https://devzone.nordicsemi.com/f/nordic-q-a/4017/chip-version-clock-problemI have two boards similar to www.aliexpress.com/.../1862953539.html openocd on one board shows: Info : nRF51822-QFAA(build code: G0) 256kB Flash and on the other it shows: Info : nRF51822-QFAA(build code: CA/C0) 256kB Flash CA/CO worksen-USTelligent Community 13Wed, 08 Oct 2014 03:24:41 GMThttps://devzone.nordicsemi.com/thread/14416?ContentTypeID=1Wed, 08 Oct 2014 03:24:41 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7ee76bde-d379-4cbb-8189-616ae574cba2Rick Bronson<ul> <li>SOLVED-</li> </ul> <p>Oops, sorry folks, I found that I was setting the XTALFREQ reg to 0 which sets it to 32 MHz. The only reason it worked on the CA/CO board is because there is an errata that says that register is non-functional on that version.</p> <p>Rick</p><div style="clear:both;"></div>