ADV7194KST(Rev0) View Datasheet(PDF) - Analog Devices
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ADV7194KST Datasheet PDF : 69 Pages
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ADV7194
HUE ADJUST CONTROL REGISTER (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 80 shows
the operation under control of this register.
HCR7 HCR6 HCR5 HCR4 HCR3 HCR2 HCR1 HCR0
HCR7 – HCR0
HUE ADJUST VALUE
Figure 80. Hue Adjust Control Register
HCR BIT DESCRIPTION
Hue Adjust Value (HCR0–HCR7)
These eight bits represent the value required to vary the hue of
the video data, i.e., the variance in phase of the subcarrier during
active video with respect to the phase of the subcarrier during
the colorburst. The ADV7194 provides a range of ±22.5° incre-
ments of 0.17578125°. For normal operation (zero adjustment)
this register is set to 80Hex. FFHex and 00Hex represent the
upper and lower limit (respectively) of adjustment attainable.
Hue Adjust [°] = 0.17578125° × (HCRd – 128); for positive Hue
Adjust Value
Example:
To adjust the hue by +4° write 97h to the Hue Adjust Control
Register:
(4/0.17578125) + 128 = 151d* = 97h
To adjust the hue by (–4°) write 69h to the Hue Adjust Control
Register:
(–4/0.17578125) + 128 = 105d* = 69h
*Rounded to the nearest integer.
BRIGHTNESS CONTROL REGISTERS (BCR)
(Address (SR5–SR0) = 21H)
The brightness control register is an 8-bit-wide register which
allows brightness control. Figure 81 shows the operation under
control of this register.
BCR BIT DESCRIPTION
Brightness Value (BCR0–BCR6)
Seven bits of this 8-bit-wide register are used to control the
brightness level. The brightness is controlled by adding a pro-
grammable setup level onto the scaled Y data. This brightness
level can be a positive or negative value.
The programmable brightness levels in NTSC without pedestal
and PAL are max 15 IRE and min –7.5 IRE, in NTSC with
pedestal max 22.5 IRE and min 0 IRE.
Table VI. Brightness Control Register Value
Setup
Level in
NTSC with
Pedestal
Setup
Level in
NTSC No
Pedestal
Setup
Level in
PAL
Brightness
Control
Register
Value
22.5 IRE
15 IRE
7.5 IRE
0 IRE
15 IRE
7.5 IRE
0 IRE
–7.5 IRE
15 IRE
1Eh
7.5 IRE
0Fh
0 IRE
00h
–7.5 IRE
71h
NOTE
Values in the range from 3Fh to 44h might result in an invalid output signal.
EXAMPLE
1. Standard: NTSC with Pedestal. To add +20 IRE brightness level, write 28H into the Brightness Control Register:
[Brightness Control Register Value]h = [IRE Value ϫ 2.015631]h = [20 × 2.015631]h = [40.31262]h = 28h
2. Standard: PAL. To add –7 IRE brightness level write 72h into the Brightness Control Register:
[|IRE Value| × 2.015631] = [7 × 2.015631] = [14.109417] = 0001110b
[0001110] into two’s complement = 1110010b = 72h
NTSC WITHOUT PEDESTAL
100 IRE
+7.5 IRE
0 IRE
NO SETUP VALUE
ADDED
POSITIVE SETUP
VALUE ADDED
WRITE TO BRIGHTNESS
CONTROL REGISTER: 12h
NEGATIVE SETUP
VALUE ADDED
WRITE TO BRIGHTNESS
CONTROL REGISTER: 6Eh
BCR7 BCR6 BCR5 BCR4 BCR3 BCR2 BCR1 BCR0
BCR7
ZERO MUST BE
WRITTEN TO
THIS BIT
BCR6 – BCR0
BRIGHTNESS VALUE
–7.5 IRE
Figure 81. Brightness Control Register
–40–
REV. 0
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