串口有关内容

int main(void)
{        
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
    usart1init();
    while(1)
    {
    
    }
}

void usart1init(void)
{

   RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA, ENABLE);    //ê1?üUSART1￡?GPIOAê±?ó
  
  GPIO_InitTypeDef g;
  g.GPIO_Pin = GPIO_Pin_9; 
  g.GPIO_Speed = GPIO_Speed_50MHz;
  g.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &g);

  g.GPIO_Pin = GPIO_Pin_10;
  g.GPIO_Mode = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &g);

    USART_InitTypeDef u;
    u.USART_BaudRate=115200;
    u.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
    u.USART_Mode=USART_Mode_Rx|USART_Mode_Tx;
    u.USART_Parity=USART_Parity_No;
    u.USART_StopBits=USART_StopBits_1;
    u.USART_WordLength=USART_WordLength_8b;
     USART_Init(USART1, &u);
    
    USART_Cmd(USART1,ENABLE);
    
    USART_ITConfig(USART1, USART_IT_RXNE,ENABLE);
    
    NVIC_InitTypeDef n;
    n.NVIC_IRQChannel=USART1_IRQn;
    n.NVIC_IRQChannelCmd=ENABLE;
    n.NVIC_IRQChannelPreemptionPriority=0;
    n.NVIC_IRQChannelSubPriority=0;
    NVIC_Init(&n);
}

void USART1_IRQHandler(void)
{
    u8 res;
    if(USART_GetITStatus(USART1,USART_IT_RXNE)!= RESET)
        {
            res=USART_ReceiveData(USART1);
            USART_SendData(USART1,res);
            USART_ClearITPendingBit(USART1,USART_IT_RXNE);
        }
}

#include "stm32f10x.h"
#include "stdlib.h"
#include "stdio.h"
#include "stm32f10x_conf.h"

int fputc(int c, FILE *stream)
{
    USART1->DR = c;
    while(!(USART1->SR & (1 << 7))){};
    return c;
}

int fgetc(FILE *stream)
{
    while(!(USART1->SR & (1 << 5))){};//等待数据接收完成
    return USART1->DR;
}

//注意 1
    USART_ITConfig(USART1, USART_IT_RXNE,ENABLE);
    USART_ITConfig(USART1, USART_IT_IDLE,ENABLE);