
2000 Feb 23
42
Philips Semiconductors
Preliminary specification
TV microcontrollers with Closed Captioning (CC)
and On-Screen Display (OSD)
SAA55xx
Fig.15 Data Capture block diagram.
handbook, full pagewidth
ADC
data<7:0>
VCS
SYNC_FILTER
TTD
TTC
DATA SLICER
AND
CLOCK RECOVERY
output data to SFRs
GSA010
ACQUISITION
FOR
CC/WSS
CVBS
SWITCH
CVBS
CVBS0
CVBS1
ACQUISITION
TIMING
SYNC
SEPARATOR
18 DISPLAY
The display section is based on the requirements for 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 synchronised 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.
18.1
Display features
Teletext style OSD and Enhanced OSD modes
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 or 16
Globally selectable character matrix (H
×
V) 12
×
9,
12
×
10, 12
×
13 or 12
×
16
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, Arabic)
G1 Mosaic graphics, Limited G3 Line drawing
characters
WST character sets and Closed (including extended)
Caption character set in a single device.