RE: Sleep and Wakeup without GPIO

Kashinath — Mon, 04 Jun 2018 09:16:56 GMT

Thank you Einar Thorsrud for your reply..

I will try with this and let you know...

Regards

Kashinath

RE: Sleep and Wakeup without GPIO

Einar Thorsrud — Mon, 04 Jun 2018 06:35:09 GMT

Hi,

The RTC (using the 32 kHz clock) is a low power timer that is typically used for exactly this. For example, the SoftDevice use RTC0 to wake up for every BLE event. I recommend you to use the app timer (Timer library) which is a user friendly software library that allows you to make an arbitrary number of single shot or repeated timers using RTC1. The application will get an event (due to a RTC interrupt) whenever the timer expires. The app timer is explained in this tutorial (unfortunately somewhat outdated).

Make sure to put the CPU to sleep when it is idle, by calling something like the following function in the main loop (assuming no SoftDevice is used):

static void sleep_handler(void)
{
    __WFE();
    __SEV();
    __WFE();
}

Alternatively, use nrf_pwr_mgmt_run() from the power management library (works both with or without SoftDevice) or sd_app_evt_wait() directly (only if SoftDevice is used).