STM32U585 IWDG Early Wakeup Interrupt and Stop modes

[BDoon.1]

The manual I have for the STM32U585 describes the Independent Watchdog (IWDG) peripheral and says it has an Early Wake-Up Interrupt (EWI) feature.  The manual says "Wake-up from Stop with interrupt is supported only in Stop 0, Stop 1, and Stop 2 modes", but I found this in the U585 Errata:

"The independent watchdog (IWDG) is functional in Stop mode and the device exits Stop 0, Stop 1, Stop 2 and
Stop 3 modes in case of IWDG reset.  However, the early wakeup interrupt does not wake up the device from Stop 0, Stop 1 and Stop 2 modes.
Note: As specified, the IWDG early wakeup interrupt does not wake up the device from Stop 3 mode."

Does this mean that the EWI will only work if the processor is in run mode when it occurs?  Will it work in Sleep mode?

[STOne-32 · Accepted solution]

Hi @BDoon.1 

Yes, your understanding is correct EWI from IWDG work only on run and sleep modes on STM32U585 series, However this Errata is fixed on others parts such as STM32U545 and others  and you can use EWI in STOP 0, 1 and 2.

STOP3 and standby not possible as the clocks are stopped.

Hope it helps you

STOne-32.