Inter-IC Sound (I2S)
Does ESP32 support using crystal oscillator as the clock source of I2S?
No. Please go to ESP32 Technical Reference Manual to read about clock source configurations of I2S.
When working as the I2S master, does ESP32 support connection to the I2S slave that only has the three signal lines, I2S_DATA, I2S_SCK, and I2S_WS?
Yes, but the connection to MCLK depends on the requirements of the codec chip on the other side.
Does the I2S interface of ESP32-C3 series chips support the PDM RX mode?
In the software driver, the I2S interface of ESP32-C3 series chips does not support the PDM RX mode. Unlike ESP32-S3, the PDM RX of ESP32-C3 does not have a module supporting converting from PDM to PCM, which means the acquired data is in the RAW PDM format. The data in this format can’t be used directly in most cases.