sd_power_system_on() not available in nrf5 SDK15.3.0

[Yogeshwaran]

I am working in nrf52840 sleep mode and it is working perfectly in system_off() mode, but while trying to wakeup from sleep using timer the device is not waking up because CPU made off using system_off() function. Basically i want my device will go to sleep and wake up using software interrupt(timers) and advertise then go to sleep. But in ble_app_uart example present in SDK 15.3.0 has sleep_mode_enter() function which has system_off(), and i could not able to run any timer(CPU off) in sleep, so i looked in other SDK examples there were sd_power_system_on() function which i could not able to find in SDK 15.3.0 documentation.

can you tell me how to make CPU on(sd_power_system_on()) in ble_app_uart example and how to implement interrupt to wakeup nrf by using timers?

[Jørgen Holmefjord]

Hi,

You can enter system ON mode by calling softdevice function sd_app_evt_wait().

Best regards,
Jørgen

[Yogeshwaran]

Thank you sd_app_evt_wait() was working and app timer running background will trigger the timer handler then i could see advertising data, but power consumption was 0.92 mA when there is no advertisement. I am measuring using multimeter with USB powered. If i use 3 v power supply ext with VEXT ON, power switch on, multimeter connected and nrfswitch is on but i could not see any board led turning On.

What could be the issue and how to reduce power?

[Jørgen Holmefjord]

Which example do you run? Are you sure that your multimeter are able to follow and measure the quickly switching current consumption?

I would recommend getting a Power Profiler Kit for accurate current measurements.

[Yogeshwaran]

i am using ble app uart example and adv timeout was 10 sec after that i am calling sd_app_evt_wait() so timer i set for 20 sec. approx 10 sec device is in idle mode and i want to measure current in this period. My doubt was how can i disconnect interface Mcu power and only make nrf run alone

[Jørgen Holmefjord]

If you set VEXT to ON and SW6 to "nRF ONLY", only nRF should consume current. Note that all LEDs on the DK are powered from VDD, and will not turn on when "nRF ONLY" is set.

Have you disabled UART in the ble_app_uart example? It could be that UART is enabled in RX mode, which will increase current.