STM32F407获取OV2640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STM32F407对200万像素OV2640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STM32F4及STM32L4系列驱动OV2640摄像头的代码参考，本例程输出分辨率（640×480）是通过DCMI的CROP方式从大图片中“剪”出，使用者也可以做不同设置“剪"出不同分辨率的图片。

2. 场景参数说明

上位机与STM32F407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。
STM32F407通过DCMI总线接口与OV2640摄像头DVP接口连接，通过IIC总线与OV2640配置端口（SCCB）连接，并通过GPIO连接控制摄像头端的Reset和PowerDown管脚。
STM32F407从OV2640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==0x02为OV2640摄像头。
STM32从OV2640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. STM32F407时钟配置

对于需要STM32F407输出24MHz时钟给OV2640摄像头模块的场景，可以用STM32 MCO功能输出24MHz时钟，此时为了便于MCO分频产生24MHz时钟，将MCO主频调整在96MHz。如果摄像头模块自带晶振，不需要STM32提供时钟,则可以提高STM32主频，或者用TIM产生24MHz时钟，但输出信号质量不如MCO专用管脚好。

5. STM32F407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：

OV2640的SCCB/I2C接口时序通过STM32的GPIO管脚模拟，不采用专用的IIC管脚。OV2640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. OV2640接口及配置代码

编写ov2640.h文件：

#include "stm32f4xx_hal.h"
#ifndef _OV2640_H
#define _OV2640_H//for not open-drain bus
/** SIOC: PB0* SIOD: PB1* VSYNC: PB7* HREF: PA4* PCLK: PA6* XCLK: PA8  //24MHz, optional to use* D7: PC6* D6: PC7* D5: PE0* D4: PE1* D3: PE4* D2: PB6* D1: PE5* D0: PE6* RESET: PD10* PWDN: PD11***/
#define SCCB_SCL_L          HAL_GPIO_WritePin(GPIOB,GPIO_PIN_0,GPIO_PIN_RESET)
#define SCCB_SCL_H          HAL_GPIO_WritePin(GPIOB,GPIO_PIN_0,GPIO_PIN_SET)
#define SCCB_SDA_L          HAL_GPIO_WritePin(GPIOB,GPIO_PIN_1,GPIO_PIN_RESET)
#define SCCB_SDA_H          HAL_GPIO_WritePin(GPIOB,GPIO_PIN_1,GPIO_PIN_SET)#define SCCB_READ_SDA       HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_1)
#define SCCB_ID_W           0X60            //OV2640 ID for Write
#define SCCB_ID_R           0X61            //OV2640 ID for Read#define OV2640_PWDN           HAL_GPIO_WritePin(GPIOD,GPIO_PIN_11,GPIO_PIN_SET)
#define OV2640_PWUP           HAL_GPIO_WritePin(GPIOD,GPIO_PIN_11,GPIO_PIN_RESET)
#define OV2640_RST            HAL_GPIO_WritePin(GPIOD,GPIO_PIN_10,GPIO_PIN_RESET)
#define OV2640_RUN            HAL_GPIO_WritePin(GPIOD,GPIO_PIN_10,GPIO_PIN_SET)
#define OV2640_VSYNC          HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_7)
#define OV2640_HREF           HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_4)
#define OV2640_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 OV2640_Auto_Exposure(uint8_t level);
void OV2640_Light_Mode(uint8_t mode);
void OV2640_Color_Saturation(uint8_t sat);
void OV2640_Brightness(uint8_t bright);
void OV2640_Contrast(uint8_t contrast);
void OV2640_Special_Effects(uint8_t eft);
void OV2640_Color_Bar(uint8_t sw);
void OV2640_Window_Set(uint16_t sx,uint16_t sy,uint16_t width,uint16_t height);
uint8_t OV2640_OutSize_Set(uint16_t width,uint16_t height);
uint8_t OV2640_ImageWin_Set(uint16_t offx,uint16_t offy,uint16_t width,uint16_t height);
uint8_t OV2640_ImageSize_Set(uint16_t width,uint16_t height);
void OV2640_RGB565_Mode(void);
void OV2640_UXGA_Init(void);#endif

