Datasheet

Table Of Contents
4 Proprietary to OmniVision Technologies Version 1.6, February 28, 2006
OV2640 Color CMOS UXGA (2.0 MegaPixel) OmniPixel2™ CAMERACHIP
O
mni ision
Figure 4 Windowing
Zooming and Panning Mode
The OV2640 provides zooming and panning modes. The
user can select this mode under SVGA/CIF mode timing.
The related zoom ratios will be 2:1 of UXGA for SVGA and
4:1 of UXGA for CIF. Registers ZOOMS[7:0] (0x49) and
COM19[1:0] (0x48) define the vertical line start point.
Register ARCOM2[2] (0x34) defines the horizontal start
point.
Sub-sampling Mode
The OV2640 supports two sub-sampling modes. Each
sub-sampling mode has different resolution and maximum
frame rate. These modes are described in the following
sections.
SVGA mode
The OV2640 can be programmed to output 800 x 600
(SVGA) sized images for applications where higher
resolution image capture is not required. In this mode,
both horizontal and vertical pixels will be sub-sampled
with an aspect ratio of 4:2 as shown in Figure 5.
Figure 5 SVGA Sub-Sampling Mode
Column
End
Sensor Array
Boundary
HREF
HREF
Column
Display
Window
Column
Start
R
ow Start
Row End
R
o
w
n
n+1
n+2
n+3
n+4
n+5
n+6
n+7
i
i+1
i+2
i+3
i+4
i+5
i+6
i+7
i+8
i+9
Column
R
ow
Skipped Pixels
BBB
BBB
GGG
GGGRRR
RRR
GGG
GGG
CIF Mode
The OV2640 can also operate at a higher frame rate to
output 400 x 296 sized images. Figure 6 shows the
sub-sampling diagram in both horizontal and vertical
directions for CIF mode.
Figure 6 CIF Sub-Sampling Mode
Timing Generator and Control Logic
In general, the timing generator controls the following:
Frame Exposure Mode Timing
Frame Rate Adjust
Frame Rate Timing
Frame Exposure Mode Timing
The OV2640 supports frame exposure mode. Typically,
the frame exposure mode must work with the aid of an
external shutter.
The frame exposure pin, FREX (pin B2), is the frame
exposure mode enable pin and the EXPST_B pin (pin A2)
serves as the sensor's exposure start trigger. When the
external master device asserts the FREX pin high, the
sensor array is quickly pre-charged and stays in reset
mode until the EXPST_B pin goes low (sensor exposure
time can be defined as the period between EXPST_B low
and shutter close). After the FREX pin is pulled low, the
video data stream is then clocked to the output port in a
line-by-line manner. After completing one frame of data
n
n+1
n+2
n+3
n+4
n+5
n+6
n+7
n+8
n+9
n+10
n+11
n+12
n+13
n+14
n+15
n+16
n+17
n+18
n+19
n+20
n+21
n+22
n+23
i
i+10
i+9
i+1
i+2
i+3
i+4
i+5
i+6
i+7
i+8
i+11
i+21
i+20
i+12
i+13
i+14
i+15
i+16
i+17
i+18
i+19
i+22
i+23
Column
R
ow
Skipped Pixels
B
B B
G G G
R R R
R R R
R R R
B B B
B B B
G G G
G G G
G G G
G G G
G G G