Datasheet

Confidential for truly Only
11.03.2009 PRELIMINARY SPECIFICATION proprietary to OmniVision Technologies
4-7
4.5 AEC and AGC algorithms
4.5.1 overview
The Auto Exposure Control (AEC) and Auto Gain Control (AGC) allows the image sensor to adjust the image brightness
to a desired range by setting the proper exposure time and gain applied to the image. Besides automatic control,
exposure time and gain can be set manually from external control. The related registers are listed in
table 4-5
table 4-5 AEC/AGC control function registers
address register name
default
value R/W description
0x3500 EXPOSURE 0x00 RW Bit[3:0]: Exposure[19:16]
0x3501 EXPOSURE 0x00 RW Bit[7:0]: Exposure[15:8]
0x3502 EXPOSURE 0x20 RW Bit[7:0]: Exposure[7:0]
0x3503 MANUAL CTRL 0x00 RW
Bit[5:4]: Gain latch timing delay
x0: Gain has no latch delay
01: Gain delay of 1 frame
11: Gain delay of 2 frames
Bit[2]: VTS manual
0: Auto enable
1: Manual enable
Bit[1]: AGC manual
0: Auto enable
1: Manual enable
Bit[0]: AEC manual
0: Auto enable
1: Manual enable
0x350A AGC 0x00 RW
Bit[1:0]: Gain[9:8]
AGC real gain output high byte
0x350B AGC 0x00 RW
Bit[7:0]: Gain[7:0]
AGC real gain output low byte
0x350C VTS DIFF 0x06 RW
Bit[7:0]: vts_diff[15:8]
When in manual mode, set to 0x00
0x350D VTS DIFF 0x18 RW
Bit[7:0]: vts_diff[7:0]
When in manual mode, set to 0x00