One persistent tech wizard’s yearning for the bygone days of Commodores and Sinclairs and early Apples — so, the ‘70s and ‘80s when we had less memory and more patience — led to one of those projects whose underlying impetus seems to be “because I can.” Dirk Grappendorf of Dortmund, Germany seems to pretty much live and breathe computers; he has an impressive background in computer science, including extensive programming experience, so this maker’s project is one you can undertake knowing the advice is solid.
Grappendorf decided to build “a simple microcomputer system with an 8-bit MOS 6502 CPU,” the kind that one could find in many homes in the ‘70s and ‘80s like the Apple II or Commodore 64 (still the highest selling home computer of all time). While his blog about the project doesn’t include a detailed tutorial, he does describe his process from its early days in September 2014 to its conclusion this month, January 2015. When he began the project, he knew that it wasn’t going to be a short-term one requiring little effort, but the challenge seems to have been part of the appeal for Grappendorf.
“The idea,” he explains, “was to design a computer… from scratch, using mostly only parts that were available when this computer,” the Commodore C64, “was manufactured.” While he did end up using mostly original parts, Grappendorf’s development tools were contemporary. High-bandwidth digital oscilloscopes, modern PCB design software, logic analyzers, and 3D printers were still distant dreams in the ‘70s and ‘80s. The majority of circuits were hand-wired and system software was, he notes, “written in assembler and often converted to machine code with pencil and paper” — definitely old school. While he acknowledges that it still takes considerable time to build a computer like the Commodore C64, the modern tools he used cut that time significantly.
Grappendorf’s blog recounts in chronological order each step in the build. With each step, he’s added more functionality, more components, and descriptions of the changes he’s made to the schematic and the printed circuit board layout. You read about how he’s progressed with building the hardware and software. It’s not exactly an action-packed, page-turner of a read, but for those tech geeks who read the headline of this story and thought, “That’s my kind of maker challenge,” there’s a wealth of info in Grappendorf’s account.
While the blog is short on what he refers to as “the nitty-gritty details of how a 6502 CPU, RAM, ROM, and IO devices work and how they communicate with each other,” Grappendorf fills in some blanks by providing links at the end of the main text and following each part of his article.
We’re most excited, of course, by the 3D printed aspects of this great project. Grappendorf designed the case for his Commodore C64 using AutoDesk 123D Design. It was inspired by the original C64C and the Amiga 500 but with this 21st-century version, all components, even the keyboard, fit into a single case, giving us a sense of, says Grappendorf, “how a C64 laptop computer might have looked.”
He used an Ultimaker 2 3D printer and shared instructions for adapting the 3D model to print in pieces on the relatively low build-volume printer. The STL files are shared via GitHub, along with source files for most of the project’s coding. The bright orange color of the finished computer is a great, contemporary twist on the otherwise kind of drab, off-white color of the original.
What do you think about this new take on an old classic? Let us know if this 3D printed update of the classic Commodore C64 stirs up any nostalgia — or desire to try to make your own — over at the 3D Printed DIY Commodore C64 Computer forum thread at 3DPB.com.