nrf91 SystemOff switch off periphicals of SoC

RE: nrf91 SystemOff switch off periphicals of SoC

Kazi Afroza Sultana — Mon, 18 Mar 2024 09:57:00 GMT

Hello,

'' Since it is not mention directly in most sample 'main.c' files, the header file describing NRF_POWER is included by means of chosing the board, f.e. "nrf9160dk_nrf9160_ns"?''

NRF_POWER->TASKS_LOWPWR is the default option (ie: reset value), which means that the 16M clock will be stopped when not needed. This will cause your wakeup time to be higher, compared to when using CONSTLAT. CONSTLAT will keep the 16M running while in sleep, which gives you a consistent wakeup time, but higher current consumption.

You can build for both secure and non-secured board. This #include <hal/nrf_power.h> header file will work for this option.

''I see that my task #3 is not feasable using only internal RTC or watchdog of 9160 sip. It would need external IC for that.''

It depends on your application. Can you show your application? For low power mode, you can start with UDP sample.

RE: nrf91 SystemOff switch off periphicals of SoC

Stefan123 — Wed, 13 Mar 2024 09:04:31 GMT

Hi,
thanks for pointing that getting started blog post. I read it, and it has few more basic information about current measurements and it is indicating to switch off modem (even if you not used it at all). Since i already looked into https://docs.nordicsemi.com/bundle/ug_nrf91_dk/page/UG/nrf91_DK/hw_measure_current.html . It would be great to see a link to addtional guides over here: https://docs.nordicsemi.com/category/nrf-91-series# Guidelines

Thanks for
NRF_POWER->TASKS_LOWPWR = 1
i placed it as first line in main method. Seem to have an effect.

Following the path to sources of "NRF_POWER" in vsCode, I see that there are more things i can enable/disable by one of the other structure there.

Question: Since it is not mention directly in most sample 'main.c' files, the header file describing NRF_POWER is included by means of chosing the board, f.e. "nrf9160dk_nrf9160_ns"?

I see that my task #3 is not feasable using only internal RTC or watchdog of 9160 sip. It would need external IC for that.

Question: What would be the memory layout if i want to use data-retention in my task #2?

RE: nrf91 SystemOff switch off periphicals of SoC

Kazi Afroza Sultana — Mon, 11 Mar 2024 14:32:45 GMT

Hello,

Have you read this blog (+) Getting started with current measurements on the nRF9160 - nRF9x - Hardware design, test and measuring - Nordic DevZone (nordicsemi.com)?

Before main function of the application, you can try to add NRF_POWER->TASKS_LOWPWR = 1 to get the low power.