Sebastian Barrera
/
ov7670
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ov7670.cpp
- Committer:
- sebbarpar
- Date:
- 2020-04-06
- Revision:
- 5:46b8114bb5dd
- Parent:
- 3:b40a945dd672
File content as of revision 5:46b8114bb5dd:
#include "ov7670.h"
OV7670::OV7670(PinName sda, PinName scl, PinName vs, PinName hr, PinName we, PinName d7, PinName d6, PinName d5, PinName d4, PinName d3, PinName d2, PinName d1, PinName d0, PinName rt, PinName o, PinName rc) : _i2c(sda,scl),vsync(vs),href(hr),wen(we),data(d7,d6,d5,d4,d3,d2,d1,d0)/*da7(d7),da6(d6),da5(d5),da4(d4),da3(d3),da2(d2),da1(d1),da0(d0)*/,rrst(rt),oe(o),rclk(rc)
{
_i2c.stop();
_i2c.frequency(OV7670_I2CFREQ);
vsync.fall(this,&OV7670::VsyncHandler); // interrupt fall edge
CaptureReq = false;
Busy = false;
Done = false;
LineCounter = 0;
rrst = 1;
oe = 1;
rclk = 1;
wen = 0;
}
OV7670::~OV7670()
{
}
// capture request
void OV7670::CaptureNext(void)
{
CaptureReq = true;
Busy = true;
}
// capture done? (with clear)
bool OV7670::CaptureDone(void)
{
bool result;
if (Busy)
{
result = false;
}else
{
result = Done;
Done = false;
}
return result;
}
// vsync handler
void OV7670::VsyncHandler(void)
{
// Capture Enable
if (CaptureReq)
{
wen = 1;
Done = false;
CaptureReq = false;
}else
{
wen = 0;
if (Busy)
{
Busy = false;
Done = true;
}
}
}
// Data Read
int OV7670:: ReadOnebyte(void)
{
int result ;
rclk = 1 ;
// wait_us(1) ;
result = data ;
rclk = 0 ;
return result ;
}
// Data Start read from FIFO
void OV7670::ReadStart(void)
{
rrst = 0;
oe = 0;
wait_us(1);
rclk = 0;
wait_us(1);
rclk = 1;
wait_us(1);
rrst = 1;
}
// Data Stop read from FIFO
void OV7670::ReadStop(void)
{
oe = 1;
ReadOnebyte();
rclk = 1;
}
void OV7670::Reset(void)
{
WriteReg(0x12, 0x80); // RESET CAMERA
wait_ms(200);
}
int OV7670::Init(char c, int n)
{
if (ReadReg(REG_PID) != 0x76) // check id camera
{
return 0;
}
Reset(); // Resets all registers to default values
Reset(); // Resets all registers to default values
WriteReg(REG_RGB444, 0x00); // Disable RGB444
WriteReg(REG_COM10, 0x02); // 0x02 VSYNC negative (http://thinksmallthings.wordpress.com/2012/03/10/cf7670c-vs-cf7670c-v2/)
WriteReg(REG_MVFP, 0x27); // mirror image
WriteReg(REG_CLKRC, 0x80); // prescaler x1
WriteReg(DBLV, 0x0a); // bypass PLL
WriteReg(REG_COM11, 0x0A) ;
WriteReg(REG_TSLB, 0x04); // 0D = UYVY 04 = YUYV
WriteReg(REG_COM13, 0x88); // connect to REG_TSLB
if(c == 'b' || c == 'y') // YUV
{
WriteReg(REG_COM7, 0x00); // YUV
