possible to shutdown soft device or BLE after init to achieve low power?

RE: possible to shutdown soft device or BLE after init to achieve low power?

Ole Bauck — Tue, 15 Dec 2015 11:49:50 GMT

If the answer was correct, please accept and close the question. This is important for the forum as other users know if the answer was correct.

RE: possible to shutdown soft device or BLE after init to achieve low power?

Ole Bauck — Thu, 26 Nov 2015 09:46:03 GMT

The SoftDevice does not stop the LFCLK when it disables because other modules may use it (like app_timer). To stop the LFCLK add this line of code (after softdevice is disabled):

NRF_CLOCK->TASKS_LFCLKSTOP = 1;

RE: possible to shutdown soft device or BLE after init to achieve low power?

Brian — Thu, 26 Nov 2015 01:34:03 GMT

Thanks Ole! Understood. But, shouldn't we be able to turn off the soft device, after we have initialized it so that we shutdown the clock all together and get back to ~2.2uA as measured before we initialized BLE?

...by calling these functions? softdevice_handler_sd_disable(); sd_softdevice_disable();

RE: possible to shutdown soft device or BLE after init to achieve low power?

Ole Bauck — Tue, 24 Nov 2015 09:28:36 GMT

You are using synthesized LFCLK. This requires the HFCLK to be running. To get 250ppm accuracy, the HFCLK must be generated from the HFCLK crystal oscillator. I tested and get around 300uA.

I suggest you use NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION instead.