ADV8005 Hardware Reference Manual
UG-707
For example, SMPTE 293M uses the following conversion:
R
=
Y
+ 1.402
Pr
G
=
Y
– 0.714
Pr
– 0.344
Pb
B
=
Y
+ 1.773
Pb
The programmable CSC matrix is used for external ED/HD pixel data and is not functional when internal test patterns are enabled.
7.4.10.1.
Programming the CSC Matrix
If the user needs to manually provide the coefficients for the CSC matrix for ED/HD, this procedure is followed:
1.
Enable the ED/HD manual CSC matrix adjust feature (
2.
Set the output to RGB (
3.
Disable sync on YPrPb (Reg 0xE435, Bit 2).
4.
Enable sync on RGB (optional) (Reg 0xE402, Bit 4).
The gy value controls the green signal output level, the bu value controls the blue signal output level, and the rv value controls the red signal
output level.
7.4.11.
SD Luma and Color Scale Control
When enabled, the SD luma and color scale control feature can be used to scale the SD Y, Cb, and Cr output levels. This feature can be enabled
using
. This feature affects all SD output signals, regardless of the encoder output, that is, CVBS, Y-C, YPrPb, and RGB.
scale_ycbcr_en
, Encoder Map,
Address 0xE487[0]
This bit is used to enable the SD luma and colour scale control feature.
Function
scale_ycbcr_en
Description
1
Enabled
0 (default)
Disabled
When enabled, three 10-bit registers (SD Y scale, SD Cb scale, and SD Cr scale) control the scaling of the SD Y, Cb, and Cr output levels. The
SD Y scale register contains the scaling factor used to scale the Y level from 0.0 to 1.5 times its initial level. The SD Cb scale and SD Cr scale
registers contain the scaling factors used to scale the Cb and Cr levels from 0.0 to 2.0 times their initial levels, respectively.
The registers needed to scale the outputs are
contrast[7:0]
, IO Map,
Address 0x1A2B[7:0]
This register is used to adjust the contrast value for Y channel. This register uses 1.7 notation.
Function
contrast[7:0]
Description
0x00
Gain of 0
0x80
Unity gain
0xFF
Gain of 2
cb_scale[9:0]
, Encoder Map,
Address 0xE49E[7:0]; Address 0xE49C[3:2]
This signal is used to set the SD Cb scale value.
cr_scale[9:0]
, Encoder Map,
Address 0xE49F[7:0]; Address 0xE49C[5:4]
This signal is used to set the SD Cr scale value.
To use this function, the values to be written to these 10-bit registers are calculated using the following equation:
Y, Cb, or Cr Scale Value = Scale Factor × 512
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