Sunday, September 19, 2010

Visual 6502 Processor Simulation

Greg James, Barry Silverman and Brian Silverman from have been working for the last year on a transistor-level visual simulation of the 6502 microprocessor.  Their work is incredibly detailed and very interesting.  The 6502 design is a classic processor, and very important in computer history as it was used in the Apple I & II, Commodore, Atari and Nintendo computing systems.

In the summer of 2009, working from a single 6502, we exposed the silicon die, photographed its surface at high resolution and also photographed its substrate.  Using these two highly detailed aligned photographs, we created vector polygon models of each of the chip's physical components - about 20,000 of them in total for the 6502.  These components form circuits in a few simple ways according to how they contact each other, so by intersecting our polygons, we were able to create a complete digital model and transistor-level simulation of the chip.