I2S signal frequency relation between ADAU1450 & AK4621, please verify


I am running ADAU1450 in FS 96khz mode along with Codec AK4621 configured for the same sampling frequency mode.

I am getting below readings

MCLK 12.288 MHZ





I want to know is my setup valid or I am doing something wrong 

Meanwhile Audio signal is fed into the codec, processed by DSP and then taken out from the codec without any issues, the sound is crystal clear.

Clarity on Audio transmission
[edited by: kanwar at 6:14 PM (GMT -4) on 11 Sep 2018]
  • The MCLK, LRCLK and BCLK frequencies are correct. It is not valid to measure the SDATA frequencies because it is data that varies from sample to sample.

    If the audio sounds good then you are probably fine. The most important thing to test is if you are getting all the bits. If you can send a sine wave into the ADC at the maximum level that it is supposed to produce a full scale signal then look at it in the DSP and see if you are reading a full scale signal. The meters in SigmaDSP will read -3dB with a full scale signal. You might end up clipping so perhaps going down one dB will give you better results. If you are missing a bit then either it will be horribly distorted until you go to like -6dB or -7dB, or the signal in the DSP will be reading 6dB low, which is -9dB.

    These are all usually caused by serial port settings that are different between the sending and receiving chip.

    Dave T