STM32H750获取OV7670摄像头图像及上位机解码（一维码&二维码）

1. 目的

针对静止拍摄图像场景，实现STM32H750对30万像素OV7670摄像头进行图像捕获，并通过串口将数据送到上位机软件进行解码。
本文可作为STM32H7及STM32F7系列驱动OV7670摄像头的代码参考，通过DCMI的CROP功能，使用者可以从OV7670最大输出分辨率（640×480）中“剪”出更小分辨率图片。

2. 场景参数说明

上位机与STM32H750通过USB全速虚拟串口（可用12000000波特率）或UART串口（230400波特率）通讯及接收图像数据。
STM32H750通过DCMI总线接口与OV7670摄像头DVP接口连接，通过IIC总线与OV7670 SCCB配置端口连接，并通过GPIO连接控制摄像头端的Reset和PowerDown管脚。
STM32H750从OV7670摄像头获取640×480分辨率的RGB图像，本实验不针对有SRAM扩展的场景，也不针对直接传送数据至嵌入式LCD显示的场景,因此，内部SRAM分区用于存放一帧数据*（640×480×2 bytes)的空间不足，因此，利用STM32 DCMI CROP功能，获取多帧图像的不同部分实现拼接效果，并最终将一整帧数据传送到上位机。
开发环境为STM32CUBEIDE（HAL库）

3. 通讯协议

上位机通过串口发送0x01指令到STM32, STM32接收指令后，回复0x55 0xaa xx三个字节，其中0x55 0xaa指示有效的回复，xx为摄像头类型说明，便于上位机程序进行后续数据的识别处理，当前xx==0x01为OV7670摄像头。
STM32从OV7670摄像头分帧获取不同部分并发送整帧640×480×2的RGB565数据到上位机。
上位机进行图像的显示，并可选进行一维码和二维码的识别（基于zbar开源库）。
简化型设计，无校验方式

4. STM32H750时钟配置

对于需要STM32H750输出24MHz时钟给OV7670摄像头模块的场景，可以用STM32 MCO功能输出24MHz时钟。如果摄像头模块自带晶振，不需要STM32提供时钟。

5. STM32H750通讯接口配置

USB虚拟串口：

USART1串口配置：

6. 摄像头接口配置

DCMI接口：
STM32H7的HAL库DCMI接口,从1.8版本升级1.9以上版本后，配置及函数存在问题。因此这里的参数配置（“Parameter Settings”）部分，会在程序里面重新配置。

而其它部分正常配置：

需要单独对DCMI接口的HSYNC和VSYNC做输入GPIO的配置：

OV7670的SCCB接口时序通过STM32的GPIO管脚模拟，不采用专用的IIC管脚。OV7670的Reset和PowerDown信号，也通过2个GPIO进行管理控制。

保存，并生成初始代码，再进行功能代码的编写。

7. OV7670接口及配置代码

编写ov7670.h文件：

#include "stm32h7xx_hal.h"
#ifndef _OV7670_H
#define _OV7670_H//for not open-drain bus
/** SIOC: PE7* SIOD: PE8* VSYNC: PB7* HREF: PA4* PCLK: PA6* XCLK: PA8 //24MHz, optional to use* D7: PB9* D6: PB8* D5: PD3* D4: PC11* D3: PE1* D2: PC8* D1: PC7* D0: PC6* RESET: PD10* PWDN: PD11***/#define SCCB_SCL_L          HAL_GPIO_WritePin(GPIOE,GPIO_PIN_7,GPIO_PIN_RESET)
#define SCCB_SCL_H          HAL_GPIO_WritePin(GPIOE,GPIO_PIN_7,GPIO_PIN_SET)
#define SCCB_SDA_L          HAL_GPIO_WritePin(GPIOE,GPIO_PIN_8,GPIO_PIN_RESET)
#define SCCB_SDA_H          HAL_GPIO_WritePin(GPIOE,GPIO_PIN_8,GPIO_PIN_SET)#define SCCB_READ_SDA       HAL_GPIO_ReadPin(GPIOE, GPIO_PIN_8)
#define SCCB_ID_W           0X42            //OV7670 ID for Write
#define SCCB_ID_R           0X43            //OV7670 ID for Read#define OV7670_PWDN           HAL_GPIO_WritePin(GPIOD,GPIO_PIN_11,GPIO_PIN_SET)
#define OV7670_PWUP           HAL_GPIO_WritePin(GPIOD,GPIO_PIN_11,GPIO_PIN_RESET)
#define OV7670_RST            HAL_GPIO_WritePin(GPIOD,GPIO_PIN_10,GPIO_PIN_RESET)
#define OV7670_RUN            HAL_GPIO_WritePin(GPIOD,GPIO_PIN_10,GPIO_PIN_SET)
#define OV7670_VSYNC          HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7)
#define OV7670_HREF           HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_4)
#define OV7670_PCLK           HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_6)void SCCB_Start(void);
void SCCB_Stop(void);
void SCCB_No_Ack(void);
uint8_t SCCB_WR_Byte(uint8_t data);
uint8_t SCCB_RD_Byte(void);
uint8_t SCCB_WR_Reg(uint8_t reg,uint8_t data);
uint8_t SCCB_RD_Reg(uint8_t reg);
uint32_t tickdelay;void SCCB_SDA_IN(void);
void SCCB_SDA_OUT(void);#define ticknumber 12*10void SCCB_Rst(void);/***********************************/
void OV7670_640_480_RGB565_Init(void);
void OV7670_Light_Mode(uint8_t mode);
void OV7670_Color_Saturation(uint8_t sat);
void OV7670_Brightness(uint8_t bright);
void OV7670_Contrast(uint8_t contrast);
void OV7670_Special_Effects(uint8_t eft);#endif

