EEPW论坛

午睡之前，版主上传了串口通讯之Uart_Int中断程序。我们知道在51单片机时代的项目设计中，在串口用于通讯使用，而通讯使用时为了避免数据丢失的现象，我们都会采用接收中断的方式，而发送采用查询的方式，但在强大的Cortex-M3系统下面，有了DMA这个功能。具体DMA的原理及用途版主这里不再给大家引用文献，请自行百度之。版主只给大家带来一个典型应用实例：发送使用DMA方式，而接收由于未知数据长度，因此，本例中仍然采用中断方式。不是我编程速度快，而是GD32F130与ST的兼容性做的较好，分分钟就搞定了~~

实验内容：

通过板载的按键，每当按下按键时，都会向串口发送一段字符串“hello EEPW”，而每接收一个字节的数据都会更新LED灯的闪烁频率。

实验现象：

由于采用了按键扫描状态机的机制，发送没有出现连发与丢失现象。LED灯的闪烁频率也随着发送的数据变化而变化。

[图片貌似与上一个没有区别，但版主的确是重新截图的~~]

实验结论：

实验结果与设计方案完全相符，STM32F0xx的固件库目前完美支持GD32F130C8芯片。

源代码：

uint16_t gCntLed[2];
uint16_t gKeyCnt;
uint8_t gKeyStatus;
int8_t  gSendBuf[256];
int8_t  gRcvBuf[256];
uint16_t TxIndex;
uint16_t RxIndex;
uint16_t gSendCnt;

uint8_t gSendCmdStatus;

/**
  * @}
  */

/** @defgroup blink_Private_FunctionPrototypes
  * @{
  */



/**
  * @}
  */

/** @defgroup blink_Private_Functions
  * @{
  */

/**
  * @brief  key check
  * @param  
  * @retval 
  * @date   2015-03-28
  * @note   
  */

void KeyCheck(void)
{
  bool KeyStatus;
  KeyStatus = KeyScan(0);
  
  switch(gKeyStatus)
  {
    case 0:  /*!< 空闲状态 */
    {
      if(KeyStatus == true)
      {
        gKeyStatus = 1;
      }
      else
      {
        gKeyStatus = 0;
        LedOff(0);
        gSendCmdStatus = 0;
      }
      break;
    }
    case 1:  /*!< 消抖状态 */
    {
      if(KeyStatus == true)
      {
        gKeyCnt = 5;
        gKeyStatus = 2;
      }
      else
      {
        gKeyCnt = 0;
        gKeyStatus = 0;
      }
      break;
    }
    case 2:  /*!< 按下状态 */
    {
      if(KeyStatus == true)
      {
        if(gKeyCnt == 0)
        {
          //按键按下执行内容
          LedOn(0);
          gSendCmdStatus |= 0x0F;
        }
        else
        {
          gKeyStatus = 2;
        }
      }
      else
      {
        gKeyCnt = 0;
        gKeyStatus = 0;
      }
      break;
    }
    case 3:  /*!< 确认按下 */
    {
      LedOn(0);
      break;
    }
    default: gKeyStatus = 0;
  }

}

/**
  * @brief  uart_int
  * @param  
  * @retval 
  * @date   2015-03-29
  * @note   发送使用DMA方式，接收使用中断
  */

void UartConfig(uint32_t band)
{
  USART_InitTypeDef USART_InitStructure;
  GPIO_InitTypeDef  GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
  DMA_InitTypeDef  DMA_InitStructure;

  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
  RCC_APB2PeriphClockCmd (RCC_APB2Periph_USART1, ENABLE);
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

  
  /* Connect pin to Periph */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_1);    
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_1); 
  
  /* Configure pins as AF pushpull */
  GPIO_InitStructure.GPIO_Pin     = GPIO_Pin_9 | GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode    = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed   = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType   = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd    = GPIO_PuPd_NOPULL; 
    
  GPIO_Init(GPIOA, &GPIO_InitStructure); 
  
  USART_InitStructure.USART_BaudRate = band;
  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);
  
  /* NVIC configuration */
  /* Enable the USARTx Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
  
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;

  DMA_DeInit(DMA1_Channel2);
  DMA_InitStructure.DMA_PeripheralBaseAddr = USART1_TDR_ADDRESS;
  DMA_InitStructure.DMA_BufferSize = (uint16_t)256;
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)(&gSendBuf[0]);
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
  DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
  
  DMA_Init(DMA1_Channel2, &DMA_InitStructure);

  USART_DMACmd(USART1, USART_DMAReq_Tx, ENABLE);
  USART_Cmd(USART1, ENABLE);
}

void main(void)
{
  uint16_t i;
  int8_t Str[] = "hello EEPW\r\n";
  gKeyStatus = 0;
  bspInit();
  gCntLed[0] = 500;
  gCntLed[1] = 500;
  TxIndex = 0;
  gSendCnt = 12;
  for(i = 0; i < gSendCnt; i++)
  {
    gSendBuf[i] = Str[i];
  }  
  UartConfig(115200);  
  if (SysTick_Config(48000)) //参数为系统时钟的向上溢出值，此配置为48000，即1ms中断一次
  {
    /* Capture error */ 
    while (1);
  }
  
  while(1)
  {
    if(gCntLed[1] == 0)
    {
      LedToggle(1);
      gCntLed[1] = gRcvBuf[0] * 4;
    }
    KeyCheck();
    
    if(gSendCmdStatus > 0)
    {
      if(gSendCmdStatus < 0x10)
      {
//        for(i = 0; i < gSendCnt; i++)
//        {
//          USART_SendData(USART1, gSendBuf[i]);
//          /* Loop until transmit data register is empty */
//          while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET)
//          {;};
//        }
        DMA_Cmd(DMA1_Channel2, DISABLE);
        DMA_SetCurrDataCounter(DMA1_Channel2, gSendCnt);
        DMA_Cmd(DMA1_Channel2, ENABLE);
        gSendCmdStatus |= 0xF0;
      }
    }

  }
}

/**
  * @brief  SysTick_Handler的中断入口函数
  * @param  
  * @retval 
  * @date   2014-11-23
  * @note   
  */

void SysTick_Handler(void)
{
  if(gCntLed[0] > 0)
  {
    gCntLed[0]--;
  }
  else
  {
    gCntLed[0] = 0;
  }
  
  if(gCntLed[1] > 0)
  {
    gCntLed[1]--;
  }
  else
  {
    gCntLed[1] = 0;
  }
  
  if(gKeyCnt > 0)
  {
    gKeyCnt--;
  }
  else
  {
    gKeyCnt = 0;
  }
}

/**
  * @brief  USART1_Handler的中断入口函数
  * @param  
  * @retval 
  * @date   2015-03-29
  * @note   
  */

void USART1_IRQHandler(void)
{
  if (USART_GetITStatus(USART1, USART_IT_RXNE) == SET)
  {
    gRcvBuf[0] = USART_ReceiveData(USART1);

  }
}

工程文件：

exp05_UartDMA.zip