Nintendo (NES) Controller - Electronics

An examination of the electronics - the 8-bit shift register and signals as well as a few bits of trivia for the NES controller.
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Music by: Wolf and Raven
#NES #Controller #Electronics

[@JamieBainbridge]

Absolutely beautiful. Some of us learn the theory and code a microcontroller to use a real controller. You attack the same problem from the entire other direction and make an entire pretend controller to interact with a real console, then view it on a scope. Not having either an oscilloscope or the experience to use one, this sort of low-level investigation was thoroughly enjoyable. Well done and thanks as always for your videos!

[@r.g.thesecond]

This channel is a goldmine for homebrew noobs (like me). Thank you for your unapologetic deep dives!

[@Cab895]

this blew my mind. How can someone be so thorough explaining something, yet at the same time make it so easy to digest.

[@antivanti]

Fun fact. UK/EU (except Scandinavia) PAL NES systems has a bunch diodes in the ports and controllers to make them only compatible with these controllers. The other way around works fine however. I learned this the hard way when I imported an RGB modded NES from England and it didn't work with my Swedish controllers and ended up having to modify the controller ports. The reason Scandinavian NES uses the same non-region locked controllers as the US is because before Nintendo themselves launched the NES in Europe a Swedish company Bergsala got an exclusive import deal for Scandinavia. Not sure exactly why the controllers were region locked in the rest of Europe but I suspect that the partner Nintendo worked with didn't want their customers buying controllers sold via Bergsala or something. I think Mattel was the initial producer of European NES before Nintendo eventually took it inhouse. Bergsala btw still has that Scandinavian distribution exclusivity for Nintendo products. A deal that was sealed via the gift of a crystal ashtray btw 😊

[@SdudyoyO]

Makes you appreciate the engineers who built these sorts of devices in the first place. Don't get me wrong, breaking this stuff down in an easy to digest way is complicated, but imagine having to design a controller before one existed. I think we take for granted just how complicated our every day devices are.

[@KuraIthys]

Well, game machine designers had an advantage here, because the kind of things they built existed in industrial control systems long before game systems. Joystick-like devices were developed hand in hand with aircraft. And while those were mechanical... Electrical switches also existed since electricity became mainstream. And well, not to be too blunt about it, but you know what an Atari 2600 controller looks like on the inside? Yeah, it's literally just a set of switches connected between wires that run to the console itself. It's about as basic as wiring a switch directly to a microcontroller at that point. This might've been novel in relation to it's use in gaming, but it was something that was in widespread use in electrical devices for decades by that point. The mechanical design of stuff like a D-pad is a lot more interesting overall. And more complex designs of course, yes, they did get pretty clever, but they had the older designs as a reference. (and many companies literally copied atari - right down to the connector used. - the various systems could all use the exact same controllers. You can even still attach a Mega Drive controller to an Atari 2600 and it mostly still works) Plus, a shift register is a very common component with a well understood purpose. (it converts parallel data to serial data and vice versa). These designs are very clever, don't get me wrong. But from an electrical engineering point of view they are extremely trivial. (the design of the plastic casing, d-pads, exact feel of the buttons and so on is actually considerably more challenging.)

[@twn5858]

Just a bunch of switches. Doesn't seem like it should be that complicated.

[@Nordlicht05]

@@twn5858 Happens to me often at work... Why haven't you see this it's obvious... Yes now in this moment it's also obvious for me. But last week. Why didn anyone say a word... Yes!

[@amiga_arcade_project]

@@twn5858 The should have just used a 1-1 connector switch and skipped all the latch-data crap ( i.e. polling every 4 frames for 4 players causing serious lag )

[@DiThi]

I bet they started by wiring the buttons directly to the CPU, then ran out of IO pins so they added the shift register to the motherboard, to then realize they can move the shift register to the controller to use half as many wires. If they wanted to reduce the 4 player lag they could have used 2 or 4 IO pins instead of one.

[@RustoKomuska]

just recently started learning electronics in college, cool to recognise the stuff ive learned in class while screwing around on youtube

[@etansivad]

As someone who just bought his first breadboard this week, this video was really helpful in understanding the fundamentals with a controller I grew up using :D

[@stillrabit73]

Biggest thing I will urge any new electrical hobbyist / maker to learn (beyond basic components) is multiplexers, opamps, and shift registers. You can make so much cool shit with just those three things and complementary components of course.