编写ov7670.c文件：

#include <ov7670.h>//for not open-drain busvoid SCCB_Start(void)
{SCCB_SDA_H;SCCB_SCL_H;tickdelay = ticknumber;while(tickdelay--);SCCB_SDA_L;tickdelay = ticknumber;while(tickdelay--);SCCB_SCL_L;
}void SCCB_Stop(void)
{SCCB_SDA_L;tickdelay = ticknumber;while(tickdelay--);SCCB_SCL_H;tickdelay = ticknumber;while(tickdelay--);SCCB_SDA_H;tickdelay = ticknumber;while(tickdelay--);
}void SCCB_No_Ack(void)
{HAL_Delay(1);SCCB_SDA_H;SCCB_SCL_H;tickdelay = ticknumber;while(tickdelay--);SCCB_SCL_L;tickdelay = ticknumber;while(tickdelay--);SCCB_SDA_L;tickdelay = ticknumber;while(tickdelay--);
}uint8_t SCCB_WR_Byte(uint8_t dat)
{uint8_t j,res;for(j=0;j<8;j++){if(dat&0x80)SCCB_SDA_H;else SCCB_SDA_L;dat<<=1;tickdelay = ticknumber;while(tickdelay--);SCCB_SCL_H;tickdelay = ticknumber;while(tickdelay--);SCCB_SCL_L;}SCCB_SDA_IN();tickdelay = ticknumber;while(tickdelay--);SCCB_SCL_H;tickdelay = ticknumber;while(tickdelay--);if(SCCB_READ_SDA)res=1;else res=0;SCCB_SCL_L;SCCB_SDA_OUT();return res;
}uint8_t SCCB_RD_Byte(void)
{uint8_t temp=0,j;SCCB_SDA_IN();for(j=8;j>0;j--){tickdelay = ticknumber;while(tickdelay--);SCCB_SCL_H;temp=temp<<1;if(SCCB_READ_SDA)temp++;tickdelay = ticknumber;while(tickdelay--);SCCB_SCL_L;}SCCB_SDA_OUT();return temp;
}uint8_t SCCB_WR_Reg(uint8_t reg,uint8_t data)
{uint8_t res=0;SCCB_Start();if(SCCB_WR_Byte(SCCB_ID_W))res=1;tickdelay = ticknumber;while(tickdelay--);if(SCCB_WR_Byte(reg))res=1;tickdelay = ticknumber;while(tickdelay--);if(SCCB_WR_Byte(data))res=1;SCCB_Stop();return  res;
}uint8_t SCCB_RD_Reg(uint8_t reg)
{uint8_t val=0;SCCB_Start();SCCB_WR_Byte(SCCB_ID_W);tickdelay = ticknumber;while(tickdelay--);SCCB_WR_Byte(reg);tickdelay = ticknumber;while(tickdelay--);SCCB_Stop();tickdelay = ticknumber;while(tickdelay--);SCCB_Start();SCCB_WR_Byte(SCCB_ID_R);tickdelay = ticknumber;while(tickdelay--);val=SCCB_RD_Byte();SCCB_No_Ack();SCCB_Stop();return val;
}void SCCB_SDA_IN(void)
{GPIO_InitTypeDef GPIO_InitStruct = {0};__HAL_RCC_GPIOE_CLK_ENABLE();GPIO_InitStruct.Pin = GPIO_PIN_8;GPIO_InitStruct.Mode = GPIO_MODE_INPUT;GPIO_InitStruct.Pull = GPIO_PULLUP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);
}void SCCB_SDA_OUT(void)
{GPIO_InitTypeDef GPIO_InitStruct = {0};__HAL_RCC_GPIOE_CLK_ENABLE();GPIO_InitStruct.Pin = GPIO_PIN_8;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);
}void SCCB_Rst(void)
{HAL_GPIO_WritePin(GPIOD,GPIO_PIN_11,GPIO_PIN_RESET)    ;HAL_GPIO_WritePin(GPIOD,GPIO_PIN_10,GPIO_PIN_RESET)    ;HAL_Delay(5);HAL_GPIO_WritePin(GPIOD,GPIO_PIN_10,GPIO_PIN_SET) ;HAL_Delay(5);
}//--------------OV7670 Functions--------------//
void  OV7670_640_480_RGB565_Init(void)
{SCCB_WR_Reg(0x11, 0x02);        // 30fpsSCCB_WR_Reg(0x6b, 0x8a);        // pclk*6SCCB_WR_Reg(0x3A, 0x04);SCCB_WR_Reg(0x12, 0x04);        //RGBSCCB_WR_Reg(0x17, 0x13);SCCB_WR_Reg(0x18, 0x01);SCCB_WR_Reg(0x32, 0xB6);SCCB_WR_Reg(0x19, 0x02);SCCB_WR_Reg(0x1A, 0x7A);SCCB_WR_Reg(0x03, 0x0F);SCCB_WR_Reg(0x0C, 0x00);SCCB_WR_Reg(0x3E, 0x00);SCCB_WR_Reg(0x70, 0x3A);SCCB_WR_Reg(0x71, 0x35);SCCB_WR_Reg(0x72, 0x11);SCCB_WR_Reg(0x73, 0xF0);SCCB_WR_Reg(0xA2, 0x3B);SCCB_WR_Reg(0x1E, 0x0F);SCCB_WR_Reg(0x7a, 0x20);SCCB_WR_Reg(0x7b, 0x03);SCCB_WR_Reg(0x7c, 0x0a);SCCB_WR_Reg(0x7d, 0x1a);SCCB_WR_Reg(0x7e, 0x3f);SCCB_WR_Reg(0x7f, 0x4e);SCCB_WR_Reg(0x80, 