https://devzone.nordicsemi.com/f/nordic-q-a/1304/segger-on-nrf51822-evaluation-board-fails-to-connectI have used the NRF51822 evaluation kit for a while now to design a product and it performed perfectly up until a few days ago: the onboard segger now fails to connect to the Nordic. Whatever I try to do, program or debug, I get an error message statingen-USTelligent Community 13Wed, 09 Apr 2014 11:55:09 GMThttps://devzone.nordicsemi.com/thread/5988?ContentTypeID=1Wed, 09 Apr 2014 11:55:09 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d73f4a7f-8336-4eba-95c4-b3a835810d94Asbj&#248;rn<p>It sounds like the power supply on the nRF51822 is too low. The Segger J-link lite must have a VDD of about 3.3 V, but battery of 3.0 V works as well. What are you using as a power source? USB or battery on the evalkit? Could you measure the VDD on the chip with a voltmeter to make sure?</p><div style="clear:both;"></div>