STM32F207VC USART1 发送寄存器DR值写不进去

只看该作者 · 2015-2-27 10:49

DR寄存器写不进去值，不知道是不是配置有问题，求大神们帮助！
void uart_init(void)
{
  USART_InitTypeDef USART_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;

  /* Enable GPIO clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

  /* Enable USART clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

  /* Connect USART pins to AF7 */
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_USART1);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_USART1);

  /* Configure USART Tx and Rx as alternate function push-pull */
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
  /* USARTx configuration ----------------------------------------------------*/
  /* USARTx configured as follow:
      - BaudRate = 3750000 baud
   - Maximum BaudRate that can be achieved when using the Oversampling by 8
      is: (USART APB Clock / 8)
   Example:
      - (USART3 APB1 Clock / 8) = (30 MHz / 8) = 3750000 baud
      - (USART1 APB2 Clock / 8) = (60 MHz / 8) = 7500000 baud
   - Maximum BaudRate that can be achieved when using the Oversampling by 16
      is: (USART APB Clock / 16)
   Example: (USART3 APB1 Clock / 16) = (30 MHz / 16) = 1875000 baud
   Example: (USART1 APB2 Clock / 16) = (60 MHz / 16) = 3750000 baud
      - Word Length = 8 Bits
      - one Stop Bit
      - No parity
      - Hardware flow control disabled (RTS and CTS signals)
      - Receive and transmit enabled
  */
  USART_InitStructure.USART_BaudRate = 115200;
  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);

  /* NVIC configuration */
  /* Configure the Priority Group to 2 bits */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

  /* Enable the USARTx Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  /* Enable USART */
  USART_Cmd(USART1, ENABLE);
  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
}

主函数如下：
int main(void)
{
uart_init();
      while (1)
  {
USART_SendData(USART1, 0x0055);
delay(1000);
  }
}