STM32F4 Discovery - DCMI does not call HAL_DCMI_FrameEventCallback Camera : ov9655 I am using CubeMX to generate the code

Hi. You must initialize DMA before calling HAL_DCMI_Start_DMA. Because HAL_DCMI_FrameEventCallback rise by setting DCMI_IT_FRAME bit. (from function DCMI_DMAXferCplt, file stm32f4xx_hal_dcmi.c). Check example for STM324xG_EVAL in your local CubeMX repository.

Thank you very much for your reply. I have already did so. Please check the full 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 */

 //MaxInitDMA1();

 /* USER CODE END SysInit */

 /* Initialize all configured peripherals */

 MX_GPIO_Init();

 MX_DMA_Init();

 MX_I2C1_Init();

 MX_USART1_UART_Init();

 MX_CRC_Init();

 MX_DCMI_Init();

 /* USER CODE BEGIN 2 */

 BSP_CAMERA_Init(RESOLUTION_R320x240);

 HAL_Delay(1000);

 HAL_DCMI_Start_DMA(&hdcmi, DCMI_MODE_SNAPSHOT, (uint32_t)CAMERA_FRAME_BUFFER, GetSize((uint8_t *)RESOLUTION_R320x240));

 //HAL_DCMI_Start_DMA(&hdcmi, DCMI_MODE_SNAPSHOT, frame_buffer, GetSize((uint8_t *)CAMERA_R160x120));

 /* USER CODE END 2 */

 /* Infinite loop */

 /* USER CODE BEGIN WHILE */

 while (1)

 {

  /* USER CODE END WHILE */

  /* USER CODE BEGIN 3 */

 //HAL_DCMI_Start_DMA(&hdcmi, DCMI_MODE_SNAPSHOT, (uint32_t)CAMERA_FRAME_BUFFER, GetSize((uint8_t *)CAMERA_R160x120));

 }

 /* USER CODE END 3 */

}

Did you properly initialize DMA for DCMI data fetching? Share you CubeMX file.

Configuration for DMA from STM32F4xG_Eval Example for DCMI Snapshot Mode

 /*** Configure the DMA streams ***/

 /* Configure the DMA handler for Transmission process */

 hdma.Init.Channel       = DMA_CHANNEL_1;

 hdma.Init.Direction      = DMA_PERIPH_TO_MEMORY;

 hdma.Init.PeriphInc      = DMA_PINC_DISABLE;

 hdma.Init.MemInc       = DMA_MINC_ENABLE;

 hdma.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;

 hdma.Init.MemDataAlignment  = DMA_MDATAALIGN_WORD;

 hdma.Init.Mode        = DMA_CIRCULAR;

 hdma.Init.Priority      = DMA_PRIORITY_HIGH;

 hdma.Init.FIFOMode      = DMA_FIFOMODE_DISABLE;     

 hdma.Init.FIFOThreshold    = DMA_FIFO_THRESHOLD_FULL;

 hdma.Init.MemBurst      = DMA_MBURST_SINGLE;

 hdma.Init.PeriphBurst     = DMA_PBURST_SINGLE; 

 hdma.Instance = DMA2_Stream1;

DMA Mode is CIRCULAR.

Thanks. I will change the setting from Normal to Circular & test. Will revert with results. Thanks for your prompt responses.

Refer to this document Digital camera interface (DCMI) for STM32 MCUs 

"In snapshot mode: the DMA must ensure the transfer of one frame (image) from the DCMI to the desired memory:

– If the image size in words does not exceed 65535, the stream can be configured in normal mode. For more detailed description of this mode, refer to Section 4.4.6: Normal mode for low resolution in snapshot capture"

So it must works in normal mode. Maybe problem with CAMERA_FRAME_BUFFER location. Where you place it?

Memory location : 0x64000000

This address mapped to external NOR/PSRAM. You didn`t initialize SRAM in your main.

I do not have any external RAM. Would you please suggest what should be the correct Memory location ? During my experiment I also tried with 0x50050028. But with that also there was no difference. Please suggest.