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ADV7190/ADV7191
–39–
REV. 0
HUE ADJUST CONTROL REGISTER (HCR)
(Address (SR5–SR0) = 20H)
T
he hue control register is an 8-bit-wide register used to adjust
the hue on the composite and chroma outputs. Figure 74 shows
the operation under control of this register.
HCR7
–
HCR0
HUE ADJUST VALUE
HCR7
HCR6
HCR5
HCR4
HCR3
HCR2
HCR1
HCR0
Figure 74. 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 ADV7190/ADV7191 provides a range of
±
22.5
°
increments of 0.17578125
°
. For normal operation (zero adjust-
ment) this register is set to 80Hex. FFHex and 00Hex represent
the upper and lower limit (respectively) of adjustment attainable.
H
ue Adjust
[
°
] = 0.17578125
°
×
(H
CR
d
–
128); for positive Hue
Adjust Value
Example:
To adjust the hue by 4
°
write 97
h
to the Hue Adjust Control
Register:
(4/0.17578125) + 128 = 151
d
*
= 97
h
To adjust the hue by (
–
4
°
) write 69
h
to the Hue Adjust Control
Register:
(
–
4/0.17578125) + 128 = 10d
d
* =
69
h
*
R
ounded to the nearest integer.
BRIGHTNESS CONTROL REGISTERS (BCR)
(Address (SR5–SR0) = 21H)
The brightness register is an 8-bit-wide register which allows
brightness control. Figure 75 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 level 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 IV. Brightness Control Register Value
S
etup
Level in
NTSC with
Pedestal
Setup
Level in
NTSC No
Pedestal
Brightness
Control
Register
Value
Setup
Level in
PAL
22.5 IRE
15 IRE
7.5 IRE
0 IRE
15 IRE
7.5 IRE
0 IRE
–
7.5 IRE
15 IRE
7.5 IRE
0 IRE
–
7.5 IRE
1E
h
0F
h
00
h
71
h
NOTE
Values in the range from 3F
h
to 44
h
might result in an invalid output signal.
EXAMPLE
1. Standard: NTSC with Pedestal. To add +20 IRE brightness level, write 28
h
into the Brightness Control Register:
[
Brightness Control Register Value
]
h
= [
IRE Value
2.015631]
h
= [20
×
2.015631]
h
= [40.31262]
h
= 28
h
2. Standard: PAL. To add
–
7 IRE brightness level write 72
h
into the Brightness Control Register:
[|
IRE Value
|
×
2.015631]
= [7
×
2.015631]
= [14.109417] = 0001110
b
[0001110]
into two’s complement
= 1110010
b
= 72
h
BCR6
–
BCR0
BRIGHTNESS VALUE
BCR7
ZERO MUST BE
WRITTEN TO
THIS BIT
BCR7
BCR6
BCR5
BCR4
BCR3
BCR2
BCR1
BCR0
100 IRE
0 IRE
+7.5 IRE
–
7.5 IRE
NTSC WITHOUT PEDESTAL
NO SETUP VALUE
ADDED
POSITIVE SETUP
VALUE ADDED
WRITE TO BRIGHTNESS
CONTROL REGISTER: 12
h
NEGATIVE SETUP
VALUE ADDED
WRITE TO BRIGHTNESS
CONTROL REGISTER: 6E
h
Figure 75. Brightness Control Register