https://devzone.nordicsemi.com/f/nordic-q-a/17241/how-many-way-for-wack-up-my-chip-nrf51i m using nrf51.... first i have call WFI(); and device goes to sleep mode...and when press any switch on gpio so, wack-up again...so, may i know that.. how many way for wack-up my chip.....like as.. switch press, interrupt call, and other.. i m not knowen-USTelligent Community 13Wed, 26 Oct 2016 07:48:52 GMThttps://devzone.nordicsemi.com/thread/66227?ContentTypeID=1Wed, 26 Oct 2016 07:48:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:144c9e4f-84b3-4bdc-b7f2-4df43880637eSigurd<p>In WFI sleep the CPU will wake up as a result of an interrupt request if the associated interrupt is enabled in the NVIC.</p> <p>If you are using the SoftDevice, you should instead use the power management functions provided by the SoftDevice. The equivalent to WFI is <a href="https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s130.api.v2.0.1/group___n_r_f___s_o_c___f_u_n_c_t_i_o_n_s.html#ga11d88d38ac99fb72cde74c9385d36433">sd_app_evt_wait()</a>, which will put the chip in System ON sleep mode until an event occurs. This function will wake up the CPU to process SoftDevice events, but it will not exit until an application event occurs, so to the application it looks like you are in sleep all the time. To wake up the chip from system ON sleep mode, any application event can be used.</p><div style="clear:both;"></div>