The interface MCU has two virtual serial ports. Serial port 0 is connected to a Universal Asynchronous Receiver/Transmitter (UART) interface on the nRF52840. Serial port 1 has no connections on the DK.
- Flexible baud rate setting up to 1 Mbps (baud rate 921 600 bps is not supported)
- Dynamic Hardware Flow Control (HWFC)
- Tri-stated UART lines when no terminal is connected
The following table describes the signals between the interface MCU and the nRF52840 System on Chip (SoC) and the associated UART GPIO pins.
| Signal | nRF52840 Serial Port 0 |
|---|---|
| RTS | P0.05 |
| TXD | P0.06 |
| CTS | P0.07 |
| RXD | P0.08 |
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 serial port on the computer. The terminal software must send a Data Terminal Ready (DTR) signal to configure the UART interface MCU pins.
P0.05 (Request to Send (RTS)) and P0.07 (Clear to Send (CTS)) can be used for other purposes when HWFC is disabled on the SoC.