求助大神 DMA DAC音频播放问题

smallshuo

求助大神：代码如下 我通过按键按下 读取flash里面的音频文件播放 但是在dma中断里 如果我不开启 DMA_Cmd(DMA1_Stream5,ENABLE); 那么播放两次就没声音了 ，但是如果开启   DMA_Cmd(DMA1_Stream5,ENABLE); 就不会出现没声音的情况 但是开启 DMA_Cmd(DMA1_Stream5,ENABLE); 之后就会有很多杂音，请问这可能是什么因素引起的啊。
void I2S2_TX_DMA_Init(u16* buf0,u16 num)
{  
    NVIC_InitTypeDef   NVIC_InitStructure;
    DMA_InitTypeDef            DMA_InitStructure;
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1 , ENABLE);

    DMA_DeInit(DMA1_Stream5);
    while (DMA_GetCmdStatus(DMA1_Stream5) != DISABLE);
    /*  DMA Stream */
    DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&DAC->DHR12L1);//DMA  DHR12L1  DHR12R1
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;

    DMA_InitStructure.DMA_Channel = DMA_Channel_7;   

    DMA_InitStructure.DMA_Memory0BaseAddr = (u32)buf0;//DMA
    DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
    DMA_InitStructure.DMA_BufferSize = num;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;

    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;//DMA_Mode_Normal;//DMA_Mode_Circular;// DMA_Mode_Normal;
    DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
    DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         
    DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;//DMA_FIFOThreshold_Full;
    DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
    DMA_InitStructure.DMA_PeripheralBurst = DMA_MemoryBurst_Single;//DMA_PeripheralBurst_Single;
    DMA_Init(DMA1_Stream5, &DMA_InitStructure);//DMA Stream
   
//    DMA_Cmd(DMA1_Stream5, DISABLE);
  DMA_ITConfig(DMA1_Stream5,DMA_IT_TC,ENABLE);
    NVIC_InitStructure.NVIC_IRQChannel = DMA1_Stream5_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x00;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}   

void DMA1_Stream5_IRQHandler(void)
{   
    static portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;  
    uint32_t sta;
    if(DMA_GetITStatus(DMA1_Stream5,DMA_IT_TCIF5) != RESET)
    {
         sta = taskENTER_CRITICAL_FROM_ISR();
     DMA_Cmd(DMA1_Stream5,DISABLE);
         DMA_ClearITPendingBit(DMA1_Stream5,DMA_IT_TCIF5);
//       DMA_Cmd(DMA1_Stream5,ENABLE);
         xSemaphoreGiveFromISR(xSemaphoreVoice, &xHigherPriorityTaskWoken);   

         portYIELD_FROM_ISR(xHigherPriorityTaskWoken);   
         taskEXIT_CRITICAL_FROM_ISR(sta);   
    }   
}  

ChenRyan

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