第一次用STM32F0系列的MCU，在用STM32F030C8T6的USART2，即PA2和PA3作为串口使用时，始终发送不出去，USART1可以正常使用，USART2的配置与USART1一样，但是USART2不能正常工作，不知道哪里的问题，希望可以得到大神的帮助，谢谢！源码如下：void USART1_INIT(void)
{
  GPIO_InitTypeDef  GPIO_InitStructure;
  USART_InitTypeDef USART_InitStructure;

  RCC_AHBPeriphClockCmd( RCC_AHBPeriph_GPIOA, ENABLE);
  GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_1);
  GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_1);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9|GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE );
  USART_InitStructure.USART_BaudRate = 9600;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(USART1, &USART_InitStructure);
  USART_Cmd(USART1, ENABLE);
}


void USART2_INIT(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  USART_InitTypeDef USART_InitStructure;

  RCC_AHBPeriphClockCmd( RCC_AHBPeriph_GPIOA, ENABLE);
  GPIO_PinAFConfig(GPIOA,GPIO_PinSource2,GPIO_AF_1);
  GPIO_PinAFConfig(GPIOA,GPIO_PinSource3,GPIO_AF_1);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE );
  USART_InitStructure.USART_BaudRate = 9600;
  USART_InitStructure.USART_WordLength = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits = USART_StopBits_1;
  USART_InitStructure.USART_Parity = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(USART2, &USART_InitStructure);
  USART_Cmd(USART2, ENABLE);
}


void UART2_Send(uint8_t *Buffer, uint32_t Length)
{
        while(Length != 0)
        {
                while(!((USART2->ISR)&(1<<7)));//µÈ´ý·¢ËÍÍê
                USART2->TDR = *Buffer;
                Buffer++;
                Length--;
        }
}

void UART1_Send(uint8_t *Buffer, uint32_t Length)
{
        while(Length != 0)
        {
                while(!((USART1->ISR)&(1<<7)));//µÈ´ý·¢ËÍÍê
                USART1->TDR = *Buffer;
                Buffer++;
                Length--;
        }
}


uint8_t Tx2_Buffer[] = "good";
uint8_t Tx1_Buffer[] = "nice";
#define countof(a) (sizeof(a) / sizeof(*(a)))

int main(void)
{
        NVIC_Configuration();
        SysTick_Start(5);
        USART1_INIT();
        USART2_INIT();

        while (1)
        {
                if (SysTick->CTRL & 0x10000)// 5ms一次任务
                {
                                UART1_Send(Tx1_Buffer, countof(Tx1_Buffer)-1);       
                                UART2_Send(Tx2_Buffer, countof(Tx2_Buffer)-1);                               
                }
        }
}

在主函数中每隔5ms发送Tx1_Buffer[]和Tx2_Buffer[]，但是在进入UART2_Send(Tx2_Buffer, countof(Tx2_Buffer)-1);之后就在while(!((USART2->ISR)&(1<<7)));这里死掉了，即出不来这个while，谢谢！

外设时钟开启没有？  
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA , ENABLE);  
RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);  

建议在cubemx试试

串口2在PA2,PA3

static void MX_USART2_UART_Init(void)
{

  huart2.Instance = USART2;
  huart2.Init.BaudRate = 9600;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;
  huart2.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&huart2) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

}

while(!((USART2->ISR)&(1<<6)));改成这样看看

4、NUCLEO-L476RG试验三_LED闪闪亮续(定时、串口)

之前曾写过一个Cubemx配置串口的例子，供您参考。
看看你的工程中
接收时，需要设置的函数
HAL_UART_RxCpltCallback(.....)
HAL_UART_Receive_IT

发送时需要设置的内容：
PUTCHAR_PROTOTYPE
用Printf(....)
看看呢？

串口很简单的。

需要清除相应的发送中断标志位，才能发送下一BIT