WriteReg(REG_COM17, 0x00); // color bar disable
WriteReg(REG_COM3, 0x04);
WriteReg(REG_COM15, 0xC0); // Set normal rgb with Full range
}else
if(c == 'r') // RGB565
{
WriteReg(REG_COM7, 0x04); // RGB + color bar disable
WriteReg(REG_RGB444, 0x00); // Disable RGB444
WriteReg(REG_COM15, 0x10); // Set rgb565 with Full range 0xD0
WriteReg(REG_COM3, 0x04);
WriteReg(REG_CLKRC, 0x80); // prescaler x1
}
WriteReg(0x70, 0x3A); // Scaling Xsc
WriteReg(0x71, 0x35); // Scaling Ysc
WriteReg(0xA2, 0x02); // pixel clock delay
if(n == 19200) // 160*120
{
WriteReg(REG_COM14, 0x1a); // divide by 4
WriteReg(0x72, 0x22); // downsample by 4
WriteReg(0x73, 0xf2); // divide by 4
WriteReg(REG_HREF, 0xa4);
WriteReg(REG_HSTART, 0x16);
WriteReg(REG_HSTOP, 0x04);
WriteReg(REG_VREF, 0x0a);
WriteReg(REG_VSTART, 0x02);
WriteReg(REG_VSTOP, 0x7a);
WriteReg(0x7a, 0x20);
WriteReg(0x7b, 0x1c);
WriteReg(0x7c, 0x28);
WriteReg(0x7d, 0x3c);
WriteReg(0x7e, 0x5a);
WriteReg(0x7f, 0x68);
WriteReg(0x80, 0x76);
WriteReg(0x81, 0x80);
WriteReg(0x82, 0x88);
WriteReg(0x83, 0x8f);
WriteReg(0x84, 0x96);
WriteReg(0x85, 0xa3);
WriteReg(0x86, 0xaf);
WriteReg(0x87, 0xc4);
WriteReg(0x88, 0xd7);
WriteReg(0x89, 0xe8);
WriteReg(0x13, 0xe0);
WriteReg(0x00, 0x00);
WriteReg(0x10, 0x00);
WriteReg(0x0d, 0x40);
WriteReg(0x14, 0x18);
WriteReg(0xa5, 0x05);
WriteReg(0xab, 0x07);
WriteReg(0x24, 0x95);
WriteReg(0x25, 0x33);
WriteReg(0x26, 0xe3);
WriteReg(0x9f, 0x78);
WriteReg(0xa0, 0x68);
WriteReg(0xa1, 0x03);
WriteReg(0xa6, 0xd8);
WriteReg(0xa7, 0xd8);
WriteReg(0xa8, 0xf0);
WriteReg(0xa9, 0x90);
WriteReg(0xaa, 0x94);
WriteReg(0x13, 0xe5);
WriteReg(0x0e, 0x61);
WriteReg(0x0f, 0x4b);
WriteReg(0x16, 0x02);
WriteReg(0x21, 0x02);
WriteReg(0x22, 0x91);
WriteReg(0x29, 0x07);
WriteReg(0x33, 0x0b);
WriteReg(0x35, 0x0b);
WriteReg(0x37, 0x1d);
WriteReg(0x38, 0x71);
WriteReg(0x39, 0x2a);
WriteReg(0x3c, 0x78);
WriteReg(0x4d, 0x40);
WriteReg(0x4e, 0x20);
WriteReg(0x69, 0x00);
WriteReg(0x74, 0x10);
WriteReg(0x8d, 0x4f);
WriteReg(0x8e, 0x00);
WriteReg(0x8f, 0x00);
WriteReg(0x90, 0x00);
WriteReg(0x91, 0x00);
WriteReg(0x92, 0x00);
WriteReg(0x96, 0x00);
WriteReg(0x9a, 0x80);
WriteReg(0xb0, 0x84);
WriteReg(0xb1, 0x0c);
WriteReg(0xb2, 0x0e);
WriteReg(0xb3, 0x82);
WriteReg(0xb8, 0x0a);
WriteReg(0x43, 0x0a);
WriteReg(0x44, 0xf0);
WriteReg(0x45, 0x34);
WriteReg(0x46, 0x58);
WriteReg(0x47, 0x28);
WriteReg(0x48, 0x3a);
WriteReg(0x59, 0x88);
WriteReg(0x5a, 0x88);
