Nucleo-C031C6 ADC maximum clock speed

[DDjur.1]

Hello,
I have an issue with the maximum speed of the ADC clock for Nucleo-C031C6. In the device datasheet, it states that the max clock speed is 35 MHz. However, in STM32 CubeIDE, I have the option to select the asynchronous clock mode, and DIV1 is accepted as the prescaler. Alternatively, I can manually set synchronous clock (DIV1) and still get the ADC to work at 48 MHz. I am getting the correct timing and accurate results.

Is this OK to do and are there any possible drawbacks? 

Thanks! 

[Stassen.C]

Hello DDjur.1,

It is not recommended to do this and ST doesn't guarantee the behavior outside the defined specifications.
It might appear to work but you may also be missing some samples for example so I don't recommend you to do it.

 

Regards,

Stassen

[DDjur.1]

Thanks a lot for your feedback!

One more question (just for clarity), why does CubeIDE allow DIV1 prescaler for ASYNC clock, but not for SYNC clock, while the system clock is at 48 MHz (I understand why it should not be allowed due to the ADC clock speed limitation)?

[Stassen.C]

Currently CubeMX is not checking frequency input when using asynchronous mode. User must ensure a proper clock setting to respect max frequency and duty cycle ADC clock.

We will internally request to cover this feature.

Regards,
Stassen