
6502 transistor level hardware simulation in JavaScript - dgellow
http://www.visual6502.org/JSSim/expert.html
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userbinator
It's a few years old now, but still quite interesting to play with. The CPU
itself is only 3.5K transistors but already looks amazingly complex until you
visualise how it's broken down into individual, mostly independent modules:

[http://forum.6502.org/viewtopic.php?t=2208&f=8](http://forum.6502.org/viewtopic.php?t=2208&f=8)

[http://breaknes.com/](http://breaknes.com/)

(The Russians seem to have a fondness for detailed IC reverse-engineering.
There's a lot of Russian-only information on the internals of the 6502, 8080,
8085, Z80, etc.)

~~~
newman8r
there's some interesting tech-related wikipedia pages which are more detailed
and useful in the russian version (easily translated of course)

~~~
SpaceRaccoon
Examples?

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jacquesm
[https://news.ycombinator.com/from?site=visual6502.org](https://news.ycombinator.com/from?site=visual6502.org)

This has to be some kind of record for re-submissions.

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zaxomi
And then there is a dis-integrated version, with a lot of LEDs that show how
the chip works internally: [http://monster6502.com/](http://monster6502.com/)

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dgellow
GitHub repository:
[https://github.com/trebonian/visual6502](https://github.com/trebonian/visual6502)

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jhallenworld
An interesting type of logic is DEC DTL "flip chip" technology, use in the
original PDP-8. It uses all PNP bipolar transistors.

It's always interesting how they make flip-flops. In this case, the slave side
is the typical latch made out of cross-connected inverters. The master side
uses a diode-capacitor-diode gate. A capacitor follows the input signal. A
pulse on the clock line transfers the charge to the slave latch.

[http://bitsavers.trailing-
edge.com/pdf/dec/handbooks/Digital...](http://bitsavers.trailing-
edge.com/pdf/dec/handbooks/Digital_Logic_Handbook_1967.pdf)

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aphextron
There's also an ARM1 version, which is even cooler IMO
[http://visual6502.org/sim/varm/armgl.html](http://visual6502.org/sim/varm/armgl.html)

[http://www.righto.com/2015/12/reverse-engineering-
arm1-ances...](http://www.righto.com/2015/12/reverse-engineering-
arm1-ancestor-of.html)

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pvg
It's a bit of an evergreen without much in the way of comments.

[https://hn.algolia.com/?query=Visual6502.org&sort=byDate&dat...](https://hn.algolia.com/?query=Visual6502.org&sort=byDate&dateRange=all&type=story&storyText=false&prefix&page=0)

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jakobdabo
Any lawyers here? Are the architectures of those old microprocessors like 6502
or 8051 copyright/patent-free by now?

Can one create a commercial game where the players should reverse engineer
programs for some virtual hardware which have, for example, a virtual 6502 on
board?

~~~
duskwuff
Totally free and clear.

Copyright on maskworks -- that is, microchip designs -- only lasts 10 years.
(It's covered by a unique and unusual portion of copyright law, as microchip
designs aren't considered creative enough to be covered by a traditional
copyright.) In any event, this would only have covered the physical design of
the 6502, not its architecture.

The 6502 was released in 1975, so any patents on its architecture would have
expired in the mid-1990s. I'm not certain that any such patents existed in the
first place -- the 6502 is largely inspired by the Motorola 6800, which was
even older.

Anyways, the architecture of the 6502 is effectively in the public domain at
this point. There are probably thousands of different hardware and software
reimplementations at this point; including one in a game would not be a
problem at all.

~~~
jakobdabo
Thank you (and others who answered). So, no copyright, no patents, and I
forgot to ask about trademarks, but I think I can do without naming things for
what they are if I ever go for my idea of that game.

~~~
duskwuff
As a number, "6502" was never trademarkable, and what was left of the original
manufacturer (MOS) was liquidated in 2001. So there's no trademark rights
either.

~~~
vidarh
Keep in mind that Western Design Centre also has/had rights to the 6502, and
they're still selling variations, so the fact that MOS was liquidated doesn't
necessarily mean much.

But presumably you're right in terms of ability to trademark it anyway.

~~~
tinus_hn
You can't trademark a number as Intel found with the 80486, which is why they
went with the 'Pentium' name instead of with 80586 for the next release.

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newman8r
this chip could cause pacman fever (pre RoHS)

