68 Katy – 68000 Linux on a Solderless Breadboard

userbinator's comments are good, and to extend his remarks obviously the solution to clock skew is to simply lower the clock rate. Good luck using a solderless breadboard at 500 MHz digital LOL. But breadboards work just fine at single digit MHz rates.

There is a problem. Many processors use dynamic registers and require a clock above a certain rate to refresh the registers. Yes, no kidding, dynamic ram cells as CPU registers. I know for a fact that the first 386 was dynamic and onlyrated down to 10 or 15 or so MHz (was fooling around with low power ops, if the thing sleeps 90% of the time at 25 MHz, you can't run the chip at 100% utilization at 3 MHz...). You can see a slight mismatch if your CPU registers are only rated down to 15 MHz and you can't reliably breadboard above maybe 5 MHz ... Of course this is analog world and a chip rated to run down to 12 Mhz will almost certainly run at 10 Mhz, maybe even 5 at least sometimes, if you're careful not to run at max temp or min power supply voltage or whatever. And adding to the fun, after (sometimes long after) the first dynamic versions of a CPU come out, someone (often a licensed competitor) makes a fully static version of the chip, sometimes pin compatible. As you can imagine, early on in development, being able to troubleshoot logic by running at a tenth of a Hz is very convenient. If you've ever wondered what "fully static" means on a microcontroller data sheet, well, now you know. And you know why you can't breadboard a classic 80386 but maybe a more recent fully static clone would work.

userbinator's comments about packages are also correct and there is a low speed workaround of carrier to DIP converter boards and proto boards. I've hand soldered many a surface mount TQFP, its very easy. There are many companies selling SMD proto boards, some cheaper, some fancier, but a realistic place to start is googling for "schmartboard", as pretty much if the SMD package exists, they sell a proto board for it, ready for projects like this.

Unfortunately the industry is moving toward BGA packages and the official new hardware to mount those is like $5K although I'm sure I could rig something up much cheaper.

I would never be able to keep all these wires straight in my head. And that's even a step-down in terms of wiring from the BOMW1 project...

Amazing, he did in 3 weeks and that seems like 3 weeks of part time work, that's amazing. It's amazing how much work we can put out in a small time if we are focused. I lost it during the video when he got tangled up in vi. In 1998, I got a Sun 3 workstation which has a 68000 cpu, the only thing I could get to run on it then was NetBSD. It's amazing that a single person can now build such a computer and run Unix on it within 3 weeks. Just amazing, how time changes things.

Well...68020+68851 PMMU chip. Regular Linux won't run on just an '020.

Not ARM microcontrollers, which the OP specifically references. NXP’s LPC810 & LPC1114 are really the only game there, and they don't support external memory AFAIK (and it's an M0). Of course, there are a lot of shops bonding an QFP ARM or similar to a slip of PCB that's DIP form factor, but that's not exactly the same.