Connect Raspberry Pi to ADAU1701 via I2S bus

Hello Salvatore,

I don't understand when you say to configure I2S as controller. I2S is a communication standard not a device.

So you can configure the ADAU1701 to be the master for the I2S clocks. You do need to have a source for MCLK for the system.

So you are planning on using I2S which is a stereo format correct? Not multiple channel TDM?

The frequencies you mentioned for FS and BCLK are correct but you should use an MCLK that is 256xfs not 1024xFS, that would be too high of a frequency. So you need a 12.288MHz master clock source.

Then the ADAU1701 needs to be configured to send and receive data on the serial port. Will the data be only coming out of the DSP, into the DSP or both?

A schematic diagram would be helpful and list of the register settings you are planning to use for the DSP.

Thanks,

Dave T

Hi Dave,

you are right, the I2S is a bus and not a device. I did not explain well myself. I would like to say that the ADAU1701 have to be configured as controller as reported in the picture of the previous post. This is the only way since the Raspberry Pi 1 and 2 do not have MCLK. Hence, the source of MCLK is the oscillator in the ADAU1701 board that drives both the ADAU1701 and the Raspberry Pi.

Yes, at the moment I'm planning to use ADAU1701 only in stereo format not TDM.

Yes, you are right again since Frame Sync Freq is 48 kHz (ADAU MCLK/256), BCLK is 3.072 MHz (ADAU MCLK/4) and MCLK is 12.288 MHz: this is the first wrong information that I found in the post. Where have I to set these values? In which configuration files?

Yes, the data will come from Raspberry Pi into ADAU1701 via I2S bus and then from ADAU1701 toward the speakers via DAC.

You can find the schematic diagram attached to the previous post. Moreover, the pin out connection for the Raspberry Pi is the following: SDATA - pin 40 -> DATA OUT LRCLK - pin 35 -> LRCLK IN/OUT

SCLK - pin 12 -> BCLK IN/OUT

GND - pin 39

MCLK - RPi does not provide Master Clock MCLK

and the pin out connection for the ADAU1701 is: SDATA - pin 7 -> DATA IN

LRCLK - pin 10 -> LRCLK OUT

LRCLK - pin 4 -> LRCLK IN

SCLK - pin 11 -> BCLK OUT

SCLK - pin 5 -> BCLK IN

GND - pin 21

MCLK - pin 19 -> MCLK IN

Finally, the pin connection between RPi and ADAU1701 is:

SDATA - pin 40 -> DATA OUT => pin 7 -> DATA IN   

LRCLK - pin 35 -> LRCLK OUT => pin 10 -> LRCLK OUT => pin 4 -> LRCLK IN

SCLK - pin 12 -> BCLK OUT => pin 11 -> BCLK OUT => pin 5 -> BCLK IN

GND - pin 39 -> GND => pin 21

Thank you

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EZ Admin