The ESP32 I2S peripheral supports an interesting feature: it can be used to push ADC samples into DMA memory. Currently the ESP32 I2S interface does not allow configuration of the peripheral in this way, though it would only require a little effort.

There is not much configuration available. Besides sample rate and number of bits (already included in the I2S module)

• which ADC peripheral to use
• which ADC channel to use

Proposal:

• create a class similar to the I2S class called I2SADC for the ESP32 port
• leverage most of the existing code (machine_i2s_init_helper) for initialization of this new class

Any thoughts? I really would like to see support for this and so will begin work on a PR asap.