Argh. So, I think I manage to get the UART outie hooked up to the USB and/or RS232 converter outie (and innie to innie) well over half the time.
And, I just did it again. The STM32F303 has a SWAP bit in its UART configuration, to swap the TX and RX pins, but that would be cheating (and besides, I did it with RTS/CTS as well).
C'mon. Say that _you_ get it right all the time!