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5.9 DVP

This chapter covers how the N32H49x DVP camera interface is organized in the development kit, its public API and its example.

5.9.1 Related files

The table lists the header, the driver implementation, the example root and the layout of one example.

Relative path Purpose
firmware/n32h49x_std_periph_driver/inc/n32h49x_dvp.h Register definitions, data types and public function declarations of the DVP peripheral.
firmware/n32h49x_std_periph_driver/src/n32h49x_dvp.c DVP driver implementation: interface and capture control, frame buffer and DMA, interrupts and status.
projects/n32h49x_EVAL/examples/DVP/Camera/ Example entry: the OV5640 captures an image and it is shown on an 800x480 ILI9806 LCD.
projects/n32h49x_EVAL/examples/DVP/Camera/src/ Source layout: main.c, dvp_demo.c, bsp_dvp.c, bsp_ov5640.c, lcd.c and n32h49x_it.c.
projects/n32h49x_EVAL/examples/DVP/Camera/inc/ Headers and declarations of the font and logo resources.

5.9.2 API reference

Search API40 functions

The 40 public functions are grouped into 6 blocks in the declaration order of n32h49x_dvp.h; each entry gives a summary and the original source comment.

Initialization and reset

DVP_DeInit, DVP_Init, DVP_StructInit, DVP_DMAStructInit, DVP_ConfigDma

Interface and capture control

DVP_EnablePort, DVP_SetCaptureMode, DVP_EnableCrop, DVP_ConfigVBlankFilter, DVP_ConfigInitSKIP, DVP_ConfigRepeatSKIP, DVP_ConfigCROPStart, DVP_ConfigCROPEnd

Signal polarity and data format

DVP_ConfigPixelClockPolarity, DVP_ConfigHSyncPolarity, DVP_ConfigVSyncPolarity, DVP_EnableDataInvert, DVP_EnableDataReverse, DVP_ConfigDataMode, DVP_ConfigPixelByte, DVP_ConfigDATAByteOrder

Embedded synchronization

DVP_ConfigEmbSyncPos, DVP_ConfigEmbSyncData, DVP_ConfigEmbSyncDataMask, DVP_EnableEmbSyncMode

Frame buffer and DMA

DVP_EnableBuffer1, DVP_SetBuffer1Address, DVP_EnableBuffer2, DVP_SetBuffer2Address, DVP_SetBufferSize, DVP_SetDisplayBufferStatus, DVP_GetDisplayBufferStatus1, DVP_GetDisplayBufferStatus2, DVP_EnableAcross1KBoundary, DVP_FrameBufferAddrIncrementEnable

Interrupts and status

DVP_ConfigInt, DVP_GetFlagStatus, DVP_ClearFlag, DVP_GetIntStatus, DVP_ClrIntPendingBit

void DVP_EnablePort(FunctionalState Cmd)DVP interface enable. This function is called after DVP initialization is successful to start moving data.
Source comment
name    DVP_EnablePort.
fun     DVP interface enable. This function is called after DVP
        initialization is successful to start moving data.
param  Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
void DVP_SetCaptureMode(uint32_t Mode)Config the capture mode.
Source comment
name    DVP_SetCaptureMode.
fun     Config the capture mode.
param  Mode:(The input parameters must be the following values)
            - DVP_CAPTURE_MODE_CONTINUE
            - DVP_CAPTURE_MODE_SINGLE
return  none
void DVP_EnableCrop(FunctionalState Cmd)DVP crop feature enable. This function should be called before to enable and start the DVP interface.
Source comment
name    DVP_EnableCrop.
fun     DVP crop feature enable. This function should be called
        before to enable and start the DVP interface.
param  Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
void DVP_ConfigVBlankFilter(uint8_t Filt)VSYNC blanking glitch filtering control. This function should be called before to enable and start the DVP interface.
Source comment
name    DVP_ConfigVBFLT.
fun     VSYNC blanking glitch filtering control. This function should be called
        before to enable and start the DVP interface.
param  Filt:(The input parameters must be the following values)
            - 0~0xF
return  none

