Commodore 65

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Commodore 65
A Commodore 65 prototype
Type Personal computer
Release date N/A
Discontinued N/A
Operating system Commodore BASIC 10.0
CPU CSG 4510 R3 @ 3.54 MHz
Memory 128 kB (8 MB maximum)
A Commodore 65 prototype opened up, revealing its internal disk drive
CSG 4510 ("Victor")
CSG 4567 ("Bill")
"Elmer" and "Igor" (programmable logic)
F011B (floppy disk controller)
Opened chassis
Motherboard inscription
Start screen

The Commodore 65 (also known as the C64DX) is a prototype computer created by Fred Bowen and others at Commodore Business Machines (CBM) (part of Commodore International) in 1990–1991. In the end of 1990 the decision to create the C65 was taken.[1] The project was cancelled later on.

The C65 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.

When Commodore International was liquidated in 1994, a number of prototypes 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.[2] As the C65 project was cancelled, the final 8-bit offering from CBM remained the triple-mode, 1–2 MHz, 128 kB (expandable), C64-compatible Commodore 128 of 1985.

Technical specifications[edit]

  • The CPU named CSG 4510 R3 is a custom CSG[3] 65CE02 (a MOS 6502 derivative), combined with two MOS 6526 complex interface adapters (CIAs)
  • 3.54 MHz clock frequency (the C64 ran at 1 MHz)
  • A new VIC-III graphics chip named CSG 4567 R5, capable of producing 256 colors from a palette of 4096 colors; available modes include 320×200×256, 640×200×256, 640×400×16, 1280×200×16, and 1280×400×4 (X×Y×color depth, i.e. number of colors/bit planes)
    • Supports all video modes of VIC-II
    • Textmode with 40/80 × 25 characters
    • Synchronizable with external video source (genlock)
    • Integrated DMA controller (bit blit)
  • Two CSG 8580R5 SID sound chips producing stereo sound (the C64 has one SID)
    • Separate control (left / right) for volume, filter and modulation
  • 128 kB RAM, expandable to 8 MB using a RAM expansion port similar to that of the Commodore Amiga 500
  • 128 kB ROM
  • Heavily improved 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" DSDD floppy disk drive
  • Keyboard with 77 keys and an inverted T directional cursor block


Left side:

  • Power +5V DC at 2.2A and +12V DC at 0.85A[4]
  • 2× Control ports DE9M[4]


Bottom flap:

  • RAM expansion[4]

Dimensions: ~ 46 cm wide, 20 cm deep, 5.1 cm high[4]

Chipset names[edit]

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, "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'."[7]

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)


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

The DOS itself is based on the Commodore PET IEEE 8250 drive DOS. Since it can only deal with two floppy disk drives, including the internal, only one external drive may be connected unlike earlier systems where up to 4 drives can be daisy chained.


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 bottom of the board.[8] The built-in floppy disk drive is connected in parallel, serial Commodore drives can be connected via the usual IEC port. A plug for a genlock was also provided. Only the port for datasette the C64 is no longer available, and the user port missing—like the Aldi C64[citation needed]—the 9 volt AC line. The expansion port differs significantly from all prior C64 variants and rather resembles that of C16.


In December 2009, a working C65 on the online auction site eBay achieved a sales price of € 6060.[9][10] A computer with missing parts was in October 2011 sold for about 20100 USD. In April 2013 an eBay auction reached the highest auction price for an C65 at 17827 EUR.[11] The latest eBay auction from February 2015 closed at 20050 EUR.[12]


  1. ^ "OLD-COMPUTERS.COM musem ~ Commodore C65". Retrieved 2013-06-20. 
  2. ^ "Secret Weapons of Commodore: The Commodore 65". 2007-07-01. Retrieved 2013-02-26. 
  3. ^ Commodore Semiconductor Group, previously known as MOS Technology, Inc
  4. ^ a b c d e f g h i j k l "C64DX System specification". 2009-08-18. Retrieved 2013-06-21. 
  5. ^ "c65_html_1410c60e.gif". 2012-12-16. Retrieved 2013-06-21. 
  6. ^ "The Story Behind 'Bill' and 'Victor'". 2013-11-16. Retrieved 2013-11-16. 
  7. ^ "File:C65-open.jpg". 1997. Retrieved 2013-06-20. 
  8. ^ "C65-Auktion auf eBay". Retrieved 2010-01-03.  (dead link)
  9. ^ "C65-Auktion auf eBay". 2012-11-10. Retrieved 2010-01-04. 
  10. ^ "Sehr seltener Prototyp Commodore C65 aka C64DX aka C90". 2013-04-14. Retrieved 2013-04-18. 
  11. ^ "Ultra rare Commodore 65 / C65 / DX64 prototype, working, serial #22". 2015-02-15. Retrieved 2015-02-15. 


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