stm32samples/F0:F030,F042,F072/uart_nucleo

This is a simple USART over DMA application with software end of string control.
Speed 115200. Received string echoes back.
run
DEFS=-DCHECK_TMOUT make
to add timeout 1.5s for each letter

DEFS="-DCHECK_TMOUT -DTIMEOUT_MS=xx" make
to make another timeout