WriteReg(0x5b, 0x44);
WriteReg(0x5c, 0x67);
WriteReg(0x5d, 0x49);
WriteReg(0x5e, 0x0e);
WriteReg(0x64, 0x04);
WriteReg(0x65, 0x20);
WriteReg(0x66, 0x05);
WriteReg(0x94, 0x04);
WriteReg(0x95, 0x08);
WriteReg(0x6c, 0x0a);
WriteReg(0x6d, 0x55);
WriteReg(0x6e, 0x11);
WriteReg(0x6f, 0x9f);
WriteReg(0x6a, 0x40);
WriteReg(0x01, 0x40);
WriteReg(0x02, 0x40);
WriteReg(0x13, 0xe7);
//WriteReg(0x15, 0x02);
WriteReg(0x4f, 0x80);
WriteReg(0x50, 0x80);
WriteReg(0x51, 0x00);
WriteReg(0x52, 0x22);
WriteReg(0x53, 0x5e);
WriteReg(0x54, 0x80);
WriteReg(0x58, 0x9e);
WriteReg(0x41, 0x08);
WriteReg(0x3f, 0x00);
WriteReg(0x75, 0x05);
WriteReg(0x76, 0xe1);
WriteReg(0x4c, 0x00);
WriteReg(0x77, 0x01);
WriteReg(0x3d, 0xc1);
WriteReg(0x4b, 0x09);
WriteReg(0xc9, 0x60);
WriteReg(0x41, 0x38);
WriteReg(0x56, 0x40);
WriteReg(0x34, 0x11);
WriteReg(0x3b, 0x02);
WriteReg(0xa4, 0x88);
WriteReg(0x96, 0x00);
WriteReg(0x97, 0x30);
WriteReg(0x98, 0x20);
WriteReg(0x99, 0x30);
WriteReg(0x9a, 0x84);
WriteReg(0x9b, 0x29);
WriteReg(0x9c, 0x03);
WriteReg(0x9d, 0x4c);
WriteReg(0x9e, 0x3f);
WriteReg(0x78, 0x04);
WriteReg(0x79, 0x01);
WriteReg(0xc8, 0xf0);
WriteReg(0x79, 0x0f);
WriteReg(0xc8, 0x00);
WriteReg(0x79, 0x10);
WriteReg(0xc8, 0x7e);
WriteReg(0x79, 0x0a);
WriteReg(0xc8, 0x80);
WriteReg(0x79, 0x0b);
WriteReg(0xc8, 0x01);
WriteReg(0x79, 0x0c);
WriteReg(0xc8, 0x0f);
WriteReg(0x79, 0x0d);
WriteReg(0xc8, 0x20);
WriteReg(0x79, 0x09);
WriteReg(0xc8, 0x80);
WriteReg(0x79, 0x02);
WriteReg(0xc8, 0xc0);
WriteReg(0x79, 0x03);
WriteReg(0xc8, 0x40);
WriteReg(0x79, 0x05);
WriteReg(0xc8, 0x30);
WriteReg(0x79, 0x26);
WriteReg(0x09, 0x03);
WriteReg(0x3b, 0x42);
WriteReg(0xff, 0xff); /* END MARKER */
}
if(n == 76800) // 320*240
{
WriteReg(REG_COM14, 0x19);
WriteReg(0x72, 0x11);
WriteReg(0x73, 0xf1);
WriteReg(REG_HREF, 0x24);
WriteReg(REG_HSTART, 0x16);
WriteReg(REG_HSTOP, 0x04);
WriteReg(REG_VREF, 0x0a);
WriteReg(REG_VSTART,0x02);
WriteReg(REG_VSTOP, 0x7a);
WriteReg(0x7a, 0x20);
WriteReg(0x7b, 0x1c);
WriteReg(0x7c, 0x28);
WriteReg(0x7d, 0x3c);
WriteReg(0x7e, 0x55);
WriteReg(0x7f, 0x68);
WriteReg(0x80, 0x76);
WriteReg(0x81, 0x80);
WriteReg(0x82, 0x88);
WriteReg(0x83, 0x8f);
WriteReg(0x84, 0x96);
WriteReg(0x85, 0xa3);
WriteReg(0x86, 0xaf);
WriteReg(0x87, 0xc4);
WriteReg(0x88, 0xd7);
WriteReg(0x89, 0xe8);
WriteReg(0x13, 0xe0);
WriteReg(0x00, 0x00);
WriteReg(0x10, 0x00);
WriteReg(0x0d, 0x00);
WriteReg(0x14, 0x28);
WriteReg(0xa5, 0x05);
