LOUP Engineering: Hardware Bring-Up · advanced
The ES7210 Channel Map Matters More Than the Channel Number in Code
AEC depends on what signal actually lands in each TDM slot.
The useful question in The ES7210 Channel Map Matters More Than the Channel Number in Code was where the behaviour actually originated. The application expected the far-end reference on channel 0 and microphone audio on channel 1 or 3, but hardware routing had to be verified rather than assumed.
Codec configuration, board wiring and firmware slot order can each change what a numeric channel means. Capturing raw channels and identifying their content was necessary before trusting an AEC reference. A channel index that compiles correctly can still carry the wrong physical signal.
I treated the known-good configuration as a control sample, changed only the layer under investigation, and recorded the regression or improvement before the next experiment. Evidence marker: aec-ref-ch0-mic-ch1-ch3.
Signal identity has to be proven at the boundary where hardware becomes samples. DSP tuning cannot repair a mislabeled input. Keeping the rule explicit means the same decision can be checked again on the next board revision or firmware branch.
Project evidence
LOUP engineering marker: aec-ref-ch0-mic-ch1-ch3. This note records the design or debugging lesson without publishing device credentials, private keys, customer data or manufacturing secrets.