怎么利用配置DFSDM滤波器采集特定频率范围内的音频信号

只看该作者 · 2018-11-30 16:42

只想采集20-2000Hz以内的音频信号改怎么配置DFSDM，44.1K代码如下：
void DFSDM_Init(void)
{
  /* Initialize channel 2 */
  __HAL_DFSDM_CHANNEL_RESET_HANDLE_STATE(&DfsdmChannelHandle);
  DfsdmChannelHandle.Instance                   = DFSDM1_Channel2;
  DfsdmChannelHandle.Init.OutputClock.Activation = ENABLE;
  DfsdmChannelHandle.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  DfsdmChannelHandle.Init.OutputClock.Divider    = 4; /* 11.294MHz/4 = 2.82MHz */
  DfsdmChannelHandle.Init.Input.Multiplexer       = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  DfsdmChannelHandle.Init.Input.DataPacking       = DFSDM_CHANNEL_STANDARD_MODE; /* N.U. */
  DfsdmChannelHandle.Init.Input.Pins             = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  DfsdmChannelHandle.Init.SerialInterface.Type    = DFSDM_CHANNEL_SPI_RISING;
  DfsdmChannelHandle.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  DfsdmChannelHandle.Init.Awd.FilterOrder       = DFSDM_CHANNEL_FASTSINC_ORDER; /* N.U. */
  DfsdmChannelHandle.Init.Awd.Oversampling       = 10; /* N.U. */
  DfsdmChannelHandle.Init.Offset                = 0;
  DfsdmChannelHandle.Init.RightBitShift          =0;
  if(HAL_OK != HAL_DFSDM_ChannelInit(&DfsdmChannelHandle))
  {
Error_Handler();
  }

  /* Initialize filter 0 */
  __HAL_DFSDM_FILTER_RESET_HANDLE_STATE(&DfsdmFilterHandle);
  DfsdmFilterHandle.Instance                         = DFSDM1_Filter0;
  DfsdmFilterHandle.Init.RegularParam.Trigger       = DFSDM_FILTER_SW_TRIGGER;
  DfsdmFilterHandle.Init.RegularParam.FastMode       = ENABLE;
  DfsdmFilterHandle.Init.RegularParam.DmaMode       = ENABLE;
  DfsdmFilterHandle.Init.InjectedParam.Trigger       = DFSDM_FILTER_SW_TRIGGER; /* N.U. */
  DfsdmFilterHandle.Init.InjectedParam.ScanMode    = ENABLE; /* N.U. */
  DfsdmFilterHandle.Init.InjectedParam.DmaMode       = DISABLE; /* N.U. */
  DfsdmFilterHandle.Init.InjectedParam.ExtTrigger    = DFSDM_FILTER_EXT_TRIG_TIM1_TRGO; /* N.U. */
  DfsdmFilterHandle.Init.InjectedParam.ExtTriggerEdge = DFSDM_FILTER_EXT_TRIG_RISING_EDGE; /* N.U. */
  DfsdmFilterHandle.Init.FilterParam.SincOrder       =DFSDM_FILTER_SINC3_ORDER;

  DfsdmFilterHandle.Init.FilterParam.Oversampling    = 64; /* 11.294MHz/(4*64) = 44.1KHz */
  DfsdmFilterHandle.Init.FilterParam.IntOversampling  = 1;
  if(HAL_OK != HAL_DFSDM_FilterInit(&DfsdmFilterHandle))
  {
Error_Handler();
  }

  /* Configure regular channel and continuous mode for filter 0 */
  if(HAL_OK != HAL_DFSDM_FilterConfigRegChannel(&DfsdmFilterHandle, DFSDM_CHANNEL_2, DFSDM_CONTINUOUS_CONV_ON))
  {
Error_Handler();
  }
}