We have a need for arbitrary SPI clock frequencies. I looked at ~10 families and most STM32 micro-controllers seem to be limited to prescalers that divide the PCLK by a power of two. I found the STM32H7 but it is wildly over-specified for our application. The STM32U5 has a separate SPI kernel clock but the design of the clock tree does not seem to allow to connect it to a PLL or a timer.
Does anyone know of a less complex ST MCU that supports this directly, or a way to obtain this indirectly? I though of using the SPI peripheral as a slave, but then I'd need to generate 8 x N clock pulses which seems cumbersome. It may be possible by using a master timer (clock derivation) and a slave timer (pulse count) but I am see that from the reference manuals.