[@halonothing1]

Welcome to the world of electronics. I just got into it myself a couple of years ago. Two sites I'd strongly recommend checking out are Circuitmod on Paul Falstad's site, which is a great circuit simulator that really helps to visualize what's happening in a circuit, as well as helps to design and understand simple circuits. It has some great examples of fundamental circuits, both digital and analog. The other is the textbook section of allaboutcircuits.com It's laid out in order of what you should start with, going through DC, AC semiconductors and digital circuits in many detailed, but easy to understand chapters. Both sites were instrumental in helping me to get where I am today in terms of my knowledge, though I had many other resources to help me. These are just the two main ones. As a bonus, I'll also recommend checking out a program called Logisim. It's another circuit simulator, but it focuses purely on digital circuits. It's flexible enough that you could design and simulate a full computer within it. In terms of advice, the most important thing I can tell you is don't rush the learning process. And don't shy away from the math. I can't overstate how important math is for this. A lot of people are scared of it, but I found in the context of a practical application, it's not nearly as painful as it was to learn math in school. But enjoy the journey, and don't worry too much about the destination. There is a ton of stuff to learn in electronics. College students don't even get into transistors until 2nd year. So just try to take your time so you don't end up with any gaps in your knowledge. It's better to spend a few days or weeks making sure you learn something proper than to spend years being hindered by a gap in your knowledge. There's no harm in jumping ahead if you're curious about something, but take care not to get distracted and forget about the fundamentals. So many times I've tried to jump ahead, only to find I need to know about half a dozen other things if I want to have any understanding of whatever I jumped ahead to. And don't be put off by failure. Failure is what helps us learn more than anything else. Cheers. And happy learning. :)

[@vasili1207]

@@stillrabit73 ok i will take that on board.... how much more intrest did you get when you switched banks? 😊👐

[@stefanegger]

what is a breadboard ? He talks about NES console

[@Hamster07]

this was so well made you made me think i knew what you were talking about

[@JuanesChiwirosky]

It Would be So cool if you can make a similar video about the N64 controller, since I was a child I was impressed with the fact that its connection only uses 3 pins.. Also thanks for sharing all this information and for making it as easy to understand as possible

[@Kippykip]

I thought I was the only one that thought the NES pins didn't make sense with the amount of buttons on there. This makes way more sense now

[@benjaminbrady2385]

I just found this channel and I just needed to say how amazing it is!!

[@fintux]

I always wondered as a kid how the controller worked as there were less pins than there were buttons, and considered also that even if the d-pad only had one position, it would take three bits (none, up, left, down, right), so it didn't explain. So I figured there must be something smarter there, but I never dug out what it was... But now I know. I liked the style of the video: it explains everything from the ground up, but still progresses quickly enough even for somebody that already knows at least the basic concepts. Maybe a video on the Zapper at some point? :)

[@danieljimenez1989]

It's important to note that the latch pulse doesn't just mean 'gimme the sate of A'. The timing of the latch pulse defines the sample time for all buttons, the latch pulse says 'capture the state of all buttons right now and output A in the data pin'. The clock pulses then shift the output to the next button, but these clock pulses don't define when the buttons are sampled. Many snes games clock out slower than nes games did, because of the use of a hardware feature that automatically reads controllers, so they are 'more laggy' in that sense.

[@DisplacedGamers]

"Let's go. Gimme A" was a slang way to say that the NES latch-signals the moment in time to take a snapshot of the pressed buttons as soon as the register hits parallel mode, and the register immediately starts outputting the state of "A" to the NES. This is always the first button the NES is expecting. I mentioned it signaling a capture like a "snapshot" or a "photo" of the buttons states during the PCB section of the explanation, I believe. I suppose I could have mentioned it again in the scope section. I just wanted a bit of slang to help take away from the complexity of the scope. :) Appreciate you dropping the word about the slower clock out on the SNES, Daniel! I'd like to examine the SNES in a bit more detail in a future video. Always welcome your feedback!

