nRF52: Time from calling __WFI() to HFINT turn off?

[CurtisHx]

Assuming that all peripherals that require the high frequency clock are disabled / turned off / stopped, how long does the HFINT oscillator run after calling __WFI()?

And if it's greater than 1ms or so, is there any way to shut it off faster?

[CurtisHx]

If HFCLK is already powered down by the time __WFI() is called, then what's the CPU running off of?

[CurtisHx]

I'm not quite sure what happened there... I thought I had clicked on on the "add a comment" button, and now I can't put the original answer back. I think I just made a whoopsie doodles.

[Susheel Nuguru]

Hi, I am not thinking straight today .. sorry for that answer. I had to delete it not to look stupid to others :)

The startup time for internal HF internal CLK is given to be 3us. I am pretty sure it will be stopped faster than 1ms.

[Susheel Nuguru]

You are very sane, i am thinking like a noodle today .. sorry for that. I am curious, of why it is important for you to know HFCLK stop time. what is the use case?

[CurtisHx]

I'm working on a project where we are trying to squeeze every last electron we possibly can from our battery, since the device is essentially disposable. Once the battery runs out, the device is dead. A few 100uA for a few milliseconds can mean a few months less battery life.

[Susheel Nuguru]

I understand. Like I said, i am pretty sure it should not take more than few HFCLK cycles. I got this confirmed from the hardware designer.