STM32F407 USART不定长数据接收：空闲中断+DMA

STM32F407 USART不定长数据接收：空闲中断+DMA（纯代码）

直接上代码就对了（^_）

头文件

#ifndef __USART_H
#define __USART_H

#include "main.h"

#define USART1_RX_BUF_SIZE  128
#define USART1_TX_BUF_SIZE  64

#define USART3_RX_BUF_SIZE  128
#define USART3_TX_BUF_SIZE  64


extern uint8_t USART1_RX_Buff[USART1_RX_BUF_SIZE];
extern uint8_t USART1_TX_Buff[USART1_TX_BUF_SIZE];
extern uint8_t USART1_RC_Flag;
extern uint8_t USART1_TC_Flag;

extern uint8_t USART3_RX_Buff[USART3_RX_BUF_SIZE];
extern uint8_t USART3_TX_Buff[USART3_TX_BUF_SIZE];
extern uint8_t USART3_RC_Flag;
extern uint8_t USART3_TC_Flag;

void USART1_Init(uint32_t baud);
void USART1_DMA_ReceData(uint8_t *data);
void USART1_DMA_TranData(uint8_t *data,uint32_t dataLen);

void USART3_Init(uint32_t baud);
void USART3_DMA_ReceData(uint8_t *data);
void USART3_DMA_TranData(uint8_t *data,uint32_t dataLen);

void Usart_SendString(USART_TypeDef* USARTx,uint8_t *data,uint32_t dataLen);

#endif

源文件

#include "usart.h"
#include "main.h"

///

/******************************** 串口1 开始 **********************************/
uint32_t USART1_RX_Data_Size;
uint8_t USART1_RX_Buff[USART1_RX_BUF_SIZE] = {0};
uint8_t USART1_TX_Buff[USART1_TX_BUF_SIZE] = {0};
uint8_t USART1_RC_Flag = 0;
uint8_t USART1_TC_Flag = 0;


static void USART1_IO_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;	
  
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);	
  
  GPIO_PinAFConfig(GPIOA,GPIO_PinSource9,GPIO_AF_USART1);
  GPIO_PinAFConfig(GPIOA,GPIO_PinSource10,GPIO_AF_USART1);
  
  GPIO_StructInit(&GPIO_InitStructure);
  GPIO_InitStructure.GPIO_Pin           = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode          = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed         = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType         = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd          = GPIO_PuPd_UP;
  GPIO_Init(GPIOA,&GPIO_InitStructure);
  
  GPIO_StructInit(&GPIO_InitStructure);
  GPIO_InitStructure.GPIO_Pin           = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode          = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed         = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType         = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd          = GPIO_PuPd_UP;
  GPIO_Init(GPIOA,&GPIO_InitStructure);
}


static void USART1_Config(uint32_t baud)
{
  USART_InitTypeDef USART_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
  
  USART_DeInit(USART1);
  
  USART_StructInit(&USART_InitStructure);
  USART_InitStructure.USART_BaudRate              = baud;
  USART_InitStructure.USART_WordLength            = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits              = USART_StopBits_1;
  USART_InitStructure.USART_Parity                = USART_Parity_No ;
  USART_InitStructure.USART_Mode                  = USART_Mode_Rx | USART_Mode_Tx;
  USART_InitStructure.USART_HardwareFlowControl   = USART_HardwareFlowControl_None;  
  USART_Init(USART1,&USART_InitStructure);
  
  
  NVIC_InitStructure.NVIC_IRQChannel                    = USART1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority         = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd                 = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  
  USART_ClearFlag(USART1,USART_FLAG_TC);
  USART_ClearFlag(USART1,USART_FLAG_RXNE);
  USART_ClearFlag(USART1,USART_FLAG_IDLE);
  
  USART_ITConfig(USART1, USART_IT_IDLE, ENABLE);
  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
  
  USART_Cmd(USART1,ENABLE);
}


static void USART1_DMA_RX_TX_Config(void)
{
   DMA_InitTypeDef  DMA_InitStructure;
   NVIC_InitTypeDef NVIC_InitStructure;	           
  
