STM32H7B0 DFSDM Synchronization: Abnormal Clock Output During Register Configuration

[wenjing]

Previously, I used the HAL_DFSDM_FilterRegularStart_DMA method to enable each of the eight filters one by one. The result was a 2.4Mhz clock output, exactly as configured in CubeMX.

Now, to achieve high sync between 8 filters, i referred to the synchronization content in the reference manual(RM0455):

i followed the instruction and programmed as below:

/**
 * @brief Configurate DFSDM Filter
 * @retval None
 */
void WJ_DFSDM_FilterSyncConfig(void)
{
    // Disable Filter to set RSYNC
    hdfsdm1_filter0.Instance->FLTCR1 &= ~DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter1.Instance->FLTCR1 &= ~DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter2.Instance->FLTCR1 &= ~DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter3.Instance->FLTCR1 &= ~DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter4.Instance->FLTCR1 &= ~DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter5.Instance->FLTCR1 &= ~DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter6.Instance->FLTCR1 &= ~DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter7.Instance->FLTCR1 &= ~DFSDM_FLTCR1_DFEN;

    // Set all 7 RSYNC (let alone filter0）
    hdfsdm1_filter1.Instance->FLTCR1 |= DFSDM_FLTCR1_RSYNC;
    hdfsdm1_filter2.Instance->FLTCR1 |= DFSDM_FLTCR1_RSYNC;
    hdfsdm1_filter3.Instance->FLTCR1 |= DFSDM_FLTCR1_RSYNC;
    hdfsdm1_filter4.Instance->FLTCR1 |= DFSDM_FLTCR1_RSYNC;
    hdfsdm1_filter5.Instance->FLTCR1 |= DFSDM_FLTCR1_RSYNC;
    hdfsdm1_filter6.Instance->FLTCR1 |= DFSDM_FLTCR1_RSYNC;
    hdfsdm1_filter7.Instance->FLTCR1 |= DFSDM_FLTCR1_RSYNC;
}

Then i configurate DFSDM buffer in DMA mode:

/**
 * @brief Start DFSDM Convertion
 * @retval None
 */
void WJ_DFSDM_FilterSyncStart(void)
{
    // Enable all 8 filters
    hdfsdm1_filter0.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter1.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter2.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter3.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter4.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter5.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter6.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN;
    hdfsdm1_filter7.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN;

    // Config DMA buffer in DMA mode
    if (HAL_OK != HAL_DFSDM_FilterRegularStart_DMA(&hdfsdm1_filter0, aRecBuff0, AUDIO_BUFFER_SIZE)) {
        Error_Handler();
    }
    if (HAL_OK != HAL_DFSDM_FilterRegularStart_DMA(&hdfsdm1_filter1, aRecBuff1, AUDIO_BUFFER_SIZE)) {
        Error_Handler();
    }
    if (HAL_OK != HAL_DFSDM_FilterRegularStart_DMA(&hdfsdm1_filter2, aRecBuff2, AUDIO_BUFFER_SIZE)) {
        Error_Handler();
    }
    if (HAL_OK != HAL_DFSDM_FilterRegularStart_DMA(&hdfsdm1_filter3, aRecBuff3, AUDIO_BUFFER_SIZE)) {
        Error_Handler();
    }
    if (HAL_OK != HAL_DFSDM_FilterRegularStart_DMA(&hdfsdm1_filter4, aRecBuff4, AUDIO_BUFFER_SIZE)) {
        Error_Handler();
    }
    if (HAL_OK != HAL_DFSDM_FilterRegularStart_DMA(&hdfsdm1_filter5, aRecBuff5, AUDIO_BUFFER_SIZE)) {
        Error_Handler();
    }
    if (HAL_OK != HAL_DFSDM_FilterRegularStart_DMA(&hdfsdm1_filter6, aRecBuff6, AUDIO_BUFFER_SIZE)) {
        Error_Handler();
    }
    if (HAL_OK != HAL_DFSDM_FilterRegularStart_DMA(&hdfsdm1_filter7, aRecBuff7, AUDIO_BUFFER_SIZE)) {
        Error_Handler();
    }
}

then i started Convertion:

  hdfsdm1_filter0.Instance->FLTCR1 |= DFSDM_FLTCR1_RSWSTART;

However, when I checked the CLK output, I found that the clock frequency changed to about 3Mhz, varying from 2.6Mhz to 3.0Mhz. See below:

So I tried to debug. When the program ran through DFSDM1_Init(), the 3Mhz clock output emerged, but the waveform was abnormal. Also, after the program ran through WJ_DFSDM_FilterSyncConfig(), WJ_DFSDM_FilterSyncStart(), and hdfsdm1_filter0.Instance->FLTCR1 |= DFSDM_FLTCR1_RSWSTART, the CLK output did not change.

