Gas station without pumps

2011 January 16

Visual 6502 in JavaScript

Filed under: Uncategorized — gasstationwithoutpumps @ 20:10
Tags: , , ,

There is now a hardware simulator for the 6502 processor written in JavaScript with a beautiful visual display. It would have been nice if they had been able to do a bit better simulation, to include some timing information (like the rsim simulator we used back at about the time that chips like that were being designed). Seeing this brought back some fond memories of my days teaching VLSI design, though I think I’m now happier teaching bioinformatics (and I’m certainly no longer current in VLSI design).  The 6502 was a fine processor at the time, and Motorola produced much more elegant chip masks than Intel did.  The 6502 was designed by an engineer from Motorola who had worked on the 6800, but Motorola did not want to sell a low-price chip, so the engineers left for their own company.  The 6502 is probably best known now for its use in the Apple I, Commodore PET, and Apple II computers.

This is the image of the 6502 that is animated on the Visual 6502 website.


  1. Thanks for the pointer to rsim: it’s interesting, but looks like it’s nearly a decade later than the original 6502 design. Peter Monta has done interesting work with the netlist (re)created for the visual6502 – it’s more like rsim, but presently doesn’t use information about transistor sizes. His project is on github.

    Comment by EdS — 2011 January 18 @ 12:23 | Reply

  2. Yes, rsim was later than the 6502, but it was a surprisingly accurate timing simulator for MOS circuits.

    Comment by gasstationwithoutpumps — 2011 January 18 @ 14:09 | Reply

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