SNES Cartridges and Enhancement Chips

https://twitter.com/i/status/1177644211790729216

by ilamont • 7 years ago

256 110 7 years ago

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CodeArtisan• 7 years ago

Software implementations of these chips can be found here

https://github.com/byuu/higan/tree/master/higan/sfc/coproces...

waz0wski• 7 years ago

the owner of this repo also has some good blog posts about this topic, including an overview of some of the custom chips and their impact on the emulator they also maintain (bsnes)

https://byuu.net/cartridges/boards

throwaway20482• 7 years ago

bsnes is now named higan, and does several systems besides SNES.

floatingatoll• 7 years ago

Thanks, @byuu!

remlov• 7 years ago

Here is a very detailed programming guide for the Super FX:

https://en.wikibooks.org/wiki/Super_NES_Programming/Super_FX...

byuu2• 7 years ago

My favorite bragging point: the code in the necdsp folder (and the CPU core itself at component/processor/upd96050) there was used by Stephen Hawking when they emulated his old voice machine that used the same chip.

http://pawozniak.com/emulator/

Pretty cool that the same NEC uPD772x chip was shared between a text-to-speech engine and Super Mario Kart.

If you want to know everything there ever was to know about the chip, I mirrored every PDF datasheet I could find on it on my site:

https://byuu.net/datasheets#uPD7720

It has one of the most wild ISAs I've ever encountered, using a strict Harvard architecture and 24-bit VLIWs (very long instruction words.) Every opcode can do over a dozen different things in the same instruction at the same time. Writing code for it is quite the challenge.

jamiek88• 7 years ago

My favorite bragging point: the code in the necdsp folder (and the CPU core itself at component/processor/upd96050) there was used by Stephen Hawking when they emulated his old voice machine that used the same chip

Wow that really is amazing. The diversity of uses cannot be foreseen and is a good argument for both documentation at the time and emulation as useable history.

I’ve followed your work for a while, spent many hours playing Super Mario 3 on your emulators and reading your dev blogs.

Thanks for all you give.

aidenn04• 7 years ago

With regards to compression chips; If someone can substantiate this vague recollection I have it would be great.

I seem to recall Nintendo charged a per-unit royalty based off of the ROM size of the cartridge, which would make including a dedicated decompression chip reasonable, particularly since they are likely fairly simple to design anyways.

[edit] In addition, the two games listed as using the S-DD1 were 32M,it and 48M,it roms (there were very few 48 Mbit roms and 32Mbit was considered "large"), so these were already fairly expensive cartidges.

Found a pic of the Star Ocean PCB; note that the S-DD1 takes up less PCB space then even 1 of the two ROM chips:

https://snescentral.com/pcbboards.php?chip=SHVC-LN3B-01

[edit2] The SF Alpha PCB was much simpler by comparison:

https://snescentral.com/pcbboards.php?chip=SHVC-1N0N-01

gergles• 7 years ago

This is true (the royalty varying on the size of the memory) but the royalty was also significantly higher if there was any custom hardware involved on the cart - specifically because you actually had to purchase the "Game Pak" from Nintendo, so they would charge you "whatever they could get away with" for enhancement chips.

aidenn04• 7 years ago

Any idea if Enix was locked into buying the Game Pak already for Star Ocean by use of battery-backed SRAM or not?

bluedino• 7 years ago

I remember Street Fighter 2 being something like $69 (in ~1992 USD) when it came out, and it was something like 16 meg. A 48 meg ROM would have easily been $100+ if not $150.

walrus01• 7 years ago

Fun fact, an inflation calculator says that in 1992, a 50 dollar video game cartridge would be equivalent to $92 today. DLC and terribly unethical video game publishers aside, for the non-piracy crowd, we live in a golden age of affordable video games at $20 to $35 each.

If you can be content with buying xbox one and ps4 games on ebay a little while after they're released, you're unlikely to ever pay more than $20 for a game.

claudeganon• 7 years ago

Fascinating! Did any later gen systems besides the Nintendo 64 use these chips? Would it be possible to use a similar configuration in Switch cartridges?

bitwize• 7 years ago

I think Switch carts use a form of flash memory, which precludes this sort of extra-flexible expansion. You could include a chip on the cart, but it wouldn't have much throughput to do things like real-time graphics transformation. As for compression, most consoles just do regular decompression with the open source image libraries in the system BIOS, or on-GPU texture decompression. It wouldn't surprise me if the sprites in a game like River City Girls, for instance, were just PNGs.

monocasa8• 7 years ago

Small correction: the chips inside switch cartridges are mainly mask ROMs, not Flash.

fl0wenol• 7 years ago

The Switch is "just" an Nvidia Shield, albeit not running android. The carts are your standard mask ROM on a (proprietary) bus manufactured by Macronix and so would not be able to extend the functionality in a meaningful way.

