View source for Commodore 65

{{Short description|Prototype computer}}

{{Refimprove|date=April 2024}}

{{infobox computer
| Photo = [[File:C65alleine (no bg) (balance).jpg|300px|A Commodore 65 prototype]]
| Type = [[Personal computer]]
| Released = N/A
| Discontinued = N/A
| Processor = [[MOS Technology|CSG]] [[MOS Technology 4510|4510 R3]]
| Memory = 128&nbsp;KB (8&nbsp;MB maximum)
| OS = Commodore BASIC 10.0
| graphics = VIC-III (CSG 4567 R5)
| display = 320×200×256; 640×200×16; 640×400×16; 1280×200×4; 1280×400×4; palette of 4096 colors
| sound = Two CSG 8580R5 SID
| memory card = 3½" DSDD floppy disk drive
| CPUspeed = 3.54&nbsp;MHz
| predecessor = [[Commodore 64]]
| units shipped = 50 to 2000 units
| discontinued = 1991 (prototype cancelled)
}}

[[File:C65.jpg|thumb|A Commodore 65 prototype]]
[[File:C65-open.jpg|thumb|Commodore 65 opened up, revealing its internal disk drive]]
[[File:C65cpu.jpg|thumb|CSG 4510 ("Victor")]]
[[File:C65viciii.jpg|thumb|CSG 4567 ("Bill")]]
[[File:C65elmer.jpg|thumb|"Elmer" and "Igor" (programmable logic)]]
[[File:C65u22.jpg|thumb|F011B (floppy disk controller)]]
[[File:c65offen.jpg|thumb|Opened chassis]]
[[File:C65mainboard.jpg|thumb|Motherboard inscription]]
[[File:C65.png|thumb|Start screen]]

The '''Commodore 65''' (also known as the '''C64DX''') is a [[prototype]] computer created at [[Commodore Business Machines]] in 1990–1991. It is an improved version of the [[Commodore 64]], and it was meant to be backwards-compatible with the older computer, while still providing a number of advanced features close to those of the [[Amiga]].

== History ==
In September 1989 ''[[Compute!'s Gazette]]'' noted that "Sales of the [[Commodore 64|64]] have diminished rapidly, [[Nintendo Entertainment System|Nintendo]] has eaten big holes in the market, and the life of the old warhorse computer should somehow be extended." Noting that Apple had developed the [[IIGS]] to extend the life of its [[Apple II]] line, the magazine asked "Will [[Commodore Business Machines|Commodore]] take the same tack?", then continued:<ref name="elko198909">{{cite news | url=https://archive.org/stream/1989-09-computegazette/Compute_Gazette_Issue_75_1989_Sep#page/n5/mode/2up | title=Editor's Notes | work=Compute's Gazette | date=September 1989 | access-date=4 March 2015 | author=Elko, Lance | page=4}}</ref>

{{blockquote|The latest rumor says ''Yes''. We've heard reports from several sources of a new machine from Commodore—A 64GS, if you will. This machine is reportedly driven by a GE802, a version of the 65816 microprocessor (which is a 16-bit version of the 6502 chip), and runs at 4&nbsp;MHz (by comparison, the 64 runs at 1&nbsp;MHz; the Amiga, at slightly over 7&nbsp;MHz). It comes with 128K of RAM and is expandable to one megabyte. Fully expanded, it supports 256 colors. Maximum resolution is a stunning 640 X 400 pixels. We've also heard that it has a 64 mode so that 64 owners can purchase a much more powerful machine and still use their software library. The 64GS reportedly comes with a built-in 3 1/2-inch disk drive and will support the 1581. But, our sources say, it does not support the 1541 or the 1571 drive (uh, excuse me, please pass the bologna). All we've heard about sound in the new machine is that it's "enhanced" and features stereo output. The final tidbit is that the 64GS will retail in the $300-$350 range when it debuts in November.|author=|title=|source=}}

