Hello,
2 days ago we exchanged points of view about cheap Rockwell ICs I got from some obscure Chinese seller : viewtopic.php?f=1&t=1953&start=60#p46961
I found 2 non-working ACIAs in what I received, they were suspected to be counterfeit parts, as BDD told me.
Curious as I am, I decided to crack-open one of them, knowing there was very little chance of success (the correct method involves acid and so on). I was particularly lucky : half an hour later I managed to get one third of the silicon die intact !
I put it under my microscope (150 x magnification), and as a second lucky strike, appeared the "ROCKWELL" name near the edge. I saw other markings identifying the different levels (metal, polysilicon, ...). Still on the positive side, it clearly is a 2 or 3 micrometer process (hard to accurately tell). I also recognized the "Rockwell style" which I already saw on ultra-high resolution photos I found on the internet some months ago (R65C02). Unfortunately I lost the link.
Now there still remain some doubts : besides the "ROCKWELL" name I found the (C) marking but also a (M) which I never saw before. Technically it could be a copy made after some reverse-engineering (electron microscope...).
Then a last point, the most troubling to me : long ago I read that Rockwell spun off their semiconductor division to Conexant in 1999. So how is it possible that there are tons of chips around, made after 1999 (until 2006 !) under the Rockwell name ?

Any hint ? Thanks !
Marc

EDIT : the ultra-high resolution photo is to be found at siliconpr0n.org (a huge 225 Mb file under the R65C02P2 reference)

(M) means mask copyright - chip data has a special, shorter, copyright life compared to creative works.

At 2 or 3 micron technologies, it would be easy to reverse engineer masks from chips and make copied parts. So, difficult to tell if a chip is a legally licensed part or a copy. It needn't matter for practical purposes, setting aside legal questions, if the copy is good enough. Or, it might matter, if the copy is not good enough.

There's a different thing which can happen: unrelated chips rebadged. That's evidently not what happened here.

Hi BigEd,

I had supposed that the (M) was related to the mask just after I submitted my post -thank you ! And, copy or not, you're right : I feared to discover something totally unrelated and rebadged, now the only fact I'm sure about is that it actually is "some" 65C51 chip. And there remains the mystery of Rockwell names on chips made long after Conexant came into business...

Would these parts be worth counterfeiting? The 6551 and 6522 are still in production, so there's not a huge market for fakes.

Used 6581 SID chips are expensive and rare because new versions aren't made anymore. So I've heard most of the ones on eBay are counterfeits.

Right, the most difficult to find chips are the most counterfeit, the SID is a good candidate... as could be, to some less extent, the 65C51 because of its buggy WDC incarnation.

BTW : still no idea as to why so much Rockwell-labeled chips dating from after the spin-off to Conexant ? I'd really would like to know...