stm32f4中用SD卡存储DCMI的图像

因为自己本科做的创新性实验和飞思卡尔小车都是摄像头的,研究生也做的视频处理方向。后来,想做一个小视频监制,闲麻烦,没有用那TI的DM6446,就用的手头stm32f4开发板,由于没有LCD显示屏,我只能直接把DCMI图像保存在内部RAM中,再保存到SD里,在上位机读取SD卡转换成图片,我就用VC+OPENCV。

现在说说做的流程吧。摄像头是买的OV9665 。直接接的是DCMI接口。而SD卡不能接SDIO了,因为我这开发板是100引脚封装的,SDIO和DCMI复用引脚冲突。之后SD卡选用的是SPI接口。

1.关于SPI接口的SD卡读写操作,我在前几篇博客中写过,也附带了写好的FATFS文件系统程序,大家可以参考,我这里就不多写了。

2.重要的是关于DCMI的摄像头接口,主要是在DCMI的配置上和DMA的配置,下面着重进行讲解。

void OV9655_HW_Init(void) 
{
  GPIO_InitTypeDef GPIO_InitStructure;
  I2C_InitTypeDef  I2C_InitStruct;

  /*** Configures the DCMI GPIOs to interface with the OV9655 camera module ***/
  /* Enable DCMI GPIOs clocks */
  /* Enable DCMI GPIOs clocks */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOC |
                         RCC_AHB1Periph_GPIOE, ENABLE); 

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

  /* Connect DCMI pins to AF13 ************************************************/
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource4, GPIO_AF_DCMI);	//HSYNC
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_DCMI);	//PIXCLK

  GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_DCMI);	//DCMI_D5
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_DCMI);	//VSYNC

  GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_DCMI);	//DCMI_D0
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_DCMI);	//DCMI_D1

  GPIO_PinAFConfig(GPIOE, GPIO_PinSource0, GPIO_AF_DCMI);	//DCMI_D2
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource1, GPIO_AF_DCMI);	//DCMI_D3
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource4, GPIO_AF_DCMI);	//DCMI_D4
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource5, GPIO_AF_DCMI);	//DCMI_D6
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource6, GPIO_AF_DCMI);	//DCMI_D7
  
  /* DCMI GPIO configuration **************************************************/
  /* HSYNC(PA4), PIXCLK(PA6) */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_6;
  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(GPIOA, &GPIO_InitStructure);

  /* DCMI_D5(PB6), VSYNC(PB7) */
  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(GPIOB, &GPIO_InitStructure);

  /* DCMI_D0(PC6), DCMI_D1(PC7) */
  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);

  /* DCMI_D2(PE0), DCMI_D3(PE1), DCMI_D4(PE4), DCMI_D6(PE5), DCMI_D7(PE6),*/
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6;
  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(GPIOE, &GPIO_InitStructure);
  
  /****** Configures the I2C1 used for OV9655 camera module configuration *****/
 /* I2C1 clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);

  /* GPIOB clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE); 

  /* Connect I2C1 pins to AF4 */
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_I2C1);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_I2C1);
  
  /* Configure I2C1 GPIOs */  
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  /* Configure I2C1 */
  /* I2C DeInit */
  I2C_DeInit(I2C1);
    
  /* Enable the I2C peripheral */
  I2C_Cmd(I2C1, ENABLE);
 
  /* Set the I2C structure parameters */
  I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;
  I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;
  I2C_InitStruct.I2C_OwnAddress1 = 0xFE;
  I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;
  I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
  I2C_InitStruct.I2C_ClockSpeed = 30000;
  
  /* Initialize the I2C peripheral w/ selected parameters */
  I2C_Init(I2C1, &I2C_InitStruct);
}
关于DCMI和DMA的初始化程序如下

void OV9655_Init(ImageFormat_TypeDef ImageFormat)
{
  DCMI_InitTypeDef DCMI_InitStructure;
  DMA_InitTypeDef  DMA_InitStructure;
  

  /*** Configures the DCMI to interface with the OV9655 camera module ***/
  /* Enable DCMI clock */
  RCC_AHB2PeriphClockCmd(RCC_AHB2Periph_DCMI, ENABLE);

  /* DCMI configuration */ 
  DCMI_InitStructure.DCMI_CaptureMode = DCMI_CaptureMode_SnapShot;//DCMI_CaptureMode_Continuous;
  DCMI_InitStructure.DCMI_SynchroMode = DCMI_SynchroMode_Hardware;
  DCMI_InitStructure.DCMI_PCKPolarity = DCMI_PCKPolarity_Falling;
  DCMI_InitStructure.DCMI_VSPolarity = DCMI_VSPolarity_High;
  DCMI_InitStructure.DCMI_HSPolarity = DCMI_HSPolarity_High;
  DCMI_InitStructure.DCMI_CaptureRate = DCMI_CaptureRate_1of4_Frame;//DCMI_CaptureRate_All_Frame;
  DCMI_InitStructure.DCMI_ExtendedDataMode = DCMI_ExtendedDataMode_8b;

