https://devzone.nordicsemi.com/f/nordic-q-a/48755/uart-pullup-rxI am using UART with interupt on a project where I communicate over RS-232 with an external circuit. This circuit keep TX low until it has received a reset command from the NRF52840. When this reset command is received it pull TX high and then start sendingen-USTelligent Community 13Mon, 01 Jul 2019 10:43:48 GMThttps://devzone.nordicsemi.com/thread/195590?ContentTypeID=1Mon, 01 Jul 2019 10:43:48 GMT137ad170-7792-4731-bb38-c0d22fbe4515:62f3fffb-d735-411b-9169-22cf04a096f5ECSondre<p>The application went into error handler, by reinitializing&nbsp;the interface when it did it worked.</p> <p><a href="https://devzone.nordicsemi.com/f/nordic-q-a/39902/how-to-recover-from-nrf_serial-driver-errors">https://devzone.nordicsemi.com/f/nordic-q-a/39902/how-to-recover-from-nrf_serial-driver-errors</a>&nbsp;gave a decent guide on how to fix it in the interupt handler.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/194144?ContentTypeID=1Fri, 21 Jun 2019 14:38:28 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7887c4f6-7c56-41b3-86cb-1ed27dc3e87eJared<p>Hi,</p> <p>Does the application go into the error handler? If the RX pin is low after initializing, then it would indicate that an error has happened as the default state should be high.</p> <p>regards</p> <p>Jared</p><div style="clear:both;"></div>