The ''Gazette'' added, "Our sources also report that there is a great deal of infighting at Commodore as to whether the machine should be released. The sales staff wants to get the machine out the door, while the naysaying engineers have dubbed it 'son of [[Commodore Plus/4|Plus/4]].{{Single+double}}{{r|elko198909}} While the next issue reported that "the latest rumor is that such a machine will never see the light of day",<ref name="elko198910">{{cite news | url=https://archive.org/stream/1989-10-computegazette/Compute_Gazette_Issue_76_1989_Oct#page/n3/mode/2up | title=Editor's Notes | work=Compute's Gazette | date=October 1989 | access-date=4 March 2015 | author=Elko, Lance | page=2}}</ref> Fred Bowen and others at Commodore in 1990–1991 developed the Commodore 65 (C65) as a successor to the C64. In the end of 1990 the decision to create the C65 was taken.<ref name="oc_c65">{{cite web|title=OLD-COMPUTERS.COM museum ~ Commodore C65|url=http://www.old-computers.com/museum/computer.asp?st=1&c=273|access-date=2013-06-20|publisher=old-computers.com|archive-url=https://web.archive.org/web/20101010092053/http://www.old-computers.com/museum/computer.asp?st=1&c=273|archive-date=2010-10-10|url-status=dead}}</ref> The project was cancelled by Commodore's chairman [[Irving Gould]] in 1991.

When Commodore International was liquidated in 1994, a number of [[prototype]]s were sold on the open market, and thus a few people actually own a Commodore 65. Estimates as to the actual number of machines found on the open market range from 50 to 2000 units.<ref name="fg65">{{cite web|title=Secret Weapons of Commodore: The Commodore 65 |url=https://www.floodgap.com/retrobits/ckb/secret/65.html |date=2007-07-01|access-date=2013-02-26|publisher=floodgap.com}}</ref> As the C65 project was cancelled, the final [[8-bit computing|8-bit]] offering from CBM remained the triple-mode, 1–2&nbsp;[[Megahertz|MHz]], 128&nbsp;[[kilobyte|KB]] (expandable), C64-compatible [[Commodore 128]] of 1985.

== Technical specifications ==
* The [[Central processing unit|CPU]] named [[CSG 65CE02|CSG 4510]] R3 is a custom [[MOS Technology|CSG]]<ref>Commodore Semiconductor Group, previously known as [[MOS Technology|MOS Technology, Inc]]</ref> [[CSG 65CE02|65CE02]] (a [[MOS Technology 6502|MOS 6502]] derivative), combined with two [[MOS Technology 6526|MOS 6526]] complex interface adapters (CIAs), a UART serial interface, and a memory mapper to allow for an addressable space of 1&nbsp;MB<ref name=zm_c65man/>
* 3.54 [[megahertz|MHz]] clock frequency (the C64 runs at 1&nbsp;MHz)
* A new [[MOS Technology VIC-III|VIC-III]] [[graphics chip]] named CSG 4567 R5, capable of producing 256 colors from a palette of [[Color depth#12-bit color|4096 colors]]; available modes include 320×200×256 (8), 640×200×16 (4), 640×400×16 (4), 1280×200×4 (2), and 1280×400×4 (2) ( X×Y×color depth, i.e. number of colors ([[bit plane]]s) )
** Supports all video modes of [[MOS Technology VIC-II|VIC-II]]
** Text mode with 40/80 × 25 characters
** Synchronizable with external video source ([[genlock]])
** Integrated [[Direct memory access|DMA]] controller ([[bit blit]])
* Two CSG 8580R5 [[MOS Technology SID|SID]] [[sound chip]]s producing [[stereophonic sound|stereo]] sound (the C64 has one SID)
** Separate control (left / right) for volume, filter and modulation
* 128 [[kilobyte|KB]] [[random-access memory|RAM]], expandable with up to 1&nbsp;[[megabyte|MB]]<ref name=zm_c65man/> using a RAM expansion port similar to that of the Commodore [[Amiga 500]]
* 128&nbsp;KB ROM
* Heavily improved BASIC: [[Commodore BASIC|Commodore BASIC 10.0]] (the C64 has the relatively feature-weak BASIC 2.0, which was almost 10 years old by this time.)
* One internal 3½" [[Double-sided disk|DS]][[Double density|DD]] [[floppy disk]] drive
* Keyboard with 77 keys and an inverted T directional cursor block