Although it can normally enter the DMA transfer interrupt, this abnormal CLK output indicates a problem. I want to know how to correctly configure the registers to achieve the synchronization of DFSDM1 filter1 - 7 with filter0 as described in the reference manual. Why does the current configuration lead to an abnormal clock waveform? Are there any overlooked details or configurations?

Appended is my DFSDM1_Init():

static void MX_DFSDM1_Init(void)
{

  /* USER CODE BEGIN DFSDM1_Init 0 */

  /* USER CODE END DFSDM1_Init 0 */

  /* USER CODE BEGIN DFSDM1_Init 1 */

  /* USER CODE END DFSDM1_Init 1 */
  hdfsdm1_filter0.Instance = DFSDM1_Filter0;
  hdfsdm1_filter0.Init.RegularParam.Trigger = DFSDM_FILTER_SW_TRIGGER;
  hdfsdm1_filter0.Init.RegularParam.FastMode = ENABLE;
  hdfsdm1_filter0.Init.RegularParam.DmaMode = ENABLE;
  hdfsdm1_filter0.Init.FilterParam.SincOrder = DFSDM_FILTER_SINC4_ORDER;
  hdfsdm1_filter0.Init.FilterParam.Oversampling = 128;
  hdfsdm1_filter0.Init.FilterParam.IntOversampling = 1;
  if (HAL_DFSDM_FilterInit(&hdfsdm1_filter0) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_filter1.Instance = DFSDM1_Filter1;
  hdfsdm1_filter1.Init.RegularParam.Trigger = DFSDM_FILTER_SW_TRIGGER;
  hdfsdm1_filter1.Init.RegularParam.FastMode = ENABLE;
  hdfsdm1_filter1.Init.RegularParam.DmaMode = ENABLE;
  hdfsdm1_filter1.Init.FilterParam.SincOrder = DFSDM_FILTER_SINC4_ORDER;
  hdfsdm1_filter1.Init.FilterParam.Oversampling = 128;
  hdfsdm1_filter1.Init.FilterParam.IntOversampling = 1;
  if (HAL_DFSDM_FilterInit(&hdfsdm1_filter1) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_filter2.Instance = DFSDM1_Filter2;
  hdfsdm1_filter2.Init.RegularParam.Trigger = DFSDM_FILTER_SW_TRIGGER;
  hdfsdm1_filter2.Init.RegularParam.FastMode = ENABLE;
  hdfsdm1_filter2.Init.RegularParam.DmaMode = ENABLE;
  hdfsdm1_filter2.Init.FilterParam.SincOrder = DFSDM_FILTER_SINC4_ORDER;
  hdfsdm1_filter2.Init.FilterParam.Oversampling = 128;
  hdfsdm1_filter2.Init.FilterParam.IntOversampling = 1;
  if (HAL_DFSDM_FilterInit(&hdfsdm1_filter2) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_filter3.Instance = DFSDM1_Filter3;
  hdfsdm1_filter3.Init.RegularParam.Trigger = DFSDM_FILTER_SW_TRIGGER;
  hdfsdm1_filter3.Init.RegularParam.FastMode = ENABLE;
  hdfsdm1_filter3.Init.RegularParam.DmaMode = ENABLE;
  hdfsdm1_filter3.Init.FilterParam.SincOrder = DFSDM_FILTER_SINC4_ORDER;
  hdfsdm1_filter3.Init.FilterParam.Oversampling = 128;
  hdfsdm1_filter3.Init.FilterParam.IntOversampling = 1;
  if (HAL_DFSDM_FilterInit(&hdfsdm1_filter3) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_filter4.Instance = DFSDM1_Filter4;
  hdfsdm1_filter4.Init.RegularParam.Trigger = DFSDM_FILTER_SW_TRIGGER;
  hdfsdm1_filter4.Init.RegularParam.FastMode = ENABLE;
  hdfsdm1_filter4.Init.RegularParam.DmaMode = ENABLE;
  hdfsdm1_filter4.Init.FilterParam.SincOrder = DFSDM_FILTER_SINC4_ORDER;
  hdfsdm1_filter4.Init.FilterParam.Oversampling = 128;
  hdfsdm1_filter4.Init.FilterParam.IntOversampling = 1;
  if (HAL_DFSDM_FilterInit(&hdfsdm1_filter4) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_filter5.Instance = DFSDM1_Filter5;
  hdfsdm1_filter5.Init.RegularParam.Trigger = DFSDM_FILTER_SW_TRIGGER;
  hdfsdm1_filter5.Init.RegularParam.FastMode = ENABLE;
  hdfsdm1_filter5.Init.RegularParam.DmaMode = ENABLE;
  hdfsdm1_filter5.Init.FilterParam.SincOrder = DFSDM_FILTER_SINC4_ORDER;
  hdfsdm1_filter5.Init.FilterParam.Oversampling = 128;
  hdfsdm1_filter5.Init.FilterParam.IntOversampling = 1;
  if (HAL_DFSDM_FilterInit(&hdfsdm1_filter5) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_filter6.Instance = DFSDM1_Filter6;
  hdfsdm1_filter6.Init.RegularParam.Trigger = DFSDM_FILTER_SW_TRIGGER;
  hdfsdm1_filter6.Init.RegularParam.FastMode = ENABLE;
  hdfsdm1_filter6.Init.RegularParam.DmaMode = ENABLE;
  hdfsdm1_filter6.Init.FilterParam.SincOrder = DFSDM_FILTER_SINC4_ORDER;
  hdfsdm1_filter6.Init.FilterParam.Oversampling = 128;
  hdfsdm1_filter6.Init.FilterParam.IntOversampling = 1;
  if (HAL_DFSDM_FilterInit(&hdfsdm1_filter6) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_filter7.Instance = DFSDM1_Filter7;
  hdfsdm1_filter7.Init.RegularParam.Trigger = DFSDM_FILTER_SW_TRIGGER;
  hdfsdm1_filter7.Init.RegularParam.FastMode = ENABLE;
  hdfsdm1_filter7.Init.RegularParam.DmaMode = ENABLE;
