Communication with the UART-enabled firmware is possible through the Nucleo’s built-in ST-link using a graphical user interface written in python 3.
The program requires pyserial, matplotlib, numpy and tkinter.
Find it in under downloads (there’s also a stand-alone executable).
Jens-Ulrich Fröhlich has written a Java-based graphical user interface for the UART-firmware.
You can find his work here: