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[아두이노] OV7670 사용하기

by rudals.kim 2020. 11. 26. 댓글 개
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OV7670 사용은 아래 instructables.com의 내용을 참고하였습니다.

 

www.instructables.com/OV7670-Arduino-Camera-Sensor-Module-Framecapture-T/

 

OV7670 Arduino Camera Sensor Module Framecapture Tutorial

OV7670 Arduino Camera Sensor Module Framecapture Tutorial: DescriptionThe camera module is powered from a single +3.3V power supply. An external oscillator provide the clock source for camera module XCLK pin. With proper configuration to the camera interna

www.instructables.com

저렴한 OV7670 카메라입니다. 아두이노 우노 보드와 많이 사용되고 있습니다.

3.3V에서 동작되며 1/6인치 센서에 최대 640x480 해상도를 출력합니다. 

 

제가 구매한 OV7670 카메라입니다. FIFO 버퍼가 없는 카메라 모듈입니다.

핀 순서는 아래와 같습니다.

일반적으로 아두이노는 5V에서 동작되기 때문에 아래와 같이 몇 몇 저항을 삽입하여 3.3V에서 동작되도록 합니다.

위의 회로도를 보면 4개의 저항을 연결해야 합니다. 

저는 아두이노와 쉽게 연결하기 위해 아래와 같은 서브 컨넥터 보드를 만들었습니다. 

만드는 김에 제가 가지고 있는 카메라를 Adafruit Proto Shield에 바로 꽂을 수 있도록 핀헤더를 연결한 후 각 라인에 배선을 하였습니다.

커넥터에 부품을 전부 꽂아 주기만 하면 보다 쉽게 OV7670를 테스트할 수 있습니다.

사용된 소스 코드는 위 참고 URL에 있습니다.

//
// Source code for application to transmit image from ov7670 to PC via USB
// By Siarhei Charkes in 2015
// http://privateblog.info 
//

#include <stdint.h>
#include <avr/io.h>
#include <util/twi.h>
#include <util/delay.h>
#include <avr/pgmspace.h>

#define F_CPU 16000000UL
#define vga   0
#define qvga  1
#define qqvga   2
#define yuv422  0
#define rgb565  1
#define bayerRGB  2
#define camAddr_WR  0x42
#define camAddr_RD  0x43

/* Registers */
#define REG_GAIN    0x00  /* Gain lower 8 bits (rest in vref) */
#define REG_BLUE    0x01  /* blue gain */
#define REG_RED       0x02  /* red gain */
#define REG_VREF    0x03  /* Pieces of GAIN, VSTART, VSTOP */
#define REG_COM1    0x04  /* Control 1 */
#define COM1_CCIR656  0x40    /* CCIR656 enable */

