Inconsistent documentation for PLL FRAC N live updated operation

[ebrombaugh1]

Over in the post https://community.st.com/t5/stm32-mcus-embedded-software/stm32u5-fracn-not-working/m-p/691980 an issue was raised with the delay necessary to ensure live updates of the FRAC N PLL register. The reference manual for the STM32U5 has been updated to reflect this, but the process may be required for other STM32 PLLs that support live updates of the FRAC N parameter. I ran into the same issue on the STM32H503 but the delay requirement is not documented in the H503 reference manual and I suspect it applies to any other part with the same features. 

[KDJEM.1]

Hello @ebrombaugh1,

 

Thank you for bringing this issue to our attention. 

I reported it internally.

Internal ticket number: 203845 (This is an internal tracking number and is not accessible or usable by customers).

 

Thank you.

Kaouthar