0x5b);SCCB_WR_Reg(0x81, 0x68);SCCB_WR_Reg(0x82, 0x75);SCCB_WR_Reg(0x83, 0x7f);SCCB_WR_Reg(0x84, 0x89);SCCB_WR_Reg(0x85, 0x9a);SCCB_WR_Reg(0x86, 0xa6);SCCB_WR_Reg(0x87, 0xbd);SCCB_WR_Reg(0x88, 0xd3);SCCB_WR_Reg(0x89, 0xe8);SCCB_WR_Reg(0x13, 0xE0);SCCB_WR_Reg(0x00, 0x00);SCCB_WR_Reg(0x10, 0x00);SCCB_WR_Reg(0x0D, 0x50);SCCB_WR_Reg(0x42, 0x40);SCCB_WR_Reg(0x14, 0x28);SCCB_WR_Reg(0xA5, 0x03);SCCB_WR_Reg(0xAB, 0x03);SCCB_WR_Reg(0x24, 0x50);SCCB_WR_Reg(0x25, 0x43);SCCB_WR_Reg(0x26, 0xa3);SCCB_WR_Reg(0x9F, 0x78);SCCB_WR_Reg(0xA0, 0x68);SCCB_WR_Reg(0xA1, 0x03);SCCB_WR_Reg(0xA6, 0xd2);SCCB_WR_Reg(0xA7, 0xd2);SCCB_WR_Reg(0xA8, 0xF0);SCCB_WR_Reg(0xA9, 0x80);SCCB_WR_Reg(0xAA, 0x14);SCCB_WR_Reg(0x13, 0xE5);SCCB_WR_Reg(0x0E, 0x61);SCCB_WR_Reg(0x0F, 0x4B);         // Flip (bit4) & Mirror (bit5)SCCB_WR_Reg(0x16, 0x02);SCCB_WR_Reg(0x21, 0x02);SCCB_WR_Reg(0x22, 0x91);SCCB_WR_Reg(0x29, 0x07);SCCB_WR_Reg(0x33, 0x0B);SCCB_WR_Reg(0x35, 0x0B);SCCB_WR_Reg(0x37, 0x1D);SCCB_WR_Reg(0x38, 0x71);SCCB_WR_Reg(0x39, 0x2A);SCCB_WR_Reg(0x3C, 0x78);SCCB_WR_Reg(0x4D, 0x40);SCCB_WR_Reg(0x4E, 0x20);SCCB_WR_Reg(0x69, 0x00);SCCB_WR_Reg(0x74, 0x10);SCCB_WR_Reg(0x8D, 0x4F);SCCB_WR_Reg(0x8E, 0x00);SCCB_WR_Reg(0x8F, 0x00);SCCB_WR_Reg(0x90, 0x00);SCCB_WR_Reg(0x91, 0x00);SCCB_WR_Reg(0x96, 0x00);SCCB_WR_Reg(0x9A, 0x80);SCCB_WR_Reg(0xB0, 0x84);SCCB_WR_Reg(0xB1, 0x0C);SCCB_WR_Reg(0xB2, 0x0E);SCCB_WR_Reg(0xB3, 0x82);SCCB_WR_Reg(0xB8, 0x0A);SCCB_WR_Reg(0x43, 0x02);SCCB_WR_Reg(0x44, 0xf2);SCCB_WR_Reg(0x45, 0x46);SCCB_WR_Reg(0x46, 0x63);SCCB_WR_Reg(0x47, 0x32);SCCB_WR_Reg(0x48, 0x3b);SCCB_WR_Reg(0x59, 0x92);SCCB_WR_Reg(0x5a, 0x9b);SCCB_WR_Reg(0x5b, 0xa5);SCCB_WR_Reg(0x5c, 0x7a);SCCB_WR_Reg(0x5d, 0x4a);SCCB_WR_Reg(0x5e, 0x0a);SCCB_WR_Reg(0x6c, 0x0a);SCCB_WR_Reg(0x6d, 0x55);SCCB_WR_Reg(0x6e, 0x11);SCCB_WR_Reg(0x6f, 0x9e);SCCB_WR_Reg(0x6A, 0x40);SCCB_WR_Reg(0x01, 0x40);SCCB_WR_Reg(0x02, 0x40);SCCB_WR_Reg(0x13, 0xf7);SCCB_WR_Reg(0x4f, 0x9c);SCCB_WR_Reg(0x50, 0x99);SCCB_WR_Reg(0x51, 0x02);SCCB_WR_Reg(0x52, 0x29);SCCB_WR_Reg(0x53, 0x8b);SCCB_WR_Reg(0x54, 0xb5);SCCB_WR_Reg(0x58, 0x1e);SCCB_WR_Reg(0x62, 0x08);SCCB_WR_Reg(0x63, 0x10);SCCB_WR_Reg(0x64, 0x04);SCCB_WR_Reg(0x65, 0x00);SCCB_WR_Reg(0x66, 0x05);SCCB_WR_Reg(0x94, 0x04);SCCB_WR_Reg(0x95, 0x06);SCCB_WR_Reg(0x41, 0x08);SCCB_WR_Reg(0x3F, 0x00);SCCB_WR_Reg(0x75, 0x44);SCCB_WR_Reg(0x76, 0xe1);SCCB_WR_Reg(0x4C, 0x00);SCCB_WR_Reg(0x77, 0x01);SCCB_WR_Reg(0x3D, 0xC0);SCCB_WR_Reg(0x4B, 0x09);SCCB_WR_Reg(0xC9, 0x60);SCCB_WR_Reg(0x41, 0x38);SCCB_WR_Reg(0x56, 0x40);SCCB_WR_Reg(0x34, 0x11);SCCB_WR_Reg(0x3b, 0x02);SCCB_WR_Reg(0xa4, 0x88);        //disable  night modeSCCB_WR_Reg(0x92, 0x00);SCCB_WR_Reg(0x96, 0x00);SCCB_WR_Reg(0x97, 0x30);SCCB_WR_Reg(0x98, 0x20);SCCB_WR_Reg(0x99, 0x20);SCCB_WR_Reg(0x9A, 0x84);SCCB_WR_Reg(0x9B, 0x29);SCCB_WR_Reg(0x9C, 0x03);SCCB_WR_Reg(0x9D, 0x99);SCCB_WR_Reg(0x9E, 0x7F);SCCB_WR_Reg(0x78, 0x00);SCCB_WR_Reg(0x79, 0x01);SCCB_WR_Reg(0xc8, 0xf0);SCCB_WR_Reg(0x79, 0x0f);SCCB_WR_Reg(0xc8, 0x00);SCCB_WR_Reg(0x79, 0x10);SCCB_WR_Reg(0xc8, 0x7e);SCCB_WR_Reg(0x79, 0x0a);SCCB_WR_Reg(0xc8, 0x80);SCCB_WR_Reg(0x79, 0x0b);SCCB_WR_Reg(0xc8, 0x01);SCCB_WR_Reg(0x79, 0x0c);SCCB_WR_Reg(0xc8, 0x0f);SCCB_WR_Reg(0x79, 0x0d);SCCB_WR_Reg(0xc8, 0x20);SCCB_WR_Reg(0x79, 0x09);SCCB_WR_Reg(0xc8, 0x80);SCCB_WR_Reg(0x79, 0x02);SCCB_WR_Reg(0xc8, 0xc0);SCCB_WR_Reg(0x79, 0x03);SCCB_WR_Reg(0xc8, 0x40);SCCB_WR_Reg(0x79, 0x05);SCCB_WR_Reg(0xc8, 0x30);SCCB_WR_Reg(0x79, 0x26);SCCB_WR_Reg(0x3b, 0x02);SCCB_WR_Reg(0x43, 0x02);SCCB_WR_Reg(0x44, 0xf2);SCCB_WR_Reg(0x30, 0x4F);SCCB_WR_Reg(0x09, 0x00);SCCB_WR_Reg(0x15, 0x00);SCCB_WR_Reg(0x40, 0xd0);SCCB_WR_Reg(0x8c, 0x00);}void OV7670_config_window(uint16_t startx,uint16_t starty,uint16_t width, uint16_t height)
