how works the CSS clock detection when he is enable?

[GOnkelinx]

Hi,

We had enable the Clock secure system in out project.
How works this?
When the source clock fails what we must doing in the call-back HAL_RCC_CSSCallback()?

regards

[STTwo-32 · Accepted solution]

Hello @GOnkelinx and welcome to the ST Community 😊.

According to the RM0444 part 5.2.9, if the CSS is enabled and a HSE failure is detected:

• The HSE is automatically disabled and the system clock switch automatically to HSI.
• A clock failure event is sent to the break input of TIM1, TIM15, TIM16 and TIM17 timer.
• CSSI (clock security system interrupt) is generated.

For the HAL_RCC_CSSCallback(), you need to write the instructions you want to execute in response to the event.

Best Regards.

STTwo-32