stm32 DAC输出音频

#define DAC_DHR8R1_Address      0x40007410

// Init Structure definition
DAC_InitTypeDef            DAC_InitStructure;
DMA_InitTypeDef            DMA_InitStructure;
TIM_TimeBaseInitTypeDef    TIM_TimeBaseStructure;

void RCC_Configuration(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
u16 GetARRValue(u16 sample);

//rcc 配置时钟频率
void RCC_Configuration(void)
{
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();

  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);

  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();

  if(HSEStartUpStatus == SUCCESS)
  {
    /* Enable Prefetch Buffer */
    FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

    /* Flash 2 wait state */
    FLASH_SetLatency(FLASH_Latency_2);

    /* HCLK = SYSCLK */
    RCC_HCLKConfig(RCC_SYSCLK_Div1); 

    /* PCLK2 = HCLK */
    RCC_PCLK2Config(RCC_HCLK_Div1); 

    /* PCLK1 = HCLK/2 */
    RCC_PCLK1Config(RCC_HCLK_Div2);//36MHz

    /* PLLCLK = 8MHz * 9 = 72 MHz */
    RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

    /* Enable PLL */
    RCC_PLLCmd(ENABLE);

    /* Wait till PLL is ready */
    while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
    {
    }

    /* Select PLL as system clock source */
    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

    /* Wait till PLL is used as system clock source */
    while(RCC_GetSYSCLKSource() != 0x08)
    {
    }
  }

// Enable peripheral clocks --------------------------------------------------

  //dma dac sinewave
  // DMA clock enable
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2, ENABLE);
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
  // AFIO and GPIOA Periph clock enable
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOA, ENABLE);
  // DAC Periph clock enable
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC | RCC_APB1Periph_TIM6, ENABLE);
  // TIM8 Periph clock enable
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8, ENABLE);
}

void GPIO_Configuration(void)
{
  //init gpio
  GPIO_InitTypeDef GPIO_InitStructure;
  //dma dac sinewave
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_4| GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;//DAC输出 必须要设置成 模拟输入
  GPIO_Init(GPIOA, &GPIO_InitStructure);
}

int main(void)
{
  RCC_Configuration();
  NVIC_Configuration();
  GPIO_Configuration();  

     //DAC output SineWave (TIM8)
 /*
  //1>.This example describes how to use DAC dual channel mode with DMA to generate sine
  //waves on both DAC channels outputs.

        TIM_DeInit(TIM8);

        // TIM8 Configuration
        // Time base configuration
        TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
        TIM_TimeBaseStructure.TIM_Period = GetARRValue(44100);//72MHz 的CPU，输出44.1KHz 的音频，设置周期为1633
        TIM_TimeBaseStructure.TIM_Prescaler = 0;//分频
        TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
        TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
        TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure);

        // TIM8 TRGO selection
        TIM_SelectOutputTrigger(TIM8, TIM_TRGOSource_Update);

        // DAC channel1 Configuration
        DAC_InitStructure.DAC_Trigger = DAC_Trigger_T8_TRGO;
        DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
        DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable;

        DAC_Init(DAC_Channel_1, &DAC_InitStructure);

        // DAC channel2 Configuration
        DAC_Init(DAC_Channel_2, &DAC_InitStructure);

#if 1
  // DMA2 channel4 configuration
  DMA_DeInit(DMA2_Channel4);
#else
  // DMA1 channel4 configuration
  DMA_DeInit(DMA1_Channel4);
#endif        

        DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR8R1_Address;//DAC_DHR12RD_Address;//
        DMA_InitStructure.DMA_MemoryBaseAddr = (u32)&DualSine12bit;

        //方向：外设是目的地，还是来源
        DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
        //DMA_DIR_PeripheralDST  外设是目的地
        //DMA_DIR_PeripheralSRC  外设是来源

        DMA_InitStructure.DMA_BufferSize = 512;//
        DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
        //DMA_PeripheralInc_Enable  外设地址寄存器递增
        //DMA_PeripheralInc_Disable 外设地址寄存器不变

        DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
        //DMA_MemoryInc_Enable  内存地址寄存器递增
        //DMA_MemoryInc_Disable 内存地址寄存器不变

        DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;//外设数据宽度
        DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//内存数据宽度
        DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;//设置CAN SPI 的DMA 模式
        //DMA_Mode_Circular 工作在循环缓存模式
        //DMA_Mode_Normal   工作在正常缓存模式

        DMA_InitStructure.DMA_Priority = DMA_Priority_High;//DMA 通道优先级
        DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
        //enable 内存到内存输出
        //disable 内存到内存输出

#if 1
  DMA_Init(DMA2_Channel4, &DMA_InitStructure);
  //Enable DMA2 Channel4
  DMA_Cmd(DMA2_Channel4, ENABLE);
#else
  DMA_Init(DMA1_Channel4, &DMA_InitStructure);
  // Enable DMA1 Channel4
  DMA_Cmd(DMA1_Channel4, ENABLE);
#endif

        // Enable DAC Channel1
        DAC_Cmd(DAC_Channel_1, ENABLE);
        // Enable DAC Channel2
        DAC_Cmd(DAC_Channel_2, ENABLE);

