I have the OMAP-L137 / TMS 320C6747 Starter Kit.
I am using the code provided in <CC Studio Dir>\boards\evmomapl137_v1\dsp\tests\aic3106 in order to sample a signal on one of the input audio jacks, elaborate it and then sending it back on one of the output audio jacks. I didn't touch much of the code that is given there, the whole elaboration algorithm is done on the sample of the Left channel, the right one just gets copy pasted.
Anyway.
Even if, between reading the buffer where the sample is saved (MCASP1_RBUF0_32BIT) and writing it to the output buffer, I don't do any elaboration (I just "copy paste" it exactly as I do for the right channel), I still can observe, with an external oscilloscope, that there is a lag of approximately 40 samples between what is being input in the board and what the board is outputting (i.e., which is, again, just a copy of the input signal).
I have also observed that the output gets inverted in polarity, but this is not a huge problem.
Where does this Lag come from? I guessed it was due to some filter in the ADC/DAC process but wasn't able to find much in the AIC3106 manual.