Nrf52 XIAO keeping track of time in deep sleep?

[Philipp_W]

Is it possible to enter deep sleep, but keep track of the time?

sd_power_system_off();

I’m using the arduino framework where you can get millis() since start-up. Is there a way to get millis the device was shut down for without any additional hardware like an RTC?

[PJ_Glasso]

Hi there,
I would use RTC for most reliable and accurate* But others have used the SAMD-21
like in this link.https://forum.arduino.cc/t/low-power-sleep-how-to-keep-track-of-time/1091051

LowPower.deepSleep(milliseconds);

HTH
GL PJ

[Tobias]

Can the Nrf52 XIAO wake up from deep sleep at specific time intervals? If so, how is this achieved?

[PJ_Glasso]

Hello,
Have a LQQK at this, The Xiao Nija Msfujino’s excellent work and research on it

XIAO_BLE wakes up from System_ON_Sleep and Writes weather data to on-board Flash

In a project to periodically write data to an on-board flash memory, I used System_ON_Sleep to reduce the standby current to 1/60th of its default value. As a practical example, described here is that XIAO wakes up from System_ON_Sleep every hour and records temperature, humidity, and barometric pressure data measured by the BME280 into 2MB of > on-board flash memory.Measures to reduce current consumption include… nRF52840: REG 1 in DC/DC mode, System_ON_Sleep mode, and wake-up with RTC inter…

HTH
GL