RE: nRF9160 LFCK setup needed to be done by the app or handled inside bsd-lib?

lobaro-theo — Wed, 23 Oct 2019 17:41:33 GMT

Okey thank you. Just wanted to make sure that the bsd lib does not init it correctly on startup.

RE: nRF9160 LFCK setup needed to be done by the app or handled inside bsd-lib?

Håkon Alseth — Tue, 22 Oct 2019 07:47:46 GMT

Hi Theo,

[quote user=""]Is it in the responsibility of the application to setup the LFCLK clock accordingly or does the BSD lib do it internally if needed?
For what tasks the bsd lib and / or LTE modem does use the LFCLK? [/quote]

There is a lot of timing related operations in the M1 and NB1 protocol, and since they might also be scheduled ahead of time, let's say that you wake up every 120 seconds on eDRX, its crucial to use the LFXO (+/- 20 ppm tolerance) to obtain both low power and best tolerance timing. This is not obtainable if you are using a clock source that has a tolerance in the percent area.

If you are using the modem, you should set LFXO as your 32k clock source.

Kind regards,

Håko