#define REG_BAVE    0x05  /* U/B Average level */
#define REG_GbAVE   0x06  /* Y/Gb Average level */
#define REG_AECHH   0x07  /* AEC MS 5 bits */
#define REG_RAVE    0x08  /* V/R Average level */
#define REG_COM2    0x09  /* Control 2 */
#define COM2_SSLEEP         0x10  /* Soft sleep mode */
#define REG_PID           0x0a  /* Product ID MSB */
#define REG_VER           0x0b  /* Product ID LSB */
#define REG_COM3    0x0c  /* Control 3 */
#define COM3_SWAP         0x40  /* Byte swap */
#define COM3_SCALEEN          0x08  /* Enable scaling */
#define COM3_DCWEN          0x04  /* Enable downsamp/crop/window */
#define REG_COM4    0x0d  /* Control 4 */
#define REG_COM5    0x0e  /* All "reserved" */
#define REG_COM6    0x0f  /* Control 6 */
#define REG_AECH    0x10  /* More bits of AEC value */
#define REG_CLKRC   0x11  /* Clocl control */
#define CLK_EXT           0x40  /* Use external clock directly */
#define CLK_SCALE   0x3f  /* Mask for internal clock scale */
#define REG_COM7    0x12  /* Control 7 */ //REG mean address.
#define COM7_RESET          0x80  /* Register reset */
#define COM7_FMT_MASK         0x38
#define COM7_FMT_VGA          0x00
#define COM7_FMT_CIF          0x20  /* CIF format */
#define COM7_FMT_QVGA         0x10  /* QVGA format */
#define COM7_FMT_QCIF         0x08  /* QCIF format */
#define COM7_RGB          0x04  /* bits 0 and 2 - RGB format */
#define COM7_YUV          0x00  /* YUV */
#define COM7_BAYER          0x01  /* Bayer format */
#define COM7_PBAYER         0x05  /* "Processed bayer" */
#define REG_COM8    0x13  /* Control 8 */
#define COM8_FASTAEC          0x80  /* Enable fast AGC/AEC */
#define COM8_AECSTEP          0x40  /* Unlimited AEC step size */
#define COM8_BFILT    0x20  /* Band filter enable */
#define COM8_AGC    0x04  /* Auto gain enable */
#define COM8_AWB    0x02  /* White balance enable */
#define COM8_AEC    0x01  /* Auto exposure enable */
#define REG_COM9    0x14  /* Control 9- gain ceiling */
#define REG_COM10   0x15  /* Control 10 */
#define COM10_HSYNC         0x40  /* HSYNC instead of HREF */
#define COM10_PCLK_HB         0x20  /* Suppress PCLK on horiz blank */
#define COM10_HREF_REV          0x08  /* Reverse HREF */
#define COM10_VS_LEAD         0x04  /* VSYNC on clock leading edge */
#define COM10_VS_NEG          0x02  /* VSYNC negative */
#define COM10_HS_NEG          0x01  /* HSYNC negative */
#define REG_HSTART    0x17  /* Horiz start high bits */
#define REG_HSTOP   0x18  /* Horiz stop high bits */
#define REG_VSTART    0x19  /* Vert start high bits */
#define REG_VSTOP   0x1a  /* Vert stop high bits */
#define REG_PSHFT   0x1b  /* Pixel delay after HREF */
#define REG_MIDH    0x1c  /* Manuf. ID high */
#define REG_MIDL    0x1d  /* Manuf. ID low */
#define REG_MVFP    0x1e  /* Mirror / vflip */
#define MVFP_MIRROR         0x20  /* Mirror image */
#define MVFP_FLIP   0x10  /* Vertical flip */

