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Reverse-engineering of KR580VM80A / i8080 is complete (zeptobars.ru)
92 points by xai3luGi on Feb 2, 2015 | hide | past | favorite | 12 comments



I can find the +5v, +12v, and ground connections, but the 8080 is supposed to have a -5v supply which doesn't appear in the schematic.

It's interesting that Russians originally reverse-engineered the Intel 8080 to produce this chip, and now it appears another Russian has reverse-engineered the clone.


The -5v goes to the substrate (the bulk silicon underneath all the transistors) in order to increase the threshold voltage of the NMOS devices. Many later chips dispensed with this because they were able to tune the process to get acceptable speed without it.


They should have left a message like this, just in case: http://micro.magnet.fsu.edu/creatures/pages/russians.html


I wonder how much it costs to do one of these jobs.

I grew up with the Tandy Color Computer 3, which was a fantastic machine, but it is to this day still hampered somewhat in development by the fact that the "GIME" chip that serves as the main video/sound/everything controller was a shamefully ill-documented custom job which to this day still hasn't been fully unraveled.

Ever since the first one of these popped up on HN, I've been curious about whether that might at least help get a bit further in deconstructing the thing.


Depends heavily on the package, the process and the complexity/scale. Really old processes and easily-opened packages can be done by hobbyists for pocket change (opened with a vice/brute force or easily-purchasable chemicals; examined with optical microscopes, you can get fancy USB ones for three figures secondhand?).

Modern stuff absolutely needs high-end professional-grade labs, SEMs/TEMs, polishers, all that stuff - and that will likely run you five, six or seven figures. And then there's the analysis phase! It takes a significant amount of time either way, it just depends how much the time (and equipment) will cost!

Since you're going for something pretty old, however, it may not be beyond your grasp. Have some spares handy, though! There was a good talk at 31c3 about decapping preparation on a budget, which may get you started: https://youtu.be/RlQJHymiudc


Most of these projects I've seen done by hand, visual inspection. Is there anything that helps with automatic analysis? A sort of OCR for transistors?


http://www.degate.org/

There is also numerous proprietary/non-public tools. For example ChipWorks has some advanced software.


All this was done at no cost at the spare time by guys interested in retro computers.

All chip decapsulation/microphotography work took ~10 hours, vectorizing layers and making actual schematic/verilog took about 1000 hours.


Can somebody provide any insight about how this was accomplished?


You could read this forum (if you can read russian or ok with automatic translation) http://zx-pk.ru/showthread.php?t=23349&page=4#postmenu_71167...



Very nice - thank you.




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