=== Ports ===
Left side:

* Power +5&nbsp;V DC at 2.2&nbsp;A and +12&nbsp;V DC at 0.85&nbsp;A<ref name=zm_c65man/>
* 2× Control ports DE9M<ref name=zm_c65man/>

Back:

* Expansion port 50-pin<ref name=zm_c65man/>
* [[Commodore bus|CBM-488]] bus using a [[DIN connector|6-pin DIN]] for [[Commodore 1541|1541]]/[[Commodore 1571|1571]]/[[Commodore 1581|1581]]<ref name=zm_c65man/>
* User port: parallel 24-pin (without 9&nbsp;V AC)<ref name=zm_c65man/>
* Stereo 2× [[RCA connector]]<ref name="rc_c65">{{cite web|title=c65_html_1410c60e.gif|url=http://www.retrocommodore.com/retro/images/stories/c65resurrection/c65_html_1410c60e.gif|archive-url=https://archive.today/20130624191806/http://www.retrocommodore.com/retro/images/stories/c65resurrection/c65_html_1410c60e.gif|url-status=dead|archive-date=2013-06-24|date=2012-12-16|access-date=2013-06-21|publisher=retrocommodore.com}}</ref> for left and right channel<ref name=zm_c65man/>
* RGBA video [[D-subminiature|DE9F]]<ref name=zm_c65man/><ref name="gallery_c65">{{cite web|title=commodore.ca/gallery/hardware/c65.jpg |url=http://www.commodore.ca/gallery/hardware/c65.jpg |date=2011-03-29|access-date=2013-06-21|publisher=commodore.ca}}</ref>
* [[RF modulator|RF video]]<ref name=zm_c65man/>
* [[Composite video]] [[DIN connector|8-pin DIN]]<ref name=zm_c65man/>
* External fast floppy drive port — [[Mini-DIN connector|mini-DIN-8]]<ref name=zm_c65man/>

Bottom flap:

* RAM expansion<ref name=zm_c65man/>

Dimensions: ≈46&nbsp;cm wide, 20&nbsp;cm deep, 5.1&nbsp;cm high<!--2.2. Form Factor ; 1.2. System Overview--><ref name="zm_c65man">{{cite web|title=C64DX System specification|url=http://www.zimmers.net/anonftp/pub/cbm/c65/c65manual.txt.gz|date=2009-08-18|access-date=2013-06-21|publisher=zimmers.net|archive-date=2015-06-02|archive-url=https://web.archive.org/web/20150602171841/http://www.zimmers.net/anonftp/pub/cbm/c65/c65manual.txt.gz|url-status=dead}}</ref>

===Chipset names===
The custom chips of the C65 were not meant to have names like the custom chips in the [[Amiga]]. Although there are names printed near the chip sockets on various revisions of the circuit board, they were not intended as names for the chips. According to former Commodore engineer Bill Gardei,<ref name="cccom_bill">{{cite web|title=The Story Behind 'Bill' and 'Victor'|url=http://collectorcomputers.com/truthaboutbill.txt|date=2013-11-16|access-date=2013-11-16|publisher=collectorcomputers.com|archive-url=https://web.archive.org/web/20150610201234/http://collectorcomputers.com/truthaboutbill.txt|archive-date=2015-06-10|url-status=dead}}</ref><blockquote>The Legend on the PCB was to let others in the organization know [whom] to go to for advice on the chips. We did have an issue with that. But that wasn't the name of the chip at the time. The 4567 was always called the VIC-3. I can see why others outside of Commodore made the connection. But again—no—we never called these chips "Victor" or "Bill".</blockquote>The custom chips for the C65 are:

