Just got into trying Pushpin on the GBC again (the original version controlled thru the link port) and found out something useful: in the list of CC commands in the docs it says

Control parameters.
37  Cartridge Sound In -> Left Channel on (1) or off (0). Will have no effect.
39  Cartridge Sound In -> Right Channel on (1) or off (0). Will have no effect.

But in fact when I toggle 37 and 39,it DOES have a very nice effect: it completely kills the high pitched whine/noise I otherwise hear in my mixer from the gameboy colour! smile

I'd assume it's muting the unused 'channel 5' and stopping it picking up interference from the unused pins but if so it's kind of weird that defaults to being on rather than off?!

Also makes me wanna make a modded flash cart with an audio input wired to those pins smile if that's actually even possible

Last edited by Cementimental (Nov 12, 2022 11:04 am)

Abandoned on Fire

Interesting! I never got pushpin working but I always thought it seemed cool.


Yeah, it's possible. Nanoloop Mono work on this principle. IATM made a cartridge with a YMZ284 expansion, and I made a cartridge with a YM2413. Although neither of the latter two are fully working, or really public projects, but that has more to do with the digital side of things.