In this IEEE Spectrum article, author Stephen Cass describes how he created a fresh plug-in cartridge to power a Commodore 64 exhibit in a museum setting. The project originated from using the C64 as an artifact in a “Chips That Changed the World” traveling exhibit. Rather than forcing museum staff to load software manually, the team wanted a cartridge that could boot the demo instantly, just like original C64 cartridges did.
Working within tight constraints was part of the fun. The cartridge’s memory limit is 16 KB, which meant Cass had to compress the demo code, interface directly with the C64’s video hardware, and write in 6502 assembly. He used existing tools, such as online C64 graphics editors, the IDE 65xx, the Kick Assembler, and the VICE emulator, to design sprite effects, textual screens, and a procedural fractal routine that fit into minimal bytes.
Next came turning that code into hardware. Cass ordered a $5 printed circuit board, a programmable ROM chip (about $3), and small passive components. He soldered these to the board and printed a cartridge shell using a 3D printer. The ROM was flashed using a TL866 programmer.
On the first test, the cartridge froze the machine, and part of the code disabled a portion of the ROM unexpectedly. That hiccup was debugged, and after adjustment, the demo worked flawlessly on real hardware. The journey, Cass notes, is part nostalgia, part maker challenge. He hopes visitors enjoy the exhibit and encourages others to try reviving 8-bit classics now that components, tools, and documentation are easier to access.