EEPW论坛

首先上我的代码：

GPIO：

void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  /* Configure USARTx_Tx as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Configure USARTx_Rx as input floating */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
}

NVIC:

void NVIC_Configuration(void)
{ 
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
	NVIC_InitStructure.NVIC_IRQChannel=USART1_IRQChannel;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=15;
	NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
	NVIC_Init(&NVIC_InitStructure);
}

中断响应程序

void USART1_IRQHandler(void)
{
	while(USART_GetFlagStatus(USART1,USART_FLAG_RXNE)==RESET)
	{}
	USART_SendData(USART1,USART_ReceiveData(USART1));
	USART_ClearFlag(USART1,USART_FLAG_RXNE);
}

RCC

void RCC_Configuration(void)
{

  /* Enable GPIOx clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

  /* Enable USARTx clocks */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

}

main

int main(void)
{
#ifdef DEBUG
  debug();
#endif
  	/* System Clocks Configuration */
  	RCC_Configuration();
  	/* NVIC configuration */
  	NVIC_Configuration();
  	/* Configure the GPIO ports */
 	GPIO_Configuration();
	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);
	USART_Cmd(USART1,ENABLE);
    while (1)
    {
		printf("\n\rUSART Printf Example: retarget the C library printf function 

to the USART\n\r");
		Delay(100000);
    }
} 

我试了两种波特率(2400,115200)都不行，我使用的是usb转串口线+超级终端，板子上的连接情况如下图：

超级终端配置如下，收不到任何信息，求大神帮忙啊，搞了几天了：

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问题出现在两个地方：pringtf函数和线的连接

使用printf函数要重新定义fputc函数，printf会回调这个函数(放在main.c中就可以)，注意这个函数要设置UART端口

fputc(int ch, FILE *f)
{
  /* Write a character to the USART */
  USART_SendData(USART1, (u8) ch);

  /* Loop until the end of transmission */
  while(!(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == SET))
  {
  }

  return ch;
}

第二个问题是，TX和RX接反了，电脑的RX要接板子的TX，我接反了，真是惭愧，判断电脑上RX和TX的方法：RX的点压比TX低，usb转串口有四根线，电压关系：GND