On the LyraT board I want to output through the headphones a single audio buffer containing 1024 samples at 48 kHz. I have connected the headphone output to the AUX IN of the Lyra board with a wire and now I want to capture the waveform. From the comments in the esp-adf driver code it appears that AUXIN corresponds to audio_hal_codec_cfg.adc_input = AUDIO_HAL_ADC_INPUT_LINE2. Using the “pipeline”, even though my headphone output is as desired ( I can listen to it) just some noise is captured by the ADC.
Implementing this using i2swrite and i2sread was very easy. Any suggestions. Thanks.
UPDATE:
It turns out that once the Codec in the Lyra Board is initialized and an I2S stream is created ( as reader or writer), one can use simple i2swrite and i2sread to communicate with the codec’s DAC and ADC. There is no need for a pipeline, listener etc. For anyone interested the AUX input on the board corresponds to LINE2 of the ESP8388 ADC. Another observation is to use LEFT and RIGHT for ADC and DAC. Using ONLY_LEFT or ONLY_RIGHT seems to introduce a clock jitter.