  //----- 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);
  
  /* Configures the DMA2 to transfer Data from DCMI */
  /* Enable DMA2 clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);
  
  /* DMA2 Stream1 Configuration */
  DMA_DeInit(DMA2_Stream1);

  DMA_InitStructure.DMA_Channel = DMA_Channel_1;  
  DMA_InitStructure.DMA_PeripheralBaseAddr = DCMI_DR_ADDRESS;	
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)theMap;//FSMC_LCD_ADDRESS;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralToMemory;
  DMA_InitStructure.DMA_BufferSize = 9600;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;//DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Enable;
  DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_Full;
  DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
    //------------------------中断
        DMA_ITConfig(DMA2_Stream1, DMA_IT_TC, ENABLE);  
        DMA_ITConfig(DMA2_Stream1, DMA_IT_HT, ENABLE);   
        DMA_ITConfig(DMA2_Stream1, DMA_IT_TE, ENABLE);  
        DMA_ITConfig(DMA2_Stream1, DMA_IT_FE, ENABLE);   

                
  switch(ImageFormat)
  {
    case BMP_QQVGA:
    {
      /* DCMI configuration */
      DCMI_Init(&DCMI_InitStructure);

      /* DMA2 IRQ channel Configuration */
      DMA_Init(DMA2_Stream1, &DMA_InitStructure);
      break;
    }
    case BMP_QVGA:
    {
      /* DCMI configuration */ 
      DCMI_Init(&DCMI_InitStructure);

      /* DMA2 IRQ channel Configuration */
      DMA_Init(DMA2_Stream1, &DMA_InitStructure); 
      break;
    }
    default:
    {
      /* DCMI configuration */ 
      DCMI_Init(&DCMI_InitStructure);

      /* DMA2 IRQ channel Configuration */
      DMA_Init(DMA2_Stream1, &DMA_InitStructure);
      break;
    }
  }    
}
其中DCMI_InitStructure.DCMI_CaptureMode这里选用的是DCMI_CaptureMode_SnapShot,没有选用DCMI_CaptureMode_Continuous,因为程序存将图像存SD里,速度有限,只能采一张,存一张。
所以,只要DCMI_CaptureCmd(ENABLE);DCMI就开始拍照一张,拍完一张后,使能自动关闭。下次要再拍照的时候,重新DCMI_CaptureCmd(ENABLE); 即可。

然后关于DMA,这个配置让我头疼了些时间,主要是对DMA不熟。

DMA_InitStructure.DMA_Mode 用的是 DMA_Mode_Circular模式,因为DCMI用的是单张拍照的,所以这里用DMA_Mode_Circular模式没有问题。

DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;//外设的数据字长,DCMI的寄存器是32位的,所以这里选的word
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;//内存的数据字长,我存图像用的数组是unsigned char类型,所以这里用BYTE。

DMA_InitStructure.DMA_BufferSize = 9600;//关键是这个,因为摄像头设置的图像大小为120*160的,是RGB565格式,一个像素点占两个字节,所以存一幅图像需要38400字节。而这个buffersize是相对于DMA数据源的字长来说的,这里就是对于DCMI的数据寄存器word类型,38400/4=9600;

还有关于上位机软件读取这个文件时的方法,我用的是VC+OPENCV,38400字节中,是每两个字节表示一个像素点的RGB颜色,这两个字节是低字节在前,高字节在后,示意方法如下

for(int i=0; i     {
        rgb565 = p[2*i+0] + 256*p[2*i+1];
        
        b = (rgb565>>0)  & 0x001f;
        g = (rgb565>>5)  & 0x003f;
        r = (rgb565>>11) & 0x001f;
        b = b<<3;
        g = g<<2;
        r = r<<3;
        vec.push_back(b);
        vec.push_back(g);
        vec.push_back(r);
    }   
在OPENCV中存储图像的程序示意如下:

void vecToImage(vector & vec, IplImage* pImg8u3)
{
    int cnt=0;

    for(int y=0; yheight; y++)
    {
        unsigned char* ptr = (unsigned char*)(pImg8u3->imageData + y * pImg8u3->widthStep);
        for(int x=0; xwidth; x++)
        {
            *(ptr + 3*x+0) =  vec.at(cnt++);
            *(ptr + 3*x+1) =  vec.at(cnt++);
            *(ptr + 3*x+2) =  vec.at(cnt++);
        }
    }
}


其他的,我就不多说了,程序我上传到资源里,大家可以下载,有问题可以留言。http://download.csdn.net/detail/raoqin/5348148

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