OV7640 datasheet(3/18 Pages) OMNIVISION

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Functional Description

Version 1.3, January 15, 2003

Proprietary to OmniVision Technologies

Omni ision

Image Sensor Array

The OV7640/OV7140 CAMERACHIPS has an active image

array size of 640 columns x 480 rows (307,200 pixels).

However, the full array contains 652 columns and 486

rows, with the extra 6 rows used for black-level calibration

(“Optical Black”) and color interpolation information.

Figure 3 shows a cross-section of the image sensor array.

Figure 3 Image Sensor Array

Timing Generator

In general, the timing generator controls these functions:

•

Array control and frame generation (VGA and QVGA

outputs)

•

Internal timing signal generation and distribution

•

Frame rate timing

•

Automatic Exposure Control (AEC)

•

External timing outputs (VSYNC, HREF and PCLK)

Analog Processing Block

This block performs all analog image functions including:

•

Automatic Gain Control (AGC)

•

Automatic White Balance (AWB)

•

Image quality controls including:

– Color saturation

–Hue

–Gamma

– Sharpness (edge enhancement)

– Anti-blooming

– Zero smearing

Color Filter

Microlens

Photo Diode

A/D Converters

After the Analog Processing Block, the color channel data

signal is fed to two 8-bit Analog-to-Digital (A/D) converters

via the multiplexers, one for the Y/G channel and one

shared by the CrCb/BR channels. These A/D converters

operate

speeds

12MHz,

and

are

fully

synchronous to the pixel rate (actual conversion rate is

related to the frame rate).

In addition to the A/D conversion, this block also has the

following functions:

•

Digital Black-Level Calibration (BLC)

•

Optional U/V channel delay

•

Additional A/D range controls

In general, the combination of the A/D Range Multiplier

and A/D Range Control sets the A/D range and maximum

value to allow the user to adjust the final image brightness

as a function of the individual application.

Output Formatter

This block controls all output and data formatting required

prior to sending the image out.

Digital Video Port

These two bits increase IOL / IOH drive current and can be

adjusted as a function of the customer’s loading:

SCCB Interface

The Serial Camera Control Bus (SCCB) interface controls

the CAMERACHIP operation.

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