  hdfsdm1_filter7.Init.FilterParam.SincOrder = DFSDM_FILTER_SINC4_ORDER;
  hdfsdm1_filter7.Init.FilterParam.Oversampling = 128;
  hdfsdm1_filter7.Init.FilterParam.IntOversampling = 1;
  if (HAL_DFSDM_FilterInit(&hdfsdm1_filter7) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_channel0.Instance = DFSDM1_Channel0;
  hdfsdm1_channel0.Init.OutputClock.Activation = ENABLE;
  hdfsdm1_channel0.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  hdfsdm1_channel0.Init.OutputClock.Divider = 2;
  hdfsdm1_channel0.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  hdfsdm1_channel0.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
  hdfsdm1_channel0.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  hdfsdm1_channel0.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
  hdfsdm1_channel0.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  hdfsdm1_channel0.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
  hdfsdm1_channel0.Init.Awd.Oversampling = 1;
  hdfsdm1_channel0.Init.Offset = 0;
  hdfsdm1_channel0.Init.RightBitShift = 0x05;
  if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel0) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_channel1.Instance = DFSDM1_Channel1;
  hdfsdm1_channel1.Init.OutputClock.Activation = ENABLE;
  hdfsdm1_channel1.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  hdfsdm1_channel1.Init.OutputClock.Divider = 2;
  hdfsdm1_channel1.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  hdfsdm1_channel1.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
  hdfsdm1_channel1.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  hdfsdm1_channel1.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
  hdfsdm1_channel1.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  hdfsdm1_channel1.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
  hdfsdm1_channel1.Init.Awd.Oversampling = 1;
  hdfsdm1_channel1.Init.Offset = 0;
  hdfsdm1_channel1.Init.RightBitShift = 0x05;
  if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel1) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_channel2.Instance = DFSDM1_Channel2;
  hdfsdm1_channel2.Init.OutputClock.Activation = ENABLE;
  hdfsdm1_channel2.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  hdfsdm1_channel2.Init.OutputClock.Divider = 2;
  hdfsdm1_channel2.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  hdfsdm1_channel2.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
  hdfsdm1_channel2.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  hdfsdm1_channel2.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
  hdfsdm1_channel2.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  hdfsdm1_channel2.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
  hdfsdm1_channel2.Init.Awd.Oversampling = 1;
  hdfsdm1_channel2.Init.Offset = 0;
  hdfsdm1_channel2.Init.RightBitShift = 0x05;
  if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel2) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_channel3.Instance = DFSDM1_Channel3;
  hdfsdm1_channel3.Init.OutputClock.Activation = ENABLE;
  hdfsdm1_channel3.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  hdfsdm1_channel3.Init.OutputClock.Divider = 2;
  hdfsdm1_channel3.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  hdfsdm1_channel3.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
  hdfsdm1_channel3.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  hdfsdm1_channel3.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
  hdfsdm1_channel3.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  hdfsdm1_channel3.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
  hdfsdm1_channel3.Init.Awd.Oversampling = 1;
  hdfsdm1_channel3.Init.Offset = 0;
  hdfsdm1_channel3.Init.RightBitShift = 0x05;
  if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel3) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_channel4.Instance = DFSDM1_Channel4;
  hdfsdm1_channel4.Init.OutputClock.Activation = ENABLE;
  hdfsdm1_channel4.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  hdfsdm1_channel4.Init.OutputClock.Divider = 2;
  hdfsdm1_channel4.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  hdfsdm1_channel4.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
