nRF9160 PSM current consumption test problem

[dacheng]

Hi Nordic：

I burned the AP & Modem firmware in the picture below, and found that the current consumption when entering PSM is 500μA. Please help to analyze. What caused it?

Attachment is hardware & software & log. nrf9160.docx

Many thanks

[Håkon Alseth]

Hi,

 

The base current when UART is on, is 500 uA, so when testing with at_client, this is expected. Disabling UART in at_client essentially breaks the application, so I would not recommend to optimize it further. In general, you can add "CONFIG_SERIAL=n" to the prj.conf to disable uart printing, but there's a catch with this as there's a secure and non-secure image running.

When testing PSM with an application, remember to disable serial in the secure part, spm, as well. This can be done by adding this to the CMakeLists.txt file in your project folder, just below the "cmake_minimum_version" line:

if (EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/spm.conf")
  set(spm_CONF_FILE
    prj.conf
    ${CMAKE_CURRENT_LIST_DIR}/spm.conf
  )
endif()

 

if (EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/mcuboot.conf")
  set(mcuboot_CONF_FILE
    prj.conf
    ${CMAKE_CURRENT_LIST_DIR}/mcuboot.conf
  )
endif()

 

if (EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/${BOARD}.overlay")
  set(mcuboot_DTC_OVERLAY_FILE "${CMAKE_CURRENT_SOURCE_DIR}/${BOARD}.overlay")
  set(spm_DTC_OVERLAY_FILE "${CMAKE_CURRENT_SOURCE_DIR}/${BOARD}.overlay")
endif()

 

then you create a file named "spm.conf", with CONFIG_SERIAL=n.

 

Kind regards,

Håkon

[dacheng]

Hi Håkon

Thank you very much for your answers.The UART of my firmware is not turned off.
I have read the specification of nRF9160.Its current consumption in PSM and eDRX modes is 4uA and 19uA respectively, which is really low, especially EDRX, but I still want to actually test it. Do you have a hex file that can verify the current consumption of PSM & EDRX?

Thank you in advance.

Best regards

Dacheng

[Håkon Alseth]

Hi,

 

There's an older sample for psm available here:

https://github.com/Rallare/fw-nrfconnect-nrf/tree/nrf9160_samples/samples/nrf9160/udp_with_psm

 

If you already have an example that goes into sleep (with low consumption), you can request eDRX or PSM using these function calls:

https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/lib/lte_link_control/lte_lc.c#L458

https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/lib/lte_link_control/lte_lc.c#L349

 

Kind regards,

Håkon