SNES Drone Aims To Rock The SPC700

Way back when, home computers and consoles didn’t have the RAM or storage space for full-length recorded audio tracks. Instead, a variety of techniques were used to synthesize music on the fly. The SNES was no exception, using the SPC700 Wavetable Synthesis chip to bust out the tunes. [Foxchild] wanted to use this chip as a standalone synthesizer, but didn’t want to hack up a console to do so. Thus, the SNES Drone was born!

Instead of gutting the console for the juicy chips inside, à la most SID based builds, the SNES Drone takes a different approach. It consists of a cartridge which interfaces with a stock SNES console, making the install easy and non-invasive.

The build is in an alpha state, with the oscillators in the SNES generating continuous tones, with frequency and volume controlled by potentiometers mounted on the cartridge. Having physical controls on the cartridge makes the build feel more like a real synth, and promises to look awesome on stage for a chiptune performance.

[Foxchild] is looking for others to get involved to help get the project to the next stage, so if you’re interested, reach out on the Hackaday.io page. We’ve seen other projects to liberate the awesome chip sounds of yesteryear, too. Video after the break.

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Adding A Co-Processor To Help SNES Games With Slowdown

The Super Nintendo port of Gradius III is notable for being close to the arcade original, with its large, bright and colorful graphics. However, due to the limitation of the console’s hardware, the port is also well known for having constant slowdowns during gameplay, particularly during later sections. [Vitor] hacked away at the game and made a patched version of the ROM use a co-processor to eliminate those issues.

The slowdown seen here in Gradius is not uncommon to SNES players, many games of that era suffer from it when several sprites appear on the screen at once. This is partially due to the aging CPU Nintendo chose, supposedly in order to maintain NES backwards compatibility before the idea got scrapped. Unable to complete its tasks by the time the next frame needs to be shown, the hardware skips frames to let the processor catch up before it can continue. This is perceived as the aforementioned slowdown.

Around the later stage of the SNES’s life, games started using additional chips inside the cartridges in order to enhance the console’s performance. One of them is the SA1, which is a co-processor with the same core as the main CPU, only with a higher clock rate. By using it, games had more time to run through the logic and graphics manipulation before the next frame. What [Vitor] did was port those parts of Gradius III to the SA1, essentially making it just like any other enhanced cartridge from back in the day.

Unlike previous efforts we’ve seen to overclock the SNES by giving it a longer blanking time, this method works perfectly on real unmodified hardware. You can see the results of his efforts after the break, particularly around stage 2 where several bubbles fill the screen on the second video.

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Creative Limitation And The Super Nintendo Sound Chips

The Super Nintendo recently experienced a surge in popularity, either from a combination of nostalgic 30-somethings recreating their childhoods, or because Nintendo released a “classic” version of this nearly-perfect video game system. Or a combination of both. But what made the system worthy of being remembered at all? With only 16 bits and graphics that look ancient by modern standards, gameplay is similarly limited. This video from [Nerdwriter1] goes into depth on a single part of the console – the sound chips – and uses them to illustrate a small part of what makes this console still worth playing even now.

The SNES processed sound with two chips, a processing core and a DSP. They only had a capacity of 64 kb, meaning that all of a game’s sounds and music had to fit in this tiny space. This might seem impossible if you’ve ever played enduring classics like Donkey Kong Country, a game known for its impressive musical score. This is where the concept of creative limitation comes in. The theory says that creativity can flourish if given a set of boundaries. In this case it was a small amount of memory, and within that tiny space the composer at Rare who made this game a work of art was able to develop a musical masterpiece within strict limitations.

Even though this video only discusses the sound abilities of the SNES, which are still being put to good use, it’s a good illustration of what made this system so much fun. Even though it was limited, game developers (and composers) were able to work within its limitations to create some amazingly fun games that seem to have withstood the test of time fairly well. Not all of the games were winners, but the ones that were still get some playtime from us even now.

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A Steady Hand Makes This Chip Work Again

What do you do when you’re working with some vintage ICs and one of the tiny legs pops off? That’s what happened to [Kotomi] when working with an old Super Nintendo. A single lead for the sound chip just snapped off, leaving [Kotomi] one pin short of a working system (the Google Translatrix). This is something that can be fixed, provided you have a steady hand and a rotary tool that’s spinning at thousands of RPM.

Fixing this problem relies on a little bit of knowledge of how integrated circuits are built. There’s a small square of silicon in there, but this tiny die is bonded to a metal leadframe, which looks like the ribcage of a robotic centipede. This leadframe is covered in epoxy, the pins are bent down, and you have an IC. Removing just a tiny bit of epoxy grants access to the leadframe which you can then solder to. Don’t breathe the repair, it’s not pretty, but it does work.

While this technique makes use of a Dremel to break into the chewy nougat center of a vintage chip, and in some ways this could be called decapsulation, it really isn’t. We’ve seen people drop acid to get to the center of a chip and a really hot torch will get to the middle of a ceramic chip, but this technique is just accessing the lead frame of the IC. All ICs have a stamped (or photoetched) metal frame to which the silicone die is bonded. Running a Dremel against some epoxy doesn’t access the silicon, but it does grant access to the signals coming off the chip.

