ADAU1445 safeload readback fails

Hello to all,

i searched all your threads about my problem but find nothing to my failure.

In my system i used a adau1445 for audio signals. I load the coefficients for the biquad filters with the safeload mechanism that works almost fine but in one case not. Sometimes there are wrong coefficients in the filters and there are a lot of noise in the output signal.

To find out the problem i implement a readback function, to verify the data is correctly transfered to the safeload registers.

The Problem is that sometimes the readback values arent that i write before. For example i write that set of data:


i readback:


is this a normal behaviour? It happens almost every time i write a 0xFF to the register. Is there another way to check the coefficents written?

Thank you very much and best regards,