Testing an application

For simplicity, this guide will refer to both samples and applications as “applications”.

Follow the instructions in the testing section of the application’s documentation to make sure that the application runs as expected.

Information about the current state of the application is usually provided through the LEDs or through UART, or through both. See the user interface section of the application’s documentation for description of the LED states or available UART commands.

How to connect with the VS Code extension

The nRF Connect for Visual Studio Code extension is a complete IDE for developing applications for nRF91, nRF53 and nRF52 Series devices. The extension pack includes nRF Terminal, which is an integrated serial port and RTT terminal to connect to your board. For detailed instructions, see the nRF Terminal documentation on the nRF Connect for Visual Studio Code documentation site.


The nRF Connect for Visual Studio Code extension lets you build and program with custom options. For more information, read about the advanced Custom launch and debug configurations and Application-specific flash options in the extension documentation.

How to connect with PuTTY

To see the UART output, connect to the development kit with a terminal emulator, for example, PuTTY.

Connect with the following settings:

  • Baud rate: 115200

  • 8 data bits

  • 1 stop bit

  • No parity

  • HW flow control: None

If you want to send commands through UART, make sure to configure the required line endings and turn on local echo and local line editing:

PuTTY configuration for sending commands through UART

UART can also be used for logging purposes as one of the logging backends.

How to use RTT

To view the logging output using Real Time Transfer (RTT), modify the configuration settings of the application to override the default UART console:


SEGGER’s J-Link RTT can also be used for logging purposes as one of the logging backends.


SEGGER’s J-Link RTT is part of the J-Link Software and Documentation Pack. You must have this software installed on your platform to use RTT.

Connecting using RTT

To run RTT on your platform, complete the following steps:

  1. From the J-Link installation directory, open the J-Link RTT Viewer application:

    • On Windows, the executable is called JLinkRTTViewer.exe.

    • On Linux, the executable is called JLinkRTTViewerExe.

  2. Select the following options to configure your connection:

    • Connection to J-Link: USB

    • Target Device: Select your IC from the list

    • Target Interface and Speed: SWD, 4000 KHz

    • RTT Control Block: Auto Detection

    Example of RTT Viewer configuration
  3. Click OK to view the logging output from the device.