[@danieljimenez1989]

@@DisplacedGamers To be clear, I think this video (and all of your others) are pretty good. The explanation was ok, but I thought I'd made sure to note that, just because there may be some confusion as to when things happen, exactly. Cheers.

[@sa3270]

I noticed on the oscilloscope it showed 8 shift pulses following the latch pulse. So am I right that the 8th shift pulse was not necessary? I suppose it's just the way the software loop was written.

[@livefreeprintguns]

I've only been a subscriber for about a week now, but my god the amount of appreciation that I took for granted as a child in regards to televisions, consoles and how to interface them (ie: RF modulators, RCA cables, etc...) grows exponentially with each video of yours I watch. Truly next-level amazing stuff my dude!

[@dsuess]

Damn, i tip my hat to those engineers who made the system. That's badass! Thank you for exploring this breakdown, as the pint glass is raised to you

[@colestunden7572]

New favorite channel! Love the topics you cover like sound preservation or the history/explanation of television signals. On a binge now. This channel deserves more eyes from the gaming community. I found the channel on a algorythm reccommendation, hope others do too.

[@DisplacedGamers]

Thanks, Cole!

[@malik641]

This content is incredibly high quality. Amazing. Great work! I look forward to watching more from your channel.

[@Komagb]

This is the most in-depth analysis of the NES controller I've ever seen. Kudos!

[@null_state]

Awesome channel. A lot is over my head, I admit, but I love how professionally done your videos are, and the retro 80s music keeps me glued as well!

[@iCach0]

Amazing! You do a great job at explaining technical stuff in a way that anyone can understand and find interesting.

[@DisplacedGamers]

Thanks!

[@Sinn0100]

Fascinating!

[@twoodall88]

Well said all around! I really like the visual aid of the scope.

[@doge-of-venice]

Very well-made and informative video. Keep up the good work.

[@sickregret]

Your videos are the most indepth and detailed gaming videos on here. You deserve a million subs!

[@danielturner1891]

Wow! This video is incredible. I’ve learned so much in just one video. I feel like everything should have just flown over my head, but I was able to grasp a lot more than I’d expect due to the excellent teaching leaving in even what feels like some of the more basic information so someone like me can “catch up”. Subscribed.

[@ahobimo732]

This is one hell of an awesome video. It takes a complicated subject and explains it with perfect clarity, at the level of a total beginner. Everything is explained so rigorously and logically. This is high quality education.

[@dlang6487]

I love your videos! Keep the great content coming!

[@CAHSR2020]

Enjoyed the content and was able to keep up despite no electronics background. Well done. 👍

[@killyouwithfire]

Gotta love the 80’s music XD

[@JBiggsNewJersey]

Wow this is great! Excellent presentation and speaking. I was just searching for this specific subject but subbed for whatever you post

[@OlujaDoTokija]

KZbin recommended some of your videos yesterday and I'm not going to lie. I have been subbed and watching your videos since then.

[@FLUFFSQUEAKER]

Beautiful in-depth, but easy to understand explaination!

[@aceoft3482]

Thank you for the very clear explanation! Fascinating stuff.

[@bearmatic]

This channel is a hidden gem. So glad it popped up as a suggestion after watching some Adrian Black's Basement. Your approach is thourough, yet light! So many topics I thought: "I've seen this kins of video before elsewhere, why should I bother?" just to be drawn in, marvel at the detail, listening to your crystal clear means of explanations and understanding most of it! So good. You're highly undersubbed!

[@Mr76Pontiac]

This video is almost a year old to where I'm watching it, but, it made me giddy watching it, and I feel the need to learn more about how this style of electronics work. I was always mystified to how multi-button controllers could work with so few wires coming out (Before the advent of USB, that is). Awesome video. Thanks.

[@RestoreTechnique]

This is awesome, thanks!

[@PhantomLord24]

Very good info, thanks 👍🏻

[@Ryan-bn6kq]

Your channel is awesome, dude!

[@erniesdeck7550]

I'm a new subscriber to your channel. I've been looking for a while for a channel just like this where things get explained on a technical level. I've been taking electronics apart since my parents VCR when I was 10. So I know my way. I'm happy I found this channel keep up the great videos.

