AEC Starts with the Correct Far-End Reference
An echo canceller cannot remove playback it never receives as a reference signal.
ES7210
ES8311 and ES7210 Split the Audio Problem in Two
Speaker output and microphone capture travel through different codec responsibilities.
AEC Debugging Started with Channel Mapping, Not DSP Tuning
Before tuning echo cancellation I verified that the algorithm was receiving the microphone and far-end reference channels I thought it was.
The ES7210 Channel Map Matters More Than the Channel Number in Code
AEC depends on what signal actually lands in each TDM slot.