading other formats on Linux too as follows: The ATARI ST and DOS/PC floppy formats can be decoded whit these scripts. 9,10,11 or 18 Sectors per track. Up to 82 tracks, DD (ca. 800 kBytes) or HD (1.4 MBytes). The images usually contain a FAT12 file system which can be directly mounted by linux without any additional driver.
For more information see They need the X11-Basic interpreter from

Commodore 1581 Disks

To read commodore 1581 disks, check out the project at:

AVR Firmware

If you want to use the AVR directly instead of within the Arduino environment, then jump to [] where John Tsiombikas has ported the code.


This entire project is available under the GNU General Public License v3 licence. See licence.txt for more details.


DrawBridge aka Arduino Amiga Floppy Disk Reader/Writer - Hardware and software interface for accessing Amiga disks (read/write ADF and SCP) on non-Amiga hardware








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