{
uint16_t endx=(startx+width*2)%784;
uint16_t endy=(starty+height*2);
uint16_t x_reg, y_reg;
uint16_t temp;SCCB_WR_Reg(0x12, 0x14);x_reg = SCCB_RD_Reg(0x32);
x_reg &= 0xC0;y_reg = SCCB_RD_Reg(0x03);
y_reg &= 0xF0;temp = x_reg|((endx&0x7)<<3)|(startx&0x7);
SCCB_WR_Reg(0x32, temp );
temp = (startx&0x7F8)>>3;
SCCB_WR_Reg(0x17, temp );
temp = (endx&0x7F8)>>3;
SCCB_WR_Reg(0x18, temp );temp = y_reg|((endy&0x3)<<2)|(starty&0x3);
SCCB_WR_Reg(0x03, temp );
temp = (starty&0x3FC)>>2;
SCCB_WR_Reg(0x19, temp );
temp = (endy&0x3FC)>>2;
SCCB_WR_Reg(0x1A, temp );
}//Light_Mode
//0:auto
//1:sunny
//2,cloudy
//3,office
//4,home
void OV7670_Light_Mode(uint8_t mode)
{uint8_t reg13val=0XE7;uint8_t reg01val=0;uint8_t reg02val=0;switch(mode){case 1://sunnyreg13val=0XE5;reg01val=0X5A;reg02val=0X5C;break;case 2://cloudyreg13val=0XE5;reg01val=0X58;reg02val=0X60;break;case 3://officereg13val=0XE5;reg01val=0X84;reg02val=0X4c;break;case 4://homereg13val=0XE5;reg01val=0X96;reg02val=0X40;break;}SCCB_WR_Reg(0X13,reg13val);SCCB_WR_Reg(0X01,reg01val);SCCB_WR_Reg(0X02,reg02val);
}
//Color_Saturation
//0:-2
//1:-1
//2,0
//3,1
//4,2
void OV7670_Color_Saturation(uint8_t sat)
{uint8_t reg4f5054val=0X80;uint8_t reg52val=0X22;uint8_t reg53val=0X5E;switch(sat){case 0://-2reg4f5054val=0X40;reg52val=0X11;reg53val=0X2F;break;case 1://-1reg4f5054val=0X66;reg52val=0X1B;reg53val=0X4B;break;case 3://1reg4f5054val=0X99;reg52val=0X28;reg53val=0X71;break;case 4://2reg4f5054val=0XC0;reg52val=0X33;reg53val=0X8D;break;}SCCB_WR_Reg(0X4F,reg4f5054val);SCCB_WR_Reg(0X50,reg4f5054val);SCCB_WR_Reg(0X51,0X00);SCCB_WR_Reg(0X52,reg52val);SCCB_WR_Reg(0X53,reg53val);SCCB_WR_Reg(0X54,reg4f5054val);SCCB_WR_Reg(0X58,0X9E);
}
//Brightness
//0:-2
//1:-1
//2,0
//3,1
//4,2
void OV7670_Brightness(uint8_t bright)
{uint8_t reg55val=0X00;switch(bright){case 0://-2reg55val=0XB0;break;case 1://-1reg55val=0X98;break;case 3://1reg55val=0X18;break;case 4://2reg55val=0X30;break;}SCCB_WR_Reg(0X55,reg55val);
}
//Contrast
//0:-2
//1:-1
//2,0
//3,1
//4,2
void OV7670_Contrast(uint8_t contrast)
{uint8_t reg56val=0X40;switch(contrast){case 0://-2reg56val=0X30;break;case 1://-1reg56val=0X38;break;case 3://1reg56val=0X50;break;case 4://2reg56val=0X60;break;}SCCB_WR_Reg(0X56,reg56val);
}
//Special_Effects
//0:normal
//1,negative
//2,black-white
//3,red
//4,green
//5,blue
//6,classic
void OV7670_Special_Effects(uint8_t eft)
{uint8_t reg3aval=0X04;uint8_t reg67val=0XC0;uint8_t reg68val=0X80;switch(eft){case 1:reg3aval=0X24;reg67val=0X80;reg68val=0X80;break;case 2:reg3aval=0X14;reg67val=0X80;reg68val=0X80;break;case 3:reg3aval=0X14;reg67val=0Xc0;reg68val=0X80;break;case 4:reg3aval=0X14;reg67val=0X40;reg68val=0X40;break;case 5:reg3aval=0X14;reg67val=0X80;reg68val=0XC0;break;case 6:reg3aval=0X14;reg67val=0XA0;reg68val=0X40;break;}SCCB_WR_Reg(0X3A,reg3aval);SCCB_WR_Reg(0X68,reg67val);SCCB_WR_Reg(0X67,reg68val);
}

