Hardware Cartridge Pin 31 "audio in" : does it work in GBA

[Aeredren]

Hello there !

I try to understand the mysterious pin 31 "audio in" on the cartridge pinout for GB/C/A(SP).

Actually I only know about the nanoloop mono using it. But the nano loop mono says the internal jack out will not work on GBA(SP).

Does it mean the pin 31 is only wired up to the GBC and end with GBA ?

Then I found out about a MP3 player for GBA called Play-Yan. Does it decode the mp3 on an on-cartridge chip and forward the analogue signal to gba through pin 31 (which would mean pin31 is wired on GBA) ? Or does it decode MP3 on the GBA arm processor and audio chip ?

 

[SylverReZ]

Hello there !

I try to understand the mysterious pin 31 "audio in" on the cartridge pinout for GB/C/A(SP).

Actually I only know about the nanoloop mono using it. But the nano loop mono says the internal jack out will not work on GBA(SP).

Does it mean the pin 31 is only wired up to the GBC and end with GBA ?

Then I found out about a MP3 player for GBA called Play-Yan. Does it decode the mp3 on an on-cartridge chip and forward the analogue signal to gba through pin 31 (which would mean pin31 is wired on GBA) ? Or does it decode MP3 on the GBA arm processor and audio chip ?

https://github.com/psobot/musicboy
You might be interested in this.

 

[Aeredren]

https://github.com/psobot/musicboy
You might be interested in this.

Awesome !

It does confirm my guess : audio in pin is only a feature for GameBoy/pocket/lite/color

And it is a super cool project, it is quite uncommon to see custom cartridge hardware, the only other one I know about is wolfenstein for game boy color which render on an on cartridge coprocessor "a la superfx".