https://devzone.nordicsemi.com/f/nordic-q-a/25420/nrf52832-of-uart-problemi am using uart of nrf52832. the SDK is nRF5_SDK_12.3.0_d7731ad. the uart is app_uart .when i was testing the uart sending and receing .i find that the uart is stoping where while (!nrf_uart_event_check(p_instance-&gt;reg.p_uart, NRF_UART_EVENT_TXDRDYen-USTelligent Community 13Mon, 25 Sep 2017 09:18:54 GMThttps://devzone.nordicsemi.com/thread/100187?ContentTypeID=1Mon, 25 Sep 2017 09:18:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:106df93b-955d-46dc-ba63-490cf06c7733MartinBL<p>From what context are you starting the UART? Could it be an interrupt <a href="https://devzone.nordicsemi.com/question/79226/can-ble_nus_string_send-be-called-from-a-twi-callback/">priority</a> or <a href="https://devzone.nordicsemi.com/question/68758/twi-function-not-working-when-called-from-a-pin-interrupt-handler/">nesting</a> issue? <a href="https://devzone.nordicsemi.com/question/157734/not-getting-nrf_spi_event_ready-event/">This</a> is a very similar case, only the guy is using SPI.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/100189?ContentTypeID=1Sun, 24 Sep 2017 09:22:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:152d21f3-d325-4aaa-9c3d-e68ac852fd53RichieJH<p>First thing to do is to actually see what your return value is. This will then indicate the problem.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/100188?ContentTypeID=1Sun, 24 Sep 2017 02:06:45 GMT137ad170-7792-4731-bb38-c0d22fbe4515:68568300-1a49-45e2-8c4a-fb2adbd27d30lenli<p>the testing time is about from 1 hour to 2 hours. the problem will be happen .</p><div style="clear:both;"></div>