Author Topic: Cart audio?  (Read 1006 times)

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Offline hackbar

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Cart audio?
« on: August 28, 2019, 04:44 AM »
Can the Everdrive do cart audio, specifically the Japanese Castlevania 3?

If so, what pin does it output it on? I modified a Famicom adapter to output on an expansion port pin, then put modded the console to wire that pin to the audio in. I'd like to be able to use the same console with an Everdrive.

Offline nuu

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Re: Cart audio?
« Reply #1 on: August 28, 2019, 06:53 PM »
On the 60-pin version of the N8 expansion audio output is on pin 46 like normal, and on the 72-pin version it's pin 54 like on MMC5 and PowerPak.

Support isn't very good though. Only a few expansion audio chips are supported (including VRC6 as used by Akumajo Densetsu), most very inaccurate, and even if they were accurate the volume is way too low and is drowned out by the APU audio. If you have a modded NES you could have a potentiometer to adjust the volume, but us with Famicoms are out of luck.

Offline Sarge

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Re: Cart audio?
« Reply #2 on: August 28, 2019, 07:40 PM »
I dunno, I think a lot of the expansion chips are supported in the later releases of OS V20. Just realize that you might have other issues with the various release candidates. I'm on RC3, which seems most stable for my setup.

Also, they're a lot more accurate than they were in OS V16. Not all are perfect, but VRC6 sounds pretty solid, and the volume levels, at least on my system, seem pretty decent. If you have a modded system, though, or are thinking about it, a potentiometer is definitely the way to go, as nuu mentioned.
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Offline nuu

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Re: Cart audio?
« Reply #3 on: August 28, 2019, 11:15 PM »
I think there's at least some support for FDS, VRC6, VRC7 and Sunsoft 5b. This only leaves Namco 163, MMC5 and those Jaleco and Bandai games with special sample chips (µPD7755C, µPD7756C and M50805) that haven't even been properly dumped and fully supported by emulators yet.

FDS was totally unplayable last time I tried it, just weird beeps and bops, not sure if there's something wrong with my Everdrive though. VRC6 and Sunsoft 5b may be accurate, I don't know because I can't hear the sounds on my Famicom. If I increase the volume on my TV I do hear them but the APU sound will be way too loud. Real cartridges with expansion audio doesn't have this problem on my Famicom so it can't be my system that's wrong.

Offline Sarge

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Re: Cart audio?
« Reply #4 on: August 28, 2019, 11:57 PM »
Are you still back on V16? There's a lot of stuff missing there as opposed to the V20 release candidates. FDS sound is a lot better, and Namco 163 and MMC5 audio is present.
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Offline hackbar

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Re: Cart audio?
« Reply #5 on: August 29, 2019, 04:51 AM »
Oh, I didn't know that the PowerPak supported cart audio at all. I moved my mod to pin 54 to match the PowerPak and Everdrive.

When you say "it's pin 54 like on MMC5", no US games had cart audio, right? So pin 54 is just used by modern flash carts?

Offline nuu

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Re: Cart audio?
« Reply #6 on: August 29, 2019, 12:15 PM »
Are you still back on V16? There's a lot of stuff missing there as opposed to the V20 release candidates. FDS sound is a lot better, and Namco 163 and MMC5 audio is present.
Nah I'm on V20 but I haven't checked FDS since a long time back (the FDSStick is pretty much flawless and covers all my FDS needs anyway). People have been saying it's getting better and better for every release now but for me it has always sounded like weird beeps and bops, nothing like the real FDS do, which is why I have trouble trusting anything that is said about it lately.
I didn't know that Namco 163 and MMC5 are supported though (no mentions of it in the changelog either). In that case all expansion chips are supported (except for the Bandai and Jaleco sample chips)! I wonder if the MMC5 PCM is supported though. Only one game used it.

Quote
Oh, I didn't know that the PowerPak supported cart audio at all. I moved my mod to pin 54 to match the PowerPak and Everdrive.

When you say "it's pin 54 like on MMC5", no US games had cart audio, right? So pin 54 is just used by modern flash carts?
I don't really know, I just quoted what said on the pinout document. If you checking NES MMC5 carts (http://bootgod.dyndns.org:7777/profile.php?id=15), you can see that several pins are missing (maybe to reduce production cost a bit) but pin 54 isn't missing. Following the trace I can see that pin 54 leads to point "R9" which is unconnected, but there are markings for a 10K resistor which is missing. If a 10K resistor is added at R9, it would connect to pin 1 of the MMC5 chip which is Audio Amplifier Input. Not sure how that works, but I'm guessing Nintendo kept the possibility for expansion audio on the NES version of MMC5 boards in case they wanted to release a game that used it. That would require to release an additional accessory that connects to the expansion port on the underside, else the expansion audio can't be used. Of course no such accessory was released and no NES game supported the MMC5 audio chip in the end.

Nevertheless, pin 54 seems to be the standard for expansion audio on NES, no matter if this is really what Nintendo planned or not. NES reproductions of games like Gimmick! also uses pin 54. Only if you have a top loader NES you will have to do some workaround since it's missing the expansion port.

Offline brianvgplayer

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Re: Cart audio?
« Reply #7 on: August 29, 2019, 09:41 PM »
Namco 163 has been supported for a long time. It's not new or exclusive to v20 (v16 also supports it).

Offline nuu

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Re: Cart audio?
« Reply #8 on: August 30, 2019, 12:10 AM »
It's relatively new.

Offline brianvgplayer

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Re: Cart audio?
« Reply #9 on: September 01, 2019, 07:30 AM »
It's relatively new.

It was around before the volume adjustment was removed.