https://devzone.nordicsemi.com/f/nordic-q-a/23769/why-official-uart-application-getc-putc-get-wrong-baudrateI cloned the demo project inside the Keil MDK5, from the following path: pack installer device = &quot;nRF51822_xxAC&quot; examples = &quot;uart_pca10028, UART_Example_Application&quot; After cloning the source, I found it is nRF51422-QFAC, but I didn&#39;ten-USTelligent Community 13Wed, 26 Jul 2017 09:26:59 GMThttps://devzone.nordicsemi.com/thread/93493?ContentTypeID=1Wed, 26 Jul 2017 09:26:59 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7d394536-5034-41e6-b99b-6c4044336958J&#248;rgen Holmefjord<p>It looks like you are using an old version. I would suggest you switch to the latest SDK with support for nRF51 series, <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v12.3.0/index.html?cp=4_0_2">SDK v12.3.0</a> (<a href="https://developer.nordicsemi.com/nRF5_SDK/nRF5_SDK_v12.x.x/">download link</a>). You can find documentation on the UART example on <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v12.3.0/uart_example.html?cp=4_0_2_4_5_40">this page</a>.</p><div style="clear:both;"></div>