* CSG 4510: processor (commonly called "Victor" after Victor Andrade)
* CSG 4567: VIC-III graphics processor (commonly called "Bill" after Bill Gardei)
* CSG 4151: DMAgic DMA controller (designed by Paul Lassa)
* F011C: FDC (floppy disk controller, also designed by Bill Gardei)

The C65 also contains one or two programmable logic arrays depending on the version:

* ELMER: PAL16L8 (C65 versions 1.1, 2A, 2B), PAL20L8 (C65 versions 3–5)
* IGOR: PAL16L8 (C65 version 2B only)

===Graphics subsystem===
{{No sources|section|date=April 2024}}

The main memory of the C65 is shared between the graphics subsystem and the CPU. The memory clock runs at almost twice the speed of the C64. To further increase the bandwidth of the graphics subsystem, the memory is divided into 2× 8-bit wide banks of 64&nbsp;Kbyte which can be accessed by the CSG-4567 simultaneously. This provides an effective video-DMA bandwidth of 7.2&nbsp;MB/s which is the same specification as the original 16-bit Commodore Amiga chipset (OCS/ECS). The CPU can use up to half the available bandwidth, since it can only access a single 8-bit bank at a time. In higher demanding video modes, the CPU is slowed down due to increased cycle stealing from the video controller.

====Enhanced VIC-II modes====
In addition to having all of the C64 video modes, the CSG-4567 also supports several new character attributes such as "blink" or "bold" and can display any of the new or old video modes in 80 column or 640 horizontal pixel format, as well as the older 40 column 320 pixel format [6]. These enhanced "VIC-II" modes take up to 16&nbsp;KB of system RAM. The sprite capabilities in all VIC modes are equivalent to the C64.

=====Bitplane modes=====
A new "bitplane" video mode was added to allow the displaying of true bitplane type video, with-up to eight bitplanes in 320 pixel mode and up to four in 640 pixel mode. The CSG-4567 can also time-multiplex the bitplanes to give a true four-color 1280 pixel picture. Vertical resolution is maintained at 200 lines as standard, but can be doubled to 400 with interlace [6]. The VIC-III bitplane modes take up to 64&nbsp;KB of system RAM in non-interlaced or 128&nbsp;KB RAM in interlaced (400 line) modes. Since the C65 is equipped with only 128&nbsp;KB in its basic configuration, these modes would consume the entire RAM, and are therefore only useful in a RAM expanded system. On a basic system, it would probably have made more sense to write software which uses less demanding resolutions with fewer bitplanes—partly because this would consume less of the confined RAM space, but also because more bitplanes would demand a higher video DMA bandwidth and consequently slow down the CPU as a result.

====DAT and Blitter====
The bitplanes on the C65 are organized in a less straightforward manner than e.g. on the Commodore Amiga, which organizes the bitplanes as straight rows of pixels: On the C65, the bytes within the bitplanes are organized as 25 rows of 40 or 80 stacks of 8 sequential bytes, similar to the original 320×200 VIC modes. Because this makes it harder to derive individual byte and pixel addresses from their position in the XY coordinate frame, the C65 provides a conversion mechanism in hardware called Display Address Translator (DAT).

Further aid to the programmer comes in the form of a bit-blitter, which supports

* Copy (up,down,invert), Fill, Swap, Mix (boolean Minterms) Hold, Modulus (window), Interrupt, and Resume modes
* Block operations from 1&nbsp;byte to 64&nbsp;KB

===DOS===
{{No sources|section|date= April 2024}}

In contrast to previous 8-bit computers from Commodore, the C65 has a complete DOS through which the built-in 3.5-inch floppy disk drive can be controlled. Disks used by the C65 have a storage capacity of 880&nbsp;KB and the drive is compatible with [[Commodore 1581|C1581]]. Since this format was uncommon for the former C64 owners, the C65 retains the serial IEC port for external Commodore disk drives. <!--The reminder??-->It's possible to use a [[Commodore 1541|1541]], [[Commodore 1571|1571]], [[Commodore 1581|1581]], or other similar model.

