Project showcase: Final Cartridge III clone


I haven't seen many people showcase their GreenPAK projects here, but I think it's nice to show something. You likely have read about my Commodore 64 cartridge project below. That's still in development and progressing. However, before starting with that I had decided I did need a less ambitious project to get experience with the GreenPAK and its tools. So I decided to try if I could design a Final Cartridge III clone using a GreenPAK. Now, cloning the Final Cartridge III has been done before, so this project is not revolutionary. It is useful though: The Final Cartridge III is still a popular tool in 21th century use of the Commodore 64, so there is demand for it.

The original FC3 did consist of 7 chips, in later revisions this became 6 chips and current clones also are based on the design with 6 chips. I was interessted in how far I could simpify the design with a GreenPAK. The answer is quite a bit, my clone consists of just 3 chips:

  • An SLG46620
  • a 256KB flash ROM
  • A 74HC273 8-bit flip-flop

In addition I was able to:

  • Remove soms diodes and pull-up resistors out of the circuit using the built-in port capabilities
  • Make it compatible with the Final Cartridge III Plus, a popular extention of the firmware of the FC3.
  • Make the cartridge design compatible with the 2MHz mode of the Commodore 128
  • Add the ability to reprogram the flash memory from the Commodore 64 itself
  • Add a circuit that can generate 12V Vpp, so the cartridge is compatible both with 5V flash ROMs (such as the SST39SF020) as well as 12V flash ROMs (such as the CAT28F020). This adds again a few passive components.

The result looks as follows:

The small TSSOP20 chip at IC1 is the SLG46620.

When the cartridge case is closed, it looks like this:

The cartridge did work at the first try. The simulation capabilities of the GreenPAK software are to thank for this. Nevertheless, I do have a few bugs in the design. That's okay, I just need to build another cartridge with an updated GreenPAK design.

All in all, a succesfull little project.

  • Hi dmantione!

    I hope you're doing well! I just wanted to shoot you a quick message to say thank you for using our SLG46620 IC in your Commodore 64 cartridge project. It's really awesome to see our products being used in such a cool way.

    As an engineer, I know you have a lot of choices when it comes to selecting components for your projects, so we're really glad that you chose our SLG46620 and that it met your needs. We're stoked to see that it worked well for you and that it was compatible with older technology.

    We really appreciate your support and trust in our company and our products. It's always super rewarding to see our customers succeed and we're thrilled to have played a part in your project. We hope that you'll continue to consider us for your future projects.

    Thanks again for choosing our SLG46620 for your Commodore 64 cartridge project! We're wishing you all the best and can't wait to see what you come up with next.

    Take care,

    Oleh Sapiha,

    Application Engineer