Use note: The name field in the source comment is written as DVP_ConfigVBFLT. and differs from the function name DVP_ConfigVBlankFilter; call it by the function name.

void DVP_ConfigInt(uint32_t DVPInt, FunctionalState Cmd)DVP interrupts enable.
Source comment
name    DVP_ConfigInt.
fun     DVP interrupts enable.
param   DVPInt (The input parameters must be the following values):
          - DVP_INT_M1S
          - DVP_INT_M2S
          - DVP_INT_M1TC
          - DVP_INT_M2TC
          - DVP_INT_FO
          - DVP_INT_AHBERR
          - DVP_INT_MO
          - DVP_INT_SKIP
          - DVP_INT_CERR
          - DVP_INT_SERR
          - DVP_INT_FMS
param   Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
FlagStatus DVP_GetFlagStatus(uint32_t DVP_Flag)Get DVP flag status. Checks whether the DVP interface flag is set or not.
Source comment
name    DVP_GetFlagStatus.
fun     Get DVP flag status. Checks whether the  DVP interface flag is set or not.
param   DVP_Flag (The input parameters must be the following values):
           - DVP_FLAG_M1S
           - DVP_FLAG_M2S
           - DVP_FLAG_M1TC
           - DVP_FLAG_M2TC
           - DVP_FLAG_M1FO
           - DVP_FLAG_M2FO
           - DVP_FLAG_AHBERR1
           - DVP_FLAG_AHBERR2
           - DVP_FLAG_M1O
           - DVP_FLAG_M2O
           - DVP_FLAG_SKIP
           - DVP_FLAG_CERR
           - DVP_FLAG_SERR
           - DVP_FLAG_FMS
return  SET or RESET.
void DVP_ClearFlag(uint32_t DVP_Flag)Clears DVP flag status.
Source comment
name    DVP_ClearFlag.
fun     Clears DVP flag status.
param   DVP_Flag (The input parameters must be the following values):
           - DVP_FLAG_M1S
           - DVP_FLAG_M2S
           - DVP_FLAG_M1TC
           - DVP_FLAG_M2TC
           - DVP_FLAG_M1FO
           - DVP_FLAG_M2FO
           - DVP_FLAG_AHBERR1
           - DVP_FLAG_AHBERR2
           - DVP_FLAG_M1O
           - DVP_FLAG_M2O
           - DVP_FLAG_SKIP
           - DVP_FLAG_CERR
           - DVP_FLAG_SERR
           - DVP_FLAG_FMS
return  none.
INTStatus DVP_GetIntStatus(uint32_t DVP_Int)Get DVP interrupt status. Checks whether the DVP interrupt has occurred or not.
Source comment
name    DVP_GetIntStatus.
fun     Get DVP interrupt status. Checks whether the DVP interrupt has occurred or not.
param   DVP_Int (The input parameters must be the following values):
           - DVP_INT_M1S
           - DVP_INT_M2S
           - DVP_INT_M1TC
           - DVP_INT_M2TC
           - DVP_INT_FO
           - DVP_INT_AHBERR
           - DVP_INT_MO
           - DVP_INT_SKIP
           - DVP_INT_CERR
           - DVP_INT_SERR
           - DVP_INT_FMS
return  SET or RESET.
void DVP_ClrIntPendingBit(uint32_t DVP_Int)Clear DVP interrupt status bits.
Source comment
name    DVP_ClrIntPendingBit.
fun     Clear DVP interrupt status bits.
param   DVP_Int (The input parameters must be the following values):
           - DVP_INT_M1S
           - DVP_INT_M2S
           - DVP_INT_M1TC
           - DVP_INT_M2TC
           - DVP_INT_FO
           - DVP_INT_AHBERR
           - DVP_INT_MO
           - DVP_INT_SKIP
           - DVP_INT_CERR
           - DVP_INT_SERR
           - DVP_INT_FMS
return  none.
void DVP_ConfigPixelClockPolarity(uint32_t PLCK_POL)DVP port pixel clock polarity control.
Source comment
