I'm trying to do my research and figure out if any audio HAT supports changing the output in software between the RCA line output jacks and the headphone output without having to unplug the headphone.
It's not something the descriptions mentions unfortunately.
Anyone have experience with this?
eg. the Raspberry Pi DAC has pinouts for the headphone DETECT and MUTE pins, but I think that's hardwired together and will auto mute the RCA jacks once you plug in a headphone.
https://www.raspberrypi.com/documentation/accessories/audio.html#raspberry-pi-dac
Except maybe if the DAC chip supports ignoring the MUTE pin from it's firmware.
There are some ALSA configuration files for the Raspberry DACs (previously IQAudio) which mention something like "Heaphone Switch" which is a changeable boolean value, though I'm not sure these actually do anything:
https://github.com/raspberrypi/Pi-Codec/blob/master/Codec_Zero_Playback_only.state#L363
Can somebody with this HAT (or any other hat with an RCA + jack output) in hand test if you can toggle such thing from software, and check if it actually works?