#define REG_AEW           0x24  /* AGC upper limit */
#define REG_AEB           0x25    /* AGC lower limit */
#define REG_VPT           0x26  /* AGC/AEC fast mode op region */
#define REG_HSYST   0x30  /* HSYNC rising edge delay */
#define REG_HSYEN   0x31  /* HSYNC falling edge delay */
#define REG_HREF    0x32  /* HREF pieces */
#define REG_TSLB    0x3a  /* lots of stuff */
#define TSLB_YLAST    0x04  /* UYVY or VYUY - see com13 */
#define REG_COM11   0x3b  /* Control 11 */
#define COM11_NIGHT         0x80  /* NIght mode enable */
#define COM11_NMFR          0x60  /* Two bit NM frame rate */
#define COM11_HZAUTO          0x10  /* Auto detect 50/60 Hz */
#define COM11_50HZ          0x08  /* Manual 50Hz select */
#define COM11_EXP   0x02
#define REG_COM12   0x3c  /* Control 12 */
#define COM12_HREF          0x80  /* HREF always */
#define REG_COM13   0x3d  /* Control 13 */
#define COM13_GAMMA         0x80  /* Gamma enable */
#define COM13_UVSAT         0x40  /* UV saturation auto adjustment */
#define COM13_UVSWAP          0x01  /* V before U - w/TSLB */
#define REG_COM14   0x3e  /* Control 14 */
#define COM14_DCWEN         0x10  /* DCW/PCLK-scale enable */
#define REG_EDGE    0x3f  /* Edge enhancement factor */
#define REG_COM15   0x40  /* Control 15 */
#define COM15_R10F0         0x00  /* Data range 10 to F0 */
#define COM15_R01FE         0x80  /*      01 to FE */
#define COM15_R00FF         0xc0  /*      00 to FF */
#define COM15_RGB565          0x10  /* RGB565 output */
#define COM15_RGB555          0x30  /* RGB555 output */
#define REG_COM16   0x41  /* Control 16 */
#define COM16_AWBGAIN         0x08  /* AWB gain enable */
#define REG_COM17   0x42  /* Control 17 */
#define COM17_AECWIN          0xc0  /* AEC window - must match COM4 */
#define COM17_CBAR          0x08  /* DSP Color bar */
/*
* This matrix defines how the colors are generated, must be
* tweaked to adjust hue and saturation.
*
* Order: v-red, v-green, v-blue, u-red, u-green, u-blue
* They are nine-bit signed quantities, with the sign bit
* stored in0x58.Sign for v-red is bit 0, and up from there.
*/
#define REG_CMATRIX_BASE  0x4f
#define CMATRIX_LEN           6
#define REG_CMATRIX_SIGN  0x58
#define REG_BRIGHT    0x55  /* Brightness */
#define REG_CONTRAS         0x56  /* Contrast control */
#define REG_GFIX    0x69  /* Fix gain control */
#define REG_REG76   0x76  /* OV's name */
#define R76_BLKPCOR         0x80  /* Black pixel correction enable */
#define R76_WHTPCOR         0x40  /* White pixel correction enable */
#define REG_RGB444          0x8c  /* RGB 444 control */
#define R444_ENABLE         0x02  /* Turn on RGB444, overrides 5x5 */
#define R444_RGBX   0x01  /* Empty nibble at end */
#define REG_HAECC1    0x9f  /* Hist AEC/AGC control 1 */
#define REG_HAECC2    0xa0  /* Hist AEC/AGC control 2 */
#define REG_BD50MAX         0xa5  /* 50hz banding step limit */
#define REG_HAECC3    0xa6  /* Hist AEC/AGC control 3 */
#define REG_HAECC4    0xa7  /* Hist AEC/AGC control 4 */
#define REG_HAECC5    0xa8  /* Hist AEC/AGC control 5 */
#define REG_HAECC6    0xa9  /* Hist AEC/AGC control 6 */
#define REG_HAECC7    0xaa  /* Hist AEC/AGC control 7 */
#define REG_BD60MAX         0xab  /* 60hz banding step limit */
#define REG_GAIN    0x00  /* Gain lower 8 bits (rest in vref) */
#define REG_BLUE    0x01  /* blue gain */
#define REG_RED           0x02  /* red gain */
#define REG_VREF    0x03  /* Pieces of GAIN, VSTART, VSTOP */
#define REG_COM1    0x04  /* Control 1 */
#define COM1_CCIR656          0x40  /* CCIR656 enable */
#define REG_BAVE    0x05  /* U/B Average level */
#define REG_GbAVE   0x06  /* Y/Gb Average level */
#define REG_AECHH   0x07  /* AEC MS 5 bits */
#define REG_RAVE    0x08  /* V/R Average level */
#define REG_COM2    0x09  /* Control 2 */
#define COM2_SSLEEP         0x10  /* Soft sleep mode */
#define REG_PID           0x0a  /* Product ID MSB */
#define REG_VER           0x0b  /* Product ID LSB */
#define REG_COM3    0x0c  /* Control 3 */
#define COM3_SWAP         0x40  /* Byte swap */
#define COM3_SCALEEN          0x08  /* Enable scaling */
#define COM3_DCWEN          0x04  /* Enable downsamp/crop/window */
#define REG_COM4    0x0d  /* Control 4 */
#define REG_COM5    0x0e  /* All "reserved" */
#define REG_COM6    0x0f  /* Control 6 */
#define REG_AECH    0x10  /* More bits of AEC value */
#define REG_CLKRC   0x11  /* Clocl control */
#define CLK_EXT           0x40  /* Use external clock directly */
#define CLK_SCALE   0x3f  /* Mask for internal clock scale */
#define REG_COM7    0x12  /* Control 7 */
#define COM7_RESET          0x80  /* Register reset */
#define COM7_FMT_MASK         0x38
#define COM7_FMT_VGA          0x00
#define COM7_FMT_CIF          0x20  /* CIF format */
#define COM7_FMT_QVGA         0x10  /* QVGA format */
#define COM7_FMT_QCIF         0x08  /* QCIF format */
#define COM7_RGB    0x04  /* bits 0 and 2 - RGB format */
#define COM7_YUV    0x00  /* YUV */
#define COM7_BAYER          0x01  /* Bayer format */
#define COM7_PBAYER         0x05  /* "Processed bayer" */
#define REG_COM8    0x13  /* Control 8 */
#define COM8_FASTAEC          0x80  /* Enable fast AGC/AEC */
#define COM8_AECSTEP          0x40  /* Unlimited AEC step size */
#define COM8_BFILT    0x20  /* Band filter enable */
#define COM8_AGC    0x04  /* Auto gain enable */
#define COM8_AWB    0x02  /* White balance enable */
#define COM8_AEC    0x01  /* Auto exposure enable */
#define REG_COM9    0x14  /* Control 9- gain ceiling */
#define REG_COM10   0x15  /* Control 10 */
#define COM10_HSYNC         0x40  /* HSYNC instead of HREF */
#define COM10_PCLK_HB         0x20  /* Suppress PCLK on horiz blank */
#define COM10_HREF_REV          0x08  /* Reverse HREF */
#define COM10_VS_LEAD           0x04  /* VSYNC on clock leading edge */
#define COM10_VS_NEG          0x02  /* VSYNC negative */
#define COM10_HS_NEG          0x01  /* HSYNC negative */
#define REG_HSTART    0x17  /* Horiz start high bits */
#define REG_HSTOP   0x18  /* Horiz stop high bits */
#define REG_VSTART    0x19  /* Vert start high bits */
#define REG_VSTOP   0x1a  /* Vert stop high bits */
#define REG_PSHFT   0x1b  /* Pixel delay after HREF */
#define REG_MIDH    0x1c  /* Manuf. ID high */
#define REG_MIDL    0x1d  /* Manuf. ID low */
#define REG_MVFP    0x1e  /* Mirror / vflip */
#define MVFP_MIRROR         0x20  /* Mirror image */
#define MVFP_FLIP   0x10  /* Vertical flip */
#define REG_AEW           0x24  /* AGC upper limit */
#define REG_AEB           0x25  /* AGC lower limit */
#define REG_VPT           0x26  /* AGC/AEC fast mode op region */
#define REG_HSYST   0x30  /* HSYNC rising edge delay */
#define REG_HSYEN   0x31  /* HSYNC falling edge delay */
#define REG_HREF    0x32  /* HREF pieces */
#define REG_TSLB    0x3a  /* lots of stuff */
#define TSLB_YLAST    0x04  /* UYVY or VYUY - see com13 */
#define REG_COM11   0x3b  /* Control 11 */
#define COM11_NIGHT         0x80  /* NIght mode enable */
#define COM11_NMFR          0x60  /* Two bit NM frame rate */
#define COM11_HZAUTO          0x10  /* Auto detect 50/60 Hz */
#define COM11_50HZ          0x08  /* Manual 50Hz select */
#define COM11_EXP   0x02
#define REG_COM12   0x3c  /* Control 12 */
#define COM12_HREF          0x80  /* HREF always */
#define REG_COM13   0x3d  /* Control 13 */
#define COM13_GAMMA         0x80  /* Gamma enable */
#define COM13_UVSAT         0x40  /* UV saturation auto adjustment */
#define COM13_UVSWAP          0x01  /* V before U - w/TSLB */
#define REG_COM14   0x3e  /* Control 14 */
#define COM14_DCWEN         0x10  /* DCW/PCLK-scale enable */
#define REG_EDGE    0x3f  /* Edge enhancement factor */
#define REG_COM15   0x40  /* Control 15 */
#define COM15_R10F0         0x00  /* Data range 10 to F0 */
#define COM15_R01FE         0x80  /*      01 to FE */
#define COM15_R00FF         0xc0  /*      00 to FF */
#define COM15_RGB565          0x10  /* RGB565 output */
#define COM15_RGB555          0x30  /* RGB555 output */
#define REG_COM16   0x41  /* Control 16 */
#define COM16_AWBGAIN         0x08  /* AWB gain enable */
#define REG_COM17   0x42  /* Control 17 */
#define COM17_AECWIN          0xc0  /* AEC window - must match COM4 */
#define COM17_CBAR          0x08  /* DSP Color bar */

