https://devzone.nordicsemi.com/f/nordic-q-a/14700/wdt-reset-upon-startup-of-nrf51After releasing reset to the nRF51, its UART is responding with RX: A4 1 6F 1 CB Further requests for things like capabilities, etc go ignored, and opening a working ANT channel obviously a no-go. Looking at the ANT_Message_Protocol document (pgen-USTelligent Community 13Mon, 11 Jul 2016 12:08:46 GMThttps://devzone.nordicsemi.com/thread/56093?ContentTypeID=1Mon, 11 Jul 2016 12:08:46 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a8be6bec-11e4-4874-a297-72617fbcdac3testy<p>I have the same response (nRF51422E0/<strong>s310_nrf51422_2.0.1_softdevice.hex</strong> + <strong>ant_network_processor_s310.hex</strong>/ + virtual COM/115200Bd), and everything works. Terminal shot shows HW and SW reset responses:</p> <p><img src="https://devzone.nordicsemi.com/cfs-file/__key/communityserver-discussions-components-files/4/nRF51a.PNG" alt="image description" /></p> <p>ANTware shot shows <strong>Network processor</strong> version:</p> <p><img src="https://devzone.nordicsemi.com/cfs-file/__key/communityserver-discussions-components-files/4/nRF51b.PNG" alt="image description" /></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/56092?ContentTypeID=1Thu, 07 Jul 2016 11:43:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1c6bee64-1aca-4344-8d19-92f28111dc81Stefan Birnir Sverrisson<p>Hi</p> <p>Only the first revision of nRF51 had preprogrammed S210 softdevice, as shown in the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf51/dita/nrf51/compatibility_matrix/nRF51422_nRF51822_ic_rev_sdk_sd_comp_matrix.html?cp=3_0_3">nRF51 compatibility matrix</a>. First revision came to market summer of 2012, and second revision in summer 2013 if I remember correctly. Im not sure what N5 devices have what nRF51 revisions, perhaps <a href="https://www.thisisant.com/developer/resources/tech-support/">Dynastream</a> know more about that.</p><div style="clear:both;"></div>