SNES Portable Leverages Flash Cart For More Games

Handheld consoles have to make a lot of design choices that their TV connected brethren don’t have to worry about. Battery life is important, as is screen visibility, and the games can’t be too bulky or unwieldy if you’re going to be carrying them around all day. [Chris] is no stranger to building handheld versions of home consoles, and took a few of these lessons on board in his latest portable SNES build.

The motherboard was provided by a SNES Jr., a lightweight, compact model released towards the end of the console’s reign. This was small enough that it required no trimming, however [Chris] elected to replace the inefficient 7805 with a more modern switching regulator. The case was 3D printed on a typical FDM setup, while the buttons were produced on a Form 2 for better dimensional accuracy and surface finish.

The flash cart PCB is permanently wired to the motherboard.

The real party piece, however, is the use of an SD2SNES flash cart. This allows a huge variety of ROMs to be loaded onto a single SD card, and played on the original console hardware. This is particularly useful in a portable build, as it becomes possible to carry all the games you could want, rather than having to juggle several full-sized SNES cartridges. The SD2SNES is wired in place permanently inside the console, with an impressive number of patch wires between the motherboard and the cartridge PCB. Despite the long lead length, [Chris] reports no issues with the connection.

There are some limitations – the flash cart doesn’t work properly for games using extra chips on the cartridge, like the SuperFX in Star Fox, for example. Despite this, it’s an excellent, high quality build that we’re sure is a lot of fun to play out and about.

We’ve seen [Chris]’s work before – this portable N64 is a particularly nice example. Video after the break.

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NBA Jam ROM Hack On SNES Is Heating Up

It’s a rare game that is able to bridge the gap between sports game fans and those that identify as hardcore gamers. Midway was able to bring those two groups onto common ground when they released NBA Jam to arcades in 1993. The game was an instant hit and was ported to 16-bit home consoles that same year. Compromises were made during those ports, so an attempt to make them more inline with the arcade release came in the form of NBA Jam: Tournament Edition a year later. However, in the heart of [eskayelle] NBA Jam: TE on the Super Nintendo didn’t go far enough. Now they have released a ROM hack that completely reworks NBA Jam: TE, and it’s called the “Double Z Mod”.

The Original NBA Jam Ball from the Title Screen
The original NBA Jam ball (courtesy of Steve Lin)

The concept behind the ROM hack was to bring about the NBA Jam game that fans deserved. All facets of pop culture from the early 90s were mixed in (not just former Presidents). According to the ROM hack’s notes, some of the things that were packed into the mod include:

• Assets from the original game have been restored, such as the Mortal Kombat banners.
• Modified certain players to give them a more “arcadey” feel.
• Soar to new heights with Air Jordan!
• Play as “The Worm”, Dennis Rodman, on at least four teams.
• Forget the Rookies, now play as the 1992 Dream Team.
• Tons of new secret characters including: Hulk Hogan, David Hasselhoff, Arnie as the T-800, and more.
• Expanded rosters are now as easy as inputting the “Konami code”

(Hint: B, A, B, A, Up, Down, B, A, Left, Right, B, A at the title screen menu)

In a gesture to give back to the ROM hacking community, [eskayelle] went as far to provide a collection of helpful tools to help potential SNES ROM hackers build their own NBA Jam: TE remixes. The document details ways to alter player photos, team colors, stats, and cosmetic tweaks. Since the Double Z mod focuses on being as 90s as possible, maybe this collection of tutorials will lead to a current NBA roster update.

To play the NBA Jam TE Double Z mod, you can use devices like the Retrode that allow easy dumping of an original cartridge onto a PC. From there the dumped ROM can be patched using an IPS patcher, like LunarIPS, which is as simple as locating two files in a browser window and hitting “Apply Patch”. In case you needed to see the Double Z mod in action, there is the clip below.

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Memory Mapping Methods In The Super Nintendo

Not only is the Super Nintendo an all-around great platform, both during its prime in the 90s and now during the nostalgia craze, but its relative simplicity compared to modern systems makes it a lot more accessible from a computer science point-of-view. That means that we can get some in-depth discussion on how the Super Nintendo actually does what it does, and understand most of it, like this video from [Retro Game Mechanics Explained] which goes into an incredible amount of detail on the mechanics of the SNES’s memory system.

Two of the interesting memory systems the SNES uses are called DMA and HDMA. DMA stands for direct memory access, and is a way for the Super Nintendo to access memory independently of the CPU. The advantages to this are that it’s incredibly fast compared to more typical methods of accessing memory. This isn’t particulalry unique, but the HDMA system is. It allows the SNES to do all kinds of interesting tricks with its video output display like changing color gradients and doing all kinds of masking effects.

If you’re interested in the inner workings of classic consoles like the SNES, this video gets way down in the weeds in the system itself. It’s interesting to see how programmers were able to squeeze more capability from these limited (by modern standards) systems by manipulating memory like the DMA and HDMA systems do.  [Retro Game Mechanics Explained] is a great resource for exploring in-depth aspects of lots of classic games, like how speedrunners can execute arbitrary code in old Mario games.

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