finally got my ADAU1452 Board working. Based on the community help without any hastle. worked directly everything fine.
Now a small questions regarding programming:
I want to use a FIR filter at low frequencies. In order to avoid large amount of coefficients (getting short on computing resources rapidly!) I want to resample the low frequency part (fs/4 or similar), compute with short FIR, resample to fs and send it out.
As far as I understoof I could do it like this:
ASRC input from e.g. I2S; resample to fs/4; send to DSP core
Compute it in DSP core; send to another ASRC
Resample in ASRC to fs; send to DSP Core
Use any output in DSP core
So although my internal fs is then e.g. 48kHz I will only have computed this signal every 4. sequence. Correct?
Is there anything to remember for the FIR filter? I shorten the tabs to 1/4 and adjust to new sample rate. But is that all? Will it accordingly only be called every 4. sample? Or is it still called every sample (and I have to make it 48kHz) and no computing resources are saved?
Hope my question is clear....