I have three questions regarding the STM32U083RC：
1.Why is the reset value of EXTI_IMR1 register 0xFFF80000？The EXTI line 19-21 is configurable lines。
2.I encountered a problem: when I used the NUCLEO-U083RC demo program to PWR_STOP2_RTC, I found that when the bit28 of the EXTI_IMR1 register was configured to 0 or 1, the RTC could wake up the MCU from stop mode. Why is the function of EXTI_IMR1 register not working?
3.Why does RTC/TAMP describe combined with EXTI lines 19 & 21 in the Vector table?
