1541 Ultimate

Image:1541 ultimate plus.jpg

1541 Ultimate (often abbreviated 1541U) is a peripheral,{{cite book | first1=Bill | last1=Loguidice | title=Vintage game consoles : an inside look at Apple, Atari, Commodore, Nintendo, and the greatest gaming platforms of all time | publisher=Focal Press | date=2014 | last2=Barton | first2=Matt | page=117 | isbn=978-0-415-85600-3}} primarily an emulated floppy disk and cartridge emulator based on the FPGA Xilinx XC3S250E, for the Commodore 64 home computer. It became available in 2008.

The unit is developed by Gideon Zweijtzer and is a cartridge that can emulate other cartridges such as the Commodore REU, Action Replay, The Final Cartridge III, Super Snapshot V5, Retro Replay or TurboAss with Codenet-support, and an almost fully compatible{{cite magazine|editor-last=Parker |editor-first=Nigel |magazine=Commodore Free Magazine |url=http://www.commodorefree.com/vol3.htm |title=Commodore Free talk to Gideon Zweijtzer |date=Dec 2009 |volume=3 |issue=35 |pages=15–16 |archive-url=https://web.archive.org/web/20150311154744/http://www.commodorefree.com/vol3.htm |archive-date=2015-03-11 |url-status=live |access-date=2016-01-30 }} (including JiffyDOS support{{cite web|archive-date=2016-01-30 |archive-url=https://web.archive.org/web/20160130105246/http://www.breadbox64.com/c64-peripherals/1541-ultimate-ii/ |url-status=live |url=http://www.breadbox64.com/c64-peripherals/1541-ultimate-ii/ |title=1541 Ultimate II |website=breadbox64 }} FPGA-cloned Commodore 1541 (including 1541, 1541C, and 1541 II models{{cite web|url=http://www.retrothing.com/2010/03/replace-the-commodore-64-disk-drive-with-flash-memory.html |title=Replace Your Commodore 64 Disk Drive With Flash Memory |website=Retro Thing |date=2010-03-25 |author=James Grahame |access-date=2016-01-30 |archive-url=https://web.archive.org/web/20151017005440/http://www.retrothing.com/2010/03/replace-the-commodore-64-disk-drive-with-flash-memory.html |archive-date=2015-10-17 |url-status=live }}) floppy disk unit that can use Commodore 64-compatible files like .D64/.G64 disc images or .PRG files via a SD card reader.{{cite book|last1=Dillon|first1=Roberto|title=Ready: A Commodore 64 Retrospective|date=2015|publisher=Springer|isbn=978-981-287-340-8|page=125}} Additionally, the 1541 Ultimate is suitable for making archives of floppy disks.{{cite web|url=http://devdef.blogspot.nl/2014/11/1541-ultimate-guide-4-floppy-copy.html |title=1541 Ultimate II Guide 4 : Floppy Copy |website=DevDef |date=2014-11-04 |author=Wiebo de Wit |access-date=2016-01-30 |archive-url=https://web.archive.org/web/20150122012249/http://devdef.blogspot.nl/2014/11/1541-ultimate-guide-4-floppy-copy.html |archive-date=2015-01-22 |url-status=live }} All units after the initial production have 32 megabytes of RAM, while the original production run only had 16 megabytes.

The 1541 Ultimate is capable of running both CP/M and GEOS.{{cite web|url=http://www.rgcd.co.uk/2011/05/running-geos-on-ultimate-1541-ii-c64.html |title=Running GEOS on the Ultimate 1541-II (C64) |author=James Monkman |website=RGCD |date=2011-05-30 |access-date=2016-01-30 |archive-url=https://web.archive.org/web/20150630055813/http://www.rgcd.co.uk/2011/05/running-geos-on-ultimate-1541-ii-c64.html |archive-date=2015-06-30 |url-status=live }}

