Analog Devices ADV8005, Hardware Reference Manual

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UG-707 ADV8005 Hardware Reference Manual
Figure 47: HDMI Tx CSC
The video inputs In_A, In_B and In_C are connected by default to R, G and B. Refer to Table 17 for more information. The default routing
cannot be changed for the HDMI Tx CSCs.
Table 17: Default HDMI Tx Channel CSC Signal Routing
Input Channel Default RGB Routing Default YCbCr Routing
In_A R Cr
In_B G Y
In_C B Cb
The A1 to A3, B1 to B3, and C1 to C3 coefficients are used to scale the primary inputs. A4, B4 and C4 are added as offsets. Floating point
coefficients must be converted into 120-bit fixed decimal format then converted into binary format using twos complement for negative values
and can only be programmed in the range [-1….+1] or [-4096….+4095].
The dynamic range of the CSC is [0…..1] for unipolar signals (Y, R, G, B) or [-0.5…….+0.5] for bipolar signals. Bipolar signals (Pr/Pb) must
be offset to mid-range. Equations with a dynamic range larger than 1 need to be scaled appropriately using the
csc_scaling_factor[1:0] control.
To achieve a coefficient value of 1.0 for any given coefficient, csc_scaling_factor[1:0] should be set high and the coefficient should be
programmed to a value of 0.5. Otherwise, the largest value would be 4095/4096 = 0.9997. While this value could be interpreted as 1, it is
recommended to use the value of 0.5 and set the
csc_scaling_factor[1:0] bits for maximum accuracy.
The CSC configurations for common modes are provided in
Table 18 .
4x
2x
+ ÷ +
+ x
x
x
csc_a1
csc_a2
csc_a3
csc_a4
4096
csc_scaling_factor
0
1
2
Out_A
In_A
In_B
In_C
Rev. A | Page 96 of 317