编写ov2640.c文件：

#include <ov2640.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_GPIOB_CLK_ENABLE();GPIO_InitStruct.Pin = GPIO_PIN_1;GPIO_InitStruct.Mode = GPIO_MODE_INPUT;GPIO_InitStruct.Pull = GPIO_PULLUP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
}void SCCB_SDA_OUT(void)
{GPIO_InitTypeDef GPIO_InitStruct = {0};__HAL_RCC_GPIOB_CLK_ENABLE();GPIO_InitStruct.Pin = GPIO_PIN_1;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOB, &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);
}//--------------OV2640 Functions--------------//
//UXGA(1600*1200)
const uint8_t ov2640_uxga_init_reg_tbl[][2]=
{0xff, 0x00,0x2c, 0xff,0x2e, 0xdf,0xff, 0x01,0x3c, 0x32,//0x11, 0x00,0x09, 0x02,0x04, 0xD8,0x13, 0xe5,0x14, 0x48,0x2c, 0x0c,0x33, 0x78,0x3a, 0x33,0x3b, 0xfB,//0x3e, 0x00,0x43, 0x11,0x16, 0x10,//0x39, 0x92,//0x35, 0xda,0x22, 0x1a,0x37, 0xc3,0x23, 0x00,0x34, 0xc0,0x36, 0x1a,0x06, 0x88,0x07, 0xc0,0x0d, 0x87,0x0e, 0x41,0x4c, 0x00,0x48, 0x00,0x5B, 0x00,0x42, 0x03,//0x4a, 0x81,0x21, 0x99,//0x24, 0x40,0x25, 0x38,0x26, 0x82,0x5c, 0x00,0x63, 0x00,0x46, 0x00,0x0c, 0x3c,//0x61, 0x70,0x62, 0x80,0x7c, 0x05,//0x20, 0x80,0x28, 0x30,0x6c, 0x00,0x6d, 0x80,0x6e, 0x00,0x70, 0x02,0x71, 0x94,0x73, 0xc1,0x3d, 0x34,0x5a, 0x57,//0x12, 0x00,//UXGA 1600*12000x17, 0x11,0x18, 0x75,0x19, 0x01,0x1a, 0x97,0x32, 0x36,0x03, 0x0f,0x37, 0x40,//0x4f, 0xca,0x50, 0xa8,0x5a, 0x23,0x6d, 0x00,0x6d, 0x38,//0xff, 0x00,0xe5, 0x7f,0xf9, 0xc0,0x41, 0x24,0xe0, 0x14,0x76, 0xff,0x33, 0xa0,0x42, 0x20,0x43, 0x18,0x4c, 0x00,0x87, 0xd5,0x88, 0x3f,0xd7, 0x03,0xd9, 0x10,0xd3, 0x82,//0xc8, 0x08,0xc9, 0x80,//0x7c, 0x00,0x7d, 0x00,0x7c, 0x03,0x7d, 0x48,0x7d, 0x48,0x7c, 0x08,0x7d, 0x20,0x7d, 0x10,0x7d, 0x0e,//0x90, 0x00,0x91, 0x0e,0x91, 0x1a,0x91, 0x31,0x91, 0x5a,0x91, 0x69,0x91, 0x75,0x91, 0x7e,0x91, 0x88,0x91, 0x8f,0x91, 0x96,0x91, 0xa3,0x91, 0xaf,0x91, 0xc4,0x91, 0xd7,0x91, 0xe8,0x91, 0x20,//0x92, 0x00,0x93, 0x06,0x93, 0xe3,0x93, 0x05,0x93, 0x05,0x93, 0x00,0x93, 0x04,0x93, 0x00,0x93, 