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VGA Camera extension OV7670
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Extension module with ov7670 CMOS camera

Small camera module from the old smartphone world.

Some links:

 

  • Résolution of 640 x 480, CIF, down until CIF 40x30, 30 f/s
  • Output Formats:
    • YUV/YCbCr 4:2:2
    • RGB 565/555/444
    • GRB 4:2:2
    • Raw RGB Data
    • SCCB bus interface for command, i2c equivalent.
  • Progressive scan mode
  • i2c Addresse: Write: 0100 0010, Read: 0100 0011
  • Automatic function as:
    • AEC: Automatic Exposure Control
    • AGC: Automatic Gain Control
    • AWB: Automatic Width Balance
    • ABF: Automatic Band Filter
    • ABLC: Automatic Black-Level Calibration
  • Image quality control:
    • Color saturation
    • hue
    • gamma
    • sharpness (edge enhancement)
    • anti-blooming
  • etc
  • ..

Note: I2C Communication won't work if no XCLK is available.

Be carefull! This module is connected with a PWDN (PoWerDowN) signal (active high) and connected to an i2c device PCA9673 to control it. By default the ligne is @'1' with a strong pull up.

2 solutions: Programme the PCA9673 by i2c and provide a '0' on Port1, bit 7. Or with an iron short circuit pin 20 (Cam_PWDN) to pin 21 (Gnd) of U18, the PCA9673 (not the best way but the fastest if you have a good iron and good eyes ! 

 

Note: Initially red appears as green and green appears as pink:

https://github.com/flufy3d/ov7670_fr/blob/master/ov7670_registers.vhd

Figure from OmniVision Reference description

XClk: 10..48 MHz, 24 MHz

SIO_C: < 400 kHz

The data Bus can be programmed to be in tri-state if PWDN = '1' (Default)

Different formats for data Output D[7..0], depend on specific registers configuration by i2c registers acces

Color Formats
  Byte 0 Byte 1 Byte 2 Byte 3
Format D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
RGB 565 R4 R3 R2 R1 R0 G5 G4 G3 G2 G1 G0 B4 B3 B2 B1 B0 R4 R3 R2 R1 R0 G5 G4 G3 G2 G1 G0 B4 B3 B2 B1 B0
RGB 555 X  R4 R3 R2 R1 R0 G4 G3 G2 G1 G0 B4 B3 B2 B1 B0 0 R4 R3 R2 R1 R0 G4 G3 G2 G1 G0 B4 B3 B2 B1 B0
RGB 444 xRGB X  X  X  X  R3 R2 R1 R0 G3 G2 G1 G0 B3 B2 B1 B0 X  X  X  X  R3 R2 R1 R0 G3 G2 G1 G0 B3 B2 B1 B0
RGB 444 RGBx R3 R2 R1 R0 G3 G2 G1 G0 B3 B2 B1 B0  X  X  X  X R3 R2 R1 R0 G3 G2 G1 G0 B3 B2 B1 B0  X  X  X  X
YUV

Y U Y V

Y V Y U

U Y V Y

V Y U Y

     
RGB        
Bayer RAW        
Processed Bayer Raw        
         
         

 

Data on a Line

Data on a Frame

 

 

 

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