nRF9160/SLM sleep power consumption increases ~20uA after wakekup and AT#XSLEEP=2

[Michal Mühlpachr]

After power-up and RESET by RESET pin, power consuption of nRF9160 is ~2uA.

After wakeup by WAKEUP pin and AT#XSLEEP=2 power consuption is ~23uA.

What causes increased power consuption please ?

Power consuption is measured by Power Profiler Kit II.

NCS 2.0.2
Serial LTE Modem
nRF9160DK
modem firmware 1.3.1
prj.conf changes from default in NCS 2.0.2
CONFIG_SLM_START_SLEEP=y
CONFIG_SLM_WAKEUP_PIN=6
CONFIG_SLM_INDICATE_PIN=2
CONFIG_NRF_MODEM_LIB_TRACE_ENABLED=y

Full AT dialogue:

[PPK2] DUT Powered, Measurement started
0.15 <RESET> Wed Aug 24 23:38:37 2022
1.05 [PPK2] 100k/s AVG 4.31 mA Max 33.8 mA
2.04 [PPK2] 100k/s AVG 1.83 mA Max 32.7 mA
3.01 [PPK2] 100k/s AVG 0.002mA Max 0.008mA
4.01 [PPK2] 100k/s AVG 0.002mA Max 0.008mA
5.03 [PPK2] 100k/s AVG 0.002mA Max 0.009mA
5.08 <WAKEUP>
6.01 [PPK2] 100k/s AVG 1.32 mA Max 26.2 mA
6.46 [RX] Ready
7.05 [PPK2] 100k/s AVG 3.39 mA Max 34.7 mA
8.02 [PPK2] 100k/s AVG 1.02 mA Max 2.97 mA
9.05 [PPK2] 100k/s AVG 1.01 mA Max 1.71 mA
10.05 [PPK2] 100k/s AVG 1.01 mA Max 1.97 mA
11.03 [PPK2] 100k/s AVG 1.01 mA Max 1.75 mA
11.58 [TX] AT#XSLEEP=2
11.58 [RX] OK
12.04 [PPK2] 100k/s AVG 0.703mA Max 4.65 mA
13.02 [PPK2] 100k/s AVG 0.023mA Max 0.029mA
14.02 [PPK2] 100k/s AVG 0.023mA Max 0.031mA
15.01 [PPK2] 100k/s AVG 0.023mA Max 0.030mA
16.03 [PPK2] 100k/s AVG 0.023mA Max 0.029mA
17.02 [PPK2] 100k/s AVG 0.023mA Max 0.029mA

[Stian Røed Hafskjold]

Hello, I have not been able to test this yet, but I'm suspecting that you need to add the wakeup pin to the edge sense mask. The pin interrupts are configured to use the GPIOTE IN event by default, which will consume more current. The alternative is to use the GPIO SENSE event (GPIOTE PORT). The way to configure the GPIO to use the sense event has changed in recent versions of the nRF Connect SDK. You can read the documentation here: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/build/dts/api/bindings/gpio/nordic,nrf-gpio.html?highlight=sense%20edge%20mask

or check out my answer here:  RE: nRF9160: LIS2DW12 high current consumption

Best regards,
Stian

[Michal Mühlpachr]

Do you mean, the https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/serial_lte_modem/README.html require fix ?

Regards,
Michal

[Stian Røed Hafskjold]

Hi, I did some more testing and I can see the same current consumption here with the prj.conf changes you are using. There is no need to patch the SLM application as indicated in my first reply.

When you reset the chip, it starts up in system OFF mode, which has the lowest current consumption, because nothing is running on the chip.

Then after you wake up and go back to sleep using AT#XSLEEP you can choose between going back to system OFF again (AT#XSLEEP=1) or continue in system ON idle mode (AT#XSLEEP=2), which will keep the application RAM retention, application RTC running (and the modem connected if initialized):

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/serial_lte_modem/doc/Generic_AT_commands.html#id8

The expected current consumption for system OFF is 1.4 uA, and for system ON idle you have 2.2 uA:

https://infocenter.nordicsemi.com/topic/ps_nrf9160/_tmp/alta.nRF9160/autodita/CURRENT/parameters.id_current_sleep.html?cp=2_0_0_4_5_0_1

I can see that you enable modem trace in the prj.conf file, CONFIG_NRF_MODEM_LIB_TRACE_ENABLED=y. This will consume an additional 10-20 uA. If you set this to =n you should see around 2.2 uA after calling AT#XSLEEP=2.

Best regards,
Stian