DCMI Private Functions

Functions
static void	DCMI_DMAXferCplt (DMA_HandleTypeDef *hdma)
	DMA conversion complete callback. More...
static void	DCMI_DMAHalfXferCplt (DMA_HandleTypeDef *hdma)
	DMA Half Transfer complete callback. More...
static void	DCMI_DMAError (DMA_HandleTypeDef *hdma)
	DMA error callback. More...
static uint32_t	DCMI_TransferSize (uint32_t InputSize)
	Sub-buffers transfer size computation. More...

Detailed Description

Function Documentation

DCMI_DMAError()

static void DCMI_DMAError ( DMA_HandleTypeDef *  hdma )

static

DMA error callback.

Parameters

hdma	pointer to a DMA_HandleTypeDef structure that contains the configuration information for the specified DMA module.

Return values

None

Definition at line 1407 of file stm32l4xx_hal_dcmi.c.

{
  DCMI_HandleTypeDef* hdcmi = ( DCMI_HandleTypeDef* )((DMA_HandleTypeDef* )hdma)->Parent;

  /* Update error code */
  hdcmi->ErrorCode |= HAL_DCMI_ERROR_DMA;

  /* Change DCMI state */
  hdcmi->State = HAL_DCMI_STATE_READY;

  /* DCMI error Callback */
#if (USE_HAL_DCMI_REGISTER_CALLBACKS == 1)
  /*Call registered DCMI error callback*/
  hdcmi->ErrorCallback(hdcmi);
#else
  HAL_DCMI_ErrorCallback(hdcmi);
#endif /* USE_HAL_DCMI_REGISTER_CALLBACKS */
}

DCMI_DMAHalfXferCplt()

static void DCMI_DMAHalfXferCplt ( DMA_HandleTypeDef *  hdma )

static

DMA Half Transfer complete callback.

Parameters

hdma	pointer to a DMA_HandleTypeDef structure that contains the configuration information for the specified DMA module.

Note

When the size of the frame being captured by the DCMI peripheral is larger than 0xFFFF (DMA maximum transfer length), this API initiates another DMA transfer to copy the first half of the work buffer associated to the DCMI handle to the final destination buffer.

Return values

None

Definition at line 1349 of file stm32l4xx_hal_dcmi.c.

{
  uint32_t loop_length;     /* transfer length  */
  uint32_t * tmpBuffer_Dest;
  uint32_t * tmpBuffer_Orig;

  DCMI_HandleTypeDef* hdcmi = ( DCMI_HandleTypeDef* )((DMA_HandleTypeDef* )hdma)->Parent;

  if(hdcmi->XferCount != 0U)
  {
    /* Manage first half buffer copy in case of big transfer */

    /* Decrement half-copies counter */
    hdcmi->XferCount--;

    /* Point at DCMI final destination */
    tmpBuffer_Dest = (uint32_t *)hdcmi->pBuffPtr;

    /* Point at DCMI circular buffer start */
    tmpBuffer_Orig = (uint32_t *)hdcmi->pCircularBuffer;

    /* copy half the buffer size */
    loop_length = hdcmi->HalfCopyLength;

    /* Save next entry to write at next DMA transfer interruption */
    hdcmi->pBuffPtr += (uint32_t) loop_length*4U;
    hdcmi->XferSize -= hdcmi->HalfCopyLength;

    /* Data copy from work buffer to final destination buffer */
    /* Enable the DMA Channel */
    if (HAL_DMA_Start_IT(hdcmi->DMAM2M_Handle, (uint32_t) tmpBuffer_Orig, (uint32_t) tmpBuffer_Dest, loop_length) != HAL_OK)
    {
      /* Update error code */
      hdcmi->ErrorCode |= HAL_DCMI_ERROR_DMA;

      /* Change DCMI state */
      hdcmi->State = HAL_DCMI_STATE_READY;

      /* Process Unlocked */
      __HAL_UNLOCK(hdcmi);

      /* DCMI error Callback */
#if (USE_HAL_DCMI_REGISTER_CALLBACKS == 1)
      /*Call registered DCMI error callback*/
      hdcmi->ErrorCallback(hdcmi);
#else
      HAL_DCMI_ErrorCallback(hdcmi);
#endif /* USE_HAL_DCMI_REGISTER_CALLBACKS */
    }
  }
}

DCMI_DMAXferCplt()

static void DCMI_DMAXferCplt ( DMA_HandleTypeDef *  hdma )

static

DMA conversion complete callback.

Parameters

hdma	pointer to a DMA_HandleTypeDef structure that contains the configuration information for the specified DMA module.

Note

When the size of the frame being captured by the DCMI peripheral is larger than 0xFFFF (DMA maximum transfer length), this API initiates another DMA transfer to copy the second half of the work buffer associated to the DCMI handle to the final destination buffer.

Return values

None

Definition at line 1248 of file stm32l4xx_hal_dcmi.c.

