Mention RTCAPBAMEN in the RTC section of STM32U5 reference manual

[Uwe Bonnes]

While older MCU needed an EXTI line enabled to allow  RTC alarm to wake up the CPU from Stop, for STM32U5 both RCC->APB3SMENR (11.8.44) and RCC->SRDAMR (11.8.45)  mention a requirement to allow the RTC lto wake up from Stop modes. No further explanation is given in RM0456 Rev 5 oa AN4759 Rev9.

Please explain and update in the documentation.

[STOne-32]

Dear @Uwe Bonnes ,

in Our STM32U5 Ultra low power MCUs , we introduced « Smart Run Domain » to keep peripherals active and able to Operate . This was not the case in older series . For more details here are some Online Trainings :

 https://www.st.com/content/st_com/en/support/learning/stm32-education/stm32-online-training/stm32u5-online-training.html

• https://www.st.com/content/ccc/resource/training/technical/product_training/group1/95/38/81/9b/cb/0d/43/89/STM32U5-System-Power-management_PWRMNGMNT/files/STM32U5-System-Power-management_PWRMNGMNT.pdf/_jcr_content/translations/en.STM32U5-System-Power-management_PWRMNGMNT.pdf
  
  

• https://www.st.com/content/ccc/resource/training/technical/product_training/group1/5b/97/7e/f7/55/b5/43/15/STM32U5-System-Reset-and-clock-controller_RST_CLK_CTRL_Rev2-1/files/STM32U5-System-Reset-and-clock-controller_RST_CLK_CTRL_Rev2-0.pdf/_jcr_content/translations/en.STM32U5-System-Reset-and-clock...

Hope it helps ,

STOne-32

[Uwe Bonnes]

How to find those trainings?

A search "rtc online training" on the ST website  gives 97 results, mostely named "STM32XX online training". To scan for a fitting hit istedious!