#define CMATRIX_LEN             6
#define REG_BRIGHT    0x55  /* Brightness */
#define REG_REG76   0x76  /* OV's name */
#define R76_BLKPCOR         0x80  /* Black pixel correction enable */
#define R76_WHTPCOR         0x40  /* White pixel correction enable */
#define REG_RGB444          0x8c  /* RGB 444 control */
#define R444_ENABLE         0x02  /* Turn on RGB444, overrides 5x5 */
#define R444_RGBX   0x01  /* Empty nibble at end */
#define REG_HAECC1    0x9f  /* Hist AEC/AGC control 1 */
#define REG_HAECC2    0xa0  /* Hist AEC/AGC control 2 */
#define REG_BD50MAX         0xa5  /* 50hz banding step limit */
#define REG_HAECC3    0xa6  /* Hist AEC/AGC control 3 */
#define REG_HAECC4    0xa7  /* Hist AEC/AGC control 4 */
#define REG_HAECC5    0xa8  /* Hist AEC/AGC control 5 */
#define REG_HAECC6    0xa9  /* Hist AEC/AGC control 6 */
#define REG_HAECC7    0xaa  /* Hist AEC/AGC control 7 */
#define REG_BD60MAX         0xab  /* 60hz banding step limit */
#define MTX1            0x4f  /* Matrix Coefficient 1 */
#define MTX2            0x50  /* Matrix Coefficient 2 */
#define MTX3            0x51  /* Matrix Coefficient 3 */
#define MTX4            0x52  /* Matrix Coefficient 4 */
#define MTX5            0x53  /* Matrix Coefficient 5 */
#define MTX6            0x54  /* Matrix Coefficient 6 */
#define REG_CONTRAS         0x56  /* Contrast control */
#define MTXS            0x58  /* Matrix Coefficient Sign */
#define AWBC7           0x59  /* AWB Control 7 */
#define AWBC8           0x5a  /* AWB Control 8 */
#define AWBC9           0x5b  /* AWB Control 9 */
#define AWBC10            0x5c  /* AWB Control 10 */
#define AWBC11            0x5d  /* AWB Control 11 */
#define AWBC12            0x5e  /* AWB Control 12 */
#define REG_GFI           0x69  /* Fix gain control */
#define GGAIN           0x6a  /* G Channel AWB Gain */
#define DBLV            0x6b  
#define AWBCTR3           0x6c  /* AWB Control 3 */
#define AWBCTR2           0x6d  /* AWB Control 2 */
#define AWBCTR1           0x6e  /* AWB Control 1 */
#define AWBCTR0           0x6f  /* AWB Control 0 */