{
  uint32_t loop_length;     /* transfer length  */
  uint32_t * tmpBuffer_Dest;
  uint32_t * tmpBuffer_Orig;
  uint32_t temp;

  DCMI_HandleTypeDef* hdcmi = ( DCMI_HandleTypeDef* )((DMA_HandleTypeDef* )hdma)->Parent;


  if(hdcmi->XferCount != 0U)
  {
    /* Manage second half buffer copy in case of big transfer */

    /* Decrement half-copies counter */
    hdcmi->XferCount--;

    /* Point at DCMI final destination */
    tmpBuffer_Dest = (uint32_t *)hdcmi->pBuffPtr;

    /* Point at DCMI circular buffer mid-location */
    tmpBuffer_Orig = (uint32_t *)hdcmi->pCircularBuffer;
    temp = (uint32_t) (tmpBuffer_Orig);
    temp += hdcmi->HalfCopyLength;
    tmpBuffer_Orig = (uint32_t *) temp;

    /* copy half the buffer size */
    loop_length = hdcmi->HalfCopyLength;

    /* Save next entry to write at next half DMA transfer interruption */
    hdcmi->pBuffPtr += (uint32_t) loop_length*4U;
    hdcmi->XferSize -= hdcmi->HalfCopyLength;

    /* Data copy from work buffer to final destination buffer */
    /* Enable the DMA Channel */
    if (HAL_DMA_Start_IT(hdcmi->DMAM2M_Handle, (uint32_t) tmpBuffer_Orig, (uint32_t) tmpBuffer_Dest, loop_length) != HAL_OK)
    {
      /* Update error code */
      hdcmi->ErrorCode |= HAL_DCMI_ERROR_DMA;

      /* Change DCMI state */
      hdcmi->State = HAL_DCMI_STATE_READY;

      /* Process Unlocked */
      __HAL_UNLOCK(hdcmi);

      /* DCMI error Callback */
#if (USE_HAL_DCMI_REGISTER_CALLBACKS == 1)
      /*Call registered DCMI error callback*/
      hdcmi->ErrorCallback(hdcmi);
#else
      HAL_DCMI_ErrorCallback(hdcmi);
#endif /* USE_HAL_DCMI_REGISTER_CALLBACKS */
    }
  }
  else
  {
    /* if End of frame IT is disabled */
    if((hdcmi->Instance->IER & DCMI_IT_FRAME) == 0x0U)
    {
      /* If End of Frame flag is set */
      if(__HAL_DCMI_GET_FLAG(hdcmi, (uint32_t)DCMI_FLAG_FRAMERI) != 0x0UL)
      {
        /* Clear the End of Frame flag */
        __HAL_DCMI_CLEAR_FLAG(hdcmi, DCMI_FLAG_FRAMERI);

        /* When snapshot mode, disable Vsync, Error and Overrun interrupts */
        if((hdcmi->Instance->CR & DCMI_CR_CM) == DCMI_MODE_SNAPSHOT)
        {
          /* Disable the Vsync, Error and Overrun interrupts */
          __HAL_DCMI_DISABLE_IT(hdcmi, DCMI_IT_LINE | DCMI_IT_VSYNC | DCMI_IT_ERR | DCMI_IT_OVR);

          hdcmi->State = HAL_DCMI_STATE_READY;

          /* Process Unlocked */
          __HAL_UNLOCK(hdcmi);
        }

        /* Frame Event Callback */
#if (USE_HAL_DCMI_REGISTER_CALLBACKS == 1)
        /*Call registered DCMI frame event callback*/
        hdcmi->FrameEventCallback(hdcmi);
#else
        HAL_DCMI_FrameEventCallback(hdcmi);
#endif /* USE_HAL_DCMI_REGISTER_CALLBACKS */
      }
    }
  }
}

DCMI_TransferSize()

static uint32_t DCMI_TransferSize ( uint32_t  InputSize )

static

Sub-buffers transfer size computation.

Note

In the case of a frame size larger than the maximum DMA transfer length (0xFFFF), the tranfer from DCMI DR register to the final output buffer is carried out by a sequence of intermediate sub-copies to temporary buffers of size less than 0xFFFF. To optimize the number of DMA transfers, the API computes the temporary buffer size so that the latter is an even number less than 0xFFFF, that divides the final buffer size and is as high as possible. The API implements a sub-optimum solution for complexity's sake.

InputSize MUST be even.

Parameters

InputSize

full buffer size (in 32-bit words)

Return values

Transfer

size (in 32-bit words)

Definition at line 1439 of file stm32l4xx_hal_dcmi.c.

{
  uint32_t j = 1;
  uint32_t temp = InputSize;
  uint32_t aPrime[NPRIME] = {0};
  uint32_t output = 2; /* Want a result which is an even number */
  uint32_t PrimeArray[NPRIME] = { 1UL,  2UL,  3UL,  5UL,
                                7UL, 11UL, 13UL, 17UL,
                               19UL, 23UL, 29UL, 31UL,
                               37UL, 41UL, 43UL, 47UL};


  /* Develop InputSize in product of prime numbers */

  while (j < NPRIME)
  {
    if (temp < PrimeArray[j])
    {
      break;
    }
    while ((temp % PrimeArray[j]) == 0U)
    {
      aPrime[j]++;
      temp /= PrimeArray[j];
    }
    j++;
  }

  /*  Search for the biggest even divisor less or equal to 0xFFFE = 65534 */
  aPrime[1] -= 1U; /* output is initialized to 2, so don't count dividor 2 twice */

   /*  The algorithm below yields a sub-optimal solution
       but in an acceptable time.  */
    j =  NPRIME-1U;
  while ((j > 0U) &&  (output <= 0xFFFEU))
  {
    while (aPrime[j] > 0U)
    {
      if ((output * PrimeArray[j]) > 0xFFFEU)
      {
        break;
      }
      else
      {
        output *= PrimeArray[j];
        aPrime[j]--;
      }
    }
    j--;
  }



  return output;
}