SD2iec internal for Commodore 64
SD2IEC is an open source development created by Shadowolf and published at Forum64.de in 2008, which allows to emulate a Commodore 1541 disk drive by communicating through the Commodore IEC bus, present in several 8-bit models (VIC-20, 64, 128 and 264 series).
It uses SD cards as mass storage media and is based on the Atmega 644 or the larger Atmega 1284P microcontroller.
Original Commodore 1541 disk drive
Atmega 1284p microcontroller
What are the possibilities of SD2IEC?
SD2IEC is compatible with JiffyDOS, a C64/128 optimised disk operating system that allows higher speed and commands than the Commodore 64's factory DOS.
- It allows the use of the most common fastloaders such as Speeddisk fastloader or GEOS Fastloader.
- Supports reading and writing of .D64, .D71, .D81, .M2I, as well as .PRG and .P00 and partially .REL files.
- Supports SD and SDHC cards with FAT12, FAT16 and FAT32 file systems
- Compatible with multiple file managers: CBM FileBrowser, CBM-Command, Vic-20 Disk Menu, SD2IEC Dir Plus, ?
CBM Filebrowser for C64/C128
CBM Command for C64/C128
SD2IEC DirPlus (264 Series)
It allows a device number to be permanently assigned in the SD2IEC EEPROM by two simple commands, allowing any other Commodore disk drive (1541,1541-II,1551, 1571) connected to the IEC bus to be used simultaneously with a different device number.
For example, to configure SD2IEC with unit number 9, currently configured for 8, we would type:
OPEN1,8,15,?U0>?+CHR$(9):CLOSE1 <- Assign device 9 to SD2IEC
OPEN1,8,15,?XW?:CLOSE1 <- Store the new value in the EEPROM of SD2IEC
Being an open source development, multiple versions of SD2IEC exist and have evolved over the years.
Traditionally SD2IEC has been associated with external devices, which are connected via a 6-pin DIN cable and draw power from the user port or cassette port or an external power supply.
These devices, although versatile, require wiring when in use and in some cases prevent the use of other devices at the same time (datasette in cassette port or another device in user port) if the connector does not have a port expander, as well as adding a few more cables to the Commodore setup, in case there were not enough.
SD2iec external design by @jgilcas
From Hobbyretro.com we propose an internal SD2iec, specially adapted to the first generation Commodore 64 model (Panera or Breadbin) which includes:
SD2IEC internal for commodore 64, features:
- Internal based on Atmega 1284P
- Integration into the housing of the Commodore 64 Breadbin without modification of the housing. Just replace the metal part on the side and connect.
- Specific 3D bracket to accommodate the SD2IEC, which integrates seamlessly into the Commodore 64 case and includes reset button and disc change button.
- Replacement of the original "Power" LED with a new one showing the disk activity
- Installation of Arduino Pro Mini microcontrollerwhich allows the Commodore 64 and the SD2IEC unit to be reset simultaneously by pressing the reset button.
- Replacement of the Commodore Kernal ROM (U4 ? 9012207-0X) with a 512Kb EEPROM containing JiffyDOS and the original Commodore Kernal ROM (Switchless JiffyDOS). This allows to boot the device with JiffyDOS if no key is pressed or to switch to Commodore Kernal if after pressing the reset button of SD2IEC we keep pressed the RESTORE key or we boot the device for the first time with the same key pressed.
Detail of Hobbyretro's internal SD2IEC integrated in the custom 3D bracket
JiffyDOS when booting the C64 without any keys being pressed
SD2IEC HobbyRetro internal showing disk activity (LED)
If you want to have one of these fantastic internal SD2iec for your Commodore 64 just contact us. We will get back to you as soon as possible.