https://devzone.nordicsemi.com/f/nordic-q-a/13605/rtc1-timer-reset-after-sleepI configured my system to sleep after inactivity time. nrf_gpio_cfg_sense_input(WAKE_UP, NRF_GPIO_PIN_NOPULL, NRF_GPIO_PIN_SENSE_HIGH); err_code = sd_power_system_off(); when the system wake up from sleep (I use external acceleromter to wakeen-USTelligent Community 13Tue, 03 May 2016 06:10:23 GMThttps://devzone.nordicsemi.com/thread/51926?ContentTypeID=1Tue, 03 May 2016 06:10:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:109b70c3-4ff4-4474-bd6f-c191a78b1941Susheel Nuguru<p>system sleeping is executing ARM instruction __WFE (also called system idle) and SYSTEM OFF is deepest power state set by NRF_POWER-&gt;SYSTEM_OFF register. These two are different things. RTC will keep on running in system_idle state even after it wakes up, but, in system_OFF state, it does not.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/51925?ContentTypeID=1Tue, 03 May 2016 05:52:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:40b69012-994e-4ef8-ba20-4ac092715fe4makouda<p>answering this [question] (in the quetion comments) you said that &quot; a nordic employee said&quot; the RTC1 timer still running when the system is sleeping. if it&#39;s running how can I prevent it from resetting at startup, I really need to trace the time spent on sleep (<a href="https://devzone.nordicsemi.com/question/68976/nrf51-not-waking-up-if-sleep-time-exceed-5-hours/)">devzone.nordicsemi.com/.../)</a></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/51924?ContentTypeID=1Mon, 02 May 2016 18:29:44 GMT137ad170-7792-4731-bb38-c0d22fbe4515:016e6f3e-807a-4eab-aa96-7748742248b7Susheel Nuguru<p>Wakeup from system off (not WFE) )will cause a system reset and hence will reset almost all of the peripherals (exceptions are RAM and few registers). RTC will also be rest on wakeup from system off.</p><div style="clear:both;"></div>