Texture decompression is handled using the hardware acceleration on the Tegra if being used to save VRAM, otherwise using standard libraries (like libpng, libjpeg, etc.) in the game software.

codesushi423• 7 years ago

32X was a similar concept, with the idea of packaging up and reusing enhancement chips in a base cartridge that would add 3D support to the Genesis. The Genesis VDP is still used in 32X games, usually to render the background while the 32X's VDP renders flat shaded polygons on top.

The Saturn uses a similar architecture of using two VDPs, with one mainly dedicated to rendering the background.

velox_io• 7 years ago

I'm surprised this concept died out. Take the next-gen consoles, they're supporting games at 120fps/120hz. They could target 60fps (what the vast majority of users will use) and daisy-chain another console for the serious gamers who 'need' 120fps. This could be done through the HDMI cable (which supports ethernet in addition to video & sound), it could even be enhanced to support 8k.

Yes, this is essentially SLI/ CrossFire, something that has been around for some time, and support would be described as patchy at best. I believe the main issue is that it's left to game developers to implement, rather than something abstracted away to the graphics drivers/ GPUs.

monocasa8• 7 years ago

The N64 didn't use any chips like this AFAIK. I've seen maker prototypes using this scheme on a GameBoy, and wouldn't be surprised to see a GameBoy Advance cart that used them but don't know of any off the top of my head except as a built in peripheral (so RTC, tilt sensor, some communication mechanism, etc.)

And it'd be a real pain to add chips like this to any later systems. The architecture is a little different, and the cartridges aren't actually mapped into the system's main address space anymore. They are relatively slow buses that look more like mass storage to the rest of the system. They can't DMA directly and that hop to hit the rest of the system obviates a lot of the benefit of having a co processor on there.

Lord_Nightmare• 7 years ago

Yes: The Gameboy Player for the Gamecube has a GBA processor and some glue logic inside it. There is at least one Nintendo DS cartridge which has a bluetooth chip inside it: Pokémon: Typing Adventure/ And several Gameboy Advance cartridges in the Boktai series have a 'sun sensor' in them. I'm sure there are other examples as well.

makerofspoons• 7 years ago

There was also a Super FX 2 which powered Doom, among a few other games. Notably Winter Gold looked quite good given the platform's limitations: https://www.youtube.com/watch?v=9uQlCZVb_Ro

lostgame2• 7 years ago

Wow, yeah, this is fantastic, thank you for sharing - I love seeing the development of early polygonal 3D, such as Virtua Racing and Starfox, but I’d never seen this! Very cool.

portlander12345• 7 years ago

Never heard of this game. It has a totally different visual style from anything else on the platform. Very impressive.

vardump• 7 years ago

For a moment I thought this was an old Amiga 500 demo (older than this game). Spaceball's "State of the Art" [0].

Apparently same author for both rotoscoped animations.

[0] https://www.youtube.com/watch?v=89wq5EoXy-0

seibelj• 7 years ago

This strategy was used in most cartridge-based systems that became popular enough to warrant the engineering effort. The original NES had "mappers" which accomplished similar feats, mostly expanding ROM / RAM but also interesting actions like triggering interrupts when the PPU (Picture Processing Unit, nowadays called GPU) took certain actions. https://wiki.nesdev.com/w/index.php/Mapper

All of this was to squeeze more performance and make more advanced games.

tenebrisalietum• 7 years ago

One mapper even added audio channels to the NES, but would only work on the Japanese Famicom because the pins passing through the audio weren't present on the American NES. There's also one mapper that I guess may have been recently discovered that had a microcontroller on it that had its own ROM and IIRC was an attempt to copy protect the game.

I think you can't quite equate the PPU with GPUs - because the PPU doesn't run instructions or render things to a framebuffer. It's more like just the part of the GPU that takes memory and outputs a display signal - in VGA that's called a RAMDAC, not sure what the digital TMSS/HDMI/LVDS equivalent is.

