Oscillators regarding consumption and wake up time

[Salmat]

Hi,
I have questions regarding consumption. Especially regarding the Quartz oscillator.
I have read stabilisation is up to 0.4ms (very long).
There is also the internal RC oscillator that is much quicker : 3us

The problem is I am using Softdevice, with BLE, so I need the Quartz oscillator

I also have sensors that need 1k readings per second.

That gives a near half the time awaken ! So a much higher consumption than if I was using the internal RC oscillator !

My question is, is there any mechanism for executing code before the quartz is stabilised ?

Even for the softdevice / BLE, I imagine it does not really need the quartz to be stabilised for all processings ?

Regards,

[Simonr]

Hi Matthieu

You can see the electrical specifications of the RC oscillator (LFRC) and the crystal oscillator (LFXO) in the product specifications here. The crystal oscillator is by far the most energy-efficient, as it has a lower run current, it doesn't have to calibrate as the RC does, and it has a lower PPM. The start-up time does not have too much to say, as the LF clock will run as long as the SoftDevice is active anyway. 

The SoftDevice will start up the LF clock when it is activated, that's not optional I'm afraid, so you'll have to use the LF clock in order to use BLE on the chip.

Best regards,

Simon

[Salmat]

Hi,

Sorry I am only talking of hfclk !

But I have my response, I tested with oscilloscope on some ble examples, and Quartz is only used when requested by nrf_drv_clock_hfclk_request

The normal execution is on internal oscillator, so it is perfect for me !

Regards,