The Game and Watch was a series of single-title games consoles created by Nintendo from 1980 until 1991. Each machine contained a custom LCD screen (containing images related to the software), some sort of ROM (containing the two games and the clock) and... that's about all I could find.

Because each Game and Watch title was different and I don't know to what extent, I'm only asking about the original Game and Watch: "Ball". What was the hardware layout of the main board in this machine, and which components were used?

  • This question reminded me of a watch game we played as kids where you had to shoot little flying saucers out of the sky. Some googling and I was able to identify 1981's Nelsonic Space Attacker here: polygon.com/a/smartwatch-history-guide-evolution/watch-timeline the Nintendo Game and Watch series is also mentioned but only some historical information.
    – Geo...
    Commented Oct 26, 2016 at 16:08
  • There is a walkthrough of someone gutting and cleaning a Donkey Kong G&W here. Just ignore the fact that they cleaned off Miyamoto's signature from the case...
    – JAL
    Commented Oct 26, 2016 at 16:13
  • @JAL No! :-O I'm sorry, but I couldn't ignore it... :'-| I think somebody could make a bit of a circuit diagram from the images, if they already knew what they were looking for. Unfortunately Donkey Kong is a folding game with a D-pad though, so it doesn't answer this specific question. Do you think I should generalise it more?
    – wizzwizz4
    Commented Oct 26, 2016 at 16:33
  • I think this question is perfectly fine the way it is. We would just need someone to take a picture or make a diagram of the Ball internals. I haven't found anything online yet but I'll keep looking.
    – JAL
    Commented Oct 26, 2016 at 16:42
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3 Answers 3


I was involved with hardware remakes / clones of a few machines and we did reverse engineer one G&W game; I think it was Green House, if I remember well.

The games are build around a custom ASIC and the rest of the circuitry is essentially support for it.

As a side note, if you've ever opened a G&W game double screen game, you'll have noticed that the main chip is sitting 45° from the main board and this was done because at the time the boards were soldered through a wave soldering machine and it allows all the pins to be properly soldered without bridges between them.

Let me tell you how they work but be prepared that it will totally kill the magic:

The whole game is essentially a polynomial generator and a few shift registers.

The polynomial unit will generate the same bit stream every single time it is started. Its output is fed to a de-multiplexer and each output feeds a shift register. Each bit in these registers is tied to an element in the LCD.

All motion done by the player is also mapped in a shift register and then a simple hardwired AND determines collisions. Possible actions in a given state are encoded in a matrix and the logic can swap bits at specific positions.

The game gets faster and faster by just changing the clock (which is essentially gated by another shift register).

Now with this information in mind, play the games again and you'll be able to see the logic at work where the player is essentially always on a long bit string and that when the objects become faster, so does the player input, etc.

We didn't reverse other games, but I see no reason why they'd have a different hardware since only one small matrix on top of that system can make a different game; Zelda is different, but it came years after the rest and I have no clue how it is made.

There is a bit more logic to it, but that's essentially it; some of the logic is to drive the screen; I don't remember the reason but I was explained that LCD screens from that era needed the segments to be toggled on / off to prevent some damage, apparently it's the same in watches; if anyone worked with that technology, I'd be happy to understand the details.

The hardware is tiny and could be re-implemented in a FPGA in an afternoon, but it was really clever since there is no CPU involved; It would be trivial to recreate the ASIC in software as well with very little code where each game is a different table.

  • NES, Arari, and now G&W: is there any retro gaming tech you haven't worked on?? Great post.
    – JAL
    Commented Dec 11, 2016 at 0:43
  • 3
    I've been doing games professionally for 27 years and spent 5 years before as a hobby when I was a teen; also, I owned part of a studio for a few years and also part of a company designing electronics; although I worked on some major brands, I got really tired of this industry and I'm doing totally different stuff right now; interestingly, I see that most of the people that have been in it long have eventually left too.
    – Thomas
    Commented Dec 11, 2016 at 13:42
  • W.R.T. an explanation of the display toggling, assuming that the LCD used were Twisted Nematics, which I am hoping to get verified by my question Which LCD technology was used in Game and Watch?, then the reason is given by the answer to Do Twisted Nematic LCD need refresh (polarity reversal)? Commented Dec 27, 2016 at 2:05

It seems that they used the same circuitry (and processor) that were used for some calculators at the time. There was a limitation on the number of objects that could be displayed imposed by the hardware, that is related to the number of different digits that the original design could display (when used as a calculator).

It seems to be also that G&W games started their life as prototypes, with screens made of lamps located under a painted paper or something in order to simulate the way an LCD screen works.

There was an "Iwata Asks" Q&A article discussing all this stuff (link goes to an archived version). That was linked from this Kotaku article.

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    The archived link doesn´t show anything. Just a blank page. Commented Nov 2, 2016 at 12:07

The processors used by Nintendo Game & Watch, are Sharp SM510 or SM511 microcontroller with embedded ROM, that are indeed used also in some calculator. MAME emulates all the Game & Watch (a lot of them) of which ROM program has been extracted. Further reference: Emulation General or MAME emulator handheld source code

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