Hi all,
I am trying to capture an image using a OV7670
connected to an Arduino Uno WiFi Rev 2.
I understand that (OV7670 with both arduino uno and now mega) have some examples but none can be found relating to MegaAVR, especially on Arduino Uno WiFi Rev 2 and OV7670.
Using the example given in that forum (GitHub - ComputerNerd/ov7670-no-ram-arduino-uno: Allows you to use a non fifo ov7670 on the arudino uno without external spi ram like other examples. Sends the data to UART.), I have created a circuit connection sketch
However, running this code does not work.
#define F_CPU 16000000UL
#include <stdint.h>
#include <avr/io.h>
#include <util/twi.h>
#include <util/delay.h>
#include <avr/pgmspace.h>
#include "ov7670.h"
static const struct regval_list vga_ov7670[] PROGMEM = {
{REG_HREF,0xF6}, // was B6
{0x17,0x13}, // HSTART
{0x18,0x01}, // HSTOP
{0x19,0x02}, // VSTART
{0x1a,0x7a}, // VSTOP
{REG_VREF,0x0a}, // VREF
{0xff, 0xff}, /* END MARKER */
};
static const struct regval_list qvga_ov7670[] PROGMEM = {
{REG_COM14, 0x19},
{0x72, 0x11},
{0x73, 0xf1},
{REG_HSTART,0x16},
{REG_HSTOP,0x04},
{REG_HREF,0x24},
{REG_VSTART,0x02},
{REG_VSTOP,0x7a},
{REG_VREF,0x0a},
{0xff, 0xff}, /* END MARKER */
};
static const struct regval_list qqvga_ov7670[] PROGMEM = {
{REG_COM14, 0x1a}, // divide by 4
{0x72, 0x22}, // downsample by 4
{0x73, 0xf2}, // divide by 4
{REG_HSTART,0x16},
{REG_HSTOP,0x04},
{REG_HREF,0xa4},
{REG_VSTART,0x02},
{REG_VSTOP,0x7a},
{REG_VREF,0x0a},
{0xff, 0xff}, /* END MARKER */
};
static 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_GAMMA|*/COM13_UVSAT},
{0xff, 0xff}, /* END MARKER */
};
static const struct regval_list rgb565_ov7670[] PROGMEM = {
{REG_COM7, COM7_RGB}, /* Selects RGB mode */
{REG_RGB444, 0}, /* No RGB444 please */
{REG_COM1, 0x0},
{REG_COM15, COM15_RGB565|COM15_R00FF},
{REG_COM9, 0x6A}, /* 128x gain ceiling; 0x8 is reserved bit */
{0x4f, 0xb3}, /* "matrix coefficient 1" */
{0x50, 0xb3}, /* "matrix coefficient 2" */
{0x51, 0}, /* vb */
{0x52, 0x3d}, /* "matrix coefficient 4" */
{0x53, 0xa7}, /* "matrix coefficient 5" */
{0x54, 0xe4}, /* "matrix coefficient 6" */
{REG_COM13, /*COM13_GAMMA|*/COM13_UVSAT},
{0xff, 0xff}, /* END MARKER */
};
static const struct regval_list bayerRGB_ov7670[] PROGMEM = {
{REG_COM7, COM7_BAYER},
{REG_COM13, 0x08}, /* No gamma, magic rsvd bit */
{REG_COM16, 0x3d}, /* Edge enhancement, denoise */
{REG_REG76, 0xe1}, /* Pix correction, magic rsvd */
{0xff, 0xff}, /* END MARKER */
};
static 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, COM10_VS_NEG},
/* 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 */
};
static void errorLed(void){
DDRB|=32;//make sure led is output
while(1){//wait for reset
PORTB^=32;// toggle led
_delay_ms(100);
}
}
static 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)
errorLed();
}
static void twiWriteByte(uint8_t DATA,uint8_t type){
TWDR = DATA;
TWCR = _BV(TWINT) | _BV(TWEN); /* clear interrupt to start transmission */
while (!(TWCR & (1<<TWINT))); /* wait for transmission */
if ((TWSR & 0xF8) != type)
errorLed();
}
void wrReg(uint8_t reg,uint8_t dat){
//send start condition
twiStart();
twiWriteByte(OV7670_I2C_ADDRESS<<1,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)
errorLed();
}else{
TWCR=_BV(TWINT) | _BV(TWEN) | _BV(TWEA);
while ((TWCR & _BV(TWINT)) == 0) ; /* wait for transmission */
if ((TWSR & 0xF8) != TW_MR_DATA_ACK)
errorLed();
}
return TWDR;
}
uint8_t rdReg(uint8_t reg){
uint8_t dat;
twiStart();
twiWriteByte(OV7670_I2C_ADDRESS<<1,TW_MT_SLA_ACK);
twiWriteByte(reg,TW_MT_DATA_ACK);
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);//send stop
_delay_ms(1);
twiStart();
twiWriteByte((OV7670_I2C_ADDRESS<<1)|1,TW_MR_SLA_ACK);
dat=twiRd(1);
TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);//send stop
_delay_ms(1);
return dat;
}
static void wrSensorRegs8_8(const struct regval_list reglist[]){
const struct regval_list *next = reglist;
for(;;){
uint8_t reg_addr = pgm_read_byte(&next->reg_num);
uint8_t reg_val = pgm_read_byte(&next->value);
if((reg_addr==255)&&(reg_val==255))
break;
wrReg(reg_addr, reg_val);
next++;
}
}
void setColorSpace(enum COLORSPACE color){
switch(color){
case YUV422:
wrSensorRegs8_8(yuv422_ov7670);
break;
case RGB565:
wrSensorRegs8_8(rgb565_ov7670);
{uint8_t temp=rdReg(0x11);
_delay_ms(1);
wrReg(0x11,temp);}//according to the Linux kernel driver rgb565 PCLK needs rewriting
break;
case BAYER_RGB:
wrSensorRegs8_8(bayerRGB_ov7670);
break;
}
}
void setRes(enum RESOLUTION res){
switch(res){
case VGA:
wrReg(REG_COM3,0); // REG_COM3
wrSensorRegs8_8(vga_ov7670);
break;
case QVGA:
wrReg(REG_COM3,4); // REG_COM3 enable scaling
wrSensorRegs8_8(qvga_ov7670);
break;
case QQVGA:
wrReg(REG_COM3,4); // REG_COM3 enable scaling
wrSensorRegs8_8(qqvga_ov7670);
break;
}
}
void camInit(void){
wrReg(0x12, 0x80);//Reset the camera.
_delay_ms(100);
wrSensorRegs8_8(ov7670_default_regs);
wrReg(REG_COM10,32);//PCLK does not toggle on HBLANK.
}
Can any kind soul here please guide me on debugging the issue (both hardware and program)? Additionally, is it necessary to connect all the pins in OV7670, is there a way to reduce the wires?
