USB_HUB_UART/APP/HARDWARE/sources/usart.c

#include "usart.h"

//重定向c库函数printf到串口，重定向后可使用printf函数
int fputc(int ch, FILE *f)
{
		/* 发送一个字节数据到串口 */
		USART_SendData(USART_232, (uint8_t) ch);
		
		/* 等待发送完毕 */
		while (USART_GetFlagStatus(USART_232, USART_FLAG_TXE) == RESET);	
		return (ch);
}

//重定向c库函数scanf到串口，重写向后可使用scanf、getchar等函数
int fgetc(FILE *f)
{
		/* 等待串口输入数据 */
		while (USART_GetFlagStatus(USART_232, USART_FLAG_RXNE) == RESET);

		return (int)USART_ReceiveData(USART_232);
}
//USART3的初始化
void USART3_config()
{
	USART_InitTypeDef USART_InitStruct;
  GPIO_InitTypeDef GPIO_InitStruct;

	RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
	
	GPIO_PinAFConfig(USART3_RX_GPIO_PORT, USART3_RX_SOURCE, USART3_RX_AF);
  GPIO_PinAFConfig(USART3_TX_GPIO_PORT, USART3_TX_SOURCE, USART3_TX_AF);
	
  GPIO_InitStruct.GPIO_Pin = USART3_TX_PIN ;
  GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOD, &GPIO_InitStruct);
	
  GPIO_InitStruct.GPIO_Pin = USART3_RX_PIN;
	GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
	GPIO_Init(GPIOD, &GPIO_InitStruct);


  USART_InitStruct.USART_BaudRate = USART_BAUDRATE;
  USART_InitStruct.USART_WordLength = USART_WordLength_8b;
  USART_InitStruct.USART_StopBits = USART_StopBits_1;
  USART_InitStruct.USART_Parity = USART_Parity_No;
  USART_InitStruct.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
  USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_Init(USART3, &USART_InitStruct);

  USART_Cmd(USART3, ENABLE);
	
	USART_ClearFlag(USART3, USART_FLAG_TC);
	USART_ITConfig(USART3,USART_IT_RXNE,ENABLE);
	USART_ITConfig(USART3,USART_IT_IDLE,ENABLE);
	
	NVIC_InitTypeDef NVIC_InitStruct;
	NVIC_InitStruct.NVIC_IRQChannel = USART3_IRQn;
	NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
	NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
	NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;

	NVIC_Init(&NVIC_InitStruct);
}


// USART3的中断函数
void USART3_IRQHandler(){	
	call_back();
}