The interface MCU has a Universal Asynchronous Receiver/Transmitter (UART) interface through a virtual serial port. One port is connected to the physical port on the Development Kit (DK), and the other is not usable.
- Flexible baud rate setting up to 1 Mbps (baud rate 921 600 bps is not supported)
- Optional 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 nRF52832 System on Chip (SoC) and the associated UART GPIO pins.
| GPIO nRF52832 | nRF52832 UART | Interface MCU UART |
|---|---|---|
| P0.05 | RTS | CTS |
| P0.06 | TXD | RXD |
| P0.07 | CTS | RTS |
| P0.08 | RXD | TXD |
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.