以上代码实现对OV7670的接口访问, 实现OV7670初始化（配置为640×80 RGB模式），并持续向外输出图像。

8. DMA发送机制

STM32通过串口接收指令，程序里设计一个标识变量scmd用于指示接收到的指令。需要在USB虚拟串口的接收函数里进行处理：

static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{/* USER CODE BEGIN 6 */extern uint8_t scmd;if(Buf[0]==0x01) scmd=0x01;USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);USBD_CDC_ReceivePacket(&hUsbDeviceFS);return (USBD_OK);/* USER CODE END 6 */
}

以及在USART1的接收中断里进行处理：

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{if (huart ==  &huart1){if (aRxBuffer==0x01){scmd = 0x02;aRxBuffer=0x00;HAL_UART_Receive_IT(&huart1, (uint8_t *)&aRxBuffer, 1);}else{HAL_UART_Receive_IT(&huart1, (uint8_t *)&aRxBuffer, 1);}}return;}

STM32向上位机发送图像数据采用USB虚拟串口或串口DMA方式，程序里设计一个标识变量tx_busy，在当前DMA发送完后指示状态：

static int8_t CDC_TransmitCplt_FS(uint8_t *Buf, uint32_t *Len, uint8_t epnum)
{uint8_t result = USBD_OK;/* USER CODE BEGIN 13 */extern uint8_t tx_busy ;tx_busy = 0;UNUSED(Buf);UNUSED(Len);UNUSED(epnum);/* USER CODE END 13 */return result;
}

同样，对USART1的DMA发送完处理：

void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
{extern uint8_t tx_busy;if (huart ==  &huart1){tx_busy = 0;}}

9. DCMI DMA地址自增方式

初始化DCMI DMA配置时，如将接收地址设置为不自增方式。后续的图像捕获需要工作在DMA接收地址自增方式，因此单独设计两个函数可用于切换。

void DCMI_DMA_MemInc_En(void)
{HAL_DMA_DeInit(&hdma_dcmi);hdma_dcmi.Init.MemInc = DMA_MINC_ENABLE;if (HAL_DMA_Init(&hdma_dcmi) != HAL_OK){Error_Handler();}
}void DCMI_DMA_MemInc_Den(void)
{HAL_DMA_DeInit(&hdma_dcmi);hdma_dcmi.Init.MemInc = DMA_MINC_DISABLE;if (HAL_DMA_Init(&hdma_dcmi) != HAL_OK){Error_Handler();}
}

10. 初始化修正函数

按照1.8版本HAL库，设计DCMI的初始化修正函数：

void PY_DCMI_Full_Init(void)
{hdcmi.Instance = DCMI;hdcmi.Init.SynchroMode = DCMI_SYNCHRO_HARDWARE;hdcmi.Init.PCKPolarity = DCMI_PCKPOLARITY_RISING;hdcmi.Init.VSPolarity = DCMI_VSPOLARITY_HIGH;hdcmi.Init.HSPolarity = DCMI_HSPOLARITY_LOW;hdcmi.Init.CaptureRate = DCMI_CR_ALL_FRAME;hdcmi.Init.ExtendedDataMode = DCMI_EXTEND_DATA_8B;hdcmi.Init.JPEGMode = DCMI_JPEG_DISABLE;hdcmi.Init.ByteSelectMode = DCMI_BSM_ALL;hdcmi.Init.ByteSelectStart = DCMI_OEBS_ODD;hdcmi.Init.LineSelectMode = DCMI_LSM_ALL;hdcmi.Init.LineSelectStart = DCMI_OELS_ODD;if (HAL_DCMI_Init(&hdcmi) != HAL_OK){Error_Handler();}
}

11. 主函数代码

在程序跑起来后，会先对OV7670接口进行典型寄存器读取并USART1串口输出，用于识别接口时序是否正常。然后进入命令等待，接收到指令后，再从OV7670输出的图像中截取数据串口DMA输出。

