nRF5340 DK virtual COM port

The onboard interface MCU features a Universal Asynchronous Receiver/Transmitter (UART) interface through virtual COM ports.

The virtual COM ports have the following features:

Flexible baud rate setting up to 1 Mbps (Baud rate 921 600 is not supported)
Dynamic Hardware Flow Control (HWFC) handling
Tri-stated UART lines when no terminal is connected

The following table shows an overview of the UART connections on the nRF5340 System on Chip (SoC) and the interface MCU.

Table 1. Relationship of UART connections on nRF5340 and interface MCU
GPIO nRF5340	nRF5340 UART_2	nRF5340 UART_1
P0.19	RTS
P0.20	TXD
P0.21	CTS
P0.22	RXD
P0.11/TRACEDATA0		RTS
P1.01		TXD
P0.10/TRACEDATA1		CTS
P1.00		RXD

The UART signals are routed directly to the interface MCU. The UART pins connected to the interface MCU are tri-stated when no terminal is connected to the virtual COM port on the computer.

Note: The terminal software used must send a Data Terminal Ready (DTR) signal to configure the UART interface MCU pins.

The P0.19 (Request to Send (RTS)) and P0.21 (Clear to Send (CTS)) can be used freely when HWFC is disabled on the SoC.

Note: For nRF5340 DK v1.0.0, a third virtual COM port routed to the P24 connector of the DK is supported. The pins are labeled RxD, TxD, CTS, and RTS.

Virtual COM ports