WriteReg(0xab, 0x07);
WriteReg(0x24, 0x75);
WriteReg(0x25, 0x63);
WriteReg(0x26, 0xA5);
WriteReg(0x9f, 0x78);
WriteReg(0xa0, 0x68);
WriteReg(0xa1, 0x03);
WriteReg(0xa6, 0xdf);
WriteReg(0xa7, 0xdf);
WriteReg(0xa8, 0xf0);
WriteReg(0xa9, 0x90);
WriteReg(0xaa, 0x94);
WriteReg(0x13, 0xe5);
WriteReg(0x0e, 0x61);
WriteReg(0x0f, 0x4b);
WriteReg(0x16, 0x02);
WriteReg(0x21, 0x02);
WriteReg(0x22, 0x91);
WriteReg(0x29, 0x07);
WriteReg(0x33, 0x0b);
WriteReg(0x35, 0x0b);
WriteReg(0x37, 0x1d);
WriteReg(0x38, 0x71);
WriteReg(0x39, 0x2a);
WriteReg(0x3c, 0x78);
WriteReg(0x4d, 0x40);
WriteReg(0x4e, 0x20);
WriteReg(0x69, 0x00);
WriteReg(0x6b, 0x00);
WriteReg(0x74, 0x19);
WriteReg(0x8d, 0x4f);
WriteReg(0x8e, 0x00);
WriteReg(0x8f, 0x00);
WriteReg(0x90, 0x00);
WriteReg(0x91, 0x00);
WriteReg(0x92, 0x00);
WriteReg(0x96, 0x00);
WriteReg(0x9a, 0x80);
WriteReg(0xb0, 0x84);
WriteReg(0xb1, 0x0c);
WriteReg(0xb2, 0x0e);
WriteReg(0xb3, 0x82);
WriteReg(0xb8, 0x0a);
WriteReg(0x43, 0x14);
WriteReg(0x44, 0xf0);
WriteReg(0x45, 0x34);
WriteReg(0x46, 0x58);
WriteReg(0x47, 0x28);
WriteReg(0x48, 0x3a);
WriteReg(0x59, 0x88);
WriteReg(0x5a, 0x88);
WriteReg(0x5b, 0x44);
WriteReg(0x5c, 0x67);
WriteReg(0x5d, 0x49);
WriteReg(0x5e, 0x0e);
WriteReg(0x64, 0x04);
WriteReg(0x65, 0x20);
WriteReg(0x66, 0x05);
WriteReg(0x94, 0x04);
WriteReg(0x95, 0x08);
WriteReg(0x6c, 0x0a);
WriteReg(0x6d, 0x55);
WriteReg(0x6e, 0x11);
WriteReg(0x6f, 0x9f);
WriteReg(0x6a, 0x40);
WriteReg(0x01, 0x40);
WriteReg(0x02, 0x40);
WriteReg(0x13, 0xe7);
//WriteReg(0x15, 0x02);
WriteReg(0x4f, 0x80);
WriteReg(0x50, 0x80);
WriteReg(0x51, 0x00);
WriteReg(0x52, 0x22);
WriteReg(0x53, 0x5e);
WriteReg(0x54, 0x80);
WriteReg(0x58, 0x9e);
WriteReg(0x41, 0x08);
WriteReg(0x3f, 0x00);
WriteReg(0x75, 0x05);
WriteReg(0x76, 0xe1);
WriteReg(0x4c, 0x00);
WriteReg(0x77, 0x01);
WriteReg(0x3d, 0xc2);
WriteReg(0x4b, 0x09);
WriteReg(0xc9, 0x60);
WriteReg(0x41, 0x38);
WriteReg(0x56, 0x40);
WriteReg(0x34, 0x11);
WriteReg(0x3b, 0x02);
WriteReg(0xa4, 0x89);
WriteReg(0x96, 0x00);
WriteReg(0x97, 0x30);
WriteReg(0x98, 0x20);
WriteReg(0x99, 0x30);
WriteReg(0x9a, 0x84);
WriteReg(0x9b, 0x29);
WriteReg(0x9c, 0x03);
WriteReg(0x9d, 0x4c);
WriteReg(0x9e, 0x3f);
WriteReg(0x78, 0x04);
WriteReg(0x79, 0x01);
WriteReg(0xc8, 0xf0);
WriteReg(0x79, 0x0f);
WriteReg(0xc8, 0x00);
WriteReg(0x79, 0x10);
WriteReg(0xc8, 0x7e);
WriteReg(0x79, 0x0a);
WriteReg(0xc8, 0x80);
WriteReg(0x79, 0x0b);
WriteReg(0xc8, 0x01);
