https://devzone.nordicsemi.com/f/nordic-q-a/76863/li005-error-iarHi I am merging BLE Peripheral code and I have added all .c files and added the path in C/C++ compiler and Assembler but it still shows definition missing You can see the .c file for ble_nus and ble_nus.h path is also added but still the same erroren-USTelligent Community 13Tue, 29 Jun 2021 13:48:29 GMThttps://devzone.nordicsemi.com/thread/317747?ContentTypeID=1Tue, 29 Jun 2021 13:48:29 GMT137ad170-7792-4731-bb38-c0d22fbe4515:74c068cc-56e5-41c0-9300-7b115c4c110fembedded_noob<p>Thanks for the quick response. This was my mistake I was not adding the sdk_config.h changes macros so they were not able to find the definitions.&nbsp;</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/317701?ContentTypeID=1Tue, 29 Jun 2021 12:13:39 GMT137ad170-7792-4731-bb38-c0d22fbe4515:061a0418-e737-4a11-ba7f-cbfcd4d4f520Sigurd<p>Hi,</p> <p>Based on your screenshot, I can&#39;t see that you have added the libraries needed, e.g. app_uart_fifo.c</p> <p><img src="https://devzone.nordicsemi.com/resized-image/__size/640x480/__key/communityserver-discussions-components-files/4/pastedimage1624968585576v1.png" alt=" " /></p><div style="clear:both;"></div>