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10
Proprietary to OmniVision Technologies
Version 1.1, December 7, 2004
OV9650 Color CMOS SXGA (1.3 MegaPixel) CameraChip™
O
mni
ision
3 Timing Generator
In general, the timing generator controls the following functions:
•
Array Control and Frame Generation
(SXGA, VGA, QVGA, QQVGA, CIF, QCIF and QQCIF outputs)
•
Internal timing signal generation and distribution
•
•
•
External timing outputs (VSYNC, HREF/HSYNC, and PCLK)
3.1 Array Control and Frame Generation
3.1.1 Frame Generation (SXGA, VGA, and lower resolutions)
SXGA frame generation uses Progressive scanning of the array in which rows are sequentially read
and transferred out to the APB. The 'Raw RGB' output preserves the Bayer Filter pattern, so odd
rows follow the pattern (BG) and even rows follow the pattern (GR). Simple sub-sampling mode just
skips every other two rows and every other two columns for VGA mode. The OV9650 has built-in
VarioPixel
TM
technology to improve sub-sampled image resolution and reduce noise level.
Down-scaling technology down-scales the output size. VGA, QVGA, QQVGA, CIF, QCIF, and
QQCIF have the same view angle which cuts 6.25% of the vertical view and keeps the same
horizontal view of SXGA.
3.2 Sync Signal Selection
The OV9650 C
AMERA
C
HIP
supplies two output sync signals: VSYNC and HREF. The vertical sync
(VSYNC) signal is output on pin D2. The horizontal reference signal (HREF) is output on pin E1.
The HSYNC signal is available on pin E1 (shares with HREF) when register
[6] (0x15) value
is set to "1".
The VSYNC and HSYNC signals are continuous. The HREF signal is only valid when there is active
output data. If there is no output data, the HREF signal will remain at either high or low, depending
on the polarity selection. The HSYNC/VSYNC/HREF/PCLK polarity selection is controlled by
register
[0,1,3,4] (0x15), respectively. Usually, an application uses the rising edge of PCLK
to capture data when HREF is high.
The OV9650 can encode horizontal and vertical sync information into data. Set register
[6] (0x04) high to enable the CCIR656 format.
Refer to the
OV9650 Datasheet
for detailed signal timing information.