[@eburgos021]

Thank's for making the wiring easy to understand ! great help. Mr.G

[@WalrusFPGA]

Thanks; I learned a lot from this video. Well-explained and great visual presentation for the information shared. Can't ask for more than that!

[@volo870]

Wow! This is the longest and most detailed tutorial to shift registers on KZbin. I'd say you may recommend it to tinkerers, who are not even gamers.

[@KryptekDragon]

Your videos are amazing. Thank you

[@RobertoLicardie]

Amazing content as always

[@cosmicrdt]

Would love to see more videos with electronics. Great stuff 👍

[@FagnerLuan]

Fantastic video! Congrats

[@YNGBLD80]

Love your content dude you're one very smart cat!, keep educating the masses with 8bit goodness

[@komemiute]

Wowza! Fantastic writing!

[@GregStrike]

What an awesome explanation man, thank you! Some good information for my next video!

[@AndrewChalkley]

This is a great explanation for an enthusiast like me who knows enough but not how to decipher circuit diagrams.

[@carlwillows]

Amazing detail

[@lennonmclean]

Fun fact: the other two pins on the controller port are used for the zapper gun. One is for the trigger and the other is for the light sensor.

[@Komagb]

Fantastic deep dive!

[@jn_gutierrez]

Your channel is something my subconscious had been craving for quite a while. Congratulations and keep up the amazing work.

[@DisplacedGamers]

Thanks!

[@Riley_MDS]

So, After LGR, and other channel that cover up this type of content ( I forgot the channel name ), your video got into my Recommendation.. Finally I can watch more content like this while doing my Fanmade project.. Thanks for making me stay up and not get bored :3

[@R3TR0R4V3]

Great video! Glad to learn something new. 👍👍

[@belfrog]

Really great video!

[@cyntwix]

Hey really great video! I took a class in college where I had to interface an NES controller to an FPGA. I was responsible for generating the clock and latch signals as well as receiving the data signal, processing it, and using it to interface with a computer. It's been a few years now and your video was a perfect refresher for what I had to figure out myself back then. If your video was out at the time, it would've made the project so much easier! great job

[@SamuelCarrier]

Amazing stuff. Perfect channel for thinkering retro gamers!

[@ranger81de]

Awesome explanation! Thanks!

[@GustavoValdiviesso]

Great video. Very instructive!

[@iwir3d]

This was either the 3rd or 4th video I have seen from this channel. The quality of your videos seems to be impressive so I went ahead and subscribed. Keep up the great work, I really enjoyed watching these videos.

[@DisplacedGamers]

Thanks!

[@Megarushing]

Another incredibly interesting video! So much to learn from the devices that lived in our childhood

[@OptimusNiaa]

Very good stuff. Just found your channel yesterday. New subscriber.

[@tahustvedt]

Fantastic video!

[@theseriousaccount]

Best vid on this subject

[@Michirin9801]

How have I only just found this channel? It's awesome! I'm subscribing now!

[@DisplacedGamers]

Thanks, Michirin!

[@Pedritox0953]

Very complete explanation

[@bengineer8]

I am designing my own controller so this will be a massive help!

[@licksorestockpile1190]

really like the hardware stuff!

[@GilbertTang]

Magnificent. I continue to devour your channel.

[@TBL_stevennelson]

I learnt so much. Mind blown. Thanks

[@NeoCortex3]

Who would think controller could be that interesting. Loved it.

[@opelman5173]

Awesome. I've learned a lot.

[@geckoo9190]

this reminds me when i was a kid and tried to design my own joystick with some arcade spare parts, everything was going well until I reached that integrated circuit, years latter I made some experimental snes joysticks, i made one with a globe, one with a cardboard box and one with a sponge, the last one was very sensitive, one of the best joysticks that i ever had

[@MyLittleWalrus]

This video and the Luma video are really well done. I'd love to see more like this.

[@DisplacedGamers]

Thanks! I have one in the works...

[@MyLittleWalrus]

[eyes emoji intensifies]

[@SleepingCocoon]

ha, i remember the original release of Rockman 4 MI (fantastic hack!) had the DPCM bug, i had no clue what the hell was going on until a new hardware compatible build was rolled out again, incredible work on the videos

[@GenerationalGamer]

Excellent video. You provided a lot of information and in a way that the layman can understand.

