Hmmm - I have found some background that might be of value if anyone wants this feature…
I have never interfaced to digital audio products. I had heard of I2S (which is different from I2C) as an audio interface.
And the ST processor supports this interface. It seems it needs three pins: in effect clock, data and sync (called WS).
When WS is low the left data is clocked out and when WS is high the right data. Microphone chips have a left/right select pin,
so if you want stereo you can connect two chips in parallel with their selects wired differently.
From what I can see, The OpenMV camera can support I2S on the pins provided for SPI interface (possibly - is this right?):
PB12 = SPI2_NSS on JP1 pin 7 = I2S2_WS
PB13 = SPI2_SCLK on JP1 pin 3 = I2S2_CK
PB14 = SPI2_MISO on JP1 pin 2 = I2S2_SDI (audio in?)
PB15 = SPI2_MOSI on JP1 pin 1 = I2S2_SDO (audio out?)
An example of a digital microphone with an I2S interface is the Ivensense ICS-43434: https://invensense.tdk.com/wp-content/uploads/2016/02/DS-000069-ICS-43434-v1.2.pdf Modules with these may be available, for instance here: https://sensormaestros.com/products/audio-2/mems-microphone/smmic-ics43434/
Other I2S digital microphone modules seem to be available.
As for the software - I don’t know. Someone has got this working on an STM32 chip:
This person has done it in Python for the ESP32: I2S Microphone | Details | Hackaday.io
This this seems to describe a MicroPython I2S library (but is it only for ESP32?): GitHub - miketeachman/micropython-esp32-i2s-examples: Usage and examples for I2S support on the ESP32 microcontroller