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This is a failed/abandoned dissection of the WD1772PH02-02 floppy controller.

The WD1772-02 was used in CP/M capable Commodore floppy drives:
1570: 5 1/4 floppy drive
1571: 5 1/4 floppy drive //1571 is integral part of the C128.
1581: 3.5 floppy drive

The WD1772-02 also was used in the Atari XF551 floppy drive,
in the Atari ST, and in the SAM Coupé.

;---

Because of job related reasons, it became increasingly difficult
for me and Frank to go on with the chip dissections.

After gnawing for half a year on the chip, all on my own and without any help,
it eventually became obvious to me that I had no chance of finishing this.
So I'm just posting the schematics I have so far.
Be aware that they probably contain errors,
and that it isn't sorted whether signals actually are active LOW or active HIGH.

I do not have permission from Frank to give out the picture of the WD1772-02 silicon.
Lab costs for Frank when decapping one chip is 2.5k€+,
vectorizing a chip took him 3+ months for one chip,
he never got much in return when giving away his vectorized chip pictures.

So if you want to continue this dissection,
and you need the picture of the WD1772-02 silicon for verifying my schematics,
you can't get around negotiating with Frank (fhw72) for the price of said picture.

Small picture of the WD1772-02: WD1772-02 areas marked:

Decided to split the schematic into three parts:

The obscure 1 Bit Microcontroller: The clock PLL, which probably is related to patent US4808884: And the rest:

The Eagle 6.4 source of my schematics: The program memory of the obscure 1 Bit microcontroller:

And that's all.
From here on, you are on your own.
Good luck and god speed.

Thanks for doing what you did and sharing what you have - I can see the difficulty, and those costs are quite considerable.

Interesting, from a high level, if there's both a bit serial and a conventional micro in there - that's what was found in the 8271, which was a very large and expensive earlier chip from Intel.
8271 floppy controller reverse engineer journey write-up (stardot link)

Link to the patent (pdf within)
US4808884A High order digital phase-locked loop system

I found a couple of chip topography design patents - not the chip you looked at, but possibly contain clues or hints. Both called "Chip topography for a MOS disk memory controller circuit"
https://patents.google.com/patent/US4549262A/
https://patents.google.com/patent/US4649474A/

Sorry to read that!

Many thanks for all the work you've done!

André

Actually the stumbling block mostly was real life problems, most of them job related.
My mistake, I fixed this.

André, thanks for the kind words.

Hello 0010 all,
I wouldn't call it a failure, it's just about setting (your) priorities,
and in what state would the world be without them ?

Publishing results in this thread might encourage others to pick up and carry on.

Hello Louis,
Trying to continue would send me into burnout, I'm familiar with the warning signs.
Need to do something different from chip dissections for a while.
Over the years I always published everything: the successes and the failures.
Should be standard, because it might help other people's projects.

If you have to take a rest, take a rest!

Garth, thanks for the kind words.
This really helps.