https://devzone.nordicsemi.com/f/nordic-q-a/4097/could-not-connect-to-the-target-chip1,I use nrfgo studio and can download softdevice ,it is OK. 2,I use the s110 example,it runs ok too. 3,I modify something from the example ,and click debug(keil),but it just earse the chip,and download the xxx.hex file,and it stop debug automaticlyen-USTelligent Community 13Wed, 15 Oct 2014 08:15:55 GMThttps://devzone.nordicsemi.com/thread/14675?ContentTypeID=1Wed, 15 Oct 2014 08:15:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:95039dcf-87f6-4d7a-83ec-ba72750f7c74Asbj&#248;rn<p>Are you programming a custom board with a voltage different from 3.3 V? Are you using the J-link lite from a Nordic nRF51-DK? The J-link lite can only program boards running at (or close to) 3.3 V. Please check the voltage on your board.</p> <p>What kind of connection do you have between the j-link and the board, is it a connector or is it a custom made interface? Any wires loose or switched/flipped around?</p> <p>If you open nRFgo studio and try to run recover from there, any success with this?</p> <p>What changes did you do to the code? Did you change anything in the Keil settings for the project?</p><div style="clear:both;"></div>