After powering the ADAU1701 up, I apply a reset pulse and expect ADAU1701 will load a default program that passes the input on ADC0 through to DAC2, as shown in the datasheet. However, this does not happen. There is no audio output. What is wrong?
The default signal flow shown in the datasheet is correct (i.e. ADC0 and ADC1 will map to DAC2 and DAC3, respectively), but by default the core is muted. Register 2076 (0x081C) has a default power-on value of 0x00 0x00. You need to write 0x00 0x1C to the Core Control Register (address 2076, or 0x081C) in order to get the audio to pass through.
Now days you can find the basic settings on WONDOM website.