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Inside the Super Nintendo cartridges

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Re: Inside the Super Nintendo cartridges

#91

Post by JohnBooty »

hooby wrote: post #81
chpatrick wrote: post #35

Earlier quoted context omitted.

https://youtu.be/ar9WRwCiSr0?si=LArQqOoH2bLtTXCQ

noice but apparently the NES is a lot more limited, in that it wasn't really designed to accept enhancement chips. still absolutely amazing that he can run emulated SNES games on real NES hardware! but the SNES actually had that ability to accept enhancement chips - as seen in the SuperFX and others... I feel that should allow for doing drastically more!

Different set of challenges on the SNES.

The NES was a little unusual in that it basically had no video ram. The PPU (the graphics chip) rendered sprites and background tiles straight off of the cartridge at 60fps as if the cartridge was an extension of the CPU's address space.

So there are almost no limits to what you could do with expansion hardware, other than the fact that everything would have to ultimately be rendered thru the NES' limited color palette. You could make a cart that provides an interface to let a monster PC with multiple 4090s treating the cartridges' tile data as a "dumb" framebuffer and run Cyberpunk 2077 through an NES... although, again, in 4-bit color hahaha.

In contrast, for the Genesis and SNES, you need to copy graphics data from cartidge to VRAM. Then it gets rendered. This was presumably done because ROM of the area was not fast enough to feed the graphics chips of the 16-bit systems, thus the need for local VRAM as sort of a cache.

So on a SNES you'd have to do some more work, you'd have to DMA a whole screen's worth of data from the custom cart into VRAM 60 times per second, which I think exceeds the data rates the SNES can achieve.

My understanding may be wrong, somebody correct me

Re: Inside the Super Nintendo cartridges

#92

Post by andrekandre »

VS1999 wrote: post #14
modeless wrote: post #9

I'm wondering why the console CPU wasn't running at 4x the clock rate to begin with, if the cartridges could easily and cheaply include one so much better. I guess that's just how fast CPUs were improving back then. A CPU from just a few years prior was that obsolete. Crazy!

Nintendo likes to sell its consoles at a profit, so they might have just decided that even an extra $10 per console wasn't worth it.

sort of yea, it seems originally they wanted to use a 68000 but late 1980s chip shortages and other costs made it difficult so they went with a 6502 derivative [1]

[1] https://retrocomputing.stackexchange.com/questions/9373/did-...

* there nay be others but this is the best link i could find (my info came from elsewhere but i cant find it now)

Re: Inside the Super Nintendo cartridges

#93

Post by JohnBooty »

Dwedit wrote: post #24
MenhirMike wrote: post #4

Earlier quoted context omitted.

Some Details on the Doom Wiki ( https://doomwiki.org/wiki/Super_NES ): Randy Linden, the port's sole programmer, initiated the port of Doom for the Super NES on his own initially, as he was fascinated by the game. Since Doom's source code was not yet released at the time, Linden referred to the Unofficial Doom Specs as a means of understanding the game's lump layout in detail. The resources were extracted from the IW…

Also it was recently figured out that using the SNES's mosaic feature in an unconventional way could have nearly doubled the game's framerate.

Interesting, please do tell more!

I know that Wolf3D on the SNES uses Mode 7. Not for the walls or sprites, but for the entire screen. The graphics are rendered into a background tiles with a resolution of like 175x100 or something, then scaled up with Mode7 to fill the 224x192 screen. (those aren't the exact numbers, but you get the idea)

Re: Inside the Super Nintendo cartridges

#94

Post by JohnBooty »

eru wrote: post #38
HeckFeck wrote: post #27

Earlier quoted context omitted.

> nowadays a single game update can be around 20 GB Irrespective of the abundance of storage we now enjoy, and even though I could rationally understand the reasons, this will always make me raise an eyebrow or sigh.

You are just getting old. People used to have the same reaction to games that filled up an entire CD (or even multiple).

It's not just "getting old."

For many of us it's an engineer's mindset. We appreciate games for their art and gameplay, and we also appreciate them for their engineering.

So it's a little sad to see that one aspect of game engineering become relatively extinct, even if it's the certainly the correct tradeoff given today's constraints.