WriteReg(0x79, 0x0c);
WriteReg(0xc8, 0x0f);
WriteReg(0x79, 0x0d);
WriteReg(0xc8, 0x20);
WriteReg(0x79, 0x09);
WriteReg(0xc8, 0x80);
WriteReg(0x79, 0x02);
WriteReg(0xc8, 0xc0);
WriteReg(0x79, 0x03);
WriteReg(0xc8, 0x40);
WriteReg(0x79, 0x05);
WriteReg(0xc8, 0x30);
WriteReg(0x79, 0x26);
WriteReg(0x09, 0x03);
WriteReg(0x3b, 0x42);
WriteReg(0xff, 0xff); /* END MARKER */
}
if(n == 307200) // 640*480
{
WriteReg(REG_CLKRC, 0x01);
WriteReg(REG_TSLB, 0x04);
WriteReg(REG_COM7, 0x01);
WriteReg(DBLV, 0x4a);
WriteReg(REG_COM3, 0);
WriteReg(REG_COM14, 0);
WriteReg(REG_HSTART, 0x13);
WriteReg(REG_HSTOP, 0x01);
WriteReg(REG_HREF, 0xb6);
WriteReg(REG_VSTART, 0x02);
WriteReg(REG_VSTOP, 0x7a);
WriteReg(REG_VREF, 0x0a);
WriteReg(0x72, 0x11);
WriteReg(0x73, 0xf0);
/* Gamma curve values */
WriteReg(0x7a, 0x20);
WriteReg(0x7b, 0x10);
WriteReg(0x7c, 0x1e);
WriteReg(0x7d, 0x35);
WriteReg(0x7e, 0x5a);
WriteReg(0x7f, 0x69);
WriteReg(0x80, 0x76);
WriteReg(0x81, 0x80);
WriteReg(0x82, 0x88);
WriteReg(0x83, 0x8f);
WriteReg(0x84, 0x96);
WriteReg(0x85, 0xa3);
WriteReg(0x86, 0xaf);
WriteReg(0x87, 0xc4);
WriteReg(0x88, 0xd7);
WriteReg(0x89, 0xe8);
/* AGC and AEC parameters. Note we start by disabling those features,
then turn them only after tweaking the values. */
WriteReg(0x13, COM8_FASTAEC | COM8_AECSTEP | COM8_BFILT);
WriteReg(0x00, 0);
WriteReg(0x10, 0);
WriteReg(0x0d, 0x40);
WriteReg(0x14, 0x18);
WriteReg(0xa5, 0x05);
WriteReg(0xab, 0x07);
WriteReg(0x24, 0x95);
WriteReg(0x25, 0x33);
WriteReg(0x26, 0xe3);
WriteReg(0x9f, 0x78);
WriteReg(0xa0, 0x68);
WriteReg(0xa1, 0x03);
WriteReg(0xa6, 0xd8);
WriteReg(0xa7, 0xd8);
WriteReg(0xa8, 0xf0);
WriteReg(0xa9, 0x90);
WriteReg(0xaa, 0x94);
WriteReg(0x13, COM8_FASTAEC|COM8_AECSTEP|COM8_BFILT|COM8_AGC|COM8_AEC);
/* Almost all of these are magic "reserved" values. */
WriteReg(0x0e, 0x61);
WriteReg(0x0f, 0x4b);
WriteReg(0x16, 0x02);
WriteReg(0x1e, 0x27);
WriteReg(0x21, 0x02);
WriteReg(0x22, 0x91);
WriteReg(0x29, 0x07);
WriteReg(0x33, 0x0b);
WriteReg(0x35, 0x0b);
WriteReg(0x37, 0x1d);
WriteReg(0x38, 0x71);
WriteReg(0x39, 0x2a);
WriteReg(0x3c, 0x78);
WriteReg(0x4d, 0x40);
WriteReg(0x4e, 0x20);
WriteReg(0x69, 0);
WriteReg(0x6b, 0x0a);
WriteReg(0x74, 0x10);
WriteReg(0x8d, 0x4f);
WriteReg(0x8e, 0);
WriteReg(0x8f, 0);
WriteReg(0x90, 0);
WriteReg(0x91, 0);
WriteReg(0x96, 0);
WriteReg(0x9a, 0);
WriteReg(0xb0, 0x84);
WriteReg(0xb1, 0x0c);
WriteReg(0xb2, 0x0e);
WriteReg(0xb3, 0x82);
