One advantage of SAMD (ARM based processor) is built-in 10bit D/A converter. D/A converter driving is already well-prepared by precedent and here I quickly made a demo playing wav file stored in micro SD card in ULTRA Zero. Some primitive information are also presented on OLED display.

Actual operation can be found in the following movie.. and

Relevant source is uploaded to

https://github.com/kodera2t/ULTIMA_SAMPLE/blob/master/ULTRAZERO_player.ino

Have fun!