I set adau1772 I2S master 16bit left-justified mode, input connect to 0 Level ，the i2s data become 0 or FFFF, WHY?
I would like to know a little more about your setup. How are you getting 0 data? Where is this data coming from? The Core? The ADC directly? There are many data paths in this part.
Now, if you are using the ADCs and have the HPF engaged, then the DC offset will be removed but there still may be a little bit of noise. Since you are running in 16 bit mode the converter noise will be less than 16 bits. So it may be right on the edge of 16 bits with no noise. .
The point I want to make is that the difference between 0x0000 and 0xFFFF is one bit. The first is a zero and the second is a -1 for a 16 bit 2's compliment number. So one bit of noise may cause the data to toggle between 0 and -1. It just looks like a lot because of the one bit making the signal go negative.
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