Can't get data ADC data to be in [-1, 1) range on EZ-KIT SC589

Hi all, 

I am having a fight with the SC589 EZ-KIT. 

I am trying to process audio on the floating point domain but I can't get the incoming data from the ADC to be ranged between [-1, 1) as one would expect. 

This is what I'm doing to covert the integer samples from the ADC into a float buffer:

inBufferSplitMono [ i ] = __builtin_conv_RtoF(inSample[ NUM_CHANNELS*i ]);

But then, when plotting that buffer this is what I get for a 0.65Vpeak 1KHz sine tone:

As can be seen there, values are very little. So, I went all the way down to verifying that the samples coming from the ADC (ADAU1977) are correct and found that things are a bit strange down there. This is what the DMA'd memory region looks like:

I'm not sure why the 4th byte is 0xFF for the third channel. 

So, is there anything obvious that I am missing here?

Looking forward to hearing from you.

Thanks in advance!

Manuel

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