struct regval_list{
  uint8_t reg_num;
  uint16_t value;
};

const struct regval_list qvga_ov7670[] PROGMEM = {
  { REG_COM14, 0x19 },
  { 0x72, 0x11 },
  { 0x73, 0xf1 },

  { REG_HSTART, 0x16 },
  { REG_HSTOP, 0x04 },
  { REG_HREF, 0xa4 },
  { REG_VSTART, 0x02 },
  { REG_VSTOP, 0x7a },
  { REG_VREF, 0x0a },


/*  { REG_HSTART, 0x16 },
  { REG_HSTOP, 0x04 },
  { REG_HREF, 0x24 },
  { REG_VSTART, 0x02 },
  { REG_VSTOP, 0x7a },
  { REG_VREF, 0x0a },*/
  { 0xff, 0xff }, /* END MARKER */
};

const struct regval_list yuv422_ov7670[] PROGMEM = {
  { REG_COM7, 0x0 },  /* Selects YUV mode */
  { REG_RGB444, 0 },  /* No RGB444 please */
  { REG_COM1, 0 },
  { REG_COM15, COM15_R00FF },
  { REG_COM9, 0x6A }, /* 128x gain ceiling; 0x8 is reserved bit */
  { 0x4f, 0x80 },   /* "matrix coefficient 1" */
  { 0x50, 0x80 },   /* "matrix coefficient 2" */
  { 0x51, 0 },    /* vb */
  { 0x52, 0x22 },   /* "matrix coefficient 4" */
  { 0x53, 0x5e },   /* "matrix coefficient 5" */
  { 0x54, 0x80 },   /* "matrix coefficient 6" */
  { REG_COM13, COM13_UVSAT },
  { 0xff, 0xff },   /* END MARKER */
};

const struct regval_list ov7670_default_regs[] PROGMEM = {//from the linux driver
  { REG_COM7, COM7_RESET },
  { REG_TSLB, 0x04 }, /* OV */
  { REG_COM7, 0 },  /* VGA */
  /*
  * Set the hardware window.  These values from OV don't entirely
  * make sense - hstop is less than hstart.  But they work...
  */
  { REG_HSTART, 0x13 }, { REG_HSTOP, 0x01 },
  { REG_HREF, 0xb6 }, { REG_VSTART, 0x02 },
  { REG_VSTOP, 0x7a }, { REG_VREF, 0x0a },

