40
Proprietary to OmniVision Technologies
Version 1.1, December 7, 2004
OV9650 Color CMOS SXGA (1.3 MegaPixel) CameraChip™
O
mni
ision
9.1 Exposure Time and Gain Calculation
To get the same luminance level, the product of exposure time and gain of the still image should be
the same as the preview image. To reduce still image noise, always set the exposure time "high"
and the gain "low". If the frame rate of the preview image is higher than that of the still image,
convert as much gain as possible to exposure time. Refer to
for the gain calculation. The
maximum exposure time AEC[15:0] = {
[15:10] (0xA1),
[9:2] (0x10),
[1:0]
(0x04)} is dependent on the resolution:
•
SXGA: 000001
00000110
00
(1048)
•
VGA:
000000
01111100
10
(498)
•
QVGA:
000000
00111110
00
(248)
•
QQVGA:
000000
00111110
00
(248)
•
CIF:
000000
01011111
10
(382)
•
QCIF:
000000
00101111
10
(190)
•
QQCIF:
000000
00101111
10
(190)
10 SCCB Interface
The
OmniVision Serial Camera Control Bus (SCCB) Functional Specification
is available at
. The Functional Specification provides complete information for using the SCCB
to control the features of an OmniVision C
AMERA
C
HIP
.
The OV9650 C
AMERA
C
HIP
uses the SCCB protocol to control the features noted in this document
via the companion backend system ASIC. The device slave addresses of the OV9650 C
AMERA
C
HIP
are: 0x60 for write (7-bit address and 1-bit write) and 0x61 for read (7-bit address and 1-bit read).
The first command in the SCCB transmission must be a register reset, as most registers will rely on
the default value setting.
10.1 Control Functions
lists the SCCB control functions.
Table 10-1. SCCB Control Functions
Function
Register
Address
Register Reset
0x12
Standby Mode Enable
0x09
Tri-state Enable – D[9:0]
[1]
0x42
