STV5730 datasheet(13/19 Pages) STMICROELECTRONICS

13 / 19 page

The MUTE search time constant may be either

8 lines or 32 lines, according to the M3 mode bit.

The signal that is delivered to the MUTE output pin

is synchronized on the vertical sync if M11 is

cleared. It is forced low if the M2 mode bit is low.

This signal may be monitored by the microproces-

sor to switch the STV5730 from mixed mode to full

page mode and vice versa (using the C0 control

bit).

5 - THE LUMA GENERATION

The luma signal is generated by the STV5730 from

timing information created by the character and

video timing generators and voltage levels created

by the internal bias level generator or entered on

the LESCREEN and LECHAR pins (as selected by

the C10 control bit).

The luma signal is output on the YOUT pin to allow

the user to notch filter it. It is then re-input on the

YIN pin. YOUT and YIN may be connectedtogether

for minimal cost applications.

5.1 - Internal Bias Mode

This mode is intended for minimal cost applica-

tions. C10 must be cleared. The luma levels of the

OSD output signal are as follows :

- LEBLACK : black level

nominal value : 1.25V

± 20mV

- LESYNC : sync level

nominal value : LEBLACK - 300mV

- LESCREEN : page background level

nominal value : LEBLACK + 150mV

- LECHAR : character level

nominal value : LEBLACK + 550mV

LEBLACK is also used to clamp the VIDEO IN

signal and to create the character border.

5.2 - External Bias Mode

This mode is intended to give more flexibility to the

user. C10 must be set. The LESCREEN and

LECHAR levels may be user defined relatively to

the internal LEBLACK level. The final luma ampli-

tude should not be greater than the peak white

level. These levels may be static or dynamic. Dy-

namic levels can be easily generated by analog

sum of the R/G/B and CO STV5730 outputs (a few

resistors are necessary) to give grey scale charac-

ter shading in the mixed mode. C0 is useful to

control the character foreground luma level.

6 - THE CHROMA GENERATION

The STV5730 encoder is operates in full page

mode only. It may perform PAL or NTSC encoding

according to the C8 control bit.

A 4*fsc chroma quartz crystal is necessary

(fsc = 4.43MHz for PAL, 3.58MHz for NTSC).

The encoder can be turned off by the M6 mode bit

for black & white or for SECAM applications.

The character encoding is controlled by the C9

control bit.

The chroma signal is output on the COUT pin for

external filtering and for attenuationif necessary. It

is then re-entered on the CIN pin and added to the

YIN pin signal to create the final CVBS output

signal.

The chroma saturation is controlled by the

STV5730 :

- burst nominal amplitude : 360mVPP

- blue or yellow colors nominal amplitude :

360mVPP

- red, magenta, green or cyan colors nominal am-

plitude : 520mVPP

7 - THE MARKERS

The STV5730 can generate 3 different markers that

can be activated simultaneously (i.e. on the same

page).

The following marker features are performed :

- Blinking character, character background off.

The character foreground blinks (BK = 1, BE = 0

or C1 = 1).

- Not blinking character, character background on

(C1 = 0, BE = 1).

- Blinking character, character background on.

The character foreground blinks and the charac-

ter background remains (BK = 1, BE = 1, C1 = 0).

8 - THE TRANSLUCENT MIXED MODE

VIDEO OUT1

VIDEO OUT2

disable

STV5730

Figure 4 :

The Translucent Mixed Mode Output

Configuration

The VIDEO OUT1 and VIDEO OUT2 outputs may

be summed via two external resistors to create a

translucent text (mixed mode). In this case, the

background picture is still visible behind the text.

The background picture visibility (or level of trans-

lucence is controlled by the resistor ratio.

Another benefit from this function is to allow

PAL/SECAM/NTSC multistandard applications to

STV5730

13/19

STV5730 数据表(PDF) 13 Page - STMicroelectronics

STV5730 数据表(HTML) 13 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

数据表下载