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Proprietary to OmniVision Technologies
Version 1.1, December 7, 2004
OV9650 Color CMOS SXGA (1.3 MegaPixel) CameraChip™
O
mni
ision
4.1.2 Automatic Gain Control (AGC)
The AGC function allows the C
AMERA
C
HIP
to adjust image luminance and target level gain without
external command or control. Register setting
[2] (0x13) enables AGC. The target level
control registers are
(0x24) and
(0x25). Refer to
for additional details
regarding the target level controls. When operating in fast AEC/AGC mode, use register
[7:0] (0x26) to set the conditions for fast AGC.
shows the general controls for the
AGC.
The analog pixel data first arrives at the AGC amplifier which can be automatically controlled by the
AGC circuit or manually programmed by the user (see
). In both cases, the gain control is
active but when AGC is disabled, the gain setting is generated by the user and not updated by the
AGC circuit.
Table 4-2.
AGC General Controls
Function
Register
Address
AGC Enable
0x13
Gain Setting
0x03
0x00
Gain Ceiling Select
000: 2x
001: 4x
010: 8x
011: 16x
100: 32x
101: 64x
110: 128x
111: 128x
0x14
Table 4-3.
AGC Enable Bit
[2] (0x13)
AGC Status
[7:6] (0x03),
[7:0] (0x00)
1
Enabled
Controlled by AGC
0
Disabled
Controlled by user