stm32f405 with mp34dt... without I2s

[olpol]

I am using an adafruit stm32f405 feather, with the hal rather than arduino. I have I2c, and CDC

working now, and would like to add audio functionality with a mems mic.

The I2s pins are available pins, but the clock cannot get to a low enough speed(1MHZ) through PLL.

I thought about using divided master clock output ,and jumping to external source for I2s clock, but these

pins are not available.

 

Can I use TIM3_CH2, jumped to an SPI clock input, and read the data using that periipheral.

The data sheet for the mic says it can use I2s, SPI, DFSDM, and sai.  SPI is the only one that is 

both present, and available.

 

I haven't seen any examples doing similar, unlike I2s cube examples.

 

Any advice?

 

Many thanks in advance.

[AScha.3]

You can use the timer to get the clock for the spi.

But the i2c should have a divider to get the clock you want - did you set it?