09-24-2020, 05:31 PM
The WiFi / BT chip has an FM radio receiver function clearly visible on the spec sheet. Doesn't look like there was anywhere to route the audio it produces into the Allwinner SoC so none of those pins are connected. You need either an analog or a digital audio channel and an i2c link, plus wiring the headphone's ground wire as an antenna input. Modifying the board for all that ain't happening, especially since there isn't anywhere to send the audio anyway.
Because of the antenna requirement you would end up with a second headphone jack for the add on back plate, but other than that there isn't any real obstacle to making such a thing. You have an i2c link on the pogo pins along with sufficient access to power. Since it would need to be thick enough to have a second headphone jack you would have plenty of room to stuff some other goodies in, perhaps more battery?
Because of the antenna requirement you would end up with a second headphone jack for the add on back plate, but other than that there isn't any real obstacle to making such a thing. You have an i2c link on the pogo pins along with sufficient access to power. Since it would need to be thick enough to have a second headphone jack you would have plenty of room to stuff some other goodies in, perhaps more battery?