  hdfsdm1_channel4.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  hdfsdm1_channel4.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
  hdfsdm1_channel4.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  hdfsdm1_channel4.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
  hdfsdm1_channel4.Init.Awd.Oversampling = 1;
  hdfsdm1_channel4.Init.Offset = 0;
  hdfsdm1_channel4.Init.RightBitShift = 0x05;
  if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel4) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_channel5.Instance = DFSDM1_Channel5;
  hdfsdm1_channel5.Init.OutputClock.Activation = ENABLE;
  hdfsdm1_channel5.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  hdfsdm1_channel5.Init.OutputClock.Divider = 2;
  hdfsdm1_channel5.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  hdfsdm1_channel5.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
  hdfsdm1_channel5.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  hdfsdm1_channel5.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
  hdfsdm1_channel5.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  hdfsdm1_channel5.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
  hdfsdm1_channel5.Init.Awd.Oversampling = 1;
  hdfsdm1_channel5.Init.Offset = 0;
  hdfsdm1_channel5.Init.RightBitShift = 0x05;
  if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel5) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_channel6.Instance = DFSDM1_Channel6;
  hdfsdm1_channel6.Init.OutputClock.Activation = ENABLE;
  hdfsdm1_channel6.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  hdfsdm1_channel6.Init.OutputClock.Divider = 2;
  hdfsdm1_channel6.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  hdfsdm1_channel6.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
  hdfsdm1_channel6.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  hdfsdm1_channel6.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
  hdfsdm1_channel6.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  hdfsdm1_channel6.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
  hdfsdm1_channel6.Init.Awd.Oversampling = 1;
  hdfsdm1_channel6.Init.Offset = 0;
  hdfsdm1_channel6.Init.RightBitShift = 0x05;
  if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel6) != HAL_OK)
  {
    Error_Handler();
  }
  hdfsdm1_channel7.Instance = DFSDM1_Channel7;
  hdfsdm1_channel7.Init.OutputClock.Activation = ENABLE;
  hdfsdm1_channel7.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
  hdfsdm1_channel7.Init.OutputClock.Divider = 2;
  hdfsdm1_channel7.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
  hdfsdm1_channel7.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
  hdfsdm1_channel7.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
  hdfsdm1_channel7.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
  hdfsdm1_channel7.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
  hdfsdm1_channel7.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
  hdfsdm1_channel7.Init.Awd.Oversampling = 1;
  hdfsdm1_channel7.Init.Offset = 0;
  hdfsdm1_channel7.Init.RightBitShift = 0x05;
  if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel7) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DFSDM_FilterConfigRegChannel(&hdfsdm1_filter0, DFSDM_CHANNEL_0, DFSDM_CONTINUOUS_CONV_ON) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DFSDM_FilterConfigRegChannel(&hdfsdm1_filter1, DFSDM_CHANNEL_1, DFSDM_CONTINUOUS_CONV_ON) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DFSDM_FilterConfigRegChannel(&hdfsdm1_filter2, DFSDM_CHANNEL_2, DFSDM_CONTINUOUS_CONV_ON) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DFSDM_FilterConfigRegChannel(&hdfsdm1_filter3, DFSDM_CHANNEL_3, DFSDM_CONTINUOUS_CONV_ON) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DFSDM_FilterConfigRegChannel(&hdfsdm1_filter4, DFSDM_CHANNEL_4, DFSDM_CONTINUOUS_CONV_ON) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DFSDM_FilterConfigRegChannel(&hdfsdm1_filter5, DFSDM_CHANNEL_5, DFSDM_CONTINUOUS_CONV_ON) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DFSDM_FilterConfigRegChannel(&hdfsdm1_filter6, DFSDM_CHANNEL_6, DFSDM_CONTINUOUS_CONV_ON) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_DFSDM_FilterConfigRegChannel(&hdfsdm1_filter7, DFSDM_CHANNEL_7, DFSDM_CONTINUOUS_CONV_ON) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN DFSDM1_Init 2 */