  { REG_COM3, 0 }, { REG_COM14, 0 },
  /* Mystery scaling numbers */
  { 0x70, 0x3a }, { 0x71, 0x35 },
  { 0x72, 0x11 }, { 0x73, 0xf0 },
  { 0xa2,/* 0x02 changed to 1*/1 }, { REG_COM10, 0x0 },
  /* Gamma curve values */
  { 0x7a, 0x20 }, { 0x7b, 0x10 },
  { 0x7c, 0x1e }, { 0x7d, 0x35 },
  { 0x7e, 0x5a }, { 0x7f, 0x69 },
  { 0x80, 0x76 }, { 0x81, 0x80 },
  { 0x82, 0x88 }, { 0x83, 0x8f },
  { 0x84, 0x96 }, { 0x85, 0xa3 },
  { 0x86, 0xaf }, { 0x87, 0xc4 },
  { 0x88, 0xd7 }, { 0x89, 0xe8 },
  /* AGC and AEC parameters.  Note we start by disabling those features,
  then turn them only after tweaking the values. */
  { REG_COM8, COM8_FASTAEC | COM8_AECSTEP },
  { REG_GAIN, 0 }, { REG_AECH, 0 },
  { REG_COM4, 0x40 }, /* magic reserved bit */
  { REG_COM9, 0x18 }, /* 4x gain + magic rsvd bit */
  { REG_BD50MAX, 0x05 }, { REG_BD60MAX, 0x07 },
  { REG_AEW, 0x95 }, { REG_AEB, 0x33 },
  { REG_VPT, 0xe3 }, { REG_HAECC1, 0x78 },
  { REG_HAECC2, 0x68 }, { 0xa1, 0x03 }, /* magic */
  { REG_HAECC3, 0xd8 }, { REG_HAECC4, 0xd8 },
  { REG_HAECC5, 0xf0 }, { REG_HAECC6, 0x90 },
  { REG_HAECC7, 0x94 },
  { REG_COM8, COM8_FASTAEC | COM8_AECSTEP | COM8_AGC | COM8_AEC },
  { 0x30, 0 }, { 0x31, 0 },//disable some delays
  /* Almost all of these are magic "reserved" values.  */
  { REG_COM5, 0x61 }, { REG_COM6, 0x4b },
  { 0x16, 0x02 }, { REG_MVFP, 0x07 },
  { 0x21, 0x02 }, { 0x22, 0x91 },
  { 0x29, 0x07 }, { 0x33, 0x0b },
  { 0x35, 0x0b }, { 0x37, 0x1d },
  { 0x38, 0x71 }, { 0x39, 0x2a },
  { REG_COM12, 0x78 }, { 0x4d, 0x40 },
  { 0x4e, 0x20 }, { REG_GFIX, 0 },
  /*{0x6b, 0x4a},*/{ 0x74, 0x10 },
  { 0x8d, 0x4f }, { 0x8e, 0 },
  { 0x8f, 0 }, { 0x90, 0 },
  { 0x91, 0 }, { 0x96, 0 },
  { 0x9a, 0 }, { 0xb0, 0x84 },
  { 0xb1, 0x0c }, { 0xb2, 0x0e },
  { 0xb3, 0x82 }, { 0xb8, 0x0a },

  /* More reserved magic, some of which tweaks white balance */
  { 0x43, 0x0a }, { 0x44, 0xf0 },
  { 0x45, 0x34 }, { 0x46, 0x58 },
  { 0x47, 0x28 }, { 0x48, 0x3a },
  { 0x59, 0x88 }, { 0x5a, 0x88 },
  { 0x5b, 0x44 }, { 0x5c, 0x67 },
  { 0x5d, 0x49 }, { 0x5e, 0x0e },
  { 0x6c, 0x0a }, { 0x6d, 0x55 },
  { 0x6e, 0x11 }, { 0x6f, 0x9e }, /* it was 0x9F "9e for advance AWB" */
  { 0x6a, 0x40 }, { REG_BLUE, 0x40 },
  { REG_RED, 0x60 },
  { REG_COM8, COM8_FASTAEC | COM8_AECSTEP | COM8_AGC | COM8_AEC | COM8_AWB },

  /* Matrix coefficients */
  { 0x4f, 0x80 }, { 0x50, 0x80 },
  { 0x51, 0 },    { 0x52, 0x22 },
  { 0x53, 0x5e }, { 0x54, 0x80 },
  { 0x58, 0x9e },

