Using LED and UART on STM32 NUCLEO-F401RE. UART is UART1, PINS PA9=TX,PA10=RX. PA9 on board is 21 PIN of CN10, PA10 is 33 PIN on CN10. LED is LD2 on board, PA5 GPIO_output. stm_uart.ioc is a project STM32CubeMX.
Environment: STM32 NUCLEO-F401RE Linux Mint 18.2 Sonya STM32Cube_1.0 version 4.24.0.Repository is STM32Cube_FW_F4_V1.19.0. System Workbench for STM32 (Version: 1.13.2.201703061529) based on Eclipse IDE version Mars.2.Release 4.5.2