I’m having a hard to conceptualizing how the data from a microphone connected to the XIAO nrf52840 through I2S can be sent through an external device (e.g. Mobile phone or Laptop) using Bluetooth. Does a setup like this require additional memory module? Sampling frequency of the microphone would be set to 8kHz for context.
Hi there,
Well I would think of it this way…
The Mic is doing the Analog to Digital sound conversion so after that it’s all digital PCM data.
Once Converted,
It is used to communicate PCM audio data between integrated circuits in an electronic device. The I²S bus separates clock and serial data signals, resulting in simpler receivers than those required for asynchronous communications systems that need to recover the clock from the data stream.
BLE then just becomes a cable at that point. The connecting Digital client devices perform the reverse in decoding and Digital to Analog 'ing back to sound that was heard by the microphone.
No additional Memory or buffers are required just bandwidth for Higher fidelity.
HTH
GL 
PJ 