Data Sheet

10.13.2009 PRODUCT SPECIFICATION proprietary to OmniVision Technologies
4-5
Since the exposure time AEC[15:0] is based on row interval, the AEC needs to know 1/100 second and 1/120 second is
equal to how many rows. Banding filter registers, BD50st and BD60st, are used to set 1/100 and 1/120 second. The
banding filter can be calculated by:
where maximum exposure equals to the number of lines per frame plus the number of dummy lines minus 2.
The OV7675/OV7175 can also disable the banding filter to allow for any exposure time value. When banding filter is
enabled, the OV7675/OV7175 also allows the exposure time to be less than 1/120 or 1/100 second under strong light
condition, by setting register 0x13[4] to 1.
table 4-4 summarizes the registers of exposure time and how to set the banding filter.
table 4-4 exposure time registers (sheet 1 of 2)
address register name description
0x04 COM1
Bit[1:0]: Exposure time, the unit is t
Row interval
AEC[15:0] = {0x07[5:0], 0x10[7:0], 0x04[1:0]}
0x10 AEC
Bit[7:0]: Exposure time, the unit is t
Row interval
AEC[15:0] = {0x07[5:0], 0x10[7:0], 0x04[1:0]}
0x07 AECHH
Bit[5:0]: Exposure time, the unit is t
Row interval
AEC[15:0] = {0x07[5:0], 0x10[7:0], 0x04[1:0]}
0x13 COM8
Bit[5]: Banding filter enable/disable
0: Disable banding filter, the exposure time can be any number
1: Enable banding filter, the exposure time must be N/100 or
N/120 second.
0x3B COM11
Bit[3]: Manual banding filter selection (effective only when
COM11[4] = 0)
0: Select the value of register 0x50 as banding filter (60Hz)
1: Select the value of register 0x4F as banding filter (50Hz)
0xE1 REGE1
Bit[1:0]: Banding filter for 50Hz[9:8]
Banding filter for 50Hz[9:0] = (0xE1[1:0],0x9D[7:0])
0x9D BD50ST
Bit[7:0]: Banding filter for 50Hz[7:0]
Banding filter for 50Hz[9:0] = (0xE1[1:0],0x9D[7:0])
0xE1 REGE1
Bit[3:2]: Banding filter for 60Hz[9:8]
Banding filter for 60Hz[9:0] = (0xE1[3:2],0x9E[7:0])
0x9E BD60ST
Bit[7:0]: Banding filter for 60Hz[7:0]
Banding filter for 60Hz[9:0] = (0xE1[3:2],0x9E[7:0])
banding filter value = for 60Hz=
120 x t
Row interval
1
120
framerate x maximum exposure
banding filter value = for 50Hz=
100 x t
Row interval
1
100
framerate x maximum exposure
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