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DCMI DR (data register) problem

Question asked by kovaliov.nikolaj on Jul 8, 2013
Latest reply on Jul 8, 2013 by kovaliov.nikolaj
Good day,

I have some problems with uint32_t DCMI_ReadData(void); function.
I always have 0 data from that DCMI->DR register.
I use STM32F4DISCOVERY board, (stm32f407vgt6 MCU).

My interupt handler:

void DCMI_IRQHandler(void)
{
    if(DCMI_GetFlagStatus(DCMI_FLAG_VSYNCRI) == SET)
    {
        if(vsync == 0)
        {
            vsync = 1;
        }
        else
        {
            vsync = 0;
        }
    }
    else if(DCMI_GetFlagStatus(DCMI_FLAG_LINERI) == SET)
    {
        if(vsync == 1)
        {
            href++;
        }
        else
        {
            href = 0;
        }
    }
          
    else if(DCMI_GetFlagStatus(DCMI_FLAG_FRAMERI) == SET)
    {
        err = 1;
    }
    else if(DCMI_GetFlagStatus(DCMI_FLAG_ERRRI) == SET)
    {
        err = 2;
    }
    else if(DCMI_GetFlagStatus(DCMI_FLAG_OVFRI) == SET)
    {
        err = 3;
    }
 
 
    DCMI_ClearFlag(DCMI_FLAG_VSYNCRI);
    DCMI_ClearFlag(DCMI_FLAG_LINERI);
    DCMI_ClearFlag(DCMI_FLAG_FRAMERI);
    DCMI_ClearFlag(DCMI_FLAG_ERRRI);
    DCMI_ClearFlag(DCMI_FLAG_OVFRI);
 
}



My DCMI config:

void DCMI_Config(void)
{
  DCMI_InitTypeDef DCMI_InitStructure;
  GPIO_InitTypeDef GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;
     //DMA_InitTypeDef  DMA_InitStructure;
     
     
  /* Enable DCMI GPIOs clocks */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC | RCC_AHB1Periph_GPIOE | 
                         RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOA, ENABLE); 


  /* Enable DCMI clock */
  RCC_AHB2PeriphClockCmd(RCC_AHB2Periph_DCMI, ENABLE);


  /* Connect DCMI pins to AF13 ************************************************/
  /* PCLK */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_DCMI);
  /* D0-D7 */
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_DCMI);
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_DCMI);
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource0, GPIO_AF_DCMI);
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource1, GPIO_AF_DCMI);
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource4, GPIO_AF_DCMI);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_DCMI);
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource5, GPIO_AF_DCMI);
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource6, GPIO_AF_DCMI);
  /* VSYNC */
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_DCMI);
  /* HSYNC */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource4, GPIO_AF_DCMI);
  
  /* DCMI GPIO configuration **************************************************/
  /* D0 D1(PC6/7) */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP ;  
  GPIO_Init(GPIOC, &GPIO_InitStructure);


  /* D2..D4(PE0/1/4) D6/D7(PE5/6) */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 
                                   | GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6;
  GPIO_Init(GPIOE, &GPIO_InitStructure);


  /* D5(PB6), VSYNC(PB7) */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
  GPIO_Init(GPIOB, &GPIO_InitStructure);


  /* PCLK(PA6) HSYNC(PA4)*/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_6;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
     GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  


  DCMI_DeInit();
     DCMI_InitStructure.DCMI_CaptureMode = DCMI_CaptureMode_Continuous;
     DCMI_InitStructure.DCMI_CaptureRate = DCMI_CaptureRate_All_Frame;
     DCMI_InitStructure.DCMI_ExtendedDataMode = DCMI_ExtendedDataMode_8b;
     DCMI_InitStructure.DCMI_HSPolarity = DCMI_HSPolarity_Low;
     DCMI_InitStructure.DCMI_PCKPolarity = DCMI_PCKPolarity_Rising;
     DCMI_InitStructure.DCMI_SynchroMode = DCMI_SynchroMode_Hardware;
     DCMI_InitStructure.DCMI_VSPolarity = DCMI_VSPolarity_High;
     DCMI_Init(&DCMI_InitStructure);


     NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
  NVIC_InitStructure.NVIC_IRQChannel = DCMI_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;  
  NVIC_Init(&NVIC_InitStructure); 


     //----- mask interrupt for DCMI -----
  DCMI_ITConfig(DCMI_IT_VSYNC, ENABLE);
  DCMI_ITConfig(DCMI_IT_LINE, ENABLE);
  DCMI_ITConfig(DCMI_IT_FRAME, ENABLE);
  DCMI_ITConfig(DCMI_IT_OVF, ENABLE);
  DCMI_ITConfig(DCMI_IT_ERR, ENABLE);
     // Enable DCMI Capture mode
     DCMI_Cmd(ENABLE);
     DCMI_CaptureCmd(ENABLE);
}


while(1)
{
if(vsync&&href){
sprintf(to_uart, "\n%d %d %d", vsync, href, DCMI_ReadData());
sendstring(to_uart);
}
}


and the output (looks like vsync, href and pclk are working correctly, I actually can calculate the pclk in href, its 320):


...
1 201 0
1 203 0
1 205 0
1 206 0
1 208 0
1 210 0
1 212 0
1 214 0
1 216 0
1 218 0
1 220 0
1 222 0
1 224 0
1 226 0
1 228 0
1 230 0
1 232 0
1 234 0
1 236 0
1 238 0
1 240 0
1 240 0
1 1 0
1 2 0
1 3 0
1 5 0

....

Can somebody explain how to read the data from DCMI->DR register??

Outcomes