SAA5531 Philips Semiconductors, SAA5531 Datasheet - Page 56

• Manufacturer Part Number: SAA5531
• Description: Enhanced TV microcontrollers with On-Screen Display OSD
• Manufacturer: Philips Semiconductors

Philips Semiconductors
18.1.9
The US Closed Caption data is transmitted on line 21
(525-line timings) and is used for Captioning information,
Text information and Extended Data Services. Full details
can be found in the document “Recommended Practise for
Line 21 Data Service EIA-608” .
Closed Caption data is only acquired when TXT21.CC ON
bit is set.
Two bytes of data are stored per field in SFRs the first bye
is stored in CCDAT1 and the second byte is stored in
CCDAT2. The value in the CCDAT registers are reset to
00H at the start of the Closed Caption line defined by
CCLIN.CS<4:0>. At the end of the Closed Caption line an
interrupt is generated if IE.ECC is active.
The processing of the Closed Caption data to convert into
a displayable format is performed by software.
19 DISPLAY
The display section is based on the requirements for a
Level 1.5 WST Teletext and US Closed Caption. There are
some enhancements for use with locally generated
On-Screen Displays.
The display section reads the contents of the Display
memory and interprets the control/character codes.
From this information and other global settings, the display
produces the required RGB signals and Video/Data (Fast
Blanking) signal for a TV signal processing device.
The display is synchronized to the TV signal processing
device by way of horizontal and vertical sync signals
provided by external circuits (Slave Sync mode). From
these signals all display timings are derived.
2000 Feb 23
Enhanced TV microcontrollers with
On-Screen Display (OSD)
C
LOSED
C
APTION ACQUISITION
56
19.1
Teletext and Enhanced OSD modes
Level 1.5 WST features
US Closed Caption features
Serial and Parallel display attributes
Single/double/quadruple width and height for characters
Scrolling of display region
Variable flash rate controlled by software
Globally selectable scan lines per row 9/10/13/16
Globally selectable character matrix (H
12
Italics
Soft colours using CLUT with 4096 colour palette
Underline
Overline
Fringing (shadow) selectable from N-S-E-W direction
Fringe colour selectable
Meshing of defined area
Contrast reduction of defined area
Cursor
Special graphics characters with two planes, allowing
four colours per character
32 software redefinable On-Screen Display characters
4 WST character sets (G0/G2) in single device
(e.g. Latin, Cyrillic, Greek and Arabic)
G1 Mosaic graphics, Limited G3 Line drawing
characters
WST character sets and Closed Caption character set in
single device.
Display features
10, 12
13 or 12
16
Preliminary specification
SAA55xx
V) 12
9,