  /* USER CODE END DFSDM1_Init 2 */

}

[Saket_Om · Accepted solution]

Hello @wenjing 

The DFSDM output clock is generated after the first call of HAL_DFSDM_ChannelInit function.
In your MX_DFSDM1_Init function, the output clock is generated just after that:

hdfsdm1_channel0.Instance = DFSDM1_Channel0;
hdfsdm1_channel0.Init.OutputClock.Activation = ENABLE;
hdfsdm1_channel0.Init.OutputClock.Selection = DFSDM_CHANNEL_OUTPUT_CLOCK_AUDIO;
hdfsdm1_channel0.Init.OutputClock.Divider = 2;
hdfsdm1_channel0.Init.Input.Multiplexer = DFSDM_CHANNEL_EXTERNAL_INPUTS;
hdfsdm1_channel0.Init.Input.DataPacking = DFSDM_CHANNEL_STANDARD_MODE;
hdfsdm1_channel0.Init.Input.Pins = DFSDM_CHANNEL_SAME_CHANNEL_PINS;
hdfsdm1_channel0.Init.SerialInterface.Type = DFSDM_CHANNEL_SPI_RISING;
hdfsdm1_channel0.Init.SerialInterface.SpiClock = DFSDM_CHANNEL_SPI_CLOCK_INTERNAL;
hdfsdm1_channel0.Init.Awd.FilterOrder = DFSDM_CHANNEL_FASTSINC_ORDER;
hdfsdm1_channel0.Init.Awd.Oversampling = 1;
hdfsdm1_channel0.Init.Offset = 0;
hdfsdm1_channel0.Init.RightBitShift = 0x05;
if (HAL_DFSDM_ChannelInit(&hdfsdm1_channel0) != HAL_OK)
{
Error_Handler();
}

So you should see the audio clock divided by two.

After that, all your code doesn't modify the setting of output clock. So could you please set a breakpoint
just after the above source code and keep us informed on the generated output clock ? If output clock is not as expected, could
you also check the audio clock signal ?

In addition, I suggest to avoid the direct update of registers values.
(for instance "hdfsdm1_filter0.Instance->FLTCR1 |= DFSDM_FLTCR1_DFEN").
You can perform the synchronization of the 8 filters with only some little updates on configuration parameters.
I suggest to perform the following updates :

1) Remove the call of function WJ_DFSDM_FilterSyncConfig.

2) Remove the updates of FLTCR1 registers at the beginning of WJ_DFSDM_FilterSyncStart function.

3) Remove the start of conversion by update of FLTCR1 register.

4) On MX_DFSDM1_Init function, keep DFSDM_FILTER_SW_TRIGGER for DFSDM1_Filter0 instance
but use DFSDM_FILTER_SYNC_TRIGGER for all other filter instances
(hdfsdm1_filter1.Init.RegularParam.Trigger = DFSDM_FILTER_SYNC_TRIGGER).
This will set RSYNC bit on FLTCR1 register of corresponding filter.

5) On WJ_DFSDM_FilterSyncStart function, start acquisitions on all filters as already done by calling
HAL_DFSDM_FilterRegularStart_DMA but start first filters from 1 to 8 and finally, start filter 0.
This will first enable all filters except filter 0 and guaranty a correct synchronization when finally, you start filter 0.

This will launch synchronous acquisitions on all filters.

[wenjing]

I have implemented the synchronous configuration as your suggested, and it now works properly. However, I discovered an issue with CubeMX during this process:

I used CubeMX to change DFSDM_FILTER_SYNC_TRIGGER to DFSDM_FILTER_SW_TRIGGER , but it seems that CubeMX UI mistaken Filter0 to DFSDM0, it should be " Synchronous with Filter0 ", instead of " Synchronous with DFSDM0 ", as STM32H7B0 doesn't embed a DFSDM0, and " DFSDM0 " was not mentioned in reference manual (RM0455) as well.

Have you encountered similar discrepancies in CubeMX's DFSDM configuration for H7 series devices? It would be helpful to confirm whether this is a known issue or requires a firmware update.

[Saket_Om]

Hello @wenjing 

Follow up of the CubeMX related issue is on DFSDM filtre synchronization issue in CubeMX - STMicroelectronics Community