example code for nrf9160 RTC and PSM mode to obtain minimum current consumption

[Nikunj]

Hello community,

I am trying to obtain minimum current consumption in dk. I found lot on internet but currently there is no example code for RTC and PSM mode. 

Can anyone suggest how to obtain minimum current consumption in dk and also How can I set manual sleep time and active time in PSM mode.

Thanks and regards,

Nikunj 

[Håkon Alseth]

Hi Nikunj,

 

Here's a blog post on how to do current consumption with PSM:

https://devzone.nordicsemi.com/nordic/cellular-iot-guides/b/hardware-design/posts/measuring-psm-idle-current-on-the-nrf91-dk

The kernel k_sleep() function uses the RTC in the background, so this would be power optimized in that sense.

 

How can I set manual sleep time and active time in PSM mode.

PSM timeout does not wake up the application. This is a modem side feature only, and it is currently not conveyed to the application. PSM interval should be set according to your applications need for receiving messages, but you can still send data at will.

For the "GPRS timer 3" specification, please see 3gpp ts 24.008 v15.5.0, chapter 10.5.7.4a (page 683). I would recommend that you go straight to the spec, but I also commented shortly on the GPRS timer 3 in the source:

https://github.com/Rallare/fw-nrfconnect-nrf/blob/nrf9160_samples/samples/nrf9160/udp_with_psm/src/main.c#L91

 

The active time for PSM can be set with this config:

https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/drivers/lte_link_control/Kconfig#L37

Do note that this active time uses "GPSR timer" specification, which is different from the requested periodic TAU ("sleep time").

 

Kind regards,

Håkon