Audio real-time processing basic tutorial needed

Hi,

I'm looking for some knowledge about audio processing on DSP microcontrollers.

As far I have STM32 based board with audio codec and I2S connection between them. It's working by now, small data packages (like 2x32 values) are being received from the codec to STM and sent back to codec and outputed on speakers.

What I need is some ideas how to manage received data so I can do more but changing volume (that's what even I can do ) I want to apply some filtering, nonlinear processing, delays, echoes etc. I read something about ping pong buffers but I'm sure there's some more approaches to handle data like cycling buffers.

For now I'm going through DAFX: Digital Audio Effects (by Zolzer) book and there's many great ideas but what I need is something between I2S data communication and audio algorithms.

I'd be grateful for any clues.

Jacob