0x00,0x93, 0x00,0x93, 0x00,0x93, 0x00,0x93, 0x00,0x93, 0x00,//0x96, 0x00,0x97, 0x08,0x97, 0x19,0x97, 0x02,0x97, 0x0c,0x97, 0x24,0x97, 0x30,0x97, 0x28,0x97, 0x26,0x97, 0x02,0x97, 0x98,0x97, 0x80,0x97, 0x00,0x97, 0x00,//0xc3, 0xef,0xa4, 0x00,0xa8, 0x00,0xc5, 0x11,0xc6, 0x51,0xbf, 0x80,0xc7, 0x10,0xb6, 0x66,0xb8, 0xA5,0xb7, 0x64,0xb9, 0x7C,0xb3, 0xaf,0xb4, 0x97,0xb5, 0xFF,0xb0, 0xC5,0xb1, 0x94,0xb2, 0x0f,0xc4, 0x5c,//0xc0, 0xc8,0xc1, 0x96,0x8c, 0x00,0x86, 0x3d,0x50, 0x00,0x51, 0x90,0x52, 0x2c,0x53, 0x00,0x54, 0x00,0x55, 0x88,0x5a, 0x90,0x5b, 0x2C,0x5c, 0x05,0xd3, 0x82,//0xc3, 0xed,0x7f, 0x00,0xda, 0x09,0xe5, 0x1f,0xe1, 0x67,0xe0, 0x00,0xdd, 0x7f,0x05, 0x00,
};void OV2640_UXGA_Init(void)
{for(uint32_t i=0; i<sizeof(ov2640_uxga_init_reg_tbl)/2 ; i++){SCCB_WR_Reg(ov2640_uxga_init_reg_tbl[i][0],ov2640_uxga_init_reg_tbl[i][1]);if(i<10) HAL_Delay(5);}}const uint8_t ov2640_rgb565_reg_tbl[][2]=
{0xFF, 0x00,0xDA, 0x09,0xD7, 0x03,0xDF, 0x02,0x33, 0xa0,0x3C, 0x00,0xe1, 0x67
};//OV2640 mode: RGB565
void OV2640_RGB565_Mode(void)
{uint16_t i=0;for(i=0;i<(sizeof(ov2640_rgb565_reg_tbl)/2);i++){SCCB_WR_Reg(ov2640_rgb565_reg_tbl[i][0],ov2640_rgb565_reg_tbl[i][1]);}
}//AUTOEXPOSURE LEVEL PARAMETER: 5 levels
const static uint8_t OV2640_AUTOEXPOSURE_LEVEL[5][8]=
{{0xFF,0x01,0x24,0x20,0x25,0x18,0x26,0x60,},{0xFF,0x01,0x24,0x34,0x25,0x1c,0x26,0x00,},{0xFF,0x01,0x24,0x3e,0x25,0x38,0x26,0x81,},{0xFF,0x01,0x24,0x48,0x25,0x40,0x26,0x81,},{0xFF,0x01,0x24,0x58,0x25,0x50,0x26,0x92,},
};
//Auto_Exposure
//level:0~4
void OV2640_Auto_Exposure(uint8_t level)
{uint8_t i;uint8_t *p=(uint8_t*)OV2640_AUTOEXPOSURE_LEVEL[level];for(i=0;i<4;i++){SCCB_WR_Reg(p[i*2],p[i*2+1]);}
}
//Light_Mode
//0:auto
//1:sunny
//2:cloudy
//3:office
//4:home
void OV2640_Light_Mode(uint8_t mode)
