硬件设备：STM32VCT6

GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); //使能GPIOA时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE); //使能USART2时钟
  
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; 
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOA, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);

USART_InitStructure.USART_BaudRate = bound;//波特率
USART_InitStructure.USART_WordLength = USART_WordLength_8b;//8位数据位
USART_InitStructure.USART_StopBits = USART_StopBits_1;//一位停止位
USART_InitStructure.USART_Parity = USART_Parity_No;//无校验位
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬流控
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

//发送数据函数//
USART_Init(USART2, &USART_InitStructure); //初始化串口2

USART_Cmd(USART2, ENABLE);                    //使能串口2

USART_SendData(USART2, 1);//发送十六进制1
while(USART_GetFlagStatus(USART2,USART_FLAG_TC)!=SET);//等待发送完成