ADAU1701-I2S-Audio-Driver-for-Raspberry-Pi

Generic audio driver to use the I2S interface of the Raspberry Pi for sound output to a dsp

This is a fork of this repo: https://github.com/MKSounds/ADAU1701-I2S-Audio-Driver-for-Raspberry-Pi

I exchanged the spdif-transmitter driver with the pcm5102a driver to make it work with piCorePlayer.

Wiring and ADAU1701 configuration:

From https://digital-audio-labs.jimdofree.com/english/raspberry-pi/adau1701-i2s-driver/

In brief:

Wiring Raspberry to ADAU1701

• Pin 12 (PCM_CLK) - MP5 and MP11
• Pin 35 (PCM_FS) - MP4 and MP10
• Pin 40 (PCM_DOUT) - MP0 (or MP1, MP2, MP3)
• Pin 39 (GND) - any GND-Pin

Configuration - ADAU1701

• Sample rate: 48 kHz
• Bit depth: 24 bit
• Data format: I2S

• Clock master at the I²S output!
• MCLK = 256 * Fs = 12.288 MHz
• BCLK = 64 * Fs = 3.072 MHz --> Internal / 16
• LRCLK = Fs = 48 kHz --> Internal / 1024

• LRCLK polarity: falling edge (LRCLK = 0 = left channel, LRCLK = 1 = right channel)
• BCLK data change: falling edge
• Transmission: MSB first
• MSB position: delayed by 1 BCLK

Installation in piCorePlayer

(as documented here: https://forums.slimdevices.com/showthread.php?110964-ADAU1701-with-piCorePlayer&p=977571&viewfull=1#post977571)

Device Tree Overlay

• Copy adau1701-i2s.dtbo to boot/overlays/
• Change the content of boot/config.txt:
  • Search the following line and comment with hash: #dtparam=audio=on
  • Add the following line at the end of the file: dtoverlay=adau1701-i2s

After reboot, aplay -l should output something like:

**** List of PLAYBACK Hardware Devices ****`
card 0: Output [ADAU1701 I2S Output], device 0: bcm2835-i2s-pcm5102a-hifi pcm5102a-hifi-0 [bcm2835-i2s-pcm5102a-hifi pcm5102a-hifi-0]
Subdevices: 0/1
Subdevice #0: subdevice #0

Squeezelite configuration:

• Audio output device settings: Analog audio
• Output setting (-o) -> sysdefault:CARD=Output
• ALSA setting (<b>:<p>:<f>:<m>:<d>) -> 80::24:1:
• Max sample rate (-r) -> 48000
• Upsample setting (-R) -> vLX

Optional: adapt ALSA config file

Add the following lines to the ALSA config file /etc/asound.conf:

pcm.InterpolatedOutput {
        type plug
        slave {
                pcm "hw:0,0"
                format S24_LE
                rate 48000
        }
}
pcm.!default InterpolatedOutput