[@DisplacedGamers]

Thanks!

[@GenerationalGamer]

@@DisplacedGamers It was very well done as are the others.

[@jessewilcox7475]

Hey bro I've watched a few of your videos now and they're all really well done. I wanted to encourage you to keep making videos, and suggest you put a few more out there. You're a little bit older than me but I was playing DOS games from the time I was a young child, so I really appreciate not only your expertise but your perspective. I was super stoked to see a video on Jill of the Jungle! I think you should do more opinion/retrospective content about what makes old games continually compelling, maybe touch on how the technical limits affected developer creativity in producing such a diverse range of games as was enjoyed in that era. Your videos on dithering were outstanding in giving a glimpse into this, and in general I think your videos stand out relative to other KZbinrs on the topic, my only complaint being that most of your videos are too short and there's not enough of them. I'd really strongly encourage you to make more videos and a couple of deep dives into gaming history sometime. I'm sure this is easier said than done in terms of time, but I felt compelled to say I think your videos are not only really informative but really engaging. You're able to present the content really well too, and it's very endearing to see such an authentic passion for this era of gaming presented by an authentic person. I was pretty surprised to find out after I watched the first video of yours I saw that this channel wasn't huge. It's great stuff man, keep it up.

[@supasimon]

You are massively under-subbed my friend. Awesome video quality!

[@BambooShadow]

Amazing!

[@AndyGoth111]

6:30 It's possible to read the controller any number of times per video frame. For example, check out the pause feature in Dragon Warrior. Whenever Start is pressed, the game goes into a tight spin reading the controller as fast as it can until Start is pressed again. During this time the game does almost nothing else. The important exception is its common read-controller routine also increments the global random number generator each time. Thus, with sub-frame accurate timing, it becomes possible to use Start to continuously manipulate RNG without the game ever visibly pausing.

[@Oyocat]

Anyone else have no idea what hes talking about but is listening intently anyway? Listening to someone know what they're doing feels so relaxing for some reason.

[@Eddies_Bra-att-ha-grejer]

17:05 The Scandinavian NES was actually different from the continental European one, in that it did accept NTSC controllers. The Scandinavian SNES also used the same DC connector as the Super Famicom, while the continental one had a slightly thinner one.

[@TheKrensada]

Thanks to this video, I can make a nintendo controller that fits my big hands.

[@Rebateman]

And to think these came from the same species that drew on rocks...

[@AsilarWindsailor]

Nicely done! I think this explanation might even be better than the one given by The 8-Bit Guy

[@Zeldagamer9000]

Dang! Where was this video a year ago when I was building my own custom controller? This will be incredibly helpful with finishing that project!

[@chadwolf3840]

great stuff.

[@redseagaming7832]

what's astonishing is that the the Nintendo Entertainment System or at least a time were patching a console was impossible so they had to make sure this console worked when they released it to the stores something I can really respect Nintendo for

[@shinypb]

Great video; thanks for making it! This finally made shift registers click for me.

[@DisplacedGamers]

Awesome! Happy to hear it!

[@tomyyoung2624]

YesGraal

[@KuraIthys]