The DOS itself is based on the Commodore PET IEEE [[Commodore 8050|8250]] drive DOS. Since it can only deal with two floppy disk drives, including the internal, only one external drive may be connected to the internal floppy disk controller. Like earlier systems, up to four drives can be [[daisy chain (electrical engineering)|daisy-chained]] on the IEC port.

===Interfaces===
The C65 includes the same ports of the C64. In addition, there is a DMA port for memory expansion. The latter is attached just like on the [[Amiga 500]] via a flap in the bottom of the board.<ref name="wikipedia_file_c65">[[:commons:File:C65-open.jpg|C65 open ]]{{Circular reference|date=September 2023}}</ref> The built-in floppy disk drive is connected in parallel, serial Commodore drives can be connected via the usual [[Commodore bus|IEC port]]. A plug for a [[genlock]] was also provided. Only the port for the C64 [[Commodore Datasette|datasette]] is no longer available, and the user port missing the 9 volt AC line. The expansion port differs significantly from all prior C64 variants and rather resembles that of [[Commodore 16|C16]].

==Legacy==
Because the Commodore 65 was only a prototype, not many units were made. If one appears on [[eBay]], it may sell for around $20,000.<ref>{{cite web | url=https://hothardware.com/news/rare-commodore-c65-resurrected | title=Super-Rare Legendary Commodore C65 is About to be Resurrected for Retro Gaming Glory | date=15 October 2021 }}</ref>

===MEGA65===
In 2015, the Museum of Electronic Games & Art (MEGA)<ref>{{cite web|title = MEGA {{!}} MEGA - Museum of Electronic Games & Art|url = https://www.m-e-g-a.org/mega/|website = www.m-e-g-a.org|access-date = 2015-10-06}}</ref> announced a recreation of the Commodore 65. Also backwards compatible with the Commodore 64,<ref name="MEGA65 Computer">{{cite web|title = MEGA65 Computer|url = https://mega65.org|website = mega65.org|access-date = 2015-10-06}}</ref> the MEGA65<ref>{{cite web|title = Introducing the MEGA65 (8-bit) computer {{!}} MEGA - Museum of Electronic Games & Art|url = https://www.m-e-g-a.org/mega65-introduction/|website = www.m-e-g-a.org|access-date = 2015-10-06}}</ref><ref>{{cite web|title = MEGA 65: Commodore 65 remake gets a physical release • /r/c64|url = https://www.reddit.com/r/c64/comments/33kjp8/mega_65_commodore_65_remake_gets_a_physical/|website = reddit|date = 23 April 2015|access-date = 2015-10-06}}</ref> features Commodore 65 compatible hardware<ref name="MEGA65 Computer"/> recreated in [[Field Programmable Gate Array|FPGA]] and supports newer connectors such as HDMI, MicroSD cards and LAN.<ref>{{cite web|title = Making a C64/C65 compatible computer in an FPGA|url = https://c65gs.blogspot.com|website = c65gs.blogspot.com|access-date = 2015-10-06}}</ref>

In September 2020, the pre-release developer-kit (r3) has sold out and in total 100 systems were delivered by the end of 2020.<ref>{{Cite web|last=Mega 65|first=Trenz - The Official seller of|title=MEGA65 |date=2020-09-14|url=https://shop.trenz-electronic.de/en/30390-MEGA65-Development-Kit-highly-advanced-C64-and-C65-compatible-8-bit-computer?c=564|website=trenz}}</ref><ref>{{Cite web|last=Gardner-stephen|first=Paul|date=2020-11-25|title=Making a C64/C65 compatible computer: The DevKits have started shipping!|url=https://c65gs.blogspot.com/2020/11/the-devkits-have-started-shipping.html|access-date=2020-11-25|website=Making a C64/C65 compatible computer}}</ref><ref>{{Cite web|title=The Commodore 64 has a Successor (and it's amazing!)|author=[[Nostalgia Nerd]]|url=https://www.youtube.com/watch?v=2-voZvEtz48 |archive-url=https://ghostarchive.org/varchive/youtube/20211221/2-voZvEtz48 |archive-date=2021-12-21 |url-status=live|access-date=2020-12-02|website=www.youtube.com}}{{cbignore}}</ref>

