STM32外加了flash芯片(AT45DB321D) 直接用CPU太慢了 于是用DMA方式 但是读写都不行，求大神帮忙看下呀~~急啊~~

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配置：

    // Configures the DMA1 Channel0 for SPI3 Rx request.

void SPI_LowLevel_DMA_RxConfig(uint32_t *SPI3_Buffer_Rx, uint32_t BufferSize){

     DMA_InitTypeDef DFDMA_InitStructure;

     DMA_ClearFlag(DataFlash_SPI_DMA_STREAM_RX, DataFlash_SPI_DMA_FLAG_FEIF0 | DataFlash_SPI_DMA_FLAG_DMEIF0 |      DataFlash_SPI_DMA_FLAG_TEIF0 | DataFlash_SPI_DMA_FLAG_HTIF0 | DataFlash_SPI_DMA_FLAG_TCIF0);

    // DMA2 Stream3 disable

    DMA_Cmd(DataFlash_SPI_DMA_STREAM_RX, DISABLE);

    // DMA2 Stream3 Config

    DMA_DeInit(DataFlash_SPI_DMA_STREAM_RX);

    DFDMA_InitStructure.DMA_Channel = DataFlash_SPI_DMA_CHANNEL;

    DFDMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)SPI3_DR_ADDR;

    DFDMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)SPI3_Buffer_Rx;

    DFDMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;

    DFDMA_InitStructure.DMA_BufferSize = BufferSize;

    DFDMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

    DFDMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

    DFDMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;

    DFDMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;

    DFDMA_InitStructure.DMA_Mode = DMA_Mode_Normal;

    DFDMA_InitStructure.DMA_Priority = DMA_Priority_High;

    DFDMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;

    DFDMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;

    DFDMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;

    DFDMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;

    DMA_Init(DataFlash_SPI_DMA_STREAM_RX, &DFDMA_InitStructure);

    DMA_ITConfig(DataFlash_SPI_DMA_STREAM_RX, DMA_IT_TC, ENABLE);

    DMA_FlowControllerConfig(DataFlash_SPI_DMA_STREAM_RX, DMA_FlowCtrl_Peripheral);

    // DMA2 Stream3 enable

    DMA_Cmd(DataFlash_SPI_DMA_STREAM_RX, ENABLE);

}

// Configures the DMA1 Channel0 for SPI3 Tx request.

void SPI_LowLevel_DMA_TxConfig(uint32_t *SPI3_Buffer_Tx, uint32_t BufferSize) {

    DMA_InitTypeDef DFDMA_InitStructure;

    DMA_ClearFlag(DataFlash_SPI_DMA_STREAM_TX, DataFlash_SPI_DMA_FLAG_FEIF5 | DataFlash_SPI_DMA_FLAG_DMEIF5 |               DataFlash_SPI_DMA_FLAG_TEIF5 | DataFlash_SPI_DMA_FLAG_HTIF5 | DataFlash_SPI_DMA_FLAG_TCIF5);

    // DMA2 Stream3 disable

    DMA_Cmd(DataFlash_SPI_DMA_STREAM_TX, DISABLE);

    // DMA2 Stream3 Config

    DMA_DeInit(DataFlash_SPI_DMA_STREAM_TX);

    DFDMA_InitStructure.DMA_Channel = DataFlash_SPI_DMA_CHANNEL;

    DFDMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)SPI3_DR_ADDR;

    DFDMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)SPI3_Buffer_Tx;

    DFDMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;

    DFDMA_InitStructure.DMA_BufferSize = BufferSize;

    DFDMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;

    DFDMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

    DFDMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;

    DFDMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;

    DFDMA_InitStructure.DMA_Mode = DMA_Mode_Normal;

    DFDMA_InitStructure.DMA_Priority = DMA_Priority_High;

    DFDMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;

    DFDMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;

    DFDMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;

    DFDMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;

    DMA_Init(DataFlash_SPI_DMA_STREAM_TX, &DFDMA_InitStructure);

    DMA_FlowControllerConfig(DataFlash_SPI_DMA_STREAM_TX, DMA_FlowCtrl_Peripheral);

    DMA_Cmd(DataFlash_SPI_DMA_STREAM_TX, ENABLE);

}

调用：
读：

TestStatus dataflash_read_flash(unsigned int PageAddr,unsigned int ByteAddr,

                           unsigned char *DataBuffer,unsigned long ByteNum)

{

  unsigned long i;

  if(ByteNum<=4325376)//欲读取的数据在片内 ,范围：8192*528 Bytes

  {

    while(!(StatusRegisterRead()&0x80));// Busy or not

    Select_Flash();

    SPI_Flash_WriteByte(Continuous_Array_Read_Cmd);

    SPI_Flash_WriteByte((unsigned char)(PageAddr>>6));

    SPI_Flash_WriteByte((unsigned char)((PageAddr<<2)|(ByteAddr>>8)));

    SPI_Flash_WriteByte((unsigned char)ByteAddr);

    SPI_Flash_WriteByte(0x00); //使用命令03H时，不用再输入无用的数剧，但命令为E8H（加4个）或0BH（加1个）需加无用数据以完成读操作的初始化

    SPI_Flash_WriteByte(0x00);

SPI_Flash_WriteByte(0x00);

SPI_Flash_WriteByte(0x00);

SPI_LowLevel_DMA_RxConfig((uint32_t *)DataBuffer,ByteNum);

SPI_I2S_DMACmd(SPI3, SPI_I2S_DMAReq_Rx, ENABLE);

    NotSelect_Flash(); 

    return  ASSED;

  }

  return FAILED;

}

写：

TestStatus  DataToPage_ViaBuffer_WithErase_SecWay(unsigned char BufferNumber,unsigned int PageAddr,unsigned int ByteAddr,
                                                   unsigned char *Data,unsigned int ByteNum)
 {
   unsigned int i;
   if((ByteNum<=(528-ByteAddr))&&(ByteNum>0))
   {
      while(!(StatusRegisterRead()&0x80));
      Select_Flash();
      switch(BufferNumber)
      {
      case 1: SPI_Flash_WriteByte(0x82);break;
      case 2: SPI_Flash_WriteByte(0x85);break;
      }
      SPI_Flash_WriteByte((unsigned char)(PageAddr>>6));
      SPI_Flash_WriteByte((unsigned char)((PageAddr<<2)|(ByteAddr>>8)));
      SPI_Flash_WriteByte((unsigned char)ByteAddr);

 SPI_I2S_DMACmd(SPI3,SPI_I2S_DMAReq_Tx, DISABLE);
 SPI_LowLevel_DMA_TxConfig((uint32_t *)Data,ByteNum);  
 if( SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_TXE) ) 
            {
          SPI_I2S_DMACmd(SPI3, SPI_I2S_DMAReq_Tx, ENABLE);
            }


      NotSelect_Flash();
      return PASSED;
  }
  return FAILED;
}

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没有人吗？？？？自己顶啊~~~~

xzp114

即使你用DMA，虽然你可以释放CPU，但是SPI Flash的读写速度是一个瓶颈啊，硬件摆在那儿了，用DMA也没办法的！

正点原子

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参考下这个：http://www.openedv.com/posts/list/3159.htm