1541 Ultimate

The 1541 Ultimate is a peripheral developed for the Commodore 64 (C64) by Gideon Zweijtzer. It's a C64 compatible cartridge that carries an Action Replay, The Final Cartridge III, Super Snapshot, Retro Replay or TurboAss with Codenet support (whatever the user prefers) and a fully compatible FPGA-emulated Commodore 1541 drive that is fed from a built-in SD card slot with C64-compatible files (e.g. .D64 diskimages or .PRG single program files). The first batch of 1541 Ultimates were shipped in early April 2008, costing 100 EUR for the basic version and 120 EUR for the "plus" version with 32 MB RAM. Due to strong demand the second and third batch were produced and shipped in early October 2008. From the second batch on, the normal version without the 32 MB RAM was discontinued due to weak demand. Also, a new Ethernet option was available for an extra 40 EUR, with the Ethernet logic directly soldered onto the board and the port just below the SD-slot.
1541 Ultimate II
In June 2010, the 1541 Ultimate II was released and shipped, adding a realtime clock with battery backup and an USB 2.0-Port for USB mass storage devices such as USB sticks, hard drives and memory card readers (and USB ethernet in the future). Removed was the built-in Ethernet port and the option to run the cartridge in standalone mode. The SD slot was changed to a MicroSD slot, the slightly smaller cartridge now also comes with a fitting short cable and a matching case -- one of the major complaints with previous generations of the 1541 Ultimate was that there was no matching case available for it. The firmware was completely rewritten for a 32-bit CPU in a bigger FPGA (original CPU was a 20 MHz 6510). Previous models have been discontinued, as of June 2010, there is now only one model of the 1541u II available for 108 € (excluding VAT).
Purpose
The 1541 Ultimate's target group is fairly wide. Convenience is a dominant factor, since a 1 GB SD card can hold 5814 standard-sized Commodore disk images and is much easier to backup and copy. However, the ability to transfer data from either PC or Macintosh computers is also important, since many Commodore owners either no longer have a functioning 1541 disk drive or lack other means of transferring disk images (of self-made or downloaded content) to a real C64.
The difference between 1541 Ultimate and other SD-based & .D64 mounting cartridges (like the MMC64, Super Snapshot 2007, or MMC Replay) is that the 6502 microprocessor that powers the 1541 floppy and the 1541's mechanical behavior (even sound) is fully emulated, making it theoretically compatible with almost anything. File selection and management is done via a third button on the cartridge that brings up a new menu on screen. The 1541 Ultimate also works in standalone mode without a C64, functioning just like a normal Commodore 1541 would. Disk selection of .D64s is then done via buttons on the cartridge, and power is supplied via a mini USB-port.
There are other hobbyist projects similar to the 1541 Ultimate like 1541 III, or the follow-up [http://www.forum64.de/wbb3/index.php?pageThread&threadID21242 SD2IEC], but most of them do not emulate the 1541's internal workings and are only compatible with kernel loaders (SD2IEC being the exception, supporting at least some fast loaders). Furthermore, all of these projects are originally do-it-yourself schematics, although some shops sell readymade units. Also, being standalone units, they lack means to comfortably navigate the SD-card and select .d64 diskimages like the 1541 Ultimate does when plugged into the expansion slot.
Firmware Updates
Firmware updates are released quite frequently, and most of the time new features or cartridge images are added besides the expected bug fixes and compatibility improvements. Firmware Development has slowed down a bit since release, but thanks to an opensource release of the firmware (Instructions on compilation are on the homepage), users can now fix bugs and add features themselves if they deem so. One example for this would be the custom firmware for the REU-demo BluREU, which adds the ability to load REU images up to 16MB directly into the REU memory from the SD-card.
Features (1541 Ultimate I)
* Full emulation of a real Commodore 1541 diskdrive
* Uses .D64 files stored on SD card (supports .G64 files as well, Read only)
* Configurable diskdrive-ROM (1541/1541C/1541II or custom)
* 1541 RAMBoard memory expansion optional (16K)
* Secondary 'IEC-drive' for direct access to FAT filesystem
* FAT/FAT32 support, with sub-directories and long filenames
* Supports SD V1.1 cards as well as SD V2.0 in High Capacity mode (SDHC)
* C64 cartridge emulation: Final Cartridge III, Action Replay, Retro Replay, Super Snapshot, Turbo Assembler+Codenet
* Commodore 1750/1764 REU emulation, size selectable from 128 KB up to 16 MB
* Optional: Integrated RR-net compatible Ethernet port
* Select, mount, create .D64 images, browse disk images
* Create new directories, delete files
* Fast DMA load of single file programs (directly from SD / from a .D64 with automount and from a .T64 file)
* Configuration screen, with resident settings
* Load of last disk on power up
* Can be used in stand-alone mode to mount disks into the emulated 1541: keeps the cartridge port free, powered through Mini-USB connector, controlled through buttons and IEC. (no Ethernet support yet in stand alone mode)

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See Also

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