Commodore CHESSmate Reproduction (Winter 2024)

My Commodore CHESSmate Reproduction

Manufactured By: Commodore International

Designed By: Peter R. Jennings

Release Date: 1978

CHESSmate was developed by Peter R. Jennings, author of the MicroChess program, under contract with Commodore International. The CHESSmate’s hardware is based on the venerable KIM-1, but the ROMs are loaded with a custom MicroChess 1.5 image not the KIM-1’s monitor.

Although I was very lucky to obtain an original CHESSmate to work from, CHESSmate units are extremely hard to find, understandable given that 45 years have passed since they were introduced. I built a working CHESSmate computer using modern fabrication techniques and components, so that anyone could make one.

The hardware for the CHESSmate closely matches the KIM-1 SBC that it was based on.

• 6504 CPU (28-pin 6502)

• 8K addressable memory

• On-chip clock @ 1MHz

• 6530-0024 RIOT (64 bytes RAM, 1KB ROM, 2 I/O ports, 8-bit timer) 

• 6332 4k ROM 

• 4 7-element LED displays 

• 4 dome indicator LEDs

• Piezoelectric beeper

• 19 membrane keys

Left: CHESSmate Reproduction Middle: Minimal CHESSmate Right: Original CHESSmate

I created a couple of CHESSmate variants.

One of course is the full reproduction, as accurate a work-a-like to the original as I could make. Mind you, under the covers it is quite a different beast, using emulation running on an ESP-32 rather than reproducing the original hardware.

The second variant is a minimal viable CHESSmate, basically just the PCBs mounted onto a a basic 3D printed frame.