In his latest video, Captain Commodore offers a hands-on overview of how Commodore 64 cartridges work, breaking down their types, functions, and the hardware behind them. If you’ve ever wondered why some games load instantly or how homebrew cartridges are possible, this walkthrough is worth your time.
The discussion begins with a quick refresher on the C64’s architecture. Built around the 6510 processor—an enhanced 6502—the machine can access just 64K of addressable memory. That means everything, from game code to system routines, has to live within that space. Cartridges work by mapping data into specific memory locations, often replacing parts of the built-in ROM.
Captain Commodore explains that this memory mapping is managed by the C64’s PLA chip, which helps control when and how various chips—like cartridge ROMs—appear in memory. The system’s split clock cycle is another factor, with the CPU and VIC-II chip taking turns accessing the bus.
He then explores the cartridge types: 8K, 16K, and Ultimax. Ultimax mode, originally designed for the Commodore MAX, lets a cartridge overwrite the built-in kernel—something famously done by Jupiter Lander. This behavior makes Ultimax carts ideal for machines with bad ROM chips.
The video walks through a variety of cartridges, both DIY and commercial. The Versa64Cart, for example, is a low-cost programmable board that lets hobbyists create their own multi-game carts. Captain Commodore shows how to wire it up, set address modes using DIP switches, and load up to 64K of games using simple components and an EPROM programmer.
For those who’d rather skip the soldering, devices like the Kung Fu Flash and EasyFlash 3 are highlighted. These carts accept ROM files via SD card and support multiple formats, including advanced banking modes used in Ocean Software’s larger games. There’s even a nod to more advanced gear like the Sidekick64 (based on a Raspberry Pi) and the Ultimate II+, which emulates disk drives, tapes, and just about every cartridge format imaginable.
He rounds things out with a look at Magic Desk cartridges—EPROM-based carts with simple menu systems. Whether you want a handpicked compilation or a full 2MB archive of your favorites, the Magic Desk format offers an accessible entry point into custom cart creation.
The takeaway is clear: building and using C64 cartridges doesn’t have to be complicated. Whether you’re restoring old hardware, crafting your own compilations, or just looking to play a few games with zero loading time, there’s a cartridge option that fits. Captain Commodore’s breakdown makes the whole process easy to follow, even if you’ve never looked at a memory map before.