name    DVP_ConfigPixelClockPolarity.
fun     DVP port pixel clock polarity control.
param   PLCK_POL (The input parameters must be the following values):
           - DVP_PIXEL_POLARITY_RISING
           - DVP_PIXEL_POLARITY_FALLING
return  none.
void DVP_ConfigHSyncPolarity(uint32_t HSYNC_POL)DVP HSYNC polarity control.
Source comment
name    DVP_ConfigHSyncPolarity.
fun     DVP HSYNC polarity control.
param   HSYNC_POL (The input parameters must be the following values):
           - DVP_HSYNC_POLARITY_HIGH
           - DVP_HSYNC_POLARITY_LOW
return  none.
void DVP_ConfigVSyncPolarity(uint32_t VSYNC_POL)DVP VSYNC polarity control.
Source comment
name    DVP_ConfigVSyncPolarity.
fun     DVP VSYNC polarity control.
param   VSYNC_POL (The input parameters must be the following values):
           - DVP_VSYNC_POLARITY_HIGH
           - DVP_VSYNC_POLARITY_LOW
return  none.
void DVP_EnableDataInvert(FunctionalState Cmd)DVP data inversion enable.
Source comment
name    DVP_EnableDataInvert.
fun     DVP data inversion enable.
param  Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
void DVP_EnableDataReverse(FunctionalState Cmd)DVP data Reverse enable.
Source comment
name    DVP_EnableDataReverse.
fun     DVP data Reverse enable.
param  Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
void DVP_ConfigEmbSyncPos(uint32_t SYNC_Pos)Embedded Synchronization Code Position.
Source comment
name    DVP_ConfigEmbSyncPos.
fun     Embedded Synchronization Code Position.
param   SYNC_Pos (The input parameters must be the following values):
           - DVP_EMBSYNC_LSB
           - DVP_EMBSYNC_MSB
return  none.
void DVP_ConfigEmbSyncData(uint8_t FrameStartValue, uint8_t FrameEndValue, uint8_t LineStartValue, uint8_t LineEndValue)Embedded Synchronization Code Position.
Source comment
name    DVP_ConfigEmbSyncData.
fun     Embedded Synchronization Code Position.
param   FrameStartValue/FrameEndValue/LineStartValue/LineEndValue (The input parameters must be the following values):
           - 0x00 ~ 0xFF
return  none.
void DVP_ConfigEmbSyncDataMask(uint8_t FrameStartMask, uint8_t FrameEndMask, uint8_t LineStartMask, uint8_t LineEndMask)Embedded Synchronization Code Position.
Source comment
name    DVP_ConfigEmbSyncDataMask.
fun     Embedded Synchronization Code Position.
param   FrameStartMask/FrameEndMask/LineStartMask/LineEndMask (The input parameters must be the following values):
           - 0x00 ~ 0xFF
return  none.
void DVP_EnableEmbSyncMode(FunctionalState Cmd)Embedded Synchronization Mode enable bit.
Source comment
name    DVP_EnableEmbSyncMode.
fun     Embedded Synchronization Mode enable bit.
param  Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
void DVP_ConfigDataMode(uint32_t Mode)Config DVP data port mode.
Source comment
name    DVP_ConfigDataMode.
fun     Config DVP data port mode.
param   Mode (The input parameters must be the following values):
           - DVP_DATA_MODE1
           - DVP_DATA_MODE2
           - DVP_DATA_MODE3
           - DVP_DATA_MODE4
           - DVP_DATA_MODE5
           - DVP_DATA_MODE6
           - DVP_DATA_MODE7
           - DVP_DATA_MODE8
return  none.
void DVP_ConfigPixelByte(uint32_t Pixel_Byte)Config DVP pixel bytes.
Source comment
name    DVP_ConfigPixelByte.
fun     Config DVP pixel bytes.
