RE: question of low power mode

Håkon Alseth — Thu, 27 Feb 2014 12:13:19 GMT

Hi,

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. For your application, there's no need to keep the 16M running in sleep mode.

You can check if your code goes into system off by looking for this function call: sd_power_system_off();

Most likely, it's in the function "on_ble_evt", case "BLE_GAP_EVT_TIMEOUT". To wake up on RTC instead, make sure that "power_manage" is called in your main-loop, and comment out the function call to sd_power_system_off().

Best regards Håkon