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2,ENABLE);//DMA2时钟使能 

  //DMA2_USART1_RX:通道4，数据流5
  DMA_Cmd(DMA2_Stream5, DISABLE);
  DMA_DeInit(DMA2_Stream5);
  
  DMA_InitStructure.DMA_Channel                = DMA_Channel_4;
  DMA_InitStructure.DMA_PeripheralBaseAddr     = (uint32_t)&USART1->DR;//DMA外设地址
  DMA_InitStructure.DMA_Memory0BaseAddr        = (uint32_t)USART1_RX_Buff;//接收基地址
  DMA_InitStructure.DMA_DIR                    = DMA_DIR_PeripheralToMemory;
  DMA_InitStructure.DMA_BufferSize             = USART1_RX_BUF_SIZE;
  DMA_InitStructure.DMA_PeripheralInc          = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc              = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize     = DMA_PeripheralDataSize_Byte;
  DMA_InitStructure.DMA_MemoryDataSize         = DMA_MemoryDataSize_Byte;
  DMA_InitStructure.DMA_Mode                   = DMA_Mode_Normal;
  DMA_InitStructure.DMA_Priority               = DMA_Priority_VeryHigh;
  DMA_InitStructure.DMA_FIFOMode               = DMA_FIFOMode_Disable;
  DMA_InitStructure.DMA_FIFOThreshold          = DMA_FIFOThreshold_1QuarterFull;
  DMA_InitStructure.DMA_MemoryBurst            = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst        = DMA_PeripheralBurst_Single;
  DMA_Init(DMA2_Stream5, &DMA_InitStructure);
  
  NVIC_InitStructure.NVIC_IRQChannel                    = DMA2_Stream5_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority         = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd                 = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  
  DMA_ClearFlag(DMA2_Stream5,DMA_FLAG_TCIF5);
  DMA_ITConfig(DMA2_Stream5,DMA_IT_TC,ENABLE);
  
  USART_DMACmd(USART1,USART_DMAReq_Rx,ENABLE);//串口DMA接收使能
  DMA_Cmd(DMA2_Stream5, ENABLE);//DMA传输使能 
  
  //DMA2_USART1_TX:通道4，数据流7
  DMA_Cmd(DMA2_Stream7, DISABLE);//DMA传输失能 
  DMA_DeInit(DMA2_Stream7);

  DMA_InitStructure.DMA_Channel                = DMA_Channel_4;
  DMA_InitStructure.DMA_PeripheralBaseAddr     = (uint32_t)&USART1->DR;            //DMA外设地址
  DMA_InitStructure.DMA_Memory0BaseAddr        = (uint32_t)USART1_TX_Buff;       //发送基地址
  DMA_InitStructure.DMA_DIR                    = DMA_DIR_MemoryToPeripheral;
  DMA_InitStructure.DMA_BufferSize             = USART1_TX_BUF_SIZE;                                   
  DMA_Init(DMA2_Stream7, &DMA_InitStructure);
  
  NVIC_InitStructure.NVIC_IRQChannel                    = DMA2_Stream7_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority         = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd                 = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  
  DMA_ClearFlag(DMA2_Stream7,DMA_FLAG_TCIF7); 
  DMA_ITConfig(DMA2_Stream7,DMA_IT_TC,ENABLE);
  
  USART_DMACmd(USART1,USART_DMAReq_Tx,ENABLE);//串口DMA发送使能
  
  //DMA_Cmd(DMA2_Stream7, ENABLE);//DMA传输使能 
}



/******** 串口1初始化配置 *********/
void USART1_Init(uint32_t baud)
{
  USART1_IO_Config();
  
  USART1_Config(baud);
   
  USART1_DMA_RX_TX_Config();
  
}


/******** 串口1 DMA接收数据 *********/
void USART1_DMA_ReceData(uint8_t *data)
{
  DMA_Cmd(DMA2_Stream5, DISABLE);//关闭DMA设备（需要在DMA关闭的状态下才能进行配置）
  
  //DMA_ClearFlag(DMA2_Stream5,DMA_FLAG_TCIF5);
  
  while(DMA_GetCmdStatus(DMA2_Stream5) != DISABLE);//等待关闭完成
  
  DMA2_Stream5->M0AR = (uint32_t)data;//接收数据所放的地址

  DMA_Cmd(DMA2_Stream5, ENABLE);//开启DMA（等待接收数据）
}


/******** 串口1 DMA发送数据 *********/
void USART1_DMA_TranData(uint8_t *data,uint32_t dataLen)
{
  while(USART1_TC_Flag);//等待上一次数据传输完成
  
