DDP3310B Datasheet, PDF (12/60 Pages) Micronas – Display and Deflection Processor

DDP 3310B
ADVANCE INFORMATION
2.2. Analog Back-End
The digital RGB signals are converted to analog RGB
using three video digital to analog converters (DAC)
with 10-bit resolution. The analog RGB-outputs are
current outputs with current-sink characteristics. The
maximum current drawn by the output stage is
obtained with peak white RGB.
Each RGB signal has two additional DAC’s with 9-bit
resolution to adjust analog brightness (40 % of the full
RGB range) and cutoff / black level (60 % of the full
RGB range). An additional fixed current is applied for
the blanking level.
In order to define accurate color on different CRT dis-
plays, you must exactly adjust what color the CRT
phosphorous produces to display the color on screen.
To have the same colors for the life of the display, a
build-in automatic tube control loop checks and adjusts
the black level on every field and white point every third
field.
The back-end allows insertion of two external analog
RGB signals. The RGB signals are key-clamped and
inserted into the main RGB by the Fast-Blank switch.
The external RGB signals can be adjusted indepen-
dently as regarding DC-level (brightness) and magni-
tude (contrast). An external Half-Contrast signal can
be used to reduce the output current of the internal
RGB outputs to 50 %.
The controlling of the white-drive/analog brightness
and also the external contrast and brightness adjust-
ments is done via the internal processor.
2.2.1. Analog RGB Insertion
The DDP 3310B allows insertion of two external ana-
log RGB signals. Each RGB signal is key-clamped and
inserted into the main RGB by the Fast-Blank switch.
The selected external RGB input can be overlaid or
underlaid to the digital picture. The external RGB sig-
nals can be adjusted independently as regards DC
level (brightness) and magnitude (contrast).
It depends on the Fast-Blank input signals and the pro-
gramming of a number of I²C-register settings which
analog RGB input is selected. Both Fast-Blank inputs
must be either active-Low or active-High.
All signals for analog RGB insertion (RIN1/2, GIN1/2,
BIN1/2, FBLIN1/2, HCS) must be synchronized to the
horizontal flyback, otherwise a horizontal jitter will be
visible. The DDP 3310B has no means for timing cor-
rection of the analog RGB input signals.
Table 2–4: RGB Input Selection
Input Signals
I²C Settings
Analog
RGB Outputs
FBLIN1 FBLIN2 FBPOL FBPRIO
0
0
0
x
Video
0
1
0
x
RGB input 2
1
0
0
x
RGB input 1
1
1
0
0
RGB input 1
1
1
0
1
RGB input 2
0
0
1
0
RGB input 1
0
0
1
1
RGB input 2
0
1
1
x
RGB input 1
1
0
1
x
RGB input 2
1
1
1
x
Video
Note: with following I²C settings
FBFOH1 = FBFOH2 = FBFOL1 = FBFOL2 = 0
2.2.2. Half-Contrast Control
Insertion of transparent text pages or OSD onto the
video picture is often difficult to read, especially if the
video contrast is high. The DDP 3310B allows contrast
reduction of the video background by means of a Half-
Contrast input (HCS pin). This input can be supplied
with a fast switching signal (similar to the Fast-Blank
input), typically defining a rectangular box in which the
video picture is displayed with reduced contrast. The
analog RGB inputs are still displayed with full contrast.
HCSPOL
HCS
#
HCS intern
HCSEN HCSFOH
Fig. 2–8: Half-Contrast switch logic
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Micronas