Reading the ESP32 Technical Reference Manual (TRM) as the source of knowledge in this area, I find the register called I2S_INT_RAW_REG which contains a flag called I2S_RX_TAKE_DATA_INT_RAW. As I pump in input data into my receiving ESP32 DMA "catcher" I eventually see this bit toggle on. What I am failing to understand is what this bit/flag/interrupt indicates. Does anyone have an understanding on what this bit means?
Later:
Found a good clue in TRM
12.6 - I2S Interrupts
12.6.1 - FIFO Interrupts
I2S_RX_TAKE_DATA_INT: Triggered when the receive FIFO is almost full.