Csc In Pass-Through Mode; Color Controls - Analog Devices ADV7850 Hardware Manual

Check the value of each coefficient:
The maximum value for each coefficient on its own can only be within the range of -4095/4096 to 4095/4096, which equals
[-0.999755859375 .. 0.999755859375]. Values outside this range do not fit into the 12-bit fixed point format used to program the
coefficients.
If the value of one or more coefficients after scaling of the overall equation exceeds the supported coefficient range,
be set.
With csc_scale[1:0] set high, all coefficients must be scaled by half, which makes them fit into the given coefficient range. The overall
outputs of the CSC are gained up by a fixed value of two, thus compensating for the scaled down coefficients.
In the above example:
Each coefficient on its own is within the range of
Therefore, all coefficients can be programmed directly and
Notes:
•
To achieve a coefficient value of 1.0 for any given coefficient, csc_scale should be set high and the coefficient should actually be
programmed to a value of 0.5. Otherwise, the largest value would be 4095/4096 = 0.9997, which is not exactly 1. While this value
could be interpreted as a 1, it is recommended to use the value of 0.5 and csc_scale for maximum accuracy.
• For very large coefficient values, for example, 2.58, a combination of
• Set csc_scale high (2.58/2 = 1.29) and scale the overall equation by slightly more than 1.28 (coefficient falls within the supported
range of [-0.999 ... +0.999]).

CSC in Pass-through Mode

8.3.5
It is possible to configure the CP CSC in a pass-through mode. In this mode, the CP CSC is used but does not alter the data it processes.
The CP CSC pass-through mode is obtained using the following settings:
•
Set man_cp_csc_en
•
Set csc_coeff_sel[3:0]
•
Leave the following registers from the CP Map at the default:
CSC_SCALE = 1 (default value)

A4 = A3 = A2 = 0x000 (default value)

B4 = B3 = B1 = 0x000 (default value)

C4 = C2 = C1 = 0x000 (default value)

A1 = B2 = C3 = 0x800 (default value)

Note: The DPP CSC is always in pass-through mode unless the ADV7850 is processing an RGB input, outputting this input in the RGB
color space and vid_adj_en

8.4 COLOR CONTROLS

The ADV7850 has a color control feature that can adjust the brightness, contrast, saturation, and hue properties.
vid_adj_en, Addr 44 (CP), Address 0x3E[7]
This control is used to enable video adjustment. It is used to select whether or not the color controls feature is enabled. The color
controls feature is configured via the parameters cp_contrast[7:0], cp_saturation[7:0], cp_brightness[7:0] and cp_hue[7:0]. The CP CSC
must also be enabled for the color controls to be effective.
Rev. A May 2012
−
4095
4096
to 1'b1
to 4'b0000
is enabled.
4095
.
≤ ≤
Coeff
4096
csc_scale[1:0] should be set to 0.
csc_scale[1:0]
238
csc_scale[1:0]
and equation scaling should be used.
ADV7850
should