param   Pixel_Byte (The input parameters must be the following values):
           - DVP_PIXEL_BYTE1
           - DVP_PIXEL_BYTE2
return  none.
void DVP_ConfigDATAByteOrder(uint32_t Byte0, uint32_t Byte1, uint32_t Byte2, uint32_t Byte3)Config DVP DATA order.
Source comment
name    DVP_ConfigDATAByteOrder.
fun     Config DVP DATA order.
param   Byte0 (The input parameters must be the following values):
           - DVP_BYTE0_ORDER1
           - DVP_BYTE0_ORDER2
           - DVP_BYTE0_ORDER3
           - DVP_BYTE0_ORDER4
param   Byte1 (The input parameters must be the following values):
           - DVP_BYTE1_ORDER1
           - DVP_BYTE1_ORDER2
           - DVP_BYTE1_ORDER3
           - DVP_BYTE1_ORDER4
param   Byte2 (The input parameters must be the following values):
           - DVP_BYTE2_ORDER1
           - DVP_BYTE2_ORDER2
           - DVP_BYTE2_ORDER3
           - DVP_BYTE2_ORDER4
param   Byte3 (The input parameters must be the following values):
           - DVP_BYTE3_ORDER1
           - DVP_BYTE3_ORDER2
           - DVP_BYTE3_ORDER3
           - DVP_BYTE3_ORDER4
return  none.
void DVP_ConfigInitSKIP(uint32_t Line)Config Initial Frame Line Skip .
Source comment
name    DVP_ConfigInitSKIP.
fun     Config Initial Frame Line Skip .
param   Line (The input parameters must be the following values):
           - DVP_SKIP_LINE1
           - DVP_SKIP_LINE2
           - DVP_SKIP_LINE3
           - DVP_SKIP_LINE4
           - DVP_SKIP_LINE5
           - DVP_SKIP_LINE6
           - DVP_SKIP_LINE7
           - DVP_SKIP_LINE8
           - DVP_SKIP_LINE9
           - DVP_SKIP_LINE10
           - DVP_SKIP_LINE11
           - DVP_SKIP_LINE12
           - DVP_SKIP_LINE13
           - DVP_SKIP_LINE14
           - DVP_SKIP_LINE15
return  none.
void DVP_ConfigRepeatSKIP(uint32_t Line)Config Repeat Frame Line Skip .
Source comment
name    DVP_ConfigRepeatSKIP.
fun     Config Repeat Frame Line Skip .
param   Line (The input parameters must be the following values):
           - DVP_SKIP_LINE1
           - DVP_SKIP_LINE2
           - DVP_SKIP_LINE3
           - DVP_SKIP_LINE4
           - DVP_SKIP_LINE5
           - DVP_SKIP_LINE6
           - DVP_SKIP_LINE7
           - DVP_SKIP_LINE8
           - DVP_SKIP_LINE9
           - DVP_SKIP_LINE10
           - DVP_SKIP_LINE11
           - DVP_SKIP_LINE12
           - DVP_SKIP_LINE13
           - DVP_ODD_LINE
           - DVP_EVEN_LINE
return  none.
void DVP_EnableBuffer1(FunctionalState Cmd)Frame Buffer 1 enable.
Source comment
name    DVP_EnableBuffer1.
fun     Frame Buffer 1 enable.
param  Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
void DVP_SetBuffer1Address(uint32_t Addres)Set Frame Buffer 1 Start Address.
Source comment
name    DVP_SetBuffer1Address.
fun     Set Frame Buffer 1 Start Address.
param  Addres:(The input parameters must be the following values)
            - 0x00000000~0xFFFFFFFF
return  none
void DVP_EnableBuffer2(FunctionalState Cmd)Frame Buffer 2 enable.
Source comment
name    DVP_EnableBuffer2.
fun     Frame Buffer 2 enable.
param  Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
void DVP_SetBuffer2Address(uint32_t Addres)Set Frame Buffer 2 Start Address.
Source comment
name    DVP_SetBuffer2Address.
fun     Set Frame Buffer 2 Start Address.
param  Addres:(The input parameters must be the following values)
