TMC22091/TMC22191
PRODUCT SPECIFICATION
2-Layer Keying with the TMC22091
Assigning Video Sources to Layers with the
TMC22191
The TMC22091 facilitates the keying of PD port input data
over the CVBS bus input data. Keying is controlled on a
pixel-by-pixel basis by either the KEY input pin or the inter-
nal Data Key. The first two layers in the previous 4-Layer
Example apply to the TMC22091. The result of keying is an
effect where a MIDGROUND source image (i.e. Happy Face
from PD data) is superimposed over a BACKGROUND
source image (i.e. variable matte color from CVBS data).
Digital video inputs to the TMC22191 (PD, CVBS, Overlay)
are assigned to the four layers by choosing one of the 16
modes of the Layering Control Register. OVERLAY is
always keyed (switched on a pixel-by-pixel basis from active
to transparent) by the OL inputs. OVERLAY can not be
4-0
programmed to the BACKGROUND layer. The CVBS digi-
tal video bus can be assigned to any of the four layers and is
keyed by the KEY input signal or internal Data Key. In
modes 0 thru 7, the CLUTs are not bypassed and the
BYPASS input is ignored.
Table 14. Layer Assignments, Image Sources, and Keying Controls (TMC22191)
LCR 04
Background
Midground
Foreground
Downstream Key
Keying
Keying
Control
Keying
Control
LAYMODE
Image Source
Image Source
Image Source:
Image Source:
Control
0
PD(YC C , RGB, CI)
CVBS
KEY or
—
—
—
—
B
R
Data Key
1
PD(YC C , RGB, CI)
CVBS
KEY or
OVERLAY
OL
4-0
—
—
B
R
Data Key
2
3
4
PD(YC C , RGB, CI)
CVBS
CVBS
KEY
KEY
PD(YC C , RGB, CI) Data Key
OVERLAY
OVERLAY
—
OL
OL
B
R
B
R
4-0
PD(YC C , RGB, CI)
PD(YC C , RGB, CI) Data Key
B R
B
R
4-0
CVBS
OVERLAY
OL
4-0
PD(YC C , RGB, CI) KEY or
—
B
R
Data Key
5
CVBS
PD(YC C , RGB, CI) KEY or
OVERLAY
OL
—
—
B
R
4-0
Data Key
6
7
8
PD(YC C , RGB, CI)
CVBS
CVBS
CVBS
KEY
OVERLAY
OVERLAY
OL
OL
PD(YC C , RGB, CI) Data Key
B R
B
R
4-0
PD(YC C , RGB, CI)
KEY
PD(YC C , RGB, CI) Data Key
B
R
4-0
B
R
PD(YC C , CI)
KEY or
—
—
—
B
R
Data Key
9
A
B
C
PD(RGB)
PD(RGB)
PD(RGB)
PD(RGB)
PD(YC C , CI)
BYPASS
CVBS
KEY or
Data Key
OVERLAY
OVERLAY
OL
B
R
4-0
4-0
CVBS
CVBS
KEY or
Data Key
PD(YC C , CI)
BYPASS
OL
B
R
KEY or
Data Key
OVERLAY
OVERLAY
OL
OL
PD(YC C , CI)
BYPASS
4-0
B R
PD(YC C , CI)
BYPASS
CVBS
KEY or
B
R
4-0
Data Key
D
E
F
CVBS
CVBS
PD(RGB)
OVERLAY
OVERLAY
KEY
PD(YC C , CI)
BYPASS
KEY
OVERLAY
OL
4-0
B
R
OL
OL
PD(RGB)
CVBS
PD(YC C , CI)
BYPASS
BYPASS
4-0
B R
PD(RGB)
KEY or
PD(YC C , CI)
B R
4-0
Data Key
Notes:
1. For LAYMODE = 0 to 7, Pixel Data always passes through the CLUTs. FORMAT, INMODE, and the BYPASS pin selects the
input format for PD according to Table 6.
23-0
2. For LAYMODE = 8 to F and BYPASS = HIGH, Data Key is disabled.
3. Asserting the signal listed under "Keying Control:" enables the corresponding "Signal Source:". Signals with " " are asserted
by a logic LOW.
42
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