ADV7172KST Analog Devices Inc, ADV7172KST Datasheet - Page 14

• Manufacturer Part Number: ADV7172KST
• Manufacturer: Analog Devices Inc

Specifications of ADV7172KST

• Number Of Dac's: 6
• Adc/dac Resolution: 10b
• Screening Level: Commercial
• Package Type: LQFP
• Pin Count: 48
• Lead Free Status / RoHS Status: Not Compliant

ADV7172/ADV7173
COLOR BAR GENERATION
The ADV7172/ADV7173 can be configured to generate 100/
7.5/75/7.5 color bars for NTSC or 100/0/75/0 color bars for
PAL. These are enabled by setting MR46 of Mode Register 4 to
Logic “1.”
SQUARE PIXEL MODE
The ADV7172/ADV7173 can be used to operate in square pixel
mode. For NTSC operation, an input clock of 24.5454 MHz is
required. Alternatively, for PAL operation, an input clock of
29.5 MHz is required. The internal timing logic adjusts accord-
ingly for square pixel mode operation.
COLOR SIGNAL CONTROL
The color information can be switched on and off the video
output using Bit MR44 of Mode Register 4.
BURST SIGNAL CONTROL
The burst information can be switched on and off the video
output using Bit MR45 of Mode Register 4.
NTSC PEDESTAL CONTROL
The pedestal on both odd and even fields can be controlled on a
line-by-line basis using the NTSC Pedestal Control Registers.
This allows the pedestals to be controlled during the Vertical
Blanking Interval.
COLOR CONTROLS
The ADV7172/ADV7173 allows the user the advantage of control-
ling the brightness, contrast, hue and saturation of the color.
Contrast Control
Contrast adjustment is achieved by scaling the Y input data
by a factor programmed by the user into the Contrast Control
Register Bits 5–0. This factor allows the data to be scaled
between 75% and 125%.
Brightness Control
The brightness is controlled by adding a programmable setup
level onto the scaled Y data. This brightness level may be added
–1
–2
–3
2
4
3
1
0
0
1
2
FREQUENCY – MHz
3
4
5
6
7
onto the Y data in PAL mode, NTSC mode without pedestal or
NTSC mode with pedestal, in which case it is added directly
onto the 7.5 IRE pedestal already present.
The level added is programmed by the user into the Brightness
Control Register (Bits 4–0) and the user is capable of adding
from 0 IRE to a maximum of 14 IRE in 32 (2
of different gains in the datapath for each mode, different values
may need to be programmed to obtain the same IRE setup level
in each mode. Maximum brightness is achieved when 31 is
programmed into the Brightness Control Register. Table I illus-
trates the maximum setup/brightness amplitudes available in the
various modes. Note that if a level of less than 7.5 IRE is required
on the Y data in NTSC mode, then NTSC without pedestal
must be the mode selected.
Mode
NTSC No Pedestal
NTSC Pedestal
PAL
Color Saturation Control
Color adjustment is achieved by scaling the Cr and Cb input
data by a factor programmed by the user into the Color Control
Registers 1 and 2, Bits 5–0. This factor allows the data to be
scaled between 75% and 125%.
Hue Control
The hue adjustment is achieved on the composite and chroma
outputs by adding a phase offset onto the color subcarrier in the
active video but leaving the color burst unmodified, i.e., only
the phase between the video and the color burst is modified
and hence the hue is shifted. Hue adjustment is under the con-
trol of the Hue Control Register. The ADV7172/ADV7173
provides a range of ± 22° change in increments of 0.17578125°.
Table I. Maximum Brightness Levels Available
–10
–12
–4
–6
–2
–8
4
2
0
1
2
Brightness Control
Register
00011111
00011111
00011111
FREQUENCY – MHz
3
4
5
5
) steps. Because
6
Setup
14 IRE
13 IRE
99 mV