            - 0x00000000~0xFFFFFFFF
return  none
void DVP_SetBufferSize(uint32_t Size)Set Frame Buffer Size.
Source comment
name    DVP_SetBufferSize.
fun     Set Frame Buffer Size.
param  Size:(The input parameters must be the following values)
            - 0 ~ 4194303
return  none
void DVP_SetDisplayBufferStatus(uint32_t State_Mode)Set show current frame buffer status.
Source comment
name    DVP_SetDisplayBufferStatus.
fun     Set show current frame buffer status.
param  State_Mode:(The input parameters must be the following values)
            - DVP_DISPLAY_ADDRESS
            - DVP_DISPLAY_NUMBER
return  none
uint32_t DVP_GetDisplayBufferStatus1(void)Get current frame buffer 1 status.
Source comment
name    DVP_GetDisplayBufferStatus1.
fun     Get current frame buffer 1 status.
param   none
return  Frame Buffer 1 address or Number of data bytes
uint32_t DVP_GetDisplayBufferStatus2(void)Get current frame buffer 2 status.
Source comment
name    DVP_GetDisplayBufferStatus2.
fun     Get current frame buffer 2 status.
param   none
return  Frame Buffer 2 address or Number of data bytes
void DVP_EnableAcross1KBoundary(FunctionalState Cmd)Increamental bursting across 1K boundary is allowed/enabled
Source comment
name    DVP_EnableAcross1KBoundary.
fun     Increamental bursting across 1K boundary is allowed/enabled
param  Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none
void DVP_ConfigCROPStart(uint16_t X,uint16_t Y)Config Y-coordinate and X-coordinate of crop image start point.
Source comment
name    DVP_ConfigCROPStart.
fun     Config Y-coordinate and X-coordinate of crop image start point.
param  (X,Y):(The input parameters must be the following values)
            - (0,0) ~ (2047,2047)
return  none
void DVP_ConfigCROPEnd(uint16_t X,uint16_t Y)Config Y-coordinate and X-coordinate of crop image end point.
Source comment
name    DVP_ConfigCROPEnd.
fun     Config Y-coordinate and X-coordinate of crop image end point.
param  (X,Y):(The input parameters must be the following values)
            - (0,0) ~ (2047,2047)
return  none
void DVP_DeInit(void)Deinitializes the DVP peripheral registers to their default reset values.
Source comment
name    DVP_DeInit.
fun     Deinitializes the DVP peripheral registers to their default reset values.
param   none
return  none
void DVP_Init(DVP_InitType* DVP_InitParam)Initializes the DVP peripheral according to the specified parameters in the DVP_InitParam .
Source comment
name    DVP_Init.
fun     Initializes the DVP peripheral according to the specified
        parameters in the DVP_InitParam .
param   DVP_InitParam (The input parameters must be the following values):
          - CaptureMode
            - DVP_CAPTURE_MODE_CONTINUE
            - DVP_CAPTURE_MODE_SINGLE
          - CropMode
            - DVP_NORMAL_MODE
            - DVP_CROP_MODE
          - SynchroMode
            - DVP_SYNC_MODE_SOFTWARE
            - DVP_SYNC_MODE_HARDWARE
          - CropStartX
          - CropStartY
          - CropEndX
          - CropEndY
          - BFilter
          - PixelClkPolarity
            - DVP_PIXEL_POLARITY_RISING
            - DVP_PIXEL_POLARITY_FALLING
          - HsyncPolarity
            - DVP_HSYNC_POLARITY_HIGH
            - DVP_HSYNC_POLARITY_LOW
          - VsyncPolarity