        // Enable DMA for DAC Channel2
        DAC_DMACmd(DAC_Channel_2, ENABLE);

        // TIM8 enable counter
        TIM_Cmd(TIM8, ENABLE);

*/

    //2>.DAC output SineWave (TIM)   single sinewave 单通道

        TIM_DeInit(TIM6);

        /* TIM6 Configuration */
        TIM_PrescalerConfig(TIM6, 0x0, TIM_PSCReloadMode_Update);
        TIM_SetAutoreload(TIM6, 1633);
        /* TIM6 TRGO selection */
        TIM_SelectOutputTrigger(TIM6, TIM_TRGOSource_Update);

        /* DAC channel1 Configuration */
        DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
        DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
        DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable;
        DAC_Init(DAC_Channel_1, &DAC_InitStructure);

#if 1
  /* DMA2 channel3 configuration */
  DMA_DeInit(DMA2_Channel3);
#else
  /* DMA1 channel3 configuration */
  DMA_DeInit(DMA1_Channel3);
#endif       

          DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR8R1_Address;
          DMA_InitStructure.DMA_MemoryBaseAddr = (u32)&thx;
          DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
          DMA_InitStructure.DMA_BufferSize = 20222;
          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_Circular;
          DMA_InitStructure.DMA_Priority = DMA_Priority_High;
          DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;

#if 1
  DMA_Init(DMA2_Channel3, &DMA_InitStructure);
  /* Enable DMA2 Channel3 */
  DMA_Cmd(DMA2_Channel3, ENABLE);
#else
  DMA_Init(DMA1_Channel3, &DMA_InitStructure);
  /* Enable DMA1 Channel3 */
  DMA_Cmd(DMA1_Channel3, ENABLE);
#endif

        // Enable DAC Channel1
        DAC_Cmd(DAC_Channel_1, ENABLE);

        DAC_DMACmd(DAC_Channel_1, ENABLE);

        // TIM8 enable counter
        TIM_Cmd(TIM6, ENABLE);

while(1);

}

// 根据采样率获得定时器自动
// 摘自waveplayer.c
u16 GetARRValue(u16 sample)
{
    u16 arrValue;
    //更新OCA值以符合.WAV文件采样率
    switch (sample)
    {
    case SAMPLE_RATE_8000 :
        arrValue = (u16)(72000000/8000);
        break; // 8KHz = 2x36MHz / 9000
    case SAMPLE_RATE_11025:
        arrValue = (u16)(72000000/11025);
        break; // 11.025KHz = 2x36MHz / 6531
    case SAMPLE_RATE_16000:
         arrValue = (u16)(72000000/16000);
        break; // 16KHz = 2x36MHz / 4500
    case SAMPLE_RATE_22050:
        arrValue = (u16)(72000000/22050);
        break; // 22.05KHz = 2x36MHz / 2365
    case SAMPLE_RATE_44100:
        arrValue = (u16)(72000000/44100);
        break; // 44.1KHz = 2x36MHz / 1633
    case SAMPLE_RATE_48000:
        arrValue = (u16)(72000000/48000);
        break; // 48KHz = 2x36MHz / 1500
    default:
        arrValue = 0;
        break;
    }
    return arrValue;
} 

上面是 双通道，单通道的DAC 音频输出

需要注意的是数据，一定要是wave的格式， 下面就有检测wave格式是否正确的代码

/** @defgroup WAVEPLAYER_Private_Defines
  * @{
  */
#define  CHUNK_ID                            0x52494646  /* correspond to the letters 'RIFF' */
#define  FILE_FORMAT                         0x57415645  /* correspond to the letters 'WAVE' */
#define  FORMAT_ID                           0x666D7420  /* correspond to the letters 'fmt ' */
#define  DATA_ID                             0x64617461  /* correspond to the letters 'data' */
#define  FACT_ID                             0x66616374  /* correspond to the letters 'fact' */
#define  WAVE_FORMAT_PCM                     0x01
#define  FORMAT_CHNUK_SIZE                   0x10
#define  CHANNEL_MONO                        0x01
#define  SAMPLE_RATE_8000                    8000
#define  SAMPLE_RATE_11025                   11025
#define  SAMPLE_RATE_22050                   22050
#define  SAMPLE_RATE_44100                   44100
#define  BITS_PER_SAMPLE_8                   8
#define  WAVE_DUMMY_BYTE                     0xA5
#define  DAC_DHLCD_REG_8LCD_REG_1_ADDRESS    0x40007410

static ErrorCode WavePlayer_WaveParsing()
{
  uint32_t Temp = 0x00;
  uint32_t ExtraFormatBytes = 0;
  __IO uint32_t err = 0;

  memcpy(Wavebuffer,0,20250-1);//在这里固定了数组，实际中再用其他的buffer
  memcpy(Wavebuffer,thx,20222);

  // Read chunkID, must be 'RIFF'  ----------------------------------------------
  Temp = ReadUnit(Wavebuffer, 0, 4, BigEndian);
  if (Temp != CHUNK_ID)
  {
    return(Unvalid_RIFF_ID);
  }

