https://devzone.nordicsemi.com/f/nordic-q-a/56201/compilation-problemHello, I have a problem with SDK16 setting. I have this error : error: &#39;old_val&#39; undeclared (first use in this function) I include these files and folders # Source files common to all targets SRC_FILES += \ $(SDK_ROOT)/modules/nrfx/mdk/gcc_startup_nrf51en-USTelligent Community 13Thu, 09 Jan 2020 10:14:10 GMThttps://devzone.nordicsemi.com/thread/228315?ContentTypeID=1Thu, 09 Jan 2020 10:14:10 GMT137ad170-7792-4731-bb38-c0d22fbe4515:5d0b0225-b417-4ff7-8422-a9e5e5a55fc6Christophe<p>Thank you Susheel for your help. I will use sdk16 just for NRF52 !</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/227858?ContentTypeID=1Tue, 07 Jan 2020 10:55:27 GMT137ad170-7792-4731-bb38-c0d22fbe4515:98fa13a5-50db-42d5-923c-119ee1f4207cSusheel Nuguru<p>I am not sure if SDK16 has been tested with nRF51 variants at all. So there could be many things that compile fine for CortexM4 (nrf52) but many libs could have been broken for nRF51 in SDK16.&nbsp;</p> <p>reference of supported <a href="https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcomp_matrix_nrf51%2FCOMP%2Fnrf51%2FnRF51422_nRF51822_ic_rev_sdk_sd_comp_matrix.html&amp;cp=5_0_5">SDKs </a>for nRF51</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/227688?ContentTypeID=1Mon, 06 Jan 2020 13:31:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3ce94dd0-bb18-4c9b-b2de-38980b3ecd4eChristophe<p>Thank you Susheel. I have made the migration from SK12 to SDK 16 in order to&nbsp;update my project with nrf52. I will downgrade to continue using NRF51. However, I havn&#39;t seen that SDK16 couldn&#39;t be compatible with NRF51.</p> <p>Thank you <span>Susheel&nbsp;</span>for your help !</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/227653?ContentTypeID=1Mon, 06 Jan 2020 12:34:53 GMT137ad170-7792-4731-bb38-c0d22fbe4515:76be76c0-18a8-4799-bd4b-fd16e09e1f78Susheel Nuguru<p>You were not supposed to use SDK16 for nRF51 devices, please use SDK12.3 for that.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/227545?ContentTypeID=1Sun, 05 Jan 2020 18:56:33 GMT137ad170-7792-4731-bb38-c0d22fbe4515:16e75fe0-ba89-45e5-a3c0-ed515d915623Christophe<p>Sorry I didn&#39;t precise that the problem is linked with <code>$(SDK_ROOT)/</code>components/libraries/atomic/nrf_atomic.c</p><div style="clear:both;"></div>