TazeTSchnitzel• 7 years ago

One mapper

There were several that added extra audio. My favourite is the VRC7, Konami's mapper used in just one game, Lagrange Point, providing Yamaha OPL FM synthesis.

gvfff• 7 years ago

The pins are there actually, just not on the cartridge side.

The little expansion slot under the NES has these and other pins. Some of the pins are electrical shorts with pins on the cartridge side.

So to play Japanese games with full audio all you’d need is an expansion cartridge selectively shorting the pins on that expansion port.

patrickyeon2• 7 years ago

A little bit meta here, but I know it's going to come up: somebody is going to complain that Twitter is the wrong way to write this content. How they loved it but were infuriated to read it in snippets. Pre-emptively, I'm copy-pasting an earlier comment of mine on this:

Heh, from foone themself: https://threadreaderapp.com/thread/1066547670477488128.html
Not to humblebrag or anything, but my favorite part of getting posted on hackernews or reddit is that EVERY SINGLE TIME there's one highly-ranked reply that's "jesus man, this could have been a blog post! why make 20 tweets when you can make one blog post?" CAUSE I CAN'T MAKE A BLOG POST, GOD DAMN IT.
The short story is they are quite open about having ADHD, and that's what causes the long twitter rambles, but also what makes it very difficult to assemble it into a blog post. Every once in a while foone's wife will edit a popular thread into a blog post, examples: https://foone.wordpress.com/
If this seems like a particularly good story to you, maybe you'd like to edit it into a draft for a blog post and gift that to foone?

https://news.ycombinator.com/item?id=19884445

And yeah, as soon as I saw "SNES Cartridges and Enhancement Chips" and the twitter domain, I felt about 90% sure it wouuld be linking to a foone tweetstorm.

capsulecorp• 7 years ago

Why does ADHD prevent someone from making a blog post, and how does posting it on twitter change that? Sincerely curious.

patrickyeon2• 7 years ago

I can't speak from experience, but I can try to relay how I understand it from others. Part of the pattern of behaviour some people with ADHD describe is intense focus on topics, with no sense of when or what topics this will happen to. So someone may be intending to only post one or two tweets worth of interesting notes on enhancement chips, but find themselves going on and on without realizing that they've just spent an hour talking about the topic. They never intended to create blog-length material on the topic, but there it is.

The converse happens too: they can desperately want to write a long form article on a topic, and just can't find themselves starting it. The blank blog page is imposing and they don't know where they would start and maybe they'll distract themselves for a minute with something and whoops now they're very focussed on that distraction for a few hours.

I'm sure there's a lot more subtlety to this than I'm describing, and there's a real diversity of peoples' experiences with this, but there's one way that I understand it can lead to this situation.

m45t3r• 7 years ago

From foone itself:

they don't have the endless editing I get into with blog posts

I don't know if this is true or not, however Twitter is one of the only platforms that doesn't have an edit button. So it makes sense that Twitter may helps remove from people with ADHD the sentiment of "oh, maybe there is something that I can still improve from this post" before publishing it.

jdc• 7 years ago

The medium comes with lower expectations of structure.

lowtolerance3• 7 years ago

I’ve got ADHD pretty bad, and I can definitely understand why that’s an impediment to blogging.

For me at least, the “big picture” of a concept is definitely there, but it’s in the back of my mind. I can access it and talk about it, but particularly when writing, it takes serious concentration for me to convey that information to others, because in general, I’m more interested in fully understanding the mechanics of particular components of the picture.

When I attempt to write about a topic in-depth, I’m typically doing it in one of two ways: either it’s a sort of stream of consciousness sort of writing, full of digressions and errors, or it’s the result of a lot of planning, in which case it often takes me so long that I just give up before I finish.

I’m not a big Twitter user at all, but I have to admit that I’m drawn to the idea of writing about my interests in a more granular manner than traditional blogging generally permits.

goldcd• 7 years ago

I feel quite the converse..

..I accept twitter is here to stay, but always thought it was a a pointless snippet-fest good for nothing aside from millions being able to pile on praise/social-shaming.

Looking at this thread, it actually makes sense for once. It's a successive sequence of info & pictures - that follow a coherent thread. Great, just like any other blog.

