firefrommoonligh: > The USART2 interface available on PA2 and PA3 of the STM32 microcontroller can be
connected to ST-LINK MCU, ST morpho connector, or to ARDUINO® connector. The choice
can be changed by setting the related solder bridges. By default, the USART2
communication between the target STM32 and ST-LINK MCU is enabled, in order to
support virtual COM port for Mbed™ (SB13 and SB14 ON, SB62 and SB63 OFF). If the
communication between the target STM32 PA2 (D1) or PA3 (D0) and shield or extension
board is required, SB62 and SB63 must be ON, while SB13 and SB14 must be OFF