Expansion audio on NES?

Discuss technical or other issues relating to programming the Nintendo Entertainment System, Famicom, or compatible systems. See the NESdev wiki for more information.

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Ecernosoft
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Expansion audio on NES?

Post by Ecernosoft »

Hello!
I've got 2 questions.....
I've been wanting to make a MMC5 game (Or MMC3 if the MMC5 isn't available) if I ever did make a NES game, so I've got some questions-
1. How common/rare is MMC5?
2. Expansion audio?
3. VRC7 or VRC6 more worth it?
4. Would MMC3 be a better choice minus the reduced power?

Thanks!!!
-Ecernosoft

(p.s. I'm new here. this is my first post.)
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Dwedit
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Re: Expansion audio on NES?

Post by Dwedit »

Cartridge audio does not work on a stock NES due to a design flaw. Something needs to be connected at the bottom expansion port before cartridge audio works.
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Fiskbit
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Re: Expansion audio on NES?

Post by Fiskbit »

1. Going by nescartdb.com, MMC5 was used in 8 games in North America and 14 in Japan. It's not rare, but unlike common mappers like MMC1 and MMC3, original chips are not available in large quantities and there is no modern clone version. I generally try to direct people away from projects for which modern hardware is not available, because if the project is worth playing, old games will be destroyed in quantity for their chips to put the game on cart. MMC5 also has many caveats. It is not fully understood, and emulators tend to only implement enough of its features to support current games that use it, so you may face problems with emulator support.

2. On the NES, the fact that you need to mod your console or snap off a plastic cover and plug in an expansion device to get expansion audio means most users are not equipped for it. If you really want expansion audio in your NES game, you might be best off including an expansion board with the game to enable this, such as the infiniteneslives expansion audio dongle, but this is added expense and I suspect not all users will be comfortable removing the plastic cover. This isn't a problem on Famicom systems, of course.

3. I think expansion audio on VRC6 and VRC7 is more interesting than on the MMC5. However, these mappers were used in 3 and 2 Japanese games, respectively, so sourcing them in quantity is probably way harder. I don't believe there are clones. As above, any worthwhile project made with these mappers will result in old games being destroyed in quantity.

4. MMC3 is more than sufficient for most NES projects, and there are modern clones available. If you really want an expansion audio sound, you can use something like blarggsaw to get a sawtooth wave over the DMC channel, for which I believe a library is now available by zeta0134.
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pubby
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Re: Expansion audio on NES?

Post by pubby »

I think you're overemphasizing the importance of mapper "power" and confusing it with the amount of features offered. If you look at your favorite NES games, most of them run on simple chips. The nice thing about simple chips is that they're easy to reproduce and easy to program. Keep in mind that the most important thing a mapper does is give you more ROM space, and a simple discrete logic mapper can do that even better than an ASIC.
Fiskbit
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Re: Expansion audio on NES?

Post by Fiskbit »

Indeed, it's possible you're putting the cart before the horse here. Ideally you pick the mapper that is necessary for the game you want to make, and pare back the game as needed if hardware with features you want isn't feasible due to cost or availability. The question should be less 'Should I use MMC5 or MMC3?' and more 'What mapper features does the game I want to make actually need?' You can make great NES games without all the features available in MMC5 or even MMC3, and oftentimes there are tricks you can use to get advanced features like scanline IRQs or expansion-style audio that one would normally get from a mapper.

If you want the absolute most advanced cartridge hardware and won't settle for less, I'd suggest considering a more powerful platform like the SNES or Genesis where the console itself provides that extra power. While there's something to be said for pushing older consoles, cramming crazy hardware into a cartridge isn't that novel at this point and may defeat the purpose of targeting this platform in the first place.
Ecernosoft
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Re: Expansion audio on NES?

Post by Ecernosoft »

Good to know! I didn’t know about the bottom port having functionality, either…


Thanks!!
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za909
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Re: Expansion audio on NES?

Post by za909 »

It depends on what you're planning to do. An UxROM or BxROM board can be more than sufficient in most cases, and even if you need some kind of IRQ support you can use the DMC IRQ trick to get yourself a crude timer for parallax scrolling or fixed status bar effects. The best part about discrete logic mappers is that they are possible to scale up or down with the right chip and circuit design, so you can go anywhere from the base 32kB to 8MB with an oversized BNROM board.
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