/* USER CODE BEGIN Header */
/********************************************************************************* @file           : main.c* @brief          : Main program body******************************************************************************* @attention** <h2><center>&copy; Copyright (c) 2021 STMicroelectronics.* All rights reserved.</center></h2>** This software component is licensed by ST under BSD 3-Clause license,* the "License"; You may not use this file except in compliance with the* License. You may obtain a copy of the License at:*                        opensource.org/licenses/BSD-3-Clause********************************************************************************/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usb_device.h"/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include <string.h>
#include "ov7670.h"
/* USER CODE END Includes *//* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
void DCMI_DMA_MemInc_En(void);
void DCMI_DMA_MemInc_Den(void);
void PY_DCMI_Full_Init(void);
/* USER CODE END PTD *//* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
uint8_t aRxBuffer=0;uint8_t TxBuff[99] = {0};
uint8_t StatusFlag = 0;uint8_t OV7670_verh = 0xff, OV7670_verl=0xff;HAL_StatusTypeDef dcmi_dma_status = HAL_OK;uint32_t* dcmi_data_buff;uint32_t DCMI_RN = 0;  //row number
uint32_t DCMI_CN = 0;  //column number
uint32_t DCMI_RS = 0;  //row start
uint32_t DCMI_CS = 0;  //column startuint8_t scmd = 0;
uint8_t tx_busy = 0;
/* USER CODE END PD *//* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM *//* USER CODE END PM *//* Private variables ---------------------------------------------------------*/DCMI_HandleTypeDef hdcmi;
DMA_HandleTypeDef hdma_dcmi;UART_HandleTypeDef huart1;
DMA_HandleTypeDef hdma_usart1_tx;/* USER CODE BEGIN PV *//* USER CODE END PV *//* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_DCMI_Init(void);
static void MX_USART1_UART_Init(void);
/* USER CODE BEGIN PFP *//* USER CODE END PFP *//* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 *//* USER CODE END 0 *//*** @brief  The application entry point.* @retval int*/
int main(void)
{/* USER CODE BEGIN 1 */dcmi_data_buff = 0x30000000;/* USER CODE END 1 *//* MCU Configuration--------------------------------------------------------*//* Reset of all peripherals, Initializes the Flash interface and the Systick. */HAL_Init();/* USER CODE BEGIN Init *//* USER CODE END Init *//* Configure the system clock */SystemClock_Config();/* USER CODE BEGIN SysInit *//* USER CODE END SysInit *//* Initialize all configured peripherals */MX_GPIO_Init();MX_DMA_Init();MX_USB_DEVICE_Init();MX_DCMI_Init();MX_USART1_UART_Init();/* USER CODE BEGIN 2 */if (HAL_UART_Receive_IT(&huart1, (uint8_t *)&aRxBuffer, 1)!=HAL_OK){MX_USART1_UART_Init();HAL_UART_Receive_IT(&huart1, (uint8_t *)&aRxBuffer, 1);}SCCB_Rst();OV7670_verh = SCCB_RD_Reg(0x0a);OV7670_verl = SCCB_RD_Reg(0x0b);HAL_UART_Transmit(&huart1, &OV7670_verh, 1, 0xFFFFFF);HAL_Delay(50);HAL_UART_Transmit(&huart1, &OV7670_verl, 1, 0xFFFFFF);HAL_Delay(50);OV7670_640_480_RGB565_Init();OV7670_Light_Mode(0);OV7670_Color_Saturation(2);OV7670_Brightness(2);OV7670_Contrast(2);HAL_Delay(200);HAL_DCMI_DeInit(&hdcmi);PY_DCMI_Full_Init();/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){HAL_Delay(1);if (scmd==1){scmd = 0;TxBuff[0]=0x55;TxBuff[1]=0xaa;TxBuff[2]=0x01; //OV7670 labeltx_busy = 1;CDC_Transmit_FS(TxBuff, 3);while(tx_busy==1) HAL_Delay(1);dcmi_dma_status = HAL_DCMI_Init(&hdcmi);for (uint8_t i=0; i<10;i++){HAL_DCMI_DisableCrop (&hdcmi);DCMI_RN = 48;DCMI_CN = 1280;DCMI_RS = 48*i;DCMI_CS = 0;HAL_DCMI_ConfigCrop (&hdcmi, DCMI_CS, DCMI_RS, DCMI_CN, DCMI_RN);HAL_Delay(1);HAL_DCMI_EnableCrop (&hdcmi);HAL_Delay(1);dcmi_dma_status = HAL_DCMI_Start_DMA(&hdcmi, DCMI_MODE_SNAPSHOT, dcmi_data_buff, DCMI_CN*DCMI_RN/4);while(HAL_DMA_GetState(&hdcmi)==HAL_DMA_STATE_BUSY) ;HAL_DCMI_Stop(&hdcmi);tx_busy = 1;CDC_Transmit_FS((uint8_t *)dcmi_data_buff, 61440);while(tx_busy!=0) ;}}if (scmd==2){scmd = 0;DCMI_DMA_MemInc_En();TxBuff[0]=0x55;TxBuff[1]=0xaa;TxBuff[2]=0x01; //OV7670 labelHAL_UART_Transmit(&huart1, TxBuff, 3, 0xFFFFFF);HAL_Delay(100);dcmi_dma_status = HAL_DCMI_Init(&hdcmi);for (uint8_t i=0; i<10;i++){HAL_DCMI_DisableCrop (&hdcmi);DCMI_RN = 48;DCMI_CN = 1280;DCMI_RS = 48*i;DCMI_CS = 0;HAL_DCMI_ConfigCrop (&hdcmi, DCMI_CS, DCMI_RS, DCMI_CN, DCMI_RN);HAL_Delay(1);HAL_DCMI_EnableCrop (&hdcmi);HAL_Delay(1);dcmi_dma_status = HAL_DCMI_Start_DMA(&hdcmi, DCMI_MODE_SNAPSHOT, dcmi_data_buff, DCMI_CN*DCMI_RN/4);while(HAL_DMA_GetState(&hdcmi)==HAL_DMA_STATE_BUSY) ;HAL_DCMI_Stop(&hdcmi);tx_busy = 1;HAL_UART_Transmit_DMA(&huart1, (uint8_t *)dcmi_data_buff, 61440);while(tx_busy!=0) HAL_Delay(1);}}/* USER CODE END WHILE *//* USER CODE BEGIN 3 */}/* USER CODE END 3 */
