https://devzone.nordicsemi.com/f/nordic-q-a/103924/nrf52840-reset-pin-does-not-workNRF52840 uses 2.5V power supply. We found that when the voltage drops below 1.7V, even if the voltage returns to 2.5V, the entire system cannot work and JLINK cannot connect to the device. Short circuiting the RESET pin at this time also has no effecten-USTelligent Community 13Fri, 19 Jul 2024 18:42:28 GMThttps://devzone.nordicsemi.com/thread/494885?ContentTypeID=1Fri, 19 Jul 2024 18:42:28 GMT137ad170-7792-4731-bb38-c0d22fbe4515:88e5db8c-4dcc-4742-8eff-91964a80bc93d_b<p><a href="https://devzone.nordicsemi.com/members/yinxu951">yinxu951</a>&nbsp;did you figure out the root cause? We are dealing with something similar.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/446841?ContentTypeID=1Wed, 20 Sep 2023 11:28:42 GMT137ad170-7792-4731-bb38-c0d22fbe4515:69d456ad-4619-4f1b-9e24-a45624bb18a2Priyanka<p>Hi Tom,</p> <p>The power on reset could be occurring, possibly due to long rise times of the supply. Did you try to physically reset the device?&nbsp;</p> <p>Best Regards,</p> <p>Priyanka</p><div style="clear:both;"></div>