use rtx on S310https://devzone.nordicsemi.com/f/nordic-q-a/18142/use-rtx-on-s310hi. this is my code that i copied from ble_app_hrs_rtx . osPoolDef(ble_evt_pool, 8, ble_evt_t); /**&lt; Definition of memory pool for ble_stack_thread */ osPoolId ble_evt_pool; /**&lt; Memory pool for ble_stack_thread */ osMessageQDef(ble_stack_msg_boxen-USTelligent Community 13Tue, 06 Dec 2016 09:23:20 GMTRE: use rtx on S310https://devzone.nordicsemi.com/thread/70012?ContentTypeID=1Tue, 06 Dec 2016 09:23:20 GMT137ad170-7792-4731-bb38-c0d22fbe4515:fc111bed-26cd-4662-863b-ef97bc9db56aPetter Myhre<p>What SDK and SoftDevice version are you using? Are you sure you need an RTOS? If you need an RTOS we recommend using FreeRTOS.</p><div style="clear:both;"></div>