Commodore 65

Commodore 65

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 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 1
  • Technical specifications 2
    • Different views 2.1
    • Ports 2.2
    • Chipset names 2.3
    • DOS 2.4
    • Interfaces 2.5
  • Sales 3
  • Notes 4
  • References 5
  • External links 6


In September 1989 Compute!'s Gazette noted that "Sales of the 64 have diminished rapidly, 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 series, the magazine asked "Will Commodore take the same tack?", then continued:[1]

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 MHz (by comparison, the 64 runs at 1 MHz; the Amiga, at slightly over 7 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.

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 Plus/4.'"[1] While the next issue reported that "the latest rumor is that such a machine will never see the light of day",[2] 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.[3] The project was cancelled later on.

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.[4] 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.

In April 22, 2015 © MEGA - Museum of Electronic Games & Art[5] announced a recreation of this computer featuring similar specifications and technologies. Also backwards compatible with the Commodore 64,[6] the Mega 65[7][8] features Commodore 65 like hardware[6] and is compatible with newer technologies such as HDMI.[9] The recreation of the Commodore 65 computer will be released in the third quarter of 2016.[6]

Technical specifications

  • The CPU named CSG 4510 R3 is a custom CSG[10] 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

Different views


Left side:

  • Power +5V DC at 2.2A and +12V DC at 0.85A[11]
  • 2× Control ports DE9M[11]


Bottom flap:

  • RAM expansion[11]

Dimensions: ~ 46 cm wide, 20 cm deep, 5.1 cm high[11]

Chipset names

The custom chips of the C65 were not meant to have names like the custom chips in the [14]

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 to the internal floppy disk controller. Like earlier systems, up to 4 drives can be daisy-chained on the IEC port.


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.[15] 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—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.[16][17] 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.[18] The latest eBay auction from February 2015 closed at 20050 EUR.[19]


  1. ^ a b Elko, Lance (1989-09). "Editor's Notes". Compute's Gazette. p. 4. Retrieved 4 March 2015. 
  2. ^ Elko, Lance (1989-10). "Editor's Notes". Compute's Gazette. p. 2. Retrieved 4 March 2015. 
  3. ^ "OLD-COMPUTERS.COM museum ~ Commodore C65". Retrieved 2013-06-20. 
  4. ^ "Secret Weapons of Commodore: The Commodore 65". 2007-07-01. Retrieved 2013-02-26. 
  5. ^ "MEGA | MEGA - Museum of Electronic Games & Art". Retrieved 2015-10-06. 
  6. ^ a b c "MEGA65 Computer". Retrieved 2015-10-06. 
  7. ^ "Introducing the MEGA65 (8-bit) computer | MEGA - Museum of Electronic Games & Art". Retrieved 2015-10-06. 
  8. ^ "MEGA 65: Commodore 65 remake gets a physical release • /r/c64". reddit. Retrieved 2015-10-06. 
  9. ^ "Making a C64/C65 compatible computer in an FPGA". Retrieved 2015-10-06. 
  10. ^ Commodore Semiconductor Group, previously known as MOS Technology, Inc
  11. ^ a b c d e f g h i j k l "C64DX System specification". 2009-08-18. Retrieved 2013-06-21. 
  12. ^ "c65_html_1410c60e.gif". 2012-12-16. Retrieved 2013-06-21. 
  13. ^ "'"The Story Behind 'Bill' and 'Victor. 2013-11-16. Retrieved 2013-11-16. 
  14. ^ . 1997. Retrieved 2013-06-20. 
  15. ^ "C65-Auktion auf eBay". Retrieved 2010-01-03.  (dead link)
  16. ^ "C65-Auktion auf eBay". 2012-11-10. Retrieved 2010-01-04. 
  17. ^ "Sehr seltener Prototyp Commodore C65 aka C64DX aka C90". 2013-04-14. Retrieved 2013-04-18. 
  18. ^ "Ultra rare Commodore 65 / C65 / DX64 prototype, working, serial #22". 2015-02-15. Retrieved 2015-02-15. 


  • On the Edge: The Spectacular Rise and Fall of Commodore (2005), Variant Press. ISBN 0-9738649-0-7.

External links

  • Hi65: a high-level Commodore 65 emulator
  • C65 page at 'The Secret Weapons of Commodore' website By Cameron Kaiser and The Commodore Knowledge Base
  • FTP directory for the C65 at
  • Andre Kaesmacher's C64DX Development Site
  • C64DX System Specification document
  • C65 System ROMs and Utility Software
  • Commodore 65: Like The C64, But It's One Louder
  • LD-COMPUTERS.COM museum ~ Commodore C65, article on C65
  • 8-Bit-Nirvana: Commodore 65
  • Commodore C65 Prototyp, German C65-site with many photos and info
  • Commodore C65 Information Page by TXW
  • CCOM - Commodore 65