https://devzone.nordicsemi.com/f/nordic-q-a/3697/51822-uart-communicationHi All I has two nrf_51822 boards for uart communication. Use USB supply power to first, then first board supply power to second. When power on, it could communicate by uart. But if I power off second board,then power on, the first boad will can&#39;t recieveen-USTelligent Community 13Sat, 07 Nov 2015 02:38:52 GMThttps://devzone.nordicsemi.com/thread/13411?ContentTypeID=1Sat, 07 Nov 2015 02:38:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9a071500-4bd4-41f4-95de-a7fec9bfa901chad.ou<p>I also encountered a similar situation, and then through the analysis, the test is found UART RXD pin level does not match.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/13410?ContentTypeID=1Tue, 02 Sep 2014 11:42:25 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3a77a335-1764-42d1-94e8-a55930d24c12Knut Eldhuset<p>Can you show us the code you use to set up the UARTs and send/receive on both boards?</p><div style="clear:both;"></div>