{uint8_t regccval=0X5E;//Sunnyuint8_t regcdval=0X41;uint8_t regceval=0X54;switch(mode){case 0://autoSCCB_WR_Reg(0XFF,0X00);SCCB_WR_Reg(0XC7,0X10);//AWB ONreturn;case 2://cloudyregccval=0X65;regcdval=0X41;regceval=0X4F;break;case 3://officeregccval=0X52;regcdval=0X41;regceval=0X66;break;case 4://homeregccval=0X42;regcdval=0X3F;regceval=0X71;break;}SCCB_WR_Reg(0XFF,0X00);SCCB_WR_Reg(0XC7,0X40);    //AWB OFFSCCB_WR_Reg(0XCC,regccval);SCCB_WR_Reg(0XCD,regcdval);SCCB_WR_Reg(0XCE,regceval);
}
//Color_Saturation
//0:-2
//1:-1
//2,0
//3,+1
//4,+2
void OV2640_Color_Saturation(uint8_t sat)
{uint8_t reg7dval=((sat+2)<<4)|0X08;SCCB_WR_Reg(0XFF,0X00);SCCB_WR_Reg(0X7C,0X00);SCCB_WR_Reg(0X7D,0X02);SCCB_WR_Reg(0X7C,0X03);SCCB_WR_Reg(0X7D,reg7dval);SCCB_WR_Reg(0X7D,reg7dval);
}
//Brightness
//0:(0X00)-2
//1:(0X10)-1
//2,(0X20) 0
//3,(0X30)+1
//4,(0X40)+2
void OV2640_Brightness(uint8_t bright)
{SCCB_WR_Reg(0xff, 0x00);SCCB_WR_Reg(0x7c, 0x00);SCCB_WR_Reg(0x7d, 0x04);SCCB_WR_Reg(0x7c, 0x09);SCCB_WR_Reg(0x7d, bright<<4);SCCB_WR_Reg(0x7d, 0x00);
}
//Contrast
//0:-2
//1:-1
//2,0
//3,+1
//4,+2
void OV2640_Contrast(uint8_t contrast)
{uint8_t reg7d0val=0X20;uint8_t reg7d1val=0X20;switch(contrast){case 0://-2reg7d0val=0X18;reg7d1val=0X34;break;case 1://-1reg7d0val=0X1C;reg7d1val=0X2A;break;case 3://1reg7d0val=0X24;reg7d1val=0X16;break;case 4://2reg7d0val=0X28;reg7d1val=0X0C;break;}SCCB_WR_Reg(0xff,0x00);SCCB_WR_Reg(0x7c,0x00);SCCB_WR_Reg(0x7d,0x04);SCCB_WR_Reg(0x7c,0x07);SCCB_WR_Reg(0x7d,0x20);SCCB_WR_Reg(0x7d,reg7d0val);SCCB_WR_Reg(0x7d,reg7d1val);SCCB_WR_Reg(0x7d,0x06);
}
//Special_Effects
//0:normal
//1,negative
//2,black-white
//3,red
//4,green
//5,blue
//6,classic
void OV2640_Special_Effects(uint8_t eft)
{uint8_t reg7d0val=0X00;uint8_t reg7d1val=0X80;uint8_t reg7d2val=0X80;switch(eft){case 1://negativereg7d0val=0X40;break;case 2://black-whitereg7d0val=0X18;break;case 3://redreg7d0val=0X18;reg7d1val=0X40;reg7d2val=0XC0;break;case 4://greenreg7d0val=0X18;reg7d1val=0X40;reg7d2val=0X40;break;case 5://bluereg7d0val=0X18;reg7d1val=0XA0;reg7d2val=0X40;break;case 6://classicreg7d0val=0X18;reg7d1val=0X40;reg7d2val=0XA6;break;}SCCB_WR_Reg(0xff,0x00);SCCB_WR_Reg(0x7c,0x00);SCCB_WR_Reg(0x7d,reg7d0val);SCCB_WR_Reg(0x7c,0x05);SCCB_WR_Reg(0x7d,reg7d1val);SCCB_WR_Reg(0x7d,reg7d2val);