}/*** @brief System Clock Configuration* @retval None*/
void SystemClock_Config(void)
{RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};/** Supply configuration update enable*/HAL_PWREx_ConfigSupply(PWR_LDO_SUPPLY);/** Configure the main internal regulator output voltage*/__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE0);while(!__HAL_PWR_GET_FLAG(PWR_FLAG_VOSRDY)) {}/** Initializes the RCC Oscillators according to the specified parameters* in the RCC_OscInitTypeDef structure.*/RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI48|RCC_OSCILLATORTYPE_HSI;RCC_OscInitStruct.HSIState = RCC_HSI_DIV1;RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;RCC_OscInitStruct.HSI48State = RCC_HSI48_ON;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;RCC_OscInitStruct.PLL.PLLM = 32;RCC_OscInitStruct.PLL.PLLN = 480;RCC_OscInitStruct.PLL.PLLP = 2;RCC_OscInitStruct.PLL.PLLQ = 2;RCC_OscInitStruct.PLL.PLLR = 2;RCC_OscInitStruct.PLL.PLLRGE = RCC_PLL1VCIRANGE_1;RCC_OscInitStruct.PLL.PLLVCOSEL = RCC_PLL1VCOWIDE;RCC_OscInitStruct.PLL.PLLFRACN = 0;if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK){Error_Handler();}/** Initializes the CPU, AHB and APB buses clocks*/RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2|RCC_CLOCKTYPE_D3PCLK1|RCC_CLOCKTYPE_D1PCLK1;RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.SYSCLKDivider = RCC_SYSCLK_DIV1;RCC_ClkInitStruct.AHBCLKDivider = RCC_HCLK_DIV2;RCC_ClkInitStruct.APB3CLKDivider = RCC_APB3_DIV2;RCC_ClkInitStruct.APB1CLKDivider = RCC_APB1_DIV2;RCC_ClkInitStruct.APB2CLKDivider = RCC_APB2_DIV2;RCC_ClkInitStruct.APB4CLKDivider = RCC_APB4_DIV2;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK){Error_Handler();}HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSI48, RCC_MCODIV_2);
}/*** @brief DCMI Initialization Function* @param None* @retval None*/
static void MX_DCMI_Init(void)
{/* USER CODE BEGIN DCMI_Init 0 *//* USER CODE END DCMI_Init 0 *//* USER CODE BEGIN DCMI_Init 1 *//* USER CODE END DCMI_Init 1 */hdcmi.Instance = DCMI;hdcmi.Init.SynchroMode = DCMI_SYNCHRO_EMBEDDED;hdcmi.Init.PCKPolarity = DCMI_PCKPOLARITY_RISING;hdcmi.Init.CaptureRate = DCMI_CR_ALL_FRAME;hdcmi.Init.ExtendedDataMode = DCMI_EXTEND_DATA_8B;hdcmi.Init.SyncroCode.FrameEndCode = 0;hdcmi.Init.SyncroCode.FrameStartCode = 0;hdcmi.Init.SyncroCode.LineStartCode = 0;hdcmi.Init.SyncroCode.LineEndCode = 0;hdcmi.Init.JPEGMode = DCMI_JPEG_DISABLE;hdcmi.Init.ByteSelectMode = DCMI_BSM_ALL;hdcmi.Init.ByteSelectStart = DCMI_OEBS_ODD;hdcmi.Init.LineSelectMode = DCMI_LSM_ALL;hdcmi.Init.LineSelectStart = DCMI_OELS_ODD;if (HAL_DCMI_Init(&hdcmi) != HAL_OK){Error_Handler();}/* USER CODE BEGIN DCMI_Init 2 *//* USER CODE END DCMI_Init 2 */}/*** @brief USART1 Initialization Function* @param None* @retval None*/
static void MX_USART1_UART_Init(void)
{/* USER CODE BEGIN USART1_Init 0 *//* USER CODE END USART1_Init 0 *//* USER CODE BEGIN USART1_Init 1 *//* USER CODE END USART1_Init 1 */huart1.Instance = USART1;huart1.Init.BaudRate = 230400;huart1.Init.WordLength = UART_WORDLENGTH_8B;huart1.Init.StopBits = UART_STOPBITS_1;huart1.Init.Parity = UART_PARITY_NONE;huart1.Init.Mode = UART_MODE_TX_RX;huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;huart1.Init.OverSampling = UART_OVERSAMPLING_16;huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;huart1.Init.ClockPrescaler = UART_PRESCALER_DIV1;huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;if (HAL_UART_Init(&huart1) != HAL_OK){Error_Handler();}if (HAL_UARTEx_SetTxFifoThreshold(&huart1, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK){Error_Handler();}if (HAL_UARTEx_SetRxFifoThreshold(&huart1, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK){Error_Handler();}if (HAL_UARTEx_DisableFifoMode(&huart1) != HAL_OK){Error_Handler();}/* USER CODE BEGIN USART1_Init 2 *//* USER CODE END USART1_Init 2 */}/*** Enable DMA controller clock*/
