RTFM-rs Serial loopback for stm32f103 (black pill) Pins Function Pin UART2 Tx PA2 UART2 Rx PA3 UART3 Tx PB10 UART3 Rx PB11 Connections UART3_Tx <-> UART2_Rx UART2_Tx -> serial_adapter -> computer Build and flash bobbin load --bin rtfm-serial-loopback-example