            - DVP_VSYNC_POLARITY_HIGH
            - DVP_VSYNC_POLARITY_LOW
          - DataInvert
            - DVP_DATA_INVERT
            - DVP_DATA_NOTINVERT
          - DataReverse
            - DVP_DATA_REVERSE
            - DVP_DATA_NOTREVERSE
          - DataMode
            - DVP_DATA_MODE1
            - DVP_DATA_MODE2
            - DVP_DATA_MODE3
            - DVP_DATA_MODE4
            - DVP_DATA_MODE5
            - DVP_DATA_MODE6
            - DVP_DATA_MODE7
            - DVP_DATA_MODE8
          - PixelByte
            - DVP_PIXEL_BYTE1
            - DVP_PIXEL_BYTE2
return  none
void DVP_StructInit(DVP_InitType* DVP_InitParam)Initializes the structure parameter of type DVP_InitType used to initialize DVP. This function is usually called before initializing a parameter of type DVP_InitType.
Source comment
name    DVP_StructInit.
fun     Initializes the structure parameter of type DVP_InitType used to
        initialize DVP. This function is usually called before initializing
        a parameter of type DVP_InitType.
param   DVP_InitParam :
          - Pointer to the DVP_InitType structure which will be initialized.
return  none
void DVP_ConfigDma(DVP_DMAInitType* DVP_DMAInitParam)Initializes the structure parameter of type DVP_DMAInitType used to initialize DVP DMA. This function is usually called before initializing a parameter of type DVP_DMAInitType.
Source comment
name    DVP_ConfigDma.
fun     Initializes the structure parameter of type DVP_DMAInitType used to
        initialize DVP DMA. This function is usually called before initializing
        a parameter of type DVP_DMAInitType.
param   DVP_DMAInitType :
          - FrameBufferNum
          - FrameBufferAddress1
          - FrameBufferAddress2
          - DisplayStatus
            - DVP_DISPLAY_ADDRESS
            - DVP_DISPLAY_NUMBER
          - BurstSize
            - DVP_BURST_SIZE_BYTE_4
            - DVP_BURST_SIZE_BYTE_8
            - DVP_BURST_SIZE_BYTE_12
            - DVP_BURST_SIZE_BYTE_16
            - DVP_BURST_SIZE_BYTE_20
            - DVP_BURST_SIZE_BYTE_24
            - DVP_BURST_SIZE_BYTE_28
            - DVP_BURST_SIZE_BYTE_32
          - FifoThreshold
            - DVP_FIFO_THRSEHOLD_BYTE_4
            - DVP_FIFO_THRSEHOLD_BYTE_8
            - DVP_FIFO_THRSEHOLD_BYTE_16
            - DVP_FIFO_THRSEHOLD_BYTE_32
          - FrameBufferSize
return  none
void DVP_DMAStructInit(DVP_DMAInitType* DVP_DMAInitParam)Initializes the structure parameter of type DVP_DMAInitType used to initialize DVP. This function is usually called before initializing a parameter of type DVP_DMAInitType.
Source comment
name    DVP_DMAStructInit.
fun     Initializes the structure parameter of type DVP_DMAInitType used to
        initialize DVP. This function is usually called before initializing
        a parameter of type DVP_DMAInitType.
param   DVP_DMAInitParam :
          - Pointer to the DVP_DMAInitType structure which will be initialized.
return  none
void DVP_FrameBufferAddrIncrementEnable(FunctionalState Cmd)DVP frame buffer address increment enable.
Source comment
name    DVP_FrameBufferAddrIncrementEnable.
fun     DVP frame buffer address increment enable.
param   Cmd:(The input parameters must be the following values)
            - ENABLE
            - DISABLE
return  none

