All signals from NAU8822 are connected to goldpins included I2S, pll clock and other. 
Control I2C interface is able to work with 3.3V and 5.0V sources uC. 
Powering stage is state of the art connection multiplier capacitance and low noise LDO 3.3V regulator so you can easy power it from USB and keep excellent sound quality.

Here you can follow my code: https://github.com/analityk/nau8822

NAU8822 futures:

8 analog inputs;

I2S/PCM/a/b/time slot digital audio interfaces;

24b 48/96kHz ADC and DAC;

digital high pass filter;

digital notch filter;

automatic gain control unit for left and right differential (mic)/line input;

5 band equalizer;

3D enchancement;

DAC Dither;

6 analog mixers + 1 for differential output (power up to 1W);

PLL - clock input from 8MHz to 33MHz - also clock output - need one clock source for few boards.

low noise bias current for electret mic and ECM polarization circuit - you only need ECM button.

controlled by simple I2C interface;

https://www.nuvoton.com/resource-files/NAU8822LDataSheetRev1.9.pdf