However, if you're interested in any particular paragraph, you can click and see a whole discussion on "just that paragraph"

Not for one moment saying twitter's won me over, but it provides a cleaner way of annotating a story than any other platform I'm aware of.

dljsjr• 7 years ago

I actually agree with this, Twitter is far from my favorite way to consume content but I actually really enjoyed the format that this was presented in.

swiley• 7 years ago

Medium did that. I don't know if it still works, I haven't seen a medium post in anything other than elinks in a while.

mackrevinack• 7 years ago

I wonder how long before there is a WordPress theme that mimics these tweetstorms?

mtone• 7 years ago

if you're interested in any particular paragraph, you can click and see a whole discussion on "just that paragraph"

Only if you're subscribed.

lowtolerance3• 7 years ago

That’s an interesting way to look at it, and it got me thinking about how one might implement a blogging platform where discussion is more like comments in the margins of a book than some footnotes at the back of the book.

Scapeghost• 7 years ago

Not for one moment saying twitter's won me over, but it provides a cleaner way of annotating a story than any other platform I'm aware of.

Medium? It seems specially built for that.

werber• 7 years ago

That's a really cool way to write, I feel like it could be a methodology for students with ADHD (and maybe an addiction to their cell phone) to flesh out ideas for a paper and then reorganize (like a Trello column) them to get their base structure

rolltiide• 7 years ago

It took Star Ocean forever to be emulated properly because of that co-processor chip!

byuu2• 7 years ago

Tengai Makyou Zero (SPC7110 + RTC-4513) suffered much longer, and the fan translation of it even longer still. Absolutely worth the wait though.

codesushi423• 7 years ago

Sega had their own version for the Genesis, the SVP: https://en.m.wikipedia.org/wiki/Sega_Virtua_Processor

Virtua Racing was the only game released with it, but there were others planned for it originally. That is, until Sega decided to use the same technology for the 32X, which added a lot of power but was a terrible commercial failure.

morkfromork• 7 years ago

I had that game for the 32x. You could get the car airborne, lock the brakes and leave skidmarks in the air.

fireattack• 7 years ago

used by the Japanese-only RPG

What is the name of that game?

zerocrates• 7 years ago

I believe the name left out of that message was Daikaijuu Monogatari II

derefr• 7 years ago

Fun fact about the SuperFX chip: it was turned into its own commercially-licensable IP core (the "Argonaut RISC Core", or "ARC"), which became its own business, similar to ARM Holdings: https://en.wikipedia.org/wiki/Synopsys#ARC_International

Other fun fact: for a long while, Intel used an ARC core in its Management Engine.

That's right—not only can your motherboard run rootkits; it can also run StarFox ;)

saganus• 7 years ago

Interesting fun fact!

How is it that a chip used for 2D/3D operations gets used in the ME though?

I would've thinked that they are pretty different, but I'm no expert so, any ideas?

DiabloD34• 7 years ago

The chip never did such operations... instead they ran it as both a secondary processor and a math DSP. The operations otherwise were entirely software, and conventional.

Another interesting one was the SA-1 chip used in a few games, such as Super Mario RPG. Its a SNES-compatible 65C816 that is 3x faster, has its own RAM bank, and can interrupt and be interrupt the main CPU, among other features, and was used to offload a lot of things, including some graphics tasks.

monocasa8• 7 years ago

It's a totally different core and ISA FWIW, they're just both designed by ARC. The ME one is a pretty standard RISC, and the SuperFX one would be difficult to call a RISC given that it's two address, has pretty complex memory instructions etc.

userbinator• 7 years ago

Other fun fact: for a long while, Intel used an ARC core in its Management Engine.

I believe their wireless cards (at least the 3945ABG) also used it; I remember the disassembly looked right, but never had the time to go through with the rest of that project...

jordigh• 7 years ago

This thread mentions the Super Gameboy. There's a deeply fascinating series of blog posts about the Super Gameboy that everyone should read:

https://loveconquersallgam.es/post/2350461718/fuck-the-super...

artsyca• 7 years ago

Fascinating --

kjar• 7 years ago

Ok - everyone should feel free to publish as they prefer. On the other hand lashing out at critics is unproductive.

sdenton4• 7 years ago

Along these lines, Tom7 invented* 'reverse emulation' which effectively uses a Raspberry Pi as a co-processor, allowing him to run [spoilers ahoy!]an SNES emulator on an NES.[/spoilers]

