- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
85
Table 10.2-2 Digital clamp parameter
Parameter
Address
Description
OBLKS1
CAT22_Byte6_bit0-3 (MSB)
CAT22_Byte4_bit0-7 (LSB)
S1 series OB area integrated value (output-only parameter).
BLACKS1 is calculated by the internal firmware.
OBLKS2
CAT22_Byte6_bit4-7 (MSB)
CAT22_Byte5_bit0-7 (LSB)
S2 series OB area integrated value (output-only parameter).
BLACKS2 is calculated by the internal firmware.
BLACKS1 CAT2_Byte55_bit0-7
Black level of S1 series (control subject of firmware).
Used to remove S1 series offset level.
BLACKS2 CAT2_Byte56_bit0-7
Black level of S2 series (control subject of firmware).
Used to remove S2 series offset level.
Remarks
If CLMPHOLD (CAT12_Byte5_bit3) is 1, then the processing of overwriting BLACKS1 and BLACKS2 is
stopped. Do not set BLACKS1 and BLACKS2 to port driver input control.
<Reference Information>
In the digital clamping process, the S1 series and S2 series are separately integrated to determine the
accurate black levels (BLACKS1 and BLACKS2) for each system based on the CCD pixel array.
Fig 10.2-4 (Reference) CCD pixel array and S1/S2 series
If this signal process is not performed properly, the black level will be off, resulting in significant errors in
subsequent Y signal processing, chroma signal processing, AE/AWB control, etc. Even if an external
microcomputer is used to externally control AE or AWB, the CXD3172AR’s internal firmware should be used
for the digital clamping process.
Cy
Ye
G
Mg
Cy
Ye
Mg
G
Cy
Ye
G
Mg
Cy
Ye
Mg
G
Cy
Ye
G
Mg
Cy
Ye
Mg
G
OB OB
OB OB
OB OB
OB OB
S1 S2 S1 S2 S1 S2 S1 S2