Can someone please provide detail on the clock source for the SysTick in the nRF52? Is it clocked by the processor clock or an additional clock source? I'm trying to understand if it could be used when the processor is asleep?
There's a bit of info about the subject in this thread:
The SysTick is clocked from the cpu clock, and will only work when the CPU core is active (not in WFE/WFI).