Communicating with the board

Unless you programmed a very simple application, you probably want to connect to the board from your computer to display logging information or send input. You can use Real Time Transfer (RTT) or Universal Asynchronous Receiver/Transmitter (UART) for communicating with the board.

SEGGER Real Time Transfer (RTT) is a proprietary technology for bidirectional communication that supports J-Link devices and ARM-based microcontrollers. The advantage of using RTT is that it is very efficient and does not require any other peripheral than the J-Link debugging interface.

Connecting via UART is quick and power-efficient, but it requires dedicated use of the UART peripheral for logging. The nRF5 Development Kit (DK)s and the nRF51 Dongle include a UART to USB CDC ACM bridge, which is needed to connect to the UART. Alternatively, you can use an external UART to USB bridge. We use the term CDC-UART to refer to UART communication through the UART to USB CDC ACM bridge, to distinguish it from communication through the Nordic UART Service (NUS) over Bluetooth Low Energy.