behavior after STOPMode

[curiae]

Hello,

I observed how is going after HAL_PWR_EnterSTOPMode() execution without setting by HAL_RTCEx_SetWakeUpTimer_IT().
Then strange phenomenon occurred.
I presumed that power stop mode continues till interrupt and systick works even under power stop mode before experiment.
But after dozens of seconds from entering stop mode, MPU wokeup through reset and systick stopped.
How could I realize that systick works normally under power stop mode and not to wake up till interrupt?
Thanks,

[Sarra.S]

Hello @curiae, 

The SysTick timer is part of the Cortex core and is not clocked when the MCU is in STOP mode. After wakeup, it resumes the countdown from the value it contained before the WFI instruction.