TX RX CK CTS RTS
    USART0 PA9,PA15,PB6 PA10,PB3,PB7 PA8 PA11 PA12
    USART1 PA2,PD5 PA3,PD6 PA4,PD7 PA0,PD3 PA1,PD4
    USART2 PB10,PC10,PD8 PB11,PC5,PD9 PB12,PC12,PD10 PB13,PD11 PB14,PD12
    UART3 PA0,PC10 PA1,PC11
    UART4 PC12 PD2
    USART5 PA11,PC6,PG14 PA12,PC7,PG9 PC8,PG7 PG13,PG15 PG8,PG12
    UART6 PF7,PE8 PF6,PE7
    UART7 PE1 PE0