static void MX_DMA_Init(void)
{/* DMA controller clock enable */__HAL_RCC_DMA1_CLK_ENABLE();/* DMA interrupt init *//* DMA1_Stream0_IRQn interrupt configuration */HAL_NVIC_SetPriority(DMA1_Stream0_IRQn, 0, 0);HAL_NVIC_EnableIRQ(DMA1_Stream0_IRQn);/* DMA1_Stream1_IRQn interrupt configuration */HAL_NVIC_SetPriority(DMA1_Stream1_IRQn, 0, 0);HAL_NVIC_EnableIRQ(DMA1_Stream1_IRQn);}/*** @brief GPIO Initialization Function* @param None* @retval None*/
static void MX_GPIO_Init(void)
{GPIO_InitTypeDef GPIO_InitStruct = {0};/* GPIO Ports Clock Enable */__HAL_RCC_GPIOA_CLK_ENABLE();__HAL_RCC_GPIOE_CLK_ENABLE();__HAL_RCC_GPIOD_CLK_ENABLE();__HAL_RCC_GPIOC_CLK_ENABLE();__HAL_RCC_GPIOB_CLK_ENABLE();/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(GPIOE, GPIO_PIN_7|GPIO_PIN_8, GPIO_PIN_SET);/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(GPIOD, GPIO_PIN_10, GPIO_PIN_SET);/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(GPIOD, GPIO_PIN_11, GPIO_PIN_RESET);/*Configure GPIO pins : PE7 PE8 */GPIO_InitStruct.Pin = GPIO_PIN_7|GPIO_PIN_8;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);/*Configure GPIO pins : PD10 PD11 */GPIO_InitStruct.Pin = GPIO_PIN_10|GPIO_PIN_11;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);/*Configure GPIO pin : PA8 */GPIO_InitStruct.Pin = GPIO_PIN_8;GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;GPIO_InitStruct.Pull = GPIO_NOPULL;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;GPIO_InitStruct.Alternate = GPIO_AF0_MCO;HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);}/* USER CODE BEGIN 4 */
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{if (huart ==  &huart1){if (aRxBuffer==0x01){scmd = 0x02;aRxBuffer=0x00;HAL_UART_Receive_IT(&huart1, (uint8_t *)&aRxBuffer, 1);}else{HAL_UART_Receive_IT(&huart1, (uint8_t *)&aRxBuffer, 1);}}return;}void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
{extern uint8_t tx_busy;if (huart ==  &huart1){tx_busy = 0;}}void DCMI_DMA_MemInc_En(void)
{HAL_DMA_DeInit(&hdma_dcmi);hdma_dcmi.Init.MemInc = DMA_MINC_ENABLE;if (HAL_DMA_Init(&hdma_dcmi) != HAL_OK){Error_Handler();}
}void DCMI_DMA_MemInc_Den(void)
{HAL_DMA_DeInit(&hdma_dcmi);hdma_dcmi.Init.MemInc = DMA_MINC_DISABLE;if (HAL_DMA_Init(&hdma_dcmi) != HAL_OK){Error_Handler();}
}void PY_DCMI_Full_Init(void)
{hdcmi.Instance = DCMI;hdcmi.Init.SynchroMode = DCMI_SYNCHRO_HARDWARE;hdcmi.Init.PCKPolarity = DCMI_PCKPOLARITY_RISING;hdcmi.Init.VSPolarity = DCMI_VSPOLARITY_HIGH;hdcmi.Init.HSPolarity = DCMI_HSPOLARITY_LOW;hdcmi.Init.CaptureRate = DCMI_CR_ALL_FRAME;hdcmi.Init.ExtendedDataMode = DCMI_EXTEND_DATA_8B;hdcmi.Init.JPEGMode = DCMI_JPEG_DISABLE;hdcmi.Init.ByteSelectMode = DCMI_BSM_ALL;hdcmi.Init.ByteSelectStart = DCMI_OEBS_ODD;hdcmi.Init.LineSelectMode = DCMI_LSM_ALL;hdcmi.Init.LineSelectStart = DCMI_OELS_ODD;if (HAL_DCMI_Init(&hdcmi) != HAL_OK){Error_Handler();}
}
/* USER CODE END 4 *//*** @brief  This function is executed in case of error occurrence.* @retval None*/
void Error_Handler(void)
{/* USER CODE BEGIN Error_Handler_Debug *//* User can add his own implementation to report the HAL error return state */__disable_irq();while (1){}/* USER CODE END Error_Handler_Debug */
}#ifdef  USE_FULL_ASSERT
/*** @brief  Reports the name of the source file and the source line number*         where the assert_param error has occurred.* @param  file: pointer to the source file name* @param  line: assert_param error line source number* @retval None*/
void assert_failed(uint8_t *file, uint32_t line)
{/* USER CODE BEGIN 6 *//* User can add his own implementation to report the file name and line number,ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) *//* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT *//************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

12. STM32H750完整代码

基于STM32CUBEIDE工程：
https://download.csdn.net/download/hwytree/20372220

13. 上位机软件

配套测试用上位机软件分为一维码识别和二维码识别两个软件，下载地址：
一维码识别
https://download.csdn.net/download/hwytree/20306099
二维码识别
https://download.csdn.net/download/hwytree/20306112

14. 一维码识别效果

15. 二维码识别效果

16. 上位机实现解码原理范例

https://blog.csdn.net/hwytree/article/details/119004881

-End-