  USART1_TC_Flag = 1;//将传输标志位置1表示正在传数据
  
  //DMA_ClearFlag(DMA2_Stream7,DMA_FLAG_TCIF7);
  
  DMA_Cmd(DMA2_Stream7, DISABLE);//关闭DMA设备（需要在DMA关闭的状态下才能进行配置）
  
  while(DMA_GetCmdStatus(DMA2_Stream7) != DISABLE);//等待关闭完成
  
  DMA2_Stream7->M0AR = (uint32_t)data;//需要发送的数据地址
  DMA2_Stream7->NDTR = dataLen;//需要发送的数据长度
  //DMA_SetCurrDataCounter(DMA2_Stream7,dataLen);
 
  DMA_Cmd(DMA2_Stream7, ENABLE);//开启DMA（开始发送数据）
}


///

/******** 串口1 中断服务函数 ***********/
void USART1_IRQHandler(void)
{
  if(USART_GetITStatus(USART1, USART_IT_IDLE) == SET)
  {
    USART1_RC_Flag = 1;
    
    USART1->SR;USART1->DR;//清除串口空闲中断标志位
  }  
}


/**** 串口1 DMA接收中断服务函数 *****/
void DMA2_Stream5_IRQHandler(void)
{
  if(DMA_GetITStatus(DMA2_Stream5,DMA_IT_TCIF5) == SET)
  {
    //USART1_RC_Flag = 1;  
    
     DMA_ClearITPendingBit(DMA2_Stream5,DMA_IT_TCIF5);
  } 
 
}


/**** 串口1 DMA发送中断服务函数 *****/
void DMA2_Stream7_IRQHandler(void)
{
  if(DMA_GetITStatus(DMA2_Stream7,DMA_IT_TCIF7) == SET)
  {
    USART1_TC_Flag = 0;
    
    DMA_ClearITPendingBit(DMA2_Stream7,DMA_IT_TCIF7);
  }  
  
}

///

/******************************** 串口1 结束 **********************************/

///


///

/******************************** 串口3 开始 **********************************/

uint8_t USART3_RX_Buff[USART1_RX_BUF_SIZE] = {0};
uint8_t USART3_TX_Buff[USART1_TX_BUF_SIZE] = {0};
uint8_t USART3_RC_Flag = 0;
uint8_t USART3_TC_Flag = 0;


static void USART3_IO_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;	
  
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB,ENABLE);	
  
  GPIO_PinAFConfig(GPIOB,GPIO_PinSource10,GPIO_AF_USART3);
  GPIO_PinAFConfig(GPIOB,GPIO_PinSource11,GPIO_AF_USART3);
  
  GPIO_StructInit(&GPIO_InitStructure);
  GPIO_InitStructure.GPIO_Pin           = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode          = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed         = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType         = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd          = GPIO_PuPd_UP;
  GPIO_Init(GPIOB,&GPIO_InitStructure);
  
  GPIO_StructInit(&GPIO_InitStructure);
  GPIO_InitStructure.GPIO_Pin           = GPIO_Pin_11;
  GPIO_InitStructure.GPIO_Mode          = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed         = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType         = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd          = GPIO_PuPd_UP;
  GPIO_Init(GPIOB,&GPIO_InitStructure);
}


static void USART3_Config(uint32_t baud)
{
  USART_InitTypeDef USART_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
  
  USART_DeInit(USART3);
  
  USART_StructInit(&USART_InitStructure);
  USART_InitStructure.USART_BaudRate              = baud;
  USART_InitStructure.USART_WordLength            = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits              = USART_StopBits_1;
  USART_InitStructure.USART_Parity                = USART_Parity_No ;
  USART_InitStructure.USART_Mode                  = USART_Mode_Rx | USART_Mode_Tx;
  USART_InitStructure.USART_HardwareFlowControl   = USART_HardwareFlowControl_None;  
  USART_Init(USART3,&USART_InitStructure);
  