  // Read the file length ----------------------------------------------------
  WAVE_Format.RIFFchunksize = ReadUnit(Wavebuffer, 4, 4, LittleEndian);

  // Read the file format, must be 'WAVE' ------------------------------------
  Temp = ReadUnit(Wavebuffer, 8, 4, BigEndian);
  if (Temp != FILE_FORMAT)
  {
    return(Unvalid_WAVE_Format);
  }

  // Read the format chunk, must be'fmt ' --------------------------------------
  Temp = ReadUnit(Wavebuffer, 12, 4, BigEndian);
  if (Temp != FORMAT_ID)
  {
    return(Unvalid_FormatChunk_ID);
  }
  // Read the length of the 'fmt' data, must be 0x10 -------------------------
  Temp = ReadUnit(Wavebuffer, 16, 4, LittleEndian);
  if (Temp != 0x10)
  {
    ExtraFormatBytes = 1;
  }
  // Read the audio format, must be 0x01 (PCM) -------------------------------
  WAVE_Format.FormatTag = ReadUnit(Wavebuffer, 20, 2, LittleEndian);
  if (WAVE_Format.FormatTag != WAVE_FORMAT_PCM)
  {
    return(Unsupporetd_FormatTag);
  }

  // Read the number of channels, must be 0x01 (Mono) ------------------------
  WAVE_Format.NumChannels = ReadUnit(Wavebuffer, 22, 2, LittleEndian);
  if (WAVE_Format.NumChannels != CHANNEL_MONO)
  {
    return(Unsupporetd_Number_Of_Channel);
  }

  // Read the Sample Rate ----------------------------------------------------
  WAVE_Format.SampleRate = ReadUnit(Wavebuffer, 24, 4, LittleEndian);
  // Update the OCA value according to the .WAV file Sample Rate
  switch (WAVE_Format.SampleRate)
  {
    case SAMPLE_RATE_8000 :
      TIM6ARRValue = 4500;
      break; // 8KHz = 36MHz / 4500
    case SAMPLE_RATE_11025:
      TIM6ARRValue = 3265;
      break; // 11.025KHz = 36MHz / 3265
    case SAMPLE_RATE_22050:
      TIM6ARRValue = 1632;
      break; // 22.05KHz = 36MHz / 1632
    case SAMPLE_RATE_44100:
      TIM6ARRValue = 816;
      break; // 44.1KHz = 36MHz / 816
    default:
      return(Unsupporetd_Sample_Rate);
  }

  // Read the Byte Rate ------------------------------------------------------
  WAVE_Format.ByteRate = ReadUnit(Wavebuffer, 28, 4, LittleEndian);

  // Read the block alignment ------------------------------------------------
  WAVE_Format.BlockAlign = ReadUnit(Wavebuffer, 32, 2, LittleEndian);

  // Read the number of bits per sample --------------------------------------
  WAVE_Format.BitsPerSample = ReadUnit(Wavebuffer, 34, 2, LittleEndian);
  if (WAVE_Format.BitsPerSample != BITS_PER_SAMPLE_8)
  {
    return(Unsupporetd_Bits_Per_Sample);
  }
  SpeechDataOffset = 36;
  // If there is Extra format bytes, these bytes will be defined in "Fact Chunk"
  if (ExtraFormatBytes == 1)
  {
    // Read th Extra format bytes, must be 0x00 ------------------------------
    Temp = ReadUnit(Wavebuffer, 36, 2, LittleEndian);
    if (Temp != 0x00)
    {
      return(Unsupporetd_ExtraFormatBytes);
    }
    // Read the Fact chunk, must be 'fact' -----------------------------------
    Temp = ReadUnit(Wavebuffer, 38, 4, BigEndian);
    if (Temp != FACT_ID)
    {
      return(Unvalid_FactChunk_ID);
    }
    // Read Fact chunk data Size ---------------------------------------------
    Temp = ReadUnit(Wavebuffer, 42, 4, LittleEndian);

    SpeechDataOffset += 10 + Temp;
  }
  // Read the Data chunk, must be 'data' ---------------------------------------
  Temp = ReadUnit(Wavebuffer, SpeechDataOffset, 4, BigEndian);
  SpeechDataOffset += 4;
  if (Temp != DATA_ID)
  {
    return(Unvalid_DataChunk_ID);
  }

  // Read the number of sample data ------------------------------------------
  WAVE_Format.DataSize = ReadUnit(Wavebuffer, SpeechDataOffset, 4, LittleEndian);
  SpeechDataOffset += 4;
  wavecounter =  SpeechDataOffset;
  return(Valid_WAVE_File);
}

在处理wave 音频数据的时候

实际数据20222 byte

RIFFchunksize 是20214

Read the number of sample data 20108 (SpeechDataOffset为44 )

前面offset 是44， 而总sample data 是20108，

20222 -44 -20108 = 70

70就是不要的数据尾， 为了DAC 不发出杂音（爆音是接近 0或255的曲线， 128是中音）

实际处理数据的时候 前offset +44, 后offset -（114 -44） 就可以了

这样就没有爆音了，哈哈