Re: Inside the Super Nintendo cartridges

#95

Post by r0bbbo »

Something I've never been able to wrap my head around is how ROMs are dumped for emulators from cartridges? Dumping instructions and assets makes total sense to me, and packaging that up in a data file that can be interpreted by an emulator too, but how does an emulator model the hardware of every 'expansion' chip in a cartridge? How is that dumped from an original cartridge?

Re: Inside the Super Nintendo cartridges

#96

Post by cdchn »

r0bbbo wrote: post #95

Something I've never been able to wrap my head around is how ROMs are dumped for emulators from cartridges? Dumping instructions and assets makes total sense to me, and packaging that up in a data file that can be interpreted by an emulator too, but how does an emulator model the hardware of every 'expansion' chip in a cartridge? How is that dumped from an original cartridge?

They're not dumped. The emulator implementation recreates the expansion chip functionality in software. There are only so many expansion chips, so its not intractable.

Re: Inside the Super Nintendo cartridges

#97

Post by RainaRelanah »

LocutusOfBorges wrote: post #57
goosedragons wrote: post #48

Earlier quoted context omitted.

That's not entirely true. A few DS carts at least had IR receivers (e.g. Pokemon HeartGold). I think Learn with Pokémon: Typing Adventure adds Bluetooth through the card as well. So there was some limited capability to add features, not quite as exciting as extra CPUs but it's not like any GBA did anything super exciting there either.

> not quite as exciting as extra CPUs Not that it was an official licensed product, but for what it's worth, there was a DS flashcart that bundled a significantly faster CPU than the DS's own - the SuperCard DSTWO [1]. The extra CPU (Ingenic Jz4740, MIPS) was primarily used for GBA emulation on DS/DSi systems without the need for a GBA slot passthrough flashcart, as was otherwise required - though there was a quite s…

Still have my DSTWO. Heat was an annoying issue too. But for the longest time it was the only way to play SNES/GBA even on the 3DS.

Re: Inside the Super Nintendo cartridges

#98

Post by RiverCrochet »

r0bbbo wrote: post #95

Something I've never been able to wrap my head around is how ROMs are dumped for emulators from cartridges? Dumping instructions and assets makes total sense to me, and packaging that up in a data file that can be interpreted by an emulator too, but how does an emulator model the hardware of every 'expansion' chip in a cartridge? How is that dumped from an original cartridge?

Expansion chips aren't ROMs; they need to be emulated as well.

The situation was IMHO a bit worse with the SNESs precedessor, the NES.

There were quite a few expansion chips--called mappers--even though their general function was expanding the NES's memory space instead of adding additional processors or capabiliies - and they were in most games because without them the NES is limited to 32KB of PRG ROM and I think 4KB or 8KB of CHR (graphic) ROM. Most games after the year the NES came out had them.

These all had to be reverse engineered along with the console itself - fortunately much simpler than reverse engineering an add-on CPU or accelerator though. Some are common and in many games (MMC1, MMC3) and others are pretty much for a specific game only (MMC2 is for Punch-Out only).

Re: Inside the Super Nintendo cartridges

#99

Post by fennecbutt »

ThatPlayer wrote: post #41
qalmakka wrote: post #21

> One of the exceptional characteristics of the Super Nintendo was the ability for game cartridges (cart) to pack more than instructions and assets into ROM chips Wasn't this true even on other Nintendo consoles? Gameboy and Gameboy Color cartridges did similar if not even more outlandish things, like the GameBoy Camera

Gameboy Advance could do it too. Yoshi Topsy-Turvey and WarioWare: Twisted had gyro sensors. Boktai had a light sensor. Also the Nintendo e-Reader for scanning cards. Even the Nintendo DS could do it, though I'm not sure it was used outside of flashcarts like the SuperCard that included an additional CPU.

I got boktai 1 & 2,kirby t&t etc. I love the weird carts from that era, you don't get it these days at all.

Still need to pick up warioware and a few others tho.

There's this rad video on using the ereader with custom made cards to add events/"dlc" to pokemon: https://youtu.be/fgX36SAeTwQ

Re: Inside the Super Nintendo cartridges

#100

Post by cdchn »

fmy105 wrote: post #85

[flagged]

The lengths manufacturers of unlicensed cartridges would go to circumvent the CIC were pretty interesting. These carts and early Famicom adapters (which didn't have a CIC) would 'zap' the CIC to keep it resetting. Then Tengen made their own CIC knockoff for their games (they made unique plastic cases for their cartidges too)
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