[sdiy] Odp: Re: Analysis of the TB-303 CPU timing

[rsdio at audiobanshee.com]

The ‘bars’ in that chip mask are wires, but you can’t necessarily read bits by deciphering their lengths. You’d need a legend to identify the different layers.

Chips are grown on a silicon substrate, with chemical doping that burrows down into that substrate to create p+ and n- type regions that make up transistors, diodes, gates, et cetera. On top of that, metal layers are grown with insulators between the layers, and these make the contacts between different transistors or gates. The mask ROM has address decoding and connections to all of the bit cells, just like a microscopic printed circuit board, but I doubt that the contents of the bit cells are visibly readable in any reliable way.

Brian Willoughby


On Mar 17, 2017, at 11:07 AM, Tony Kalomiris <weplar at gmail.com> wrote:
> p.s. I had a look at the ROM area mask of that link, and counted 128 x 128 (2K x 8). Question, can some semiconductor physicist here explain please the short and longer 'bars', I am trying to make sense of the 1's and 0's, to map this out. Besides being a work of art, it's highly meditative, especially while listening to Aphex' SAW Vol.II ;) Yes I am a masochist, I read out the SH-101 bit by bit before I wired something up to do it automatically.
>