The talk is brilliant: https://www.youtube.com/watch?v=ar9WRwCiSr0

* - as far as I know...

tibbon• 7 years ago

In theory, could you make some ultra-modern SNES game using a modern ARM chip or such in the cart? Still some basic system limitations, but running pretty much everything on the add-on chip?

zamadatix2• 7 years ago

Yeah, the SNES would pretty much turn into a (crappy) AV hub.

dmitrygr2• 7 years ago

I am doing that for PalmOS 5.0 with reSpring actually: http://dmitry.gr/?r=05.Projects&proj=27.%20rePalm

zokier• 7 years ago

I settled on the 4KB part purely based on cost. Even at this measly 4KB size, this one RAM is by far the most expensive component on the board at $25. Given that the costs of putting in a 64KB part (my preferred size) were beyond my imagination (and beyond my wallet's abilities), I decided to invent a complex messaging protocol and make it work over a 4KB RAM used as a bidirectional mailbox.

Is this not the sort of memory you'd need?

https://www.digikey.com/product-detail/en/cypress-semiconduc...

https://www.digikey.com/product-detail/en/idt-integrated-dev...

just trying to understand the details here.

lostgame2• 7 years ago

Whaaa? This, good sir, is fascinating! I am a huge fan of PalmOS and still use my Palm every day. I would love to make a custom Palm with a custom PalmOS but never even considered the plausibility or possibility. I’m gonna read through this now.

sgrove• 7 years ago

In fact, you can take it even further! tom7 (all of his pieces are amazing) put a raspberry pi into an NES cartridge, and manages to "run" Super Mario World on an NES.

My short description really does it a disservice - I strongly recommend watching the video explanation https://www.youtube.com/watch?v=ar9WRwCiSr0

benj1113• 7 years ago

To be fair 'Super Mario World' already runs on the Nes.

https://m.youtube.com/watch?v=TEZ3vZIi71g

stordoff4• 7 years ago

It's more or less been done on the NES - using a cartridge with a Raspberry Pi Zero in it to run SNES games: http://radar.spacebar.org/f/a/weblog/comment/1/1157

It's also roughly how the Super Game Boy worked - it had a Game Boy CPU in it: https://en.wikipedia.org/wiki/Super_Game_Boy

tdcbfdct3• 7 years ago

This guy ported wolf3d to the Gameboy Color more or less that way (looks like all the game logic is still on the Game it's CPU and just the ray-casting is done on the co-processor)

http://www.happydaze.se/wolf/

arebours2• 7 years ago

Does anybody knows how emulators cope with such games? Can you find them as ROM files?

zamadatix2• 7 years ago

https://news.ycombinator.com/item?id=20976633

nwallin2• 7 years ago

Since there are only a small number of such chips, the emulator will also have a library of cartridges it supports. You emulate those chips the same as you would emulate the CPU or PPU. Sometimes it's easy: the add-on chip is just a regular SNES CPU at a higher clock speed. Sometimes it's hard, because it's some sort of obscure finicky twiddly bits.

The situation is significantly worse on, for instance, the NES, which had 40 or so different chips for bank switching, which is thankfully natively (and therefore uniformly) supported by the SNES.

tanr54ok• 7 years ago

Rather than try to emulate the Game Boy on the SNES, they just included the CPU in the cart!

There’s no way you could do that anyhow

ct520• 7 years ago

Wow I feel like gaming back in those days was the Wild West. So cool to edge up the competition with custom hardware

fapjacks• 7 years ago

If anyone is interested in learning a little more about the 6502, Ben Eater recently did a video about it [0]. Also just in general if you hadn't heard of his channel and are reading this comment, you'll definitely enjoy what he does.

[0] https://www.youtube.com/watch?v=LnzuMJLZRdU

BuildTheRobots2• 7 years ago

There's actually a couple variants of Pilot Wings with different math coprocessors that act ever so slightly differently:

https://twitter.com/foone/status/1126996260026605568?lang=en

BuildTheRobots2• 7 years ago

I know I'm not supposed to comment on voting, but I'm honestly curious why this deserved to be taken down to -1.

The link seems entirely related to the original article and contains interesting information.

If I'm not to do it again, I need to understand why, please.

SNES Cartridges and Enhancement Chips

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