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Category Disk emulation hardware
Developer Jan Derogee
Year 2006 (-2009)
Availability Self-build
C64 software Disk load
C64 interface Serial Bus
Remote software 1541-III firmware
Remote interface MMC/SD card
Remote platform 1541-III proprietary, with PIC microcontroller
Website jderogee.tripod.com/projects/1541-III

The 1541-III hardware is a MMC/SD card interface that provides emulation of the Commodore 1541. Fastloaders are not supported.[1]

Note[edit | edit source]

The 1541-III hardware is based on a Microchip PIC microcontroller. This microcontroller does not emulate a real 65XX processor and therefore it cannot execute machine code uploaded to the drive (a function that is not supported by the 1541-III). Therefore it cannot act exactly as the 1541, and fastloaders will not work.

Development[edit | edit source]

1541-III was created by Jan Derogee in 2006 for use with the 1541-III firmware. He created this device to fill up a gap in his SX-64 (portable Commodore 64 computer). In order to get more information he visited the HCC Commodore usergroup meeting in Maarssen, where he was asked to demonstrate his device. This got so much attention that he decided to redesign the circuit. A few months later the device was made available on a website and could be build by others. The software was released but could only be compiled with a special PIC18 Hi-tech compiler, which wasn't available to the general public. Therefore the open-source community did not further develop this design.

However the device has made an impression on the Commodore scene and other people were inspired by this design and started to make their own. For example, the MMC2IEC was also strongly inspired by the 1541-III.[2] The MMC2IEC evolved into the SD2IEC which was developed into device with a much higher compatibility to the original disk drive than the 1541-III.

A smaller stripped-down version (no display or buttons) was created for the C64DTV by Pyrofer and Jussi Saily.[3] This device was also used in the Commodore 64 laptop project made by Ben Heck [4] This stripped-down version used the exact same version of the firmware as the original 1541-III and using some special hardware version detection tricks this firmware could enable disabled display and button functionality without additional configuration by the user.

Current development status: a beta version supporting Jiffy DOS has been released but never got out of the beta stage. This project is no longer actively supported.

Availability[edit | edit source]

Resources needed to build your own 1541-III, such as the printed circuit board layout, can be downloaded from the project homepage.[1]

References[edit | edit source]