Need to set up NRF51822 to low power mode each 2 seconds.

[Sergey]

We been developing device based on NRF 51822 (NRF51822-CFAC-R) (62-UFBGA, WLCSP).

We plan to use 2032 battery, and need at least one year of autonomous BLE work, our device configured like Ibeacon .

Now our developers have some questions regarding power consumption:

• What is the best way to switch MCU to low power mode? And what periphery will not work?
• How can we turn on/off low power mode by software let’s say each 2 seconds?

[Håkon Alseth]

Hi,

Since you need to wake up every two seconds, I would recommend using the app_timer module with a repeated instance. Most of our BLE examples (if not all) use the app_timer module, so it should be straight forward to add a new instance. The app_timer module uses the RTC peripheral, which provides low consumption in sleep.

To enter sleep, you can use the softdevice call "sd_app_evt_wait()" function. Between the intervals, the consumption shall then around 2-3 uA, given that no other high-speed peripherals are running (TIMERx, UART, TWI, or similar).

Cheers, Håkon

[Sergey]

Hi,

We will try it.