https://devzone.nordicsemi.com/f/nordic-q-a/32454/setting-up-freertos-on-nrf52832Hi All, I&#39;m trying to add FreeRTOS into an existing project that is based off the UART example but has a lot of stuff stripped out of it. I&#39;ve been referencing the HRS FreeRTOS project to migrate differences. However, I&#39;m stuck at a point now whereen-USTelligent Community 13Mon, 19 Mar 2018 01:11:37 GMThttps://devzone.nordicsemi.com/thread/124887?ContentTypeID=1Mon, 19 Mar 2018 01:11:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:470d5cff-b683-4102-b427-6f0be76876f1leonhart88<p>Thanks RK.&nbsp; Yes I realize it means that the IRQHandler is being defined multiple times, but the Nordic SDK examples have both nrf_sdh.c and nrf_sdh_freertos.c both present in the project tree so I wasn&#39;t sure about simply removing one of them.<br /><br />After closer inspection at the source files for both nrf_sdh.c and nrf_sdh_freertos.c, the handler which the compiler is complaining about is only defined in nrf_sdh.c if the NRF_SDH_DISPATCH_MODEL == NRF_SDH_DISTPATCH_MODEL_INTERRUPT, which is what my working example was set to in the sdk_config.h.</p> <p>Looking closer at the SDK FreeRTOS example, I can see that sdk config parameter is set to polling, not interrupt.&nbsp; Changing to polling solved the issue.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/124848?ContentTypeID=1Sat, 17 Mar 2018 02:45:56 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c6c02b20-4f35-4cca-89fa-ef9dda90e7c0RK<p>the error message tells you where the symbol is multiply defined. You have two versions of the *sdh* routines in there, one the freertos one and one the usual one. Either remove nrf_sdh.c or nrf_sdh_freertos.c, I would expect removing the former is correct.&nbsp;</p><div style="clear:both;"></div>