stm32l151串口

只看该作者 · 2013-8-12 18:22

最近做一个东西用到了串口，串口连接是买的宇泰的TTL转232 3.3v的转换器，转换器的初始信号是高电平，不把串口插到板子上面时，用示波器观察，发送数据是正常的，但是一插到板子上面串口的输出信号就直接被拉低了，这时给串口发数据也没没有任何反应，请问各位，这是个怎么回事？？
串口配置如下：
void Usart1_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef  USART_InitStructure;

/* Enable USART1 clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
/* Enable GPIO clock */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA,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;

   /* Connect PA9 to USARTx_Tx */
  GPIO_PinAFConfig(Test_COM_PORT, Test_COM_TX_BIT,GPIO_AF_USART1);

  /* Connect  PA10 to USARTx_Rx */
  GPIO_PinAFConfig(Test_COM_PORT, Test_COM_RX_BIT,GPIO_AF_USART1);

/* Configure USART Tx as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = Test_COM_TX_BIT;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(Test_COM_PORT, &GPIO_InitStructure);

  /* Configure USART Rx as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = Test_COM_RX_BIT;
  GPIO_Init(Test_COM_PORT,&GPIO_InitStructure);

  /* USART configuration */
  USART_Init(Test_COM,&USART_InitStructure);

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