  NVIC_InitStructure.NVIC_IRQChannel                    = USART3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority         = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd                 = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  
  USART_ClearFlag(USART3,USART_FLAG_TC);
  USART_ClearFlag(USART3,USART_FLAG_RXNE);
  USART_ClearFlag(USART3,USART_FLAG_IDLE);
  
  USART_ITConfig(USART3, USART_IT_IDLE, ENABLE);
  USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);
  
  USART_Cmd(USART3,ENABLE);
}


static void USART3_DMA_RX_TX_Config(void)
{
  DMA_InitTypeDef  DMA_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;	           
  
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1,ENABLE);//DMA2时钟使能 

  //DMA1_USART3_RX:通道4，数据流1
  DMA_Cmd(DMA1_Stream1, DISABLE);
  DMA_DeInit(DMA1_Stream1);
  
  DMA_InitStructure.DMA_Channel                = DMA_Channel_4;
  DMA_InitStructure.DMA_PeripheralBaseAddr     = (uint32_t)&USART3->DR;//DMA外设地址
  DMA_InitStructure.DMA_Memory0BaseAddr        = (uint32_t)USART3_RX_Buff;//接收基地址
  DMA_InitStructure.DMA_DIR                    = DMA_DIR_PeripheralToMemory;
  DMA_InitStructure.DMA_BufferSize             = USART3_RX_BUF_SIZE;
  DMA_InitStructure.DMA_PeripheralInc          = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc              = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize     = DMA_PeripheralDataSize_Byte;
  DMA_InitStructure.DMA_MemoryDataSize         = DMA_MemoryDataSize_Byte;
  DMA_InitStructure.DMA_Mode                   = DMA_Mode_Normal;
  DMA_InitStructure.DMA_Priority               = DMA_Priority_VeryHigh;
  DMA_InitStructure.DMA_FIFOMode               = DMA_FIFOMode_Disable;
  DMA_InitStructure.DMA_FIFOThreshold          = DMA_FIFOThreshold_1QuarterFull;
  DMA_InitStructure.DMA_MemoryBurst            = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst        = DMA_PeripheralBurst_Single;
  DMA_Init(DMA1_Stream1, &DMA_InitStructure);
  
  NVIC_InitStructure.NVIC_IRQChannel                    = DMA1_Stream1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority         = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd                 = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  
  DMA_ClearFlag(DMA1_Stream1,DMA_FLAG_TCIF1);
  DMA_ITConfig(DMA1_Stream1,DMA_IT_TC,ENABLE);
  
  USART_DMACmd(USART3,USART_DMAReq_Rx,ENABLE);//串口DMA接收使能
  DMA_Cmd(DMA1_Stream1, ENABLE);//DMA传输使能 
  
  //DMA1_USART3_TX:通道4，数据流3
  DMA_Cmd(DMA1_Stream3, DISABLE);//DMA传输失能 
  DMA_DeInit(DMA1_Stream3);

  DMA_InitStructure.DMA_Channel                = DMA_Channel_4;
  DMA_InitStructure.DMA_PeripheralBaseAddr     = (uint32_t)&USART3->DR;            //DMA外设地址
  DMA_InitStructure.DMA_Memory0BaseAddr        = (uint32_t)USART3_TX_Buff;       //发送基地址
  DMA_InitStructure.DMA_DIR                    = DMA_DIR_MemoryToPeripheral;
  DMA_InitStructure.DMA_BufferSize             = USART3_TX_BUF_SIZE;                                   
  DMA_Init(DMA1_Stream3, &DMA_InitStructure);
  
  NVIC_InitStructure.NVIC_IRQChannel                    = DMA1_Stream3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority         = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd                 = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  
  DMA_ClearFlag(DMA1_Stream3,DMA_FLAG_TCIF3); 
  DMA_ITConfig(DMA1_Stream3,DMA_IT_TC,ENABLE);
  
  USART_DMACmd(USART3,USART_DMAReq_Tx,ENABLE);//串口DMA发送使能
  
  //DMA_Cmd(DMA1_Stream3, ENABLE);//DMA传输使能 
}


/******** 串口3初始化配置 *********/
void USART3_Init(uint32_t baud)
{
  USART3_IO_Config();
  
