DCMI only triggering line interrupt

[wyattcurtis]

I have an OV7670 camera that I am trying to capture images with. I am able to communicate with and set registers for the camera. When power, GND, and XLCK (16 MHz) pins are supplied to the pin I am also able to detect that proper image data is being sent via a logic analyzer.

When acquiring the image (via HAL drivers), I only ever receive an infinite amount of "Line Interrupts" which execute the callback function HAL_DCMI_LineEventCallback. Whether I try to perform an acquisition in snapshot or continuous mode, I still receive an infinite amount of these interrupts. I also never receive any other interrupts or error functions. What could be causing this?

Shouldn't I only ever receive the amount of line interrupts associated with a single image in snapshot mode? I believe I have enabled all DCMI interrupts, is this not the case? Why am I not receiving any other interrupts? Could this be an error on the DMA side of things?

If I understand this code correctly, once the snapshot has been taken the pixel data should simply be allocated in the data_buffer variable?

DCMI Initialization:

void HAL_DCMI_MspInit(DCMI_HandleTypeDef* hdcmi)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(hdcmi->Instance==DCMI)
  {
  /* USER CODE BEGIN DCMI_MspInit 0 */
 
  /* USER CODE END DCMI_MspInit 0 */
    /* Peripheral clock enable */
    __HAL_RCC_DCMI_CLK_ENABLE();
  
    __HAL_RCC_GPIOE_CLK_ENABLE();
    __HAL_RCC_GPIOA_CLK_ENABLE();
    __HAL_RCC_GPIOC_CLK_ENABLE();
    __HAL_RCC_GPIOB_CLK_ENABLE();
    /**DCMI GPIO Configuration    
    PE4     ------> DCMI_D4
    PE5     ------> DCMI_D6
    PE6     ------> DCMI_D7
    PA4     ------> DCMI_HSYNC
    PA6     ------> DCMI_PIXCLK
    PC6     ------> DCMI_D0
    PC7     ------> DCMI_D1
    PC8     ------> DCMI_D2
    PC9     ------> DCMI_D3
    PB6     ------> DCMI_D5
    PB7     ------> DCMI_VSYNC 
    */
    GPIO_InitStruct.Pin = GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF13_DCMI;
    HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);
 
    GPIO_InitStruct.Pin = GPIO_PIN_4|GPIO_PIN_6;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF13_DCMI;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 
    GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_7|GPIO_PIN_8|GPIO_PIN_9;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF13_DCMI;
    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
 
    GPIO_InitStruct.Pin = GPIO_PIN_6|GPIO_PIN_7;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    GPIO_InitStruct.Alternate = GPIO_AF13_DCMI;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
 
    /* DCMI DMA Init */
    /* DCMI Init */
    hdma_dcmi.Instance = DMA2_Stream1;
    hdma_dcmi.Init.Channel = DMA_CHANNEL_1;
    hdma_dcmi.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_dcmi.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_dcmi.Init.MemInc = DMA_MINC_ENABLE;
    hdma_dcmi.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;
    hdma_dcmi.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;
    hdma_dcmi.Init.Mode = DMA_NORMAL;
    hdma_dcmi.Init.Priority = DMA_PRIORITY_LOW;
    hdma_dcmi.Init.FIFOMode = DMA_FIFOMODE_ENABLE;
    hdma_dcmi.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_FULL;
    hdma_dcmi.Init.MemBurst = DMA_MBURST_INC4;
    hdma_dcmi.Init.PeriphBurst = DMA_PBURST_SINGLE;
    if (HAL_DMA_Init(&hdma_dcmi) != HAL_OK)
    {
      Error_Handler();
    }
 
    __HAL_LINKDMA(hdcmi,DMA_Handle,hdma_dcmi);
 
    /* DCMI interrupt Init */
    HAL_NVIC_SetPriority(DCMI_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(DCMI_IRQn);
  /* USER CODE BEGIN DCMI_MspInit 1 */
 
  /* USER CODE END DCMI_MspInit 1 */
  }
 
}

Main Function:

int main(void)
{
  /* USER CODE BEGIN 1 */
 
  /* USER CODE END 1 */
  
 
  /* MCU Configuration--------------------------------------------------------*/
 
  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();
 
  /* USER CODE BEGIN Init */
	
 
  /* USER CODE END Init */
 
  /* Configure the system clock */
  SystemClock_Config();
 
  /* USER CODE BEGIN SysInit */
 
  /* USER CODE END SysInit */
 
  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_DCMI_Init();
  /* USER CODE BEGIN 2 */
	Delay_Init();  //Set up sccb delay pins
	BB_SCCB_HardwareInit();  //set up sccb communication pins
	Init_OV7670();		//write camera registers to desired values
	
	uint32_t data_buffer;		//define buffer to store pixel data
 
	
	HAL_DCMI_Start_DMA(&hdcmi, DCMI_MODE_SNAPSHOT, data_buffer, 320*240/2);  //capture in snapshot
	
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

[waclawek.jan]

Are you sure it's the line interrupt? Is it cleared properly in the ISR? Do you need the line interrupt? If not, disable it - any difference?

For general troubleshooting, read out and check the DCMI registers' content.

I don't use DCMI, I don't Cube.

JW

[wyattcurtis]

Yes I am sure it is line interrupt. I have spent a significant amount of time in the debugger watching it trigger in the DCMI registers. Turning off the interrupt makes it so no interrupts are transmitted