FRDM boards are great. However they follow Arduino layout and IO oriented. Maybe we should have some fun on it.
I found I2S port is available on FRDM-KL26Z and FRDM-K20. So I will like to propose to design an audio shield for them.
I2S output (interface to low cost UDA1330 DAC)
on board amplifier for headphone or small loudspeaker.
USB host for MSD
I2S input (interface to UDA1341 codec, a legacy silicon since MiniDisk age)
on board amps for headphone and microphone
I want to know your feedback on this idea. Maybe I should place it into POLL module?
It can playback wav file with simple driver, however it will take more efforts for a complete MP3 decoding. So community and open source is important.