Author Topic: Question about Expansion Audio on a NES  (Read 618 times)

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Offline dirtybob

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Question about Expansion Audio on a NES
« on: January 03, 2020, 10:42 PM »
If someone could explain this. Does the Everdrive detect something like an ENIO expansion board? To be honest I can't tell the difference if it works or not. To be honest I'm still confused on what it is other than an extra channel that the NES never had. I don't see how one resistor can create a missing channel.

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Offline nuu

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Re: Question about Expansion Audio on a NES
« Reply #1 on: January 04, 2020, 04:15 PM »
The resistor doesn't create any sound. It's only for connecting the expansion audio pin to the cartridge connector so that cartridges with an extra audio chip could mix in extra channels to the sound output. The NES is designed like this because Nintendo might had planned to release a disk system or cartridges with an extra audio chip. Something like an ENIO module would also be required if such cartridges were released. MMC5 does provide 3 extra channels (2 square and 1 sample channel), but no MMC5 games released on the NES uses this, so no such module was released.

The Famicom has the expansion audio pin connected from the start, so it doesn't need an ENIO.

BTW I think you posted in the wrong forum.