Hi Dominic,
(1) Because when enter in LLS mode, the core clock will be off, so your systick will stop work.
If you want your systick work again after your wakeup from the LLS mode, you'd better reenabale your systick again.
(2) if you want to enter the LLS lowpower mode, after you wakeup, you don't need to call Cpu_SetOperationMode(DOM_RUN, NULL, NULL); because after you use LLWU wakeup source, the MCU will
automatically went to RUN, you don't need to call the function in the LLSWakeUp interrupt.
Wish it helps you!
If you still have question, please contact me!
Have a great day,
Jingjing
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