Ah, The good old atari joystick port. As used by Atari, Commodore, Sega and a ton of other companies... Sometimes with incompatibilities, and later on with very strange workarounds... I'm most familiar with it on the 800XL... Where it has so many functions mapped to the same pins it's kinda crazy. The basics are obvious enough; 5 'buttons', ground, an unconnected pin (technically held at +5 volts), and two analogue input pins. The buttons map to the standard controller, and the analogue pins are used for the paddles... But also for a mouse, if you use one (never officially had one, but you can use both Amiga and Atari ST mice with the system if you do the programming correctly), and the atari drawing tablet. You can also use the analogue pins as extra buttons if you build a controller a certain way and program the software the right way. So, is that everything? Actually, no it isn't. See, the 4 'button' pins that the joystick directions map to are technically a serial port. If you write to appropriate registers you can set the communications direction. By default they're all set as input pins (understandable), but you can also write to them and use them as outputs. And thus we got things like an electronics lab, a modem, and an 80 column text display device that all connected to the controller ports. This observation also means you can, with some basic conversion circuitry, wire up an NES or SNES controller and communicate with it properly as long as you write a custom program to do so. The NES approach is certainly interesting though. It's very flexible but also quite expandable, and uses quite simple circuitry (shift registers are very basic generic parts) The proof of this is that the SNES is electrically compatible with the NES, and the SNES contains internal logic to read controllers the way the NES does. The SNES controller simply has a larger shift register, hence more buttons. The Sega Master system (and turbographx in fact - which uses the same circuitry) as well as the 3 button mega drive controller also use a fairly simple bit of circuitry - a multiplexer chip, which takes an input line and a set of output lines to 'select' which set of buttons you can read at once. This is a fairly clever solution, but it doesn't scale easily with simple circuitry. Hence the 6 button Mega Drive controller contains a microprocessor and some fairly complicated timing logic to give the extra buttons without adding more lines to the connector... The SNES meanwhile would really only have to change the controller access programming to increase the buttons even further. (also there's a FLASH memory storage device that attaches to controller port 2. RPG maker uses it to let you save your work on something other than the RPG maker cartridge.)

[@MissNorington]

Awesome!

[@shadymaint1]

I built an arcade stick for my NES. Even has turbo. Wish I had one when I was a kid.

[@tastymonkey]

I still have my NES Advantage and SNES Advantage controllers.

[@john-tk2dn]

Funny. I am working on the same project. However I am running into an issue. Every 6 seconds, the nintendo will not recieve any inputs, then it will work for 6 seconds, and then not again for another 6. Kinda stumped

[@shadymaint1]

@@john-tk2dn sounds like a clock timing issue. Are you DIYing the circuitry or robbing parts from a controller. If your DIYing your shift register may be wrong. I took the guts out of a old turbo controller . Tapped into the ground plane and to each button. Was cheaper to go that route as opposed to building one. Controller only cost a couple bucks on eBay. Plus you get a cord.

[@john-tk2dn]

@@shadymaint1 HA! i literally just came to post that yah, somehow i had one of my grounds connected to the clock pin LOL Not using breadboard, just using some prototyping board. And im well aware I can just tap into an existing board, but wanted to build from the ground up. I actually bout some of those really crappy controllers just for the cord and the connector :) Im just laying everything out and gonna have a custom PCB printed so i dont have to use jumper wires and have actual traces. Its just been a fun project :)

[@shadymaint1]

@@john-tk2dn right on man.

[@alejmc]

This is incredibly fascinating. As an BSEE myself, I wish we would have done a deep dive on video game gadgets and electronics just like you just did, we didn’t do that at all... would have been a great way to motivate the crowd. Electronics Engineering in my time at least had a very high percentage of flunked or, in the worst case, expelled students. A sad sight.

[@ImperatorScab]

Excellent video! I enjoy this technical, "deep in the weeds" type of stuff. Watching this and seeing how the old NES controller works got me thinking about something. How did the controllers with turbo buttons work?

[@DisplacedGamers]

Thanks, ImperatorScab! I will probably talk about turbo functionality in a future video.

[@donchaput8278]

I'd would be interested in additional breakdowns of controllers and the differences! Part 2?

[@Alakazam2047]

This is a super well done video and does a great job explaining how it works. If possible, when you get to the SNES controller can you compare the improvements from the NES controller? As Sdudyoy pointed out, it's really remarkable how they decided to go the route they did in designing this. Even though this controller is decades old, the stuff in it is still the material that I learned about in university.

[@corkbulb2895]

1:02 are those HAND DRAWN traces on an NES controller? In the mid 1980s? Damn Nintendo! Props for that!

[@ThePerfectKiosk]

The DMC bug causes a read operation from the CPU to be performed twice, and reading the controller state register is what sends the clock pulse to the controller. The controller state is corrupted because one of the button states is lost when this happens. In 2014, it was found that the DMC read occurs on only even (maybe it was only odd?) CPU cycles, as well as the object DMA function. When DMA completes, the CPU is always on an even or odd cycle (I forget which it is), so controller state can be reliably processed even while DMC samples are in use.