USART1_CK —— PA8
USART1_TX —— PA9
USART1_RX —– PA10
USART1_CTS —– PA11
USART1_RTS —– PA12
USART2_CTS —– PA0
USART2_RTS—– PA1
USART2_TX —– PA2
USART2_RX —– PA3
USART2_CK —– PA4
USART3_TX —– PB10
USART3_RX —– PB11
USART3_CK —– PB12
USART3_CTS —– PB13
USART3_RTS —– PB14
USART4_TX —– PC10
USART4_RX —– PC11
USART5_TX —– PC12
USART5_RX —– PD2