  { REG_COM16, COM16_AWBGAIN }, { REG_EDGE, 0 },
  { 0x75, 0x05 }, { REG_REG76, 0xe1 },
  { 0x4c, 0 },     { 0x77, 0x01 },
  { REG_COM13, /*0xc3*/0x48 }, { 0x4b, 0x09 },
  { 0xc9, 0x60 },   /*{REG_COM16, 0x38},*/
  { 0x56, 0x40 },

  { 0x34, 0x11 }, { REG_COM11, COM11_EXP | COM11_HZAUTO },
  { 0xa4, 0x82/*Was 0x88*/ }, { 0x96, 0 },
  { 0x97, 0x30 }, { 0x98, 0x20 },
  { 0x99, 0x30 }, { 0x9a, 0x84 },
  { 0x9b, 0x29 }, { 0x9c, 0x03 },
  { 0x9d, 0x4c }, { 0x9e, 0x3f },
  { 0x78, 0x04 },

  /* Extra-weird stuff.  Some sort of multiplexor register */
  { 0x79, 0x01 }, { 0xc8, 0xf0 },
  { 0x79, 0x0f }, { 0xc8, 0x00 },
  { 0x79, 0x10 }, { 0xc8, 0x7e },
  { 0x79, 0x0a }, { 0xc8, 0x80 },
  { 0x79, 0x0b }, { 0xc8, 0x01 },
  { 0x79, 0x0c }, { 0xc8, 0x0f },
  { 0x79, 0x0d }, { 0xc8, 0x20 },
  { 0x79, 0x09 }, { 0xc8, 0x80 },
  { 0x79, 0x02 }, { 0xc8, 0xc0 },
  { 0x79, 0x03 }, { 0xc8, 0x40 },
  { 0x79, 0x05 }, { 0xc8, 0x30 },
  { 0x79, 0x26 },
  { 0xff, 0xff }, /* END MARKER */
};


void error_led(void){
  DDRB |= 32;//make sure led is output
  while (1){//wait for reset
    PORTB ^= 32;// toggle led
    _delay_ms(100);
  }
}

void twiStart(void){
  TWCR = _BV(TWINT) | _BV(TWSTA) | _BV(TWEN);//send start
  while (!(TWCR & (1 << TWINT)));//wait for start to be transmitted
  if ((TWSR & 0xF8) != TW_START)
    error_led();
}

void twiWriteByte(uint8_t DATA, uint8_t type){
  TWDR = DATA;
  TWCR = _BV(TWINT) | _BV(TWEN);
  while (!(TWCR & (1 << TWINT))) {}
  if ((TWSR & 0xF8) != type)
    error_led();
}

void twiAddr(uint8_t addr, uint8_t typeTWI){
  TWDR = addr;//send address
  TWCR = _BV(TWINT) | _BV(TWEN);    /* clear interrupt to start transmission */
  while ((TWCR & _BV(TWINT)) == 0); /* wait for transmission */
  if ((TWSR & 0xF8) != typeTWI)
    error_led();
}

void wrReg(uint8_t reg, uint8_t dat){
  //send start condition
  twiStart();
  twiAddr(camAddr_WR, TW_MT_SLA_ACK);
  twiWriteByte(reg, TW_MT_DATA_ACK);
  twiWriteByte(dat, TW_MT_DATA_ACK);
  TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);//send stop
  _delay_ms(1);
}

static uint8_t twiRd(uint8_t nack){
  if (nack){
    TWCR = _BV(TWINT) | _BV(TWEN);
    while ((TWCR & _BV(TWINT)) == 0); /* wait for transmission */
    if ((TWSR & 0xF8) != TW_MR_DATA_NACK)
      error_led();
    return TWDR;
  }
  else{
    TWCR = _BV(TWINT) | _BV(TWEN) | _BV(TWEA);
    while ((TWCR & _BV(TWINT)) == 0); /* wait for transmission */
    if ((TWSR & 0xF8) != TW_MR_DATA_ACK)
      error_led();
    return TWDR;
  }
}

uint8_t rdReg(uint8_t reg){
  uint8_t dat;
  twiStart();
  twiAddr(camAddr_WR, TW_MT_SLA_ACK);
  twiWriteByte(reg, TW_MT_DATA_ACK);
  TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);//send stop
  _delay_ms(1);
  twiStart();
  twiAddr(camAddr_RD, TW_MR_SLA_ACK);
  dat = twiRd(1);
  TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);//send stop
  _delay_ms(1);
  return dat;
}

