If you’re nostalgic for the golden age of microprocessors and dream of building your own computer, this story might spark your imagination. [Eric Lind], passionate retro enthusiast and his 14-year-old son, embarked on a mission to craft a microcomputer from scratch, centred around the exotic Motorola 6809 chip: the µLind.
What sets this project apart is its ambition: bridging retro computing with modern enhancements. Starting with just a 6809 and some basic peripherals, the men designed a multi-stage roadmap to realize their dream. Each stage brought new challenges: debugging an address decoder, reworking memory management, and evolving glue logic into programmable GAL chips. Fascinatingly, the project isn’t just about nostalgia—it’s a playground for exploring multitasking operating systems and pushing the boundaries of 8-bit computing.
Their creativity shines in solutions like a C64-compatible joystick port, add-on expansion cards, and a memory overkill of 1MB RAM. With every setback—a missing pull-up resistor or a misrouted IRQ signal—their determination grew stronger. By combining old-school know-how with modern tools like KiCad, they’ve created something that is both personal and profoundly inspiring.
[Eric]’s hope and goal is to establish a community of people that want to expand beyond the traditional Z80 and 6502 based SBC’s. Interested? Read [Eric]’s project log on Hackaday.io and start crafting!
8 bit/ 16bit!! look it up!
Looks like an early baby Macintosh board!
Maybe someone can design and debug a board that fits Macintosh but runs Linux, that would save a lot of dead Mac’s and their crt screens!!
Oh, that actually sounds like an interesting project! Good idea! I really love the look of those machines.
Wasn’t the 6809 considered at one point as the processor for the first Mac?
Yes, at least according to https://www.i-programmer.info/history/9-machines/111-the-mac.html
I never bothered with the 6809 and went straight from the 6800 to the 68000 and 68008, wire-wrapping my boards and writing a debugger in assembly language on my TRS-80 Model II running CP/M. I even wrote a book on the 68000!
Motorola did it right. I programmed on the Z80, i805i, TMS34082 and all were clunky. Motorola did it right. I may have used your book to guide my work.
I wonder, if multiple V9958 chips were used, with a looped ram acting as a mask to switch between them, perhaps multiple modes could have been combined on one display. Something like that would have seemed amazing back them.
MCM 6809.
Easily the best 16 bit processor. Lovely orthogonal instruction set, addressing modes etc., allowing for relocatable multiply renterant code. Last “hard wired” MPU, but soon eclipsed by its 32-bit rivals ☹️.
Yeah, it was a bit late to the party. But I had not even heard about it and when i was given 3 of them my and my sons curiosity was really triggered, since my son knows the C128 platform and was really interested in what could be done with an processor that on the paper is far superior to the 6502. And to be honest, so was I. And when we found out it had a pin compatible sibling, the 6309, that even have a 32-bit register we where sold. This project just had to be done!
Thanks for the backstory!
Yep.
The 6809
Part 1: Design Philosophy
https://techheap.packetizer.com/processors/6809/the_6809.pdf
Ah, thank you for that story!
I built a 6809 based system in the early 1980’s, all wire wrapped. With an audio cassette tape interface for programme storage. I also hand coded a two-pass assembler and disassembler for the 6809, a lot of sheets of paper. Many hours of fun!
I had a close friends father that was that kind of guy and he lent me my first computer back in the early 80’s, and that is when my computer interest really took off! I even got his, by then old, Spectrum to tinker with, so hats of to your generation!
I did the same with the Intel 8051. Wire wrap. Enter code in hex. Store with a cassette player. 1200 baud is a 1, 2400 baud is a zero. It worked. But segmented addressing??
In 1987, for work at TI, I built a MC68030 board interfacing to a TMS34081 (CoPro) to replace the 68331 CoPro. Board was plugged into a PC ISA bud. C code booted up and downloaded assembly code to buffers in both the Mot and TI parts. 16, 32 and 64 bit coding. Little Endian. Big Endian. Oy weh. It worked. Then I went into product management.
Writing code for Motorola was so much easier and straightforward. They did it right.
I did a load of work with these at a well known UK fruit machine manufacturer. The 6809 has two stacks which made it ideal for running the Forth development system we were using at the time.
I’m working on a 6809 based computer. I intend to write a Forth-based ROM.
May the forth be with you.
Good luck! Forth is always a good choice for bringing up a new system, or when one wants an interactive programming system in minimal space.
Ignore the first three tries….Then go Forth.
I had a Dragon 64 with 6809 for some weeks but had to leave it.
We started a project to replace 6502 of VIC20 with 6809, saw very fast, that VIC20 will be history and left it.
I built a tiny board with 68hc11 with full memory and an expansio buss, but had to leave it, because it was impossible to get the chips. What we got straight from Motorola, had already some code in their OTP ROM.