}
//Color_Bar
//sw:0,close
//   1,open
void OV2640_Color_Bar(uint8_t sw)
{uint8_t reg;SCCB_WR_Reg(0XFF,0X01);reg=SCCB_RD_Reg(0X12);reg&=~(1<<1);if(sw)reg|=1<<1;SCCB_WR_Reg(0X12,reg);
}void OV2640_Window_Set(uint16_t sx,uint16_t sy,uint16_t width,uint16_t height)
{uint16_t endx;uint16_t endy;uint8_t temp;endx=sx+width/2;endy=sy+height/2;SCCB_WR_Reg(0XFF,0X01);temp=SCCB_RD_Reg(0X03);temp&=0XF0;temp|=((endy&0X03)<<2)|(sy&0X03);SCCB_WR_Reg(0X03,temp);SCCB_WR_Reg(0X19,sy>>2);SCCB_WR_Reg(0X1A,endy>>2);temp=SCCB_RD_Reg(0X32);temp&=0XC0;temp|=((endx&0X07)<<3)|(sx&0X07);SCCB_WR_Reg(0X32,temp);SCCB_WR_Reg(0X17,sx>>3);SCCB_WR_Reg(0X18,endx>>3);
}uint8_t OV2640_OutSize_Set(uint16_t width,uint16_t height)
{uint16_t outh;uint16_t outw;uint8_t temp;if(width%4)return 1;if(height%4)return 2;outw=width/4;outh=height/4;SCCB_WR_Reg(0XFF,0X00);SCCB_WR_Reg(0XE0,0X04);SCCB_WR_Reg(0X5A,outw&0XFF);SCCB_WR_Reg(0X5B,outh&0XFF);temp=(outw>>8)&0X03;temp|=(outh>>6)&0X04;SCCB_WR_Reg(0X5C,temp);SCCB_WR_Reg(0XE0,0X00);return 0;
}uint8_t OV2640_ImageWin_Set(uint16_t offx,uint16_t offy,uint16_t width,uint16_t height)
{uint16_t hsize;uint16_t vsize;uint8_t temp;if(width%4)return 1;if(height%4)return 2;hsize=width/4;vsize=height/4;SCCB_WR_Reg(0XFF,0X00);SCCB_WR_Reg(0XE0,0X04);SCCB_WR_Reg(0X51,hsize&0XFF);SCCB_WR_Reg(0X52,vsize&0XFF);SCCB_WR_Reg(0X53,offx&0XFF);SCCB_WR_Reg(0X54,offy&0XFF);temp=(vsize>>1)&0X80;temp|=(offy>>4)&0X70;temp|=(hsize>>5)&0X08;temp|=(offx>>8)&0X07;SCCB_WR_Reg(0X55,temp);SCCB_WR_Reg(0X57,(hsize>>2)&0X80);SCCB_WR_Reg(0XE0,0X00);return 0;
}uint8_t OV2640_ImageSize_Set(uint16_t width,uint16_t height)
{uint8_t temp;SCCB_WR_Reg(0XFF,0X00);SCCB_WR_Reg(0XE0,0X04);SCCB_WR_Reg(0XC0,(width)>>3&0XFF);SCCB_WR_Reg(0XC1,(height)>>3&0XFF);temp=(width&0X07)<<3;temp|=height&0X07;temp|=(width>>4)&0X80;SCCB_WR_Reg(0X8C,temp);SCCB_WR_Reg(0XE0,0X00);return 0;
}

