OV7670 Camera Driver Documentation

Overview

This driver provides initialization and control routines for the OV7670 camera module using STM32F4 microcontrollers. It configures the camera through I2C (SCCB protocol), sets up DCMI for image capture, and manages DMA transfers for efficient data handling.

Features

I2C initialization and communication with OV7670 camera registers
DCMI peripheral setup for image data capture
DMA configuration for circular buffering of camera data
Clock generation for camera (XCLK) using MCU MCO output
Camera register initialization with default settings for QVGA RGB565 output format

Supported Hardware Pins

MCU Pin	Camera Signal
PB8	SIOC (I2C Clock)
PB9	SIOD (I2C Data)
PB7	VSYNC
PA4	HS
PA6	PCLK
PA8	XCLK
PE6	D7
PE5	D6
PD3	D5
PE4	D4
PC9	D3
PC8	D2
PC7	D1
PC6	D0

API Reference

te_CAMERA_ERROR_CODES Camera_Open(void)

Initializes all required peripherals and configures the OV7670 camera module.

Returns:

E_CAMERA_ERR_NONE on success, otherwise an error code indicating the failure reason.

Enumerations

te_CAMERA_ERROR_CODES

Enum	Description
E_CAMERA_ERR_NONE	No error
E_CAMERA_ERR_I2C_INIT	I2C initialization failed
E_CAMERA_ERR_DCMI_INIT	DCMI initialization failed
E_CAMERA_ERR_DMA_INIT	DMA initialization failed
E_CAMERA_ERR_CAMERA_INIT	Camera register init failed

Internal Functions (Static)

These functions are not exposed publicly but form the internal implementation of the driver:

static te_CAMERA_ERROR_CODES Camera_Init(void)
Writes default configuration registers to the OV7670 via I2C.
static void Camera_GPIO_Init(void)
Configures GPIO pins for camera data, control signals, and I2C.
static te_CAMERA_ERROR_CODES Camera_DCMI_Init(void)
Initializes the DCMI peripheral with proper parameters for OV7670 data capture.
static void Camera_XCLK_Init(void)
Sets up the MCU clock output (MCO) to provide the external clock (XCLK) signal to the camera.
static te_CAMERA_ERROR_CODES Camera_DMA_Init(void)
Configures the DMA stream for circular buffer mode linked to DCMI.
static te_CAMERA_ERROR_CODES Camera_I2C_Init(void)
Sets up the I2C peripheral for SCCB communication with OV7670.

Data Structures and Definitions

Macro / Constant	Description
OV7670_REG_NUM	Number of camera registers configured (122)
OV7670_WRITE_ADDR	I2C write address for OV7670 (0x42)
IMG_ROWS	Image height in pixels (320)
IMG_COLUMNS	Image width in pixels (240)

How It Works

Camera_Open() is called to start initialization.
I2C peripheral is configured for communication.
DCMI peripheral is set up to capture data synchronized with camera signals.
DMA is configured to transfer image data continuously to memory.
Camera external clock (XCLK) is generated using MCU's MCO pin.
OV7670 registers are written to via I2C to configure resolution, color format, and other camera parameters.
After successful initialization, the camera is ready to capture images.

Usage Example

#include "camera_drv.h"

int main(void) {
    // HAL initialization here

    te_CAMERA_ERROR_CODES status = Camera_Open();
    if (status != E_CAMERA_ERR_NONE) {
        // Handle error
    }

    // Start DCMI capture, DMA, etc.
}

LCD Driver Documentation

This document describes the functions of the SPI-based 320x240 LCD driver for STM32F4.

Overview

The LCD is controlled via SPI5 interface.
GPIO pins are configured for LCD control and SPI communication.
Basic LCD control functions and a generic IOCTL interface are provided.

Functions

te_LCD_ERROR_CODES LCD_Open(void* vpParam)

Description:

Initializes the LCD driver. Configures GPIO and SPI peripherals, resets the LCD, and performs initial setup.

Parameters:

vpParam: Generic parameter pointer (currently unused).

Returns:

E_LCD_ERR_NONE: Initialization successful.
E_LCD_ERR_SPI_INIT: SPI initialization failed.

te_LCD_ERROR_CODES LCD_Ioctl(te_LCD_IOCTL_COMMANDS eCommand, void * vpParam)

Description:

General control interface for the LCD. Supports operations like drawing a pixel, filling the screen, displaying images, rotating the screen, etc.

Parameters:

eCommand: The control command to execute (e.g., E_LCD_IOCTL_DRAW_PIXEL).
vpParam: Pointer to the data or parameters required by the command.

Returns:

E_LCD_ERR_NONE: Operation successful.
E_LCD_ERR_WRONG_IOCTL_CMD: Unsupported command.

te_LCD_ERROR_CODES LCD_Write(const void *pvBuffer, const uint32_t xBytes)

Description:

Writes pixel color data to the currently active window on the LCD.

Parameters:

pvBuffer: Pointer to the color data buffer (of type ts_LCD_WR_TYPE).
xBytes: Number of bytes to write (not used in current implementation).

Returns:

E_LCD_ERR_NONE: Write operation successful.

te_LCD_ERROR_CODES LCD_Close(void* vpParam)

Description:

Closes the LCD driver, turns off the display, and stops SPI communication.

Parameters:

vpParam: Generic parameter pointer (currently unused).

Returns:

E_LCD_ERR_NONE: Successfully closed.

static te_LCD_ERROR_CODES LCD_GPIO_Init(void)

Description:

Configures GPIO pins and clocks required for the LCD and SPI interface.

Returns:

E_LCD_ERR_NONE: GPIO initialization successful.

static te_LCD_ERROR_CODES LCD_SPI_Init(void)

Description:

Initializes SPI5 peripheral as a master with the necessary settings for LCD communication.

Returns:

E_LCD_ERR_NONE: SPI initialization successful.
E_LCD_ERR_SPI_INIT: SPI initialization failed.

void LCD_Reset(void)

Description:
Performs a hardware reset on the LCD by toggling the reset pin.

Error Codes (te_LCD_ERROR_CODES)

Code	Meaning
E_LCD_ERR_NONE	Operation successful
E_LCD_ERR_SPI_INIT	SPI initialization error
E_LCD_ERR_WRONG_IOCTL_CMD	Invalid IOCTL command

Usage Example

if (LCD_Open(NULL) != E_LCD_ERR_NONE) {
    // Handle error
}

ts_LCD_DRAW_PIXEL pixel = {x, y, color};
LCD_Ioctl(E_LCD_IOCTL_DRAW_PIXEL, &pixel);

LCD_Close(NULL);