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