上传自己写的串口实验

cason1991 · 发表于 2013-6-5 00:38:30

功能：从电脑端发送数据给32，再由32返回至PC端
疑问：调试了很多次，发现不开启中断才能正常收发数据，请问例程里为什么要打开中断

#include "led.h"
#include "delay.h"
#include "sys.h"
#include "key.h"
#include "usart.h"

//ALIENTEK Mini STM32??·?°?·????ú??3
//???????é
//????????:www.openedv.com
void Uart_init(u32 bound)
{
  //?¨???á????±???
  GPIO_InitTypeDef GPIO_InitStructure;
  USART_InitTypeDef USART_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  //??????????IO?±??
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOA|RCC_APB2Periph_AFIO, ENABLE);
  //RCC->APB2ENR|=1<<2; // ????GPIOA?±??
  //RCC->APB2ENR|=1<<14;// ????????1?±??
  //GPIO????
  GPIO_InitStructure.GPIO_Pin =GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode =GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  GPIO_InitStructure.GPIO_Pin =GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode =GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  //Usart1 NVIC ????
  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=3 ;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;  //

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;   //IRQ?¨??????
  NVIC_Init(&NVIC_InitStructure); //?ù??NVIC_InitStruct?????¨???????????????èNVIC?????÷USART1
  //USART ???????è??
  USART_InitStructure.USART_BaudRate=bound;
  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);
}
int main(void)
{
  u8 res;
  SystemInit();//
  delay_init(72);
  NVIC_Configuration();
  Uart_init(9600);
  while(1)
  {
    if(USART_GetFlagStatus(USART1,USART_FLAG_RXNE)==1)
    {
      res=USART1->DR;
      USART_SendData(USART1,res);
      while( USART_GetFlagStatus(USART1,USART_FLAG_TC)!= SET);
    }
  }
}

cason1991 · 发表于 2013-6-5 02:05:43

   while(1)
  {
    if(USART_GetFlagStatus(USART1,USART_FLAG_RXNE)==1)
    {
      res=USART1->DR;
      USART_SendData(USART1,res);
      while( USART_GetFlagStatus(USART1,USART_FLAG_TC)!= SET);
    }
  }
}
自己试着分析了一下，一旦打开中断使能，在收到数据时立即进入中断函数，而原子哥的中断函数里有对收到的数据进行读取，这将对USART_FLAG_RXNE复位，因此不能进入
if(USART_GetFlagStatus(USART1,USART_FLAG_RXNE)==1)