STV5730 Datasheet, PDF (14/19 Pages) STMicroelectronics – MULTISTANDARD ON-SCREEN DISPLAY FOR VCR, PAY-TV, SATELLITE RECEIVER

STV5730
be built with no SECAM chroma re-insertion filter
and no additional control switches.
The sum may be cancelled by setting the M8 mode
bit. In this case, the VIDEO OUT2 pin is in high
impedance state and the resistor network delivers
VIDEO OUT1 only.
When using the resistor network, please set M8 in
the following cases :
- in full page mode
- when OSD in not displayed
- to select opaque text. This allows the viewer to
select by software the preferred display mode.
without colored background.
Presence detection is permanently active to keep
the microcontroller informed of the input signal
quality. The information is delivered by the MUTE
pin.
This information can be used by the microcontroller
to force the STV5730 into the mixed mode (set C0
low) when the input signal becomes good enough.
In the video full page mode, it can be usefull to set
the M11 (mode register) bit high, so that the mute
signal is not synchronized on the vertical sync, thus
accelerating the VIDEO IN presence detection.
The DC levels of the VIDEO OUT1, VIDEO OUT2
and the sum signals are high enough to directly
drive a NPN emitter follower driver (see Table 1).
9 - VIDEO FULL PAGE MODE
In addition to the normal full page mode in which a
uniformely colored screen background is gener-
ated, the STV5730 is able to support a ”video full
page mode”.
Normal and video full page mode are selected by
the control bit C11 (respectively set high and low).
By using the video full page mode the channel
capture operation can be easily monitored on the
screen since the signal at the VIDEO IN input is
displayed, unlocked, in the screen background
area ; the text being stable and colored, with or
10 - S-VHS APPLICATION (see Figure 5)
The STV5730 can be used in S-VHS applications
easily.
The Y signal must be delivered to the VIDEO IN
input. The VIDEO OUT1 output then delivers a
Y + text signal, whilst the VIDEO OUT2 delivers the
Y input signal, provided that the CIN input is con-
nected to a bias DC level.
An external switch must be used to select the C
signal in mixed mode or the COUT output signal in
full page mode.
In mixed mode the chroma signal (C) can be exter-
nally attenuated (multistandard translucent opera-
tion) or killed (PAL/NTSC opaque operation only)
during the character gate controlled by the fast
blanking signal.
Table 1
FULL PAGE
PAL/NTSC
MIXED MODE
TRANSLUCENT PAL/NTSC/SECAM
OPAQUE PAL/NTSC
VIDEO OUT1
VIDEO OUT2
S
CVBS (OSD)
High impedance
CVBS
(OSD)
VIDEO IN or Text
VIDEO IN
VIDEO IN or
R₂ x Text + R₁ x VIDEO IN
R₁ + R₂
VIDEO IN or Text
High Impedance
VIDEO IN
or Text
Figure 5 : S-VHS Input/OutputConfiguration
STV5730
Y
2 VIDEO IN VIDEO OUT1 1
VIDEO OUT2 ²⁸
INTERNAL BIAS
23 CIN
COUT 22
FB
15
CHARACTER
C
GATED
ATTENUATOR
R₁
Y_OSD
Full page mode
Y or Text
Opaque mixed mode
R₂
Y or ^{R 2 * Text R 1 * Y}
R₁ R₂
Translucent mixed mode
FP
OPTIONAL
FILTER
EXTERNAL
MM SWITCH
C
Mixed Mode (MM)
Full Page Mode (FP)
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