使用STM32实现简单的摄像头应用

1万 · 2024-7-11 13:22

使用STM32实现简单的摄像头应用可以分为以下几个步骤：

硬件准备：选择合适的STM32开发板和摄像头模块。可以考虑使用带有摄像头接口的STM32F4 Discovery开发板和OV7670摄像头模块。

连接摄像头模块：将摄像头模块的引脚与开发板的对应引脚相连。根据OV7670摄像头模块的引脚定义，连接摄像头模块的SCL、SDA、VSYNC、HREF等引脚到STM32开发板的GPIO引脚。

初始化GPIO：使用STM32的GPIO库初始化摄像头模块所需的引脚为输入或输出，并设置相应的模式和速度。

GPIO_InitTypeDef GPIO_InitStruct;
/* Enable GPIO clock */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB, ENABLE);

/* Configure GPIO pins as alternate function */
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_Init(GPIOB, &GPIO_InitStruct);

/* Select alternate function */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_MCO);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_MCO);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_MCO);
配置I2C总线：摄像头模块使用I2C进行通信，因此需要配置STM32的I2C总线。
I2C_InitTypeDef I2C_InitStruct;
/* Enable I2C clock */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);

/* Configure I2C1 pins */
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStruct);

/* Select alternate function */
GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_I2C1);

/* Configure I2C1 */
I2C_DeInit(I2C1);
I2C_InitStruct.I2C_ClockSpeed = 100000;
I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;
I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;
I2C_InitStruct.I2C_OwnAddress1 = 0x00;
I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;
I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_Init(I2C1, &I2C_InitStruct);
I2C_Cmd(I2C1, ENABLE);

配置摄像头模块：根据OV7670摄像头模块的通信协议和寄存器设置，配置摄像头模块的分辨率、采样格式等参数。
void SCCB_Write(uint8_t reg, uint8_t data) {
/* Start transmission */
I2C_GenerateSTART(I2C1, ENABLE);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

/* Send address and direction */
I2C_Send7bitAddress(I2C1, SCCB_ADDRESS, I2C_Direction_Transmitter);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

/* Send register address */
I2C_SendData(I2C1, reg);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

/* Send data */
I2C_SendData(I2C1, data);
while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

/* Stop transmission */
I2C_GenerateSTOP(I2C1, ENABLE);
}

void OV7670_Init() {
/* Reset the camera module */
GPIO_ResetBits(GPIOB, GPIO_Pin_3);
delay_ms(100);
GPIO_SetBits(GPIOB, GPIO_Pin_3);
delay_ms(100);

/* Write registers */
SCCB_Write(0x12, 0x80); // Reset all registers
SCCB_Write(0x12, 0x00); // Normal operation mode

SCCB_Write(0x0C, 0x04); // RGB565 output format
SCCB_Write(0x3A, 0x04); // UYVY format

SCCB_Write(0x11, 0x00); // Clock prescaler for internal clock
SCCB_Write(0x0D, 0x40); // PCLK divider for internal clock

SCCB_Write(0x12, 0x82); // Reset all registers
}

读取图像数据：配置摄像头模块后，可以通过I2C读取摄像头模块输出的图像数据。根据OV7670摄像头模块的输出格式，可以选择使用DMA或者中断方式读取数据。
void DMA_Config() {
DMA_InitTypeDef DMA_InitStruct;

/* Enable DMA clock */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA2, ENABLE);

/* Reset DMA controller */
DMA_DeInit(DMA2_Stream2);

/* Configure DMA controller */
DMA_InitStruct.DMA_Channel = DMA_Channel_1;
DMA_InitStruct.DMA_PeripheralBaseAddr = (uint32_t)&DCMI->DR;
DMA_InitStruct.DMA_Memory0BaseAddr = (uint32_t)imageBuffer;
DMA_InitStruct.DMA_DIR = DMA_DIR_PeripheralToMemory;
DMA_InitStruct.DMA_BufferSize = IMAGE_WIDTH * IMAGE_HEIGHT * 2; // RGB565 format
DMA_InitStruct.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStruct.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStruct.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;
DMA_InitStruct.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStruct.DMA_Mode = DMA_Mode_Circular;
DMA_InitStruct.DMA_Priority = DMA_Priority_High;
DMA_InitStruct.DMA_FIFOMode = DMA_FIFOMode_Disable;
DMA_InitStruct.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
DMA_InitStruct.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStruct.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_Init(DMA2_Stream2, &DMA_InitStruct);

/* Set DMA interrupt */
NVIC_InitTypeDef NVIC_InitStruct;
NVIC_InitStruct.NVIC_IRQChannel = DMA2_Stream2_IRQn;
NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStruct);

DMA_ITConfig(DMA2_Stream2, DMA_IT_TC, ENABLE);

/* Enable DMA transfer */
DMA_Cmd(DMA2_Stream2, ENABLE);
}

void DMA2_Stream2_IRQHandler() {
if (DMA_GetITStatus(DMA2_Stream2, DMA_IT_TCIF2)) {
      /* Process image data */

      /* Clear DMA interrupt */
      DMA_ClearFlag(DMA2_Stream2, DMA_FLAG_TCIF2);
}
}

int main() {
/* Initialize hardware */
GPIO_Config();
I2C_Config();
OV7670_Init();
DMA_Config();

/* Start image acquisition */
DCMI_Cmd(ENABLE);
DCMI_CaptureCmd(ENABLE);

while (1) {
      /* Process image data */

      /* Delay for image processing */
      delay_ms(1000);
}
}

以上是一个简单的使用STM32实现摄像头应用的代码示例。在实际使用过程中，需要根据具体的摄像头模块和应用需求进行相应的配置和调整。
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原文链接：https://blog.csdn.net/qq_67153941/article/details/140268759