adv7390 Analog Devices, Inc., adv7390 Datasheet - Page 51

• Manufacturer Part Number: adv7390
• Description: Low Power, Chip Scale 10-bit Sd/hd Video Encoder
• Manufacturer: Analog Devices, Inc.

If RGB output is selected, the ED/HD CSC matrix scalar uses
the following equations:
Note that subtractions are implemented in hardware.
If YPrPb output is selected, the following equations are used:
where:
GY = Subaddress 0x05, Bits[7:0] and Subaddress 0x03, Bits[1:0].
GU = Subaddress 0x06, Bits[7:0] and Subaddress 0x04, Bits[7:6].
GV = Subaddress 0x07, Bits[7:0] and Subaddress 0x04, Bits[5:4].
BU = Subaddress 0x08, Bits[7:0] and Subaddress 0x04, Bits[3:2].
RV = Subaddress 0x09, Bits[7:0] and Subaddress 0x04, Bits[1:0].
Upon power-up, the CSC matrix is programmed with the
default values shown in Table 43.
Table 43. ED/HD Manual CSC Matrix Default Values
Subaddress
0x03
0x04
0x05
0x06
0x07
0x08
0x09
When the ED/HD manual CSC matrix adjust feature is
enabled, the default coefficient values in Subaddress 0x03
to Subaddress 0x09 are correct for the HD color space only.
The color components are converted according to the following
1080i and 720p standards (SMPTE 274M, SMPTE 296M):
The conversion coefficients should be multiplied by 315 before
being written to the ED/HD CSC matrix registers. This is
reflected in the default values for GY = 0x13B, GU = 0x03B,
GV = 0x093, BU = 0x248, and RV = 0x1F0.
If the ED/HD manual CSC matrix adjust feature is enabled and
another input standard (such as ED) is used, the scale values for
GY, GU, GV, BU, and RV must be adjusted according to this
input standard color space. The user should consider that the
color component conversion might use different scale values.
R = GY × Y + RV × Pr
G = GY × Y − (GU × Pb) − (GV × Pr)
B = GY × Y + BU × Pb
Y = GY × Y
Pr = RV × Pr
Pb = BU × Pb
R = Y + 1.575Pr
G = Y − 0.468Pr − 0.187Pb
B = Y + 1.855Pb
Default
0x03
0xF0
0x4E
0x0E
0x24
0x92
0x7C
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For example, SMPTE 293M uses the following conversion:
The programmable CSC matrix is used for external ED/HD
pixel data and is not functional when internal test patterns are
enabled.
Programming the CSC Matrix
If custom manipulation of the ED/HD CSC matrix coefficients
is required for a YCrCb-to-RGB color space conversion, follow
the following procedure:
1.
2.
3.
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.
SD LUMA AND COLOR CONTROL
Subaddress 0x9C to Subaddress 0x9F
SD Y Scale, SD Cb Scale, and SD Cr Scale are three 10-bit
control registers that scale the SD Y, Cb, and Cr output levels.
Each of these registers represent the value required to scale the
Cb or Cr level from 0.0 to 2.0 and the Y level from 0.0 to 1.5
times its initial level. The value of these 10 bits is calculated
using the following equation:
For example, if Scale Factor = 1.3
Subaddress 0x9C, SD Scale LSB Register = 0x2A
Subaddress 0x9D, SD Y Scale Register = 0xA6
Subaddress 0x9E, SD Cb Scale Register = 0xA6
Subaddress 0x9F, SD Cr Scale Register = 0xA6
Note that this feature affects all interlaced output signals, that is,
CVBS, Y-C, YPrPb, and RGB.
ADV7390/ADV7391/ADV7392/ADV7393
R = Y + 1.402Pr
G = Y − 0.714Pr − 0.344Pb
B = Y + 1.773Pb
Enable the ED/HD manual CSC matrix adjust feature
(Subaddress 0x02, Bit 3).
Set the output to RGB (Subaddress 0x02, Bit 5).
Disable sync on PrPb (Subaddress 0x35, Bit 2).
Enable sync on RGB (optional) (Subaddress 0x02, Bit 4).
Y, Cb, or Cr Scale Value = Scale Factor × 512
Y, Cb, or Cr Scale Value = 1.3 × 512 = 665.6
Y, Cb, or Cr Scale Value = 666 (rounded to the nearest integer)
Y, Cb, or Cr Scale Value = 1010 0110 10b