https://devzone.nordicsemi.com/f/nordic-q-a/41383/how-to-improve-uart-driving-forceNRF52832 SDK 15.2 Two MCUs communicate through serial port. If the other MCU is not powered on, nrf52832 will not run (LOG error &gt; app: Fatal error). If UART is not initialized and used, it will run normally. But if &quot;NRF_LOG_BACKEND_UART_ENABLED&quot;en-USTelligent Community 13Sun, 09 Dec 2018 10:47:49 GMThttps://devzone.nordicsemi.com/thread/160846?ContentTypeID=1Sun, 09 Dec 2018 10:47:49 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bb566daf-6697-4808-890f-97d04371ea66awneil[quote userid="73639" url="~/f/nordic-q-a/41383/how-to-improve-uart-driving-force"]LOG error &gt; app: Fatal error[/quote] <p>Copy and paste the full text of the error.</p> <p>Does this help:&nbsp;<a href="https://devzone.nordicsemi.com/f/nordic-q-a/40697/how-to-resolve-the-error-nrf_error_no_mem-at-the-case-app_uart_communication_error-in-uart_event_handle">https://devzone.nordicsemi.com/f/nordic-q-a/40697/how-to-resolve-the-error-nrf_error_no_mem-at-the-case-app_uart_communication_error-in-uart_event_handle</a>&nbsp;?</p> [quote userid="73639" url="~/f/nordic-q-a/41383/how-to-improve-uart-driving-force"]is it related to driving force?[/quote] <p>Not sure what you mean by that - but probably not.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/160843?ContentTypeID=1Sun, 09 Dec 2018 06:43:49 GMT137ad170-7792-4731-bb38-c0d22fbe4515:330b16ca-183b-4cfc-a25b-8d7204e24563shenwrt<p>Shielding &quot;APP_ERROR_HANDLER (p_event - &gt; data. Error_communication);&quot;Normal。。</p><div style="clear:both;"></div>