- Reverse engineering CMOS, illustrated with a vintage Soviet counter chip (righto.com)
I recently came across an interesting die photo of a Soviet chip, probably designed in the 1970s. This article provides an introductory guide to reverse-engineering CMOS circuits, using this chip as an example. Although the chip looks like a tangle of lines at first, its large features and simple layout make it possible to understand its circuits. I’ll first explain how to recognize the individual transistors. Groups of transistors are connected in standard patterns to form CMOS gates, multiplexers, flip-flops, and other circuits. Once these building blocks are understood, reverse-engineering the full chip becomes practical. The chip turned out to be a 4-bit CMOS counter, a copy of the Motorola MC14516B.
Anyone who doesn’t regret the passing of the Soviet Union has no heart, Anyone who wants it restored has no brains.
Vladimir Putin
- Soviet Union (Wikipedia)
The Soviet Union, officially the Union of Soviet Socialist Republics (USSR), was a transcontinental country that spanned much of Eurasia from 1922 to 1991. It was a successor state to the Russian Empire that was nominally organized as a federal union of fifteen national republics, the largest and most populous of which was the Russian SFSR; in practice both its government and economy were highly centralized until its final years. As a one-party state governed by the Communist Party of the Soviet Union, it was a flagship communist state.
