I am putting here my ALSA program in order to have a backup.
This also serves as an Arduino library for the SAMD21 board with the PCM5102A DAC
PCM5102A SAMD21
Vcc 5V
GND GND
FLT
DMP
SCL GND
BCK D1
DIN D9
LCK D0
FMT GND
XMT 3.3 V
MIDI IN D11
./modular <program> to exec the program
./modular -c <program> to list the SAMD21 synth.ino program
./modular -p <program> to list the synth.cc program