In 2010, the 1541 Ultimate II was developed. The Ultimate II is about 30% smaller than the 1541 Ultimate, comes in a plastic case,{{cite web|url=https://ilesj.wordpress.com/2013/04/13/1541-ultimate-original-vs-ultimate-ii/ |title=1541 Ultimate, original vs Ultimate-II |author=Ilkka Sjöstedt |date=2013-04-13 |access-date=2016-02-08 |archive-url=https://web.archive.org/web/20150101225810/http://ilesj.wordpress.com/2013/04/13/1541-ultimate-original-vs-ultimate-ii/ |archive-date=2015-01-01 |url-status=live }} and adds support for dual SIDs (plus a SID/MOD player),{{cite web

|url=http://www.indieretronews.com/2015/01/1541-ultimate-ii-is-this-ultimate.html

|title=1541 Ultimate-II - Is this the ultimate device for a C64/128? [ Hardware Review ]

|author=

|date=2015-01-09

|website=Indie Retro News

|access-date=2016-01-30

|archive-url=https://archive.today/20150109150756/http://www.indieretronews.com/2015/01/1541-ultimate-ii-is-this-ultimate.html

|archive-date=2015-01-09

|url-status=live

}}

a USB host controller, tape emulation via a tape adapter{{cite web |url=http://www.1541ultimate.net/content/doc/1541U2Doc_v0.3.pdf |title=1541 Ultimate II technical documentation}} (though use with a Commodore 128D requires modification{{cite web|access-date=2016-01-30 |archive-date=2016-01-08 |archive-url=https://web.archive.org/web/20160108222245/http://www.retro-commodore.eu/2014/12/25/extending-the-1541ultimate-2-tape-extender/ |url-status=live |url=http://www.retro-commodore.eu/2014/12/25/extending-the-1541ultimate-2-tape-extender/ |title=Extending the 1541Ultimate 2 tape extender |date=2014-12-25 |author=Carsten Jensen |website=Retro Commodore }}), a real-time clock (for accurate file date and time), and the SD card slot is replaced by a microSD{{Broken anchor|date=2024-06-13|bot=User:Cewbot/log/20201008/configuration|target_link=Secure Digital#Mini- and micro-cards|reason= The anchor (Mini- and micro-cards) has been deleted.}} card slot. In addition, all firmware and VHDL code for the Ultimate II is available under an open source GPLv3 license,{{cite web | url=http://www.1541ultimate.net/content/index.php?option=com_content&view=article&id=26:opensource&catid=14&Itemid=127 | title=1541 Ultimate Open Source announcement and build requirements}} allowing hobbyists and others to freely modify all aspects of its functionality, including the FPGA-emulated hardware.

The 1541 Ultimate has an option for on-board Ethernet, while the 1541 Ultimate II supports Ethernet via a compatible USB to Ethernet adapter.

Besides being useful to retrocomputing hobbyists, it has also found use in educational laboratory settings.{{cite tech report |first=Nick |last=Montfort |authorlink=Nick Montfort |author2=Federova, Natalia |title=Creative Material Computing in a Laboratory Context |page=7 |url=http://hdl.handle.net/1721.1/78888 |institution=The Trope Tank, Massachusetts Institute of Technology |series=TROPE |number=12-03 |location=Cambridge, Massachusetts |date=2012-04-25 |access-date=2015-02-08 |format=PDF |hdl=1721.1/78888}}

In 2017 the Ultimate II+ was released with the following feature differentiation from the II:

Removal of the MicroSD slot, More USB ports, Integrated Ethernet, Dual Flash, Integrated Speaker, External power supply connector with auto-switch over circuit, Improved power supply circuits, and a slightly bigger and faster FPGA, as to control the new features. {{cite web | url=http://1541ultimate.net/content/index.php | archive-url=https://web.archive.org/web/20170408152233/http://1541ultimate.net/content/index.php | archive-date=2017-04-08 | title=Home }}

The II and II+ share a firmware image and the software features are substantially similar.