void wrSensorRegs8_8(const struct regval_list reglist[]){
  uint8_t reg_addr, reg_val;
  const struct regval_list *next = reglist;
  while ((reg_addr != 0xff) | (reg_val != 0xff)){
    reg_addr = pgm_read_byte(&next->reg_num);
    reg_val = pgm_read_byte(&next->value);
    wrReg(reg_addr, reg_val);
    next++;
  }
}

void setColor(void){
  wrSensorRegs8_8(yuv422_ov7670);
}

void setRes(void){
  wrReg(REG_COM3, 4); // REG_COM3 enable scaling
  wrSensorRegs8_8(qvga_ov7670);
}

void camInit(void){
  wrReg(0x12, 0x80);
  _delay_ms(100);
  wrSensorRegs8_8(ov7670_default_regs);
  wrReg(REG_COM10, 32);//PCLK does not toggle on HBLANK.
}

void arduinoUnoInut(void) {
  cli();//disable interrupts
  
    /* Setup the 8mhz PWM clock
  * This will be on pin 11*/
  DDRB |= (1 << 3);//pin 11
  ASSR &= ~(_BV(EXCLK) | _BV(AS2));
  TCCR2A = (1 << COM2A0) | (1 << WGM21) | (1 << WGM20);
  TCCR2B = (1 << WGM22) | (1 << CS20);
  OCR2A = 0;//(F_CPU)/(2*(X+1))
  DDRC &= ~15;//low d0-d3 camera
  DDRD &= ~252;//d7-d4 and interrupt pins
  _delay_ms(3000);
  
    //set up twi for 100khz
  TWSR &= ~3;//disable prescaler for TWI
  TWBR = 72;//set to 100khz
  
    //enable serial
  UBRR0H = 0;
  UBRR0L = 1;//0 = 2M baud rate. 1 = 1M baud. 3 = 0.5M. 7 = 250k 207 is 9600 baud rate.
  UCSR0A |= 2;//double speed aysnc
  UCSR0B = (1 << RXEN0) | (1 << TXEN0);//Enable receiver and transmitter
  UCSR0C = 6;//async 1 stop bit 8bit char no parity bits
}


void StringPgm(const char * str){
  do{
      while (!(UCSR0A & (1 << UDRE0)));//wait for byte to transmit
      UDR0 = pgm_read_byte_near(str);
      while (!(UCSR0A & (1 << UDRE0)));//wait for byte to transmit
  } while (pgm_read_byte_near(++str));
}

static void captureImg(uint16_t wg, uint16_t hg){
  uint16_t y, x;

  StringPgm(PSTR("*RDY*"));

  while (!(PIND & 8));//wait for high
  while ((PIND & 8));//wait for low

    y = hg;
  while (y--){
        x = wg;
      //while (!(PIND & 256));//wait for high
    while (x--){
      while ((PIND & 4));//wait for low
            UDR0 = (PINC & 15) | (PIND & 240);
          while (!(UCSR0A & (1 << UDRE0)));//wait for byte to transmit
      while (!(PIND & 4));//wait for high
      while ((PIND & 4));//wait for low
      while (!(PIND & 4));//wait for high
    }
    //  while ((PIND & 256));//wait for low
  }
    _delay_ms(100);
}

void setup(){
  arduinoUnoInut();
  camInit();
  setRes();
  setColor();
  wrReg(0x11, 10); //Earlier it had the value: wrReg(0x11, 12); New version works better for me :) !!!!
}


void loop(){
  captureImg(320, 240);
}

 

위의 instructables.com에서는 OV7670의 이미지를 읽어 오기 위해 자바 환경을 사용합니다.

 

COM 포트를 자바에서 사용하기 위해 여러 가지 파일을 복사 해 넣는 작업이 불편하여 간단히 PC상에서 카메라 영상을 확인할 수 있게 OV7670 시리얼 캡처 뷰어를 만들어 보았습니다.

기능 테스트를 위해 간략하게 만들다 보니 치명적인 버그도 있지만 테스트 용도로는 사용할 수 있습니다.

 

간단히 아두이노에서 사용하는 COM 포트를 설정 후 "캡처 시작" 버튼을 누르면 왼쪽 pictureBox 영역에 읽어 들인 이미지를 보여줍니다. 시리얼을 통해서 읽다 보니 한 프레임을 읽어 들이는데 4초 이상으로 엄청 오래 걸립니다.

아래는 저의 테스트 환경입니다.

 

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