On 30 September 2021, the final version of the MEGA65 with recreated C65 case, was available for pre-order. The first batch of 400 computers has sold out and been released to customers as of May 2022.<ref>https://shop.trenz-electronic.de/en/TE0765-03-S001-MEGA65-highly-advanced-C64-and-C65-compatible-8-bit-computer?
(davidjseibuhr journalist, reports: New Mega65 Corporation began thereafter, they periodically remanufactured pcb revised computers, prebuilt or kits)
Cc=564</ref>

As of 10 May 2023, the second batch of 400 computers has also sold out and been released to customers.<ref>[https://m65digest.substack.com/p/mega65-the-next-batch Dan's MEGA65 Digest], confirmation on batch 2 size</ref><ref>[https://shop.trenz-electronic.de/en/TE0765-03-S001-MEGA65-highly-advanced-C64-and-C65-compatible-8-bit-computer Trenz website], confirmation that both batch 1 and 2 have sold out</ref>

The third batch followed a few months later and incorporates a few technical updates on the mainboard [reference to be added]. As of writing (October 2024), the MEGA65 is no longer delivered per batch, and is readily available.

==References==
{{reflist}}

==Further reading==
* [https://worldcat.org/isbn/0973864907 On the Edge: The Spectacular Rise and Fall of Commodore] (2005), Variant Press. {{ISBN|0-9738649-0-7}}.

==External links==
{{commons category|Commodore 65}}
* [https://devilmaster.altervista.org/hi65.html Hi65: a high-level Commodore 65 emulator]
* [https://www.floodgap.com/retrobits/ckb/secret/65.html C65 page at 'The Secret Weapons of Commodore' website] By Cameron Kaiser and The Commodore Knowledge Base
* [https://web.archive.org/web/20240811202403/ftp://ftp.zimmers.net/pub/cbm/c65 FTP directory for the C65 at ftp.zimmers.net]
* [https://web.archive.org/web/20070927003419/http://www.onlinekunst.de/c65/ Andre Kaesmacher's C64DX Development Site]
* [https://www.devili.iki.fi/Computers/Commodore/C65/System_Specification/page1.html C64DX System Specification document]
* [https://www.theoldcomputer.com/roms/index.php?folder=Commodore/C65 C65 System ROMs and Utility Software] (requires an Unlimited account to download ROMs)
* [https://www.retrothing.com/2008/08/commodore-65-it.html Commodore 65: Like The C64, But It's One Louder]
* [https://web.archive.org/web/20101010092053/http://www.old-computers.com/museum/computer.asp?st=1&c=273 old-computers.com: LD-COMPUTERS.COM museum ~ Commodore C65], article on C65
* [https://www.zock.com/8-Bit/D_C65.HTML 8-Bit-Nirvana: Commodore 65]
* [http://www.heimcomputer.de/english/comp/c65.html heimcomputer.de: Commodore C65 Prototyp], German C65-site with many photos and info
* [https://www.toxic-waste.de/c65/ toxic-waste.de: Commodore C65 Information Page by TXW]
* [https://cbmmuseum.kuto.de/home_c65.html cbmmuseum.kuto.de: CCOM - Commodore 65]

{{Commodore International}}

[[Category:Commodore 64|65]]
[[Category:Commodore computers|65]]
[[Category:Home computers]]
[[Category:Prototype computers]]