5.9.3 Demo descriptions

This section describes the DVP Camera example.

5.9.3.1 Camera OV5640 capture shown on the LCD

Example directory: projects/n32h49x_EVAL/examples/DVP/Camera/

Initialize the serial port and LCD→Configure the OV5640 over SCCB→Configure the DVP interface and DMA→Enable DVP capture→Move the frame to the LCD frame buffer in the frame interrupt

Item Source analysis
Function Receives the image data produced by the OV5640.
Shows the image on the ILI9806 LCD through the FEMC.
Source files src/main.c: calls dvp_demo and then loops.
src/dvp_demo.c: LCD initialization, the logo display and the example entry.
src/bsp_dvp.c: the DVP interface, DMA and interrupt configuration.
src/bsp_ov5640.c: SCCB timing and OV5640 register configuration.
src/lcd.c: the FEMC-based LCD driver and image transfer.
src/n32h49x_it.c: the DVP_IRQHandler interrupt service routine.
readme.txt: function, environment and usage notes.
MDK-ARM/, EWARM/: the Keil and IAR projects.
Key configuration Clock source HSI+PLL, system frequency 240MHz.
The OV5640 uses an 8-bit data interface: PCLK on PE4, HSYNC on PE2, VSYNC on PE3, with SCCB on PB6 and PB7.
The LCD is an 800x480 ILI9806 driven by the FEMC over a 16-bit parallel bus.
The frame buffer sits in on-chip SRAM and its size is set by DVP_IMAGE_SIZE.
Program and data path main calls dvp_demo.
dvp_demo initializes the serial port and LCD and then calls DVPDemo_Init.
DVPDemo_Init configures the NVIC, initializes the OV5640, configures the DVP interface and DMA, and enables them.
DVP_IRQHandler clears the flag in the frame interrupt and writes one frame into the LCD frame buffer.
Main APIs DVP_Init, DVP_ConfigDma, DVP_ConfigInt, DVP_EnableBuffer1, DVP_EnablePort
Verification After flashing and resetting, the camera image appears on the LCD.
The serial port can be used for debug output.
Use note J30 on the evaluation board controls the LCD reset and must be fitted.
The development environment is KEIL MDK-ARM 5.34 or IAR EWARM 8.50.1.
Core-code walkthrough and porting

The example shows the OV5640 image captured by the DVP directly on the LCD through the FEMC, a complete path from sensor to screen.

Data path: OV5640 outputs pixels -> the DVP interface and its internal DMA move them -> the frame buffer -> DVP_IRQHandler fires on the frame interrupt -> lcd_ov5640 writes the image into the LCD frame buffer

1. The example entry lights the screen before configuring capture. dvp_demo initializes the serial port and LCD, shows the logo, then calls DVPDemo_Init and finally enables the interface.

src/dvp_demo.csrc/dvp_demo.c · dvp_demo
void dvp_demo(void)
{
    log_init();
    /* LCD configuration */
    LCD_Configuration();
    LCD_GramScan(0);
    LCD_SetColors(RED,WHITE);
    LCD_Clear(0,0,lcd_width,lcd_height);
    LCD_Logo_init();
    /* DVP configuration */
    DVPDemo_Init();
    DVP_EnablePort(ENABLE);

2. Initialization goes sensor, then interface, then interrupt. DVPDemo_Init configures the NVIC, initializes the OV5640 port and registers, configures the DVP interface and DMA, and enables them.

src/bsp_dvp.csrc/bsp_dvp.c · DVPDemo_Init
void DVPDemo_Init(void)
{
    DVP_NVIC_Configuration();
    OV5640_InitPort();
    OV5640_Init();
    OV5640_RGB565_Config();
    DVP_InitInterface();
    DVP_ConfigInt(DVP_INT_M1TC,ENABLE);
    DVP_EnableBuffer1(ENABLE);
    DVP_EnablePort(ENABLE);

3. The interface and DMA are configured through structures. DVP_InitInterface enables the DVP clock, fills DVP_InitType and DVP_DMAInitType, and calls DVP_Init and DVP_ConfigDma.

