Fake MC68010s Spotted

When you’re in the market for Motorola 68k CPUs (as I am), chances are at some point you’ll turn to eBay. And sure, there are plenty listed on there, with prices ranging from super-cheap to fairly-reasonable.

However, as always with eBay, caveat emptor is king! When you receive your chips, have a good look at them. They should look like this:

Click to enlarge

Notice that the Motorola logo looks good, the text is kinda small, and the date code makes sense (1992, week 51 in this case).

Now, check these out:

Click to enlarge

Notice here that the logo isn’t complete, the text is bigger than on the previous chip, and the date code suggests these were produced in the very first week of 2019 (or maybe 1919!?). I’m pretty sure Motorola weren’t producing these chips at that time…

You can’t see it too well in this picture, but the surface of the chip is sort-of rough, suggesting someone’s used some kind of tool to grind the part number off…

It turns out that these chips are either fakes, or re-badged original parts, and they’re not 68010s at all, but rather 68000s. If they’re fakes, they’re reasonably good ones – they work quite well as 68000s. Of course, the 68010 is pin-compatible with the 68000, so unless you have code that specifically uses the added features in the former, you might never know these aren’t the real deal.

I’m not sure why anyone is faking (or re-badging) these chips – given that these cost me a couple of dollars each I can’t really see where the margins are. I guess someone, somewhere has a bunch of 68000s, a facility for re-badging them, and the belief that they’ll sell much better if people think they’re buying a 68010. Who knows, maybe they’re right (I mean, I bought some, so… 🤷)

Now, I know that some people like to buy a 68010 as an “upgrade” for their old Amiga or ST (and maybe MegaDrive too, are people doing those?). It occurs to me that some of them might inadvertently purchased one of these imposters, and because the software on those machines isn’t generally written to take advantage of the 68010s features, they might not know it.

If you’ve upgraded your machine and your worried, and you have the facility to assemble some code, the following will let you know if you’re running on The Real Deal or one of these rebadged 68000s:

movec.l VBR,A0    ; Copy vector base register to A0...
movec.l A0,VBR    ; ... and load it back into VBR

If you’re running on a bona-fide 68010 (or above), this shouldn’t do anything. On the other hand, on a 68000 (even a cleverly-disguised one) this will cause an instant illegal instruction exception (vector 0x04). How your computer tells you about this will vary, but I’m guessing it’ll let you know…


Published by roscopeco

IT guy, code junkie, mobile app developer, occasional blender artist and open-source activist.

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