STM32 DAC 音频音质不清晰求解

会偶一笑 · 发表于 2016-9-1 17:20:00

   STM32F103VCT6 用DAC通道1的直接输出wav音频数据后，出现破音现象。在DAC引脚输出后，经过两级无源低通滤波(截止频率10k)，一级有源低通滤波（截止频率10k），再接功放电路。

贴上代码
//dac初始化
void DAC_Configuartion(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);

//??TX PIN???
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;    //PA4
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN; // GPIO_Mode_AIN
GPIO_Init(GPIOA, &GPIO_InitStructure);

DAC_InitStructure.DAC_Trigger = DAC_Trigger_Software;//DAC_Trigger_Software;
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bits8_0;//DAC_LFSRUnmask_Bit0;
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_1, &DAC_InitStructure);
DAC_Cmd(DAC_Channel_1, ENABLE);



//DAC_SetChannel1Data(DAC_Align_12b_R,4000/*0x0000*/);

//DAC_SoftwareTriggerCmd(DAC_Channel_1,ENABLE);
}

void TIM_Configuration(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
// GPIO_InitTypeDef GPIO_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);
//RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);

//GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 |GPIO_Pin_3;//PA0,PA1,PA2,PA3
//GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;//?????????
//GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
//GPIO_Init(GPIOA, &GPIO_InitStructure);

TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = 125;//GetARRValue(8000);//80;
TIM_TimeBaseStructure.TIM_Prescaler = 71;//0;//;
TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM6, &TIM_TimeBaseStructure);//
TIM_ClearITPendingBit(TIM6, TIM_IT_Update); //Çå3y¸üDÂÖD¶Ï±êÖ¾
// TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update); //éèÖÃ¸úDÂêÂ¼t
TIM_ITConfig(TIM6, TIM_IT_Update, ENABLE); //ê1Äüdma
}

void TIM6_IRQHandler(void)
{
if (TIM_GetITStatus(TIM6, TIM_IT_Update) != RESET)
{

}
if(0 == is_finish)
{
DAC_SetChannel1Data(DAC_Align_12b_R, (((u8)(p_test1[a1+1]-0x80)<<4)|(p_test1[a1]>>4)));
DAC_SoftwareTriggerCmd(DAC_Channel_1,ENABLE);
a1 += 2;
if(a1 >= 320)
{
a1 = 0;
is_finish = 1;
}
}

TIM_ClearITPendingBit(TIM6, TIM_IT_Update);
}

软件调试过程，各段频率多试过。。出现结果语音播放快慢。 dac 波形输出波形，三角波，方波，及其附带参数也调过。。没多大用。
硬件方面，增加各种滤波，用示波器看可以看出波形比较圆滑。

经过以上调试，输出音质还是不行，没有杂音，破音。。。
求各路大神解。。。。。