src/bsp_dvp.csrc/bsp_dvp.c · DVP_InitInterface
    DVP_InitType DVP_InitStructure;
    DVP_DMAInitType DVP_DMAInitStructure;

    RCC_EnableAHBPeriphClk(RCC_AHB_PERIPHEN_DVP, ENABLE);

    DVP_StructInit(&DVP_InitStructure);

    DVP_InitStructure.CaptureMode      = DVP_CAPTURE_MODE_CONTINUE;
    DVP_InitStructure.CropMode         = DVP_NORMAL_MODE;
    DVP_InitStructure.VBFilter         = 3;
    DVP_InitStructure.PixelClkPolarity = DVP_PIXEL_POLARITY_FALLING;
    DVP_InitStructure.HsyncPolarity    = DVP_HSYNC_POLARITY_HIGH;
    DVP_InitStructure.VsyncPolarity    = DVP_VSYNC_POLARITY_LOW;
    DVP_InitStructure.DataInvert       = DVP_DATA_NOTINVERT;
    DVP_InitStructure.DataReverse      = DVP_DATA_NOTREVERSE;
    DVP_InitStructure.DataMode         = DVP_DATA_MODE1;
    DVP_InitStructure.PixelByte        = DVP_PIXEL_BYTE1;

    DVP_Init(&DVP_InitStructure);

    DVP_DMAStructInit(&DVP_DMAInitStructure);

    DVP_DMAInitStructure.FrameBufferNum      = 1;
    DVP_DMAInitStructure.FrameBufferAddress1 = LCD_IMAGE_ADDRESS;
    DVP_DMAInitStructure.DisplayStatus       = DVP_DISPLAY_ADDRESS;
    DVP_DMAInitStructure.BurstSize           = DVP_BURST_SIZE_BYTE_4;
    DVP_DMAInitStructure.FifoThreshold       = DVP_FIFO_THRSEHOLD_BYTE_4;
    DVP_DMAInitStructure.FrameBufferSize     = DVP_IMAGE_SIZE;
    DVP_ConfigDma(&DVP_DMAInitStructure);

4. One frame is moved in the frame interrupt. DVP_IRQHandler checks the frame flag and interrupt status, clears the pending bit, and then writes the image to the LCD.

src/n32h49x_it.csrc/n32h49x_it.c · DVP_IRQHandler
void DVP_IRQHandler(void)
{
    if((DVP_GetFlagStatus(DVP_FLAG_M1TC)==1)&&(DVP_GetIntStatus(DVP_INT_M1TC)==1))
    {
        DVP_ClrIntPendingBit(DVP_INT_M1TC);

Corresponding source files: src/main.c, src/dvp_demo.c, src/bsp_dvp.c, src/n32h49x_it.c

5.9.4 Notes and troubleshooting

The table lists the operational constraints stated in the user manual for this peripheral.

Scenario Check & action Source
DVP enabled after the vertical sync The DVP port enable bit must be set at least 4 pixel clock cycles before DVP_VSYNC becomes active, otherwise the current frame is discarded. User manual
Interface clock too slow The AHB interface clock (hclk) must be equal to or faster than the pixel clock. User manual
Crop coordinates not written first Write the start and end coordinates before setting the CROPEN bit for the crop function. User manual
Frame buffer DMA burst too large The single-transfer size of the frame buffer DMA must be greater than or equal to the FIFO threshold. User manual
Embedded sync data width Embedded sync mode supports only 8-bit, 10-bit and 12-bit data modes. User manual
Interrupt flag not cleared Clear the relevant flag in DVP_INTSTS (write 0 to clear) before using an interrupt, so earlier state does not affect reporting. User manual
Missing gap between lines There must be at least one pixel clock cycle between any two lines. User manual
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Datasheets, SDK, driver APIs and demo guides for Nations Technologies MCU development kits, organized by chip series.

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