Commodore 65

Commodore 65

Type	Home computer
Discontinued	1991 (project cancelled)
Units shipped	Estimated fewer than 200 prototypes
Operating system	Commodore BASIC 10.0
CPU	CSG CSG 4510 R3
Memory	128 KB (expandable to 8 MB)
Storage	Internal 3½″ DSDD floppy (880 KB)
Display	320×200×256; 640×200×16; 640×400×16; 1280×200×4; 1280×400×4; palette of 4096 colors
Graphics	VIC‑III (CSG 4567 R5)
Sound	Dual CSG 8580 SID chips, stereo output
Predecessor	Commodore 64
Website	N/A

The Commodore 65 (C65, also marketed as the C64DX) was a prototype 8-bit personal computer developed by Commodore Business Machines between 1990 and 1991. Intended as a successor to the Commodore 64, it was designed to offer improved graphics, sound, and storage capabilities while maintaining backward compatibility with C64 software.

History

Development of the C65 began around 1989–1990, under the guidance of engineers including Fred Bowen, Bill Gardei, Paul Lassa, and Victor Andrade. The project aimed to revitalize the Commodore 64 product line before Commodore redirected its focus to the Amiga series. Full development commenced in late 1990, but internal disputes and financial pressures led Commodore chairman Irving Gould to cancel the project in 1991.

Following Commodore's liquidation in 1994, an estimated 200 prototype units were released onto the collector market. Several units have since been sold at auction, occasionally reaching prices above €20,000.

Technical specifications

CPU: CSG 4510 R3 (based on the 65CE02), running at 3.54 MHz

Memory: 128 KB onboard RAM, expandable to approximately 8 MB via a RAM expansion port on the underside of the case

Graphics: VIC-III (CSG 4567) chip supporting:

320×200 with 256 colors

640×200 or 640×400 with 16 colors

1280×200 or 1280×400 with 4 colors

Hardware blitter, DMA, and genlock support

Sound: Dual CSG 8580 SID chips for stereo audio

Storage: Integrated 3½″ double-sided double-density floppy drive (880 KB), compatible with the Commodore 1581 format

Operating system: Commodore BASIC 10.0, including extended graphics and disk commands

Ports and expansion

The Commodore 65 included several ports and interfaces:

Two DE-9 joystick ports

50-pin expansion connector and Amiga-style RAM expansion flap

IEC serial port for disk drives

RGB (DE-9F), composite video, RF modulator, and stereo audio outputs

User port (parallel), DMA expansion bus, and built-in floppy controller

Legacy

Despite never reaching the market, the Commodore 65 gained near-mythical status among retro computing enthusiasts. Its extreme rarity—fewer than 200 working units are known—has made it one of the most collectible Commodore prototypes ever produced.

MEGA65

In 2015, the non-profit Museum of Electronic Games & Art (MEGA) launched the MEGA65, a modern open-source re-implementation of the C65 using FPGA technology. The system builds upon the C65 architecture while adding features for modern usability:

HDMI and composite video output

microSD card storage, Ethernet, USB, and real-time clock

A 45GS02 FPGA-based CPU core clocked at up to 40.5 MHz

Optional 8 MB RAM expansion and accelerated DMA

Full-size mechanical keyboard and functioning floppy drive in a replica Commodore case

Developer preview models shipped in late 2020, followed by retail production units in 2021. As of 2024, the MEGA65 remains in production and is available through official channels.

Further reading

Kaiser, Cameron. "Secret Weapons of Commodore: The Commodore 65". Floodgap.com. [4]

Bagnall, Brian. On the Edge: The Spectacular Rise and Fall of Commodore. Variant Press, 2005. ISBN 0‑9738649‑0‑7

Zimmers, Bo. "Commodore 65 Computer". zimmers.net. [5]

"The MEGA65: A Modernization of a Classic Commodore Computer". Slashdot, 2021. [6]

External links

Secret Weapons of Commodore – C65 overview

Official MEGA65 site

8‑Bit Nirvana – Commodore 65

Hi65 emulator