ADV7172 Datasheet, PDF (39/59 Pages) Analog Devices – Digital PAL/NTSC Video Encoder with Six DACs 10 Bits, Color Control and Enhanced Power Management

ADV7172/ADV7173
COLOR CONTROL REGISTERS 2–1 (CC2–CC1)
(Address (SR4–SR0) = 1EH–1FH)
The color control registers are 8-bit-wide registers used to scale
the U and V output levels. Figure 64 shows the operations un-
der control of these registers.
CC1 BIT DESCRIPTION
Reserved (CC17–CC16)
A Logic “0” must be written to these bits.
U Scalar Value (CC15–CC10)
These six bits represent the value required to scale the U level
from 0.75 to 1.25 of its initial level. The value of these six bits is
calculated using the following equation:
Color Control Register 1 = (X – 0.75) × 128
where X = Scaling factor for U
e.g., Scale U by 0.8
Color Control Register 1 = (0.8 – 0.75) × 128 = 6.4 = 000110
(rounded to the nearest integer)
CC2 BIT DESCRIPTION
Reserved (CC27–CC26)
A Logic “0” must be written to these bits.
V Scalar Value (CC25–CC20)
These six bits represent the value required to scale the V pixel
data from 0.75 to 1.25 of its initial level. The value of these six
bits is calculated using the following equation:
Color Control Register 2 = (X – 0.75) × 128
where X = Scaling factor for V
e.g., Scale V by 1.2
Color Control Register 2 = (1.2 – 0.75) × 128 = 57.6 = 111001
(rounded to the nearest integer)
HUE CONTROL REGISTERS (HCR)
(Address (SR5–SR0) = 20H)
The hue control register is an 8-bit-wide register used to adjust
the hue on the composite and chroma outputs. Figure 65 shows
the operation under control of this register.
HCR BIT DESCRIPTION
Hue Control Value (HCR7–HCR0)
These eight bits represent the value required to vary the hue of
the video data, i.e., the variance in phase of the subcarrier with
respect to the phase of the subcarrier during the color burst.
The ADV7172/ADV7173 provides a range of ±22° in incre-
ments of 0.17578125°. For normal operation (zero adjustment)
this register is set to 80 Hex. FFHex and 00Hex represent the
upper and lower limit (respectively) of adjustment attainable.
Hue Adjust = (0.17568125 × [HCR7 – HCR0 – 128]).
CC17
CC16
CC15
CC14
CC13
CC12
CC11
CC10
CC17 CC16
ZERO SHOULD
BE WRITTEN
TO THESE BITS
CC15–CC10
U SCALAR VALUE
CC27
CC26
CC25
CC24
CC23
CC22
CC21
CC20
CC27 CC26
ZERO SHOULD
BE WRITTEN
TO THESE BITS
CC25–CC20
V SCALAR VALUE
Figure 64. Color Control Registers
HCR7
HCR6
HCR5
HCR4
HCR3
HCR2
HCR1
HCR0
HCR7–HCR0
HUE ADJUST VALUE
Figure 65. Hue Control Register
REV. A
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