以上代码实现对OV2640的接口访问, 实现OV2640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=1;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)
{

if (huart ==  &huart1)
{tx_busy = 0;
}

}

9. DCMI DMA地址自增方式

初始时DCMI DMA如果配置在接收地址不自增方式。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. 主函数代码

在程序跑起来后，会先对OV2640接口进行典型寄存器读取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OV2640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) 2020 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 "ov2640.h"void DCMI_DMA_MemInc_En(void);
void DCMI_DMA_MemInc_Den(void);
void PY_OV2640_RGB565_CONFIG(void);
/* USER CODE END Includes *//* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
uint8_t aRxBuffer=0;uint8_t TxBuff[99] = {0};
uint8_t StatusFlag = 0;uint8_t ov2640_verh = 0xff, ov2640_verl=0xff;HAL_StatusTypeDef dcmi_dma_status = HAL_OK;uint32_t dcmi_data_buff[16000]={0};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 PTD *//* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD *//* 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_USART1_UART_Init(void);
static void MX_DCMI_Init(void);
static void MX_NVIC_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 *//* 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_USART1_UART_Init();MX_DCMI_Init();MX_USB_DEVICE_Init();/* Initialize interrupts */MX_NVIC_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);}PY_OV2640_RGB565_CONFIG();/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){/* USER CODE END WHILE *//* USER CODE BEGIN 3 */HAL_Delay(1);if (scmd==1){scmd = 0;DCMI_DMA_MemInc_En();TxBuff[0]=0x55;TxBuff[1]=0xaa;TxBuff[2]=0x02; //OV2640 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]=0x02; //OV2640 labeltx_busy=1;HAL_UART_Transmit(&huart1, TxBuff, 3, 0xFFFFFF);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;HAL_UART_Transmit_DMA(&huart1, (uint8_t *)dcmi_data_buff, 61440);while(tx_busy!=0) ;}}}/* USER CODE END 3 */
}/*** @brief System Clock Configuration* @retval None*/
void SystemClock_Config(void)
{RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};/** Configure the main internal regulator output voltage*/__HAL_RCC_PWR_CLK_ENABLE();__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);/** Initializes the RCC Oscillators according to the specified parameters* in the RCC_OscInitTypeDef structure.*/RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;RCC_OscInitStruct.HSEState = RCC_HSE_ON;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLM = 25;RCC_OscInitStruct.PLL.PLLN = 192;RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;RCC_OscInitStruct.PLL.PLLQ = 4;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_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3) != HAL_OK){Error_Handler();}HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_PLLCLK, RCC_MCODIV_4);
}/*** @brief NVIC Configuration.* @retval None*/
static void MX_NVIC_Init(void)
{/* USART1_IRQn interrupt configuration */HAL_NVIC_SetPriority(USART1_IRQn, 1, 0);HAL_NVIC_EnableIRQ(USART1_IRQn);
}/*** @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_HARDWARE;hdcmi.Init.PCKPolarity = DCMI_PCKPOLARITY_RISING;hdcmi.Init.VSPolarity = DCMI_VSPOLARITY_LOW;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;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;if (HAL_UART_Init(&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_DMA2_CLK_ENABLE();/* DMA interrupt init *//* DMA2_Stream1_IRQn interrupt configuration */HAL_NVIC_SetPriority(DMA2_Stream1_IRQn, 0, 0);HAL_NVIC_EnableIRQ(DMA2_Stream1_IRQn);/* DMA2_Stream7_IRQn interrupt configuration */HAL_NVIC_SetPriority(DMA2_Stream7_IRQn, 0, 0);HAL_NVIC_EnableIRQ(DMA2_Stream7_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_GPIOE_CLK_ENABLE();__HAL_RCC_GPIOH_CLK_ENABLE();__HAL_RCC_GPIOA_CLK_ENABLE();__HAL_RCC_GPIOB_CLK_ENABLE();__HAL_RCC_GPIOD_CLK_ENABLE();__HAL_RCC_GPIOC_CLK_ENABLE();/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(GPIOB, GPIO_PIN_0|GPIO_PIN_1, 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 : PB0 PB1 */GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;GPIO_InitStruct.Pull = GPIO_PULLUP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;HAL_GPIO_Init(GPIOB, &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_LOW;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_LOW;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)
{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_OV2640_RGB565_CONFIG(void)
{/*Camera Interface*/SCCB_Rst();     //hard resetHAL_Delay(100);//SCCB_WR_Reg(0xff, 0x01);   //soft reset//SCCB_WR_Reg(0x12, 0x80);//HAL_Delay(100);ov2640_verh = SCCB_RD_Reg(0x1c);HAL_Delay(50);ov2640_verl = SCCB_RD_Reg(0x1d);HAL_Delay(50);while ((ov2640_verh==0xff)||(ov2640_verl==0xff)){HAL_UART_Transmit(&huart1, &ov2640_verh, 1, 0xFFFFFF);HAL_Delay(500);HAL_UART_Transmit(&huart1, &ov2640_verl, 1, 0xFFFFFF);HAL_Delay(500);}OV2640_UXGA_Init();//pix speed adjustmentSCCB_WR_Reg(0xff, 0x00);SCCB_WR_Reg(0xd3, 0x00);SCCB_WR_Reg(0XFF, 0X01);SCCB_WR_Reg(0X11, 0x01);OV2640_RGB565_Mode();OV2640_OutSize_Set(640, 480);HAL_Delay(200);}
/* 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 *//* 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,tex: 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****/

11. STM32F407完整代码

基于STM32CUBEIDE工程：
https://download.csdn.net/download/hwytree/20387639

12. 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

13. 一维码识别效果

14. 二维码识别效果

15. 上位机实现解码原理范例

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

-End-