  USART3_Config(baud);
   
  USART3_DMA_RX_TX_Config();
}


/******** 串口1 DMA接收数据 *********/
void USART3_DMA_ReceData(uint8_t *data)
{
  DMA_Cmd(DMA1_Stream1, DISABLE);//关闭DMA设备（需要在DMA关闭的状态下才能进行配置）
  
  //DMA_ClearFlag(DMA1_Stream1,DMA_FLAG_TCIF1);
  
  while(DMA_GetCmdStatus(DMA1_Stream1) != DISABLE);//等待关闭完成
  
  DMA1_Stream1->M0AR = (uint32_t)data;//接收数据所放的地址
 
  DMA_Cmd(DMA1_Stream1, ENABLE);//开启DMA（等待接收数据）
}


/******** 串口1 DMA发送数据 *********/
void USART3_DMA_TranData(uint8_t *data,uint32_t dataLen)
{
  while(USART3_TC_Flag);//等待上一次数据传输完成
  
  USART3_TC_Flag = 1;//将传输标志位置1表示正在传数据
  
  //DMA_ClearFlag(DMA1_Stream3,DMA_FLAG_TCIF3);
  
  DMA_Cmd(DMA1_Stream3, DISABLE);//关闭DMA设备（需要在DMA关闭的状态下才能进行配置）
  
  while(DMA_GetCmdStatus(DMA1_Stream3) != DISABLE);//等待关闭完成
  
  DMA1_Stream3->M0AR = (uint32_t)data;//需要发送的数据地址
  DMA1_Stream3->NDTR = dataLen;//需要发送的数据长度
  //DMA_SetCurrDataCounter(DMA1_Stream3,dataLen);
 
  DMA_Cmd(DMA1_Stream3, ENABLE);//开启DMA（开始发送数据）
}

///

/******** 串口3 中断服务函数 ***********/
void USART3_IRQHandler(void)
{
  if(USART_GetITStatus(USART3, USART_IT_IDLE) == SET)
  {
    USART3_RC_Flag = 1;
    
    USART3->SR;USART3->DR;//清除串口空闲中断标志位
  }  
}


/**** 串口3 DMA接收中断服务函数 *****/
void DMA1_Stream1_IRQHandler(void)
{
  if(DMA_GetITStatus(DMA1_Stream1,DMA_IT_TCIF1) == SET)
  {
    //USART1_RC_Flag = 1;  
    
     DMA_ClearITPendingBit(DMA1_Stream1,DMA_IT_TCIF1);
  } 
 
}


/**** 串口3 DMA发送中断服务函数 *****/
void DMA1_Stream3_IRQHandler(void)
{
  if(DMA_GetITStatus(DMA1_Stream3,DMA_IT_TCIF3) == SET)
  {
    USART3_TC_Flag = 0;
    
    DMA_ClearITPendingBit(DMA1_Stream3,DMA_IT_TCIF3);
  }  
  
}

///

/******************************** 串口3 结束 **********************************/


/******** 串口 发送字符串 *********/
void Usart_SendString(USART_TypeDef* USARTx,uint8_t *data,uint32_t dataLen)
{
  uint32_t i;
  
  for(i = 0;i < dataLen;i ++)
  {
    USART_SendData(USARTx,data[i]);
    while(USART_GetFlagStatus(USARTx,USART_FLAG_TXE) == RESET);
  }
}

主函数

int main()
{
  uint32_t temp = 0;
  
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
  
  USART1_Init(115200);
  USART3_Init(115200);
  delay(10);
    
  while (1)
  {
    
    if(USART1_RC_Flag == 1)
    {
      USART1_DMA_TranData(USART1_RX_Buff,strlen((char*)USART1_RX_Buff));
      USART1_DMA_ReceData(USART1_RX_Buff);
      
      USART1_RC_Flag = 0;
    }
    
    if(USART3_RC_Flag == 1)
    {
      USART3_DMA_TranData(USART3_RX_Buff,strlen((char*)USART3_RX_Buff));
      USART3_DMA_ReceData(USART3_RX_Buff);
      
      USART3_RC_Flag = 0;
    }
    
    delay(500);
  }
  
  return 0;
}