Hello!
Question about the sound in Lagrange Point.
As far as I know, the game cartridge contains an FM chip.
I'm interested in the mechanism that communicates between the FM chip on the cartridge and the standard NES sound chip to produce high-quality 6-channel FM sound.
Thank you!
How work FM sound in Langrange Point?
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lidnariq
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Re: How work FM sound in Langrange Point?
On the Famicom, there is a pair of pins that's just dedicated to carrying audio. In normal cartridges, it's a jumper so that the 2A03's audio gets to the RF modulator.
In all cartridges that add audio, there's a variety of mixing circuits to combine the two. See the following pages on the wiki:
https://www.nesdev.org/wiki/MMC5_pinout
https://www.nesdev.org/wiki/VRC6_pinout
https://www.nesdev.org/wiki/VRC7_pinout
https://www.nesdev.org/wiki/Sunsoft_5_pinout
https://www.nesdev.org/wiki/RP2C33_pinout
Specifically in the narrow case of the Karaoke software Family Noraebang, the 2A03's audio isn't even mixed in at all.
In all cartridges that add audio, there's a variety of mixing circuits to combine the two. See the following pages on the wiki:
https://www.nesdev.org/wiki/MMC5_pinout
https://www.nesdev.org/wiki/VRC6_pinout
https://www.nesdev.org/wiki/VRC7_pinout
https://www.nesdev.org/wiki/Sunsoft_5_pinout
https://www.nesdev.org/wiki/RP2C33_pinout
Specifically in the narrow case of the Karaoke software Family Noraebang, the 2A03's audio isn't even mixed in at all.