CXA2126 Sony Corporation, CXA2126 Datasheet - Page 27

• Manufacturer Part Number: CXA2126
• Description: Audio/Video Switch with Electronic Volume for 2 Scart
• Manufacturer: Sony Corporation

4. Fast Blanking Operation (Pin 16 on SCART), FBLK
The fast blanking signal instructs the TV to select either the external CVBS information or the external RGB
information. This is used to superimpose an on screen display (OSD) presentation (normally RGB) upon a
CVBS background. Fast blanking information has the same nominal phase as the RGB and CVBS signal, and
is defined as follows,
Fast blanking output at scart,
Threshold voltage is approximately 0.75V at the scart input.
Fast Blanking I
In the CXA2126Q, there are two fast blanking inputs, one associated with the VCR RGB/CVBS input
(FBLANK_IN2), and another associated with the Digital Encoder input (FBLANK_IN1). These can be selected
by I
means of the I
table.
FBLK Control
Note) After power on the output is 0V.
Fast Blank output circuit
The output requires an external buffer stage to drive the required 75Ω scart termination.
The levels at the IC output are 0V and +5V.
0
1
2
3
4
5
6
7
2
C. In addition to the two blanking inputs, the fast blank pin output can be set to a constant 0V or 5V by
x x 0 0 0 x x x
x x 0 0 1 x x x
x x 0 1 0 x x x
x x 0 1 1 x x x
x x 1 0 0 x x x
x x 1 0 1 x x x
x x 1 1 0 x x x
x x 1 1 1 x x x
I
2
C Setting
1. CVBS mode
2. RGB mode
2
C control. Hence there are four possible states. These are controlled according to the following
2
C Control
Data 5 Bits 3, 4, 5
0V
+5V
Same level as Fast Blank in 1 (0/+5V)
Same level as Fast Blank in 2 (0/+5V)
Not used
0V
0V
0V
CXA2126Q
Fast Blank
Fig. 4-1. Fast Blanking Interface to TV SCART
Fast Blank Output
0V/5V
Scart pin voltage = 0 to 0.4V
Scart pin voltage = 1 to 3.0V
1k
75
V
CC
– 27 –
Scart line 16
75
TV
CXA2126Q