WriteReg(0xb8, 0x0a);
/* More reserved magic, some of which tweaks white balance */
WriteReg(0x43, 0x0a);
WriteReg(0x44, 0xf0);
WriteReg(0x45, 0x34);
WriteReg(0x46, 0x58);
WriteReg(0x47, 0x28);
WriteReg(0x48, 0x3a);
WriteReg(0x59, 0x88);
WriteReg(0x5a, 0x88);
WriteReg(0x5b, 0x44);
WriteReg(0x5c, 0x67);
WriteReg(0x5d, 0x49);
WriteReg(0x5e, 0x0e);
WriteReg(0x6c, 0x0a);
WriteReg(0x6d, 0x55);
WriteReg(0x6e, 0x11);
WriteReg(0x6f, 0x9f);
WriteReg(0x6a, 0x40);
WriteReg(0x01, 0x40);
WriteReg(0x02, 0x60);
WriteReg(0x13, COM8_FASTAEC|COM8_AECSTEP|COM8_BFILT|COM8_AGC|COM8_AEC|COM8_AWB);
/* Matrix coefficients */
WriteReg(0x4f, 0x80);
WriteReg(0x50, 0x80);
WriteReg(0x51, 0);
WriteReg(0x52, 0x22);
WriteReg(0x53, 0x5e);
WriteReg(0x54, 0x80);
WriteReg(0x58, 0x9e);
WriteReg(0x41, 0x08);
WriteReg(0x3f, 0);
WriteReg(0x75, 0x05);
WriteReg(0x76, 0xe1);
WriteReg(0x4c, 0);
WriteReg(0x77, 0x01);
WriteReg(0x3d, 0xc3);
WriteReg(0x4b, 0x09);
WriteReg(0xc9, 0x60);
WriteReg(0x41, 0x38);
WriteReg(0x56, 0x40);
WriteReg(0x34, 0x11);
WriteReg(0x3b, COM11_EXP|COM11_HZAUTO);
WriteReg(0xa4, 0x88);
WriteReg(0x96, 0);
WriteReg(0x97, 0x30);
WriteReg(0x98, 0x20);
WriteReg(0x99, 0x30);
WriteReg(0x9a, 0x84);
WriteReg(0x9b, 0x29);
WriteReg(0x9c, 0x03);
WriteReg(0x9d, 0x4c);
WriteReg(0x9e, 0x3f);
WriteReg(0x78, 0x04);
/* Extra-weird stuff. Some sort of multiplexor register */
WriteReg(0x79, 0x01);
WriteReg(0xc8, 0xf0);
WriteReg(0x79, 0x0f);
WriteReg(0xc8, 0x00);
WriteReg(0x79, 0x10);
WriteReg(0xc8, 0x7e);
WriteReg(0x79, 0x0a);
WriteReg(0xc8, 0x80);
WriteReg(0x79, 0x0b);
WriteReg(0xc8, 0x01);
WriteReg(0x79, 0x0c);
WriteReg(0xc8, 0x0f);
WriteReg(0x79, 0x0d);
WriteReg(0xc8, 0x20);
WriteReg(0x79, 0x09);
WriteReg(0xc8, 0x80);
WriteReg(0x79, 0x02);
WriteReg(0xc8, 0xc0);
WriteReg(0x79, 0x03);
WriteReg(0xc8, 0x40);
WriteReg(0x79, 0x05);
WriteReg(0xc8, 0x30);
WriteReg(0x79, 0x26);
WriteReg(0xff, 0xff); /* END MARKER */
}
return 1;
}
// write to camera
void OV7670::WriteReg(int addr,int data)
{
_i2c.start();
_i2c.write(OV7670_WRITE);
wait_us(OV7670_WRITEWAIT);
_i2c.write(addr);
wait_us(OV7670_WRITEWAIT);
_i2c.write(data);
_i2c.stop();
}
// read from camera
int OV7670::ReadReg(int addr)
{
int data;
_i2c.start();
_i2c.write(OV7670_WRITE);
wait_us(OV7670_WRITEWAIT);
_i2c.write(addr);
_i2c.stop();
wait_us(OV7670_WRITEWAIT);
_i2c.start();
_i2c.write(OV7670_READ);
wait_us(OV7670_WRITEWAIT);
data = _i2c.read(OV7670_NOACK);
_i2c.stop();
return data;
}