TDA935x Philips, TDA935x Datasheet - Page 40

• Manufacturer Part Number: TDA935x
• Description: TV Signal Processor-Teletext Decoder with Embedded u-Controller
• Manufacturer: Philips

Philips Semiconductors
teletext decoder is error checked and stored in row 25,
block 9 of the basic page memory. The device
automatically detects whether teletext or VPS is being
transmitted on this line and decodes the data
appropriately.
Each VPS byte in the memory consists of 4 bi-phase
decoded data bits (bits 0-3), a bi-phase error flag (bit 4)
and three 0s (bits5-7). The TXT13. VPS Received bit is set
by the hardware whenever VPS data is acquired. The flag
can be reset by writing a 0 into the SFR bit.
WSS A
The Wide Screen Signalling data transmitted on line 23
gives information on the aspect ratio and display position
of the transmitted picture, the position of subtitles and on
the camera/film mode. Some additional bits are reserved
for future use. A total of 14 data bits are transmitted. All of
the available data bits transmitted by the Wide Screen
Signalling signal are captured and stored in SFRs WSS1,
WSS2 and WSS3. The bits are stored as groups of related
bits and an error flag is provided for each group to indicate
when a transmission error has been detected in one or
more of the bits in the group. Wide screen signalling data
is only acquired when the TXT8.WSS ON bit is set. The
TXT8.WSS RECEIVED bit is set by the hardware
whenever wide screen signalling data is acquired. The flag
can be reset by writing a 0 into the SFR bit.
C
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. 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.
2001 Jan 18
LOSED
TV signal processor-Teletext decoder with
embedded -Controller
row 25
column
CQUISITION
Teletext page
0
C
header data
APTION
9 10 11
Fig.13 VPS Data Storage
A
byte 11
CQUISITION
VPS
12 13 14
byte 12
VPS
byte 13
VPS
15 16 17 18 19 20 21
byte 14
VPS
byte 15
VPS
VPS
byte 4
22 23
byte 5
VPS
40
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. Using
this information and other global settings, the display
produces the required RGB signals and Video/Data (Fast
Blanking) signal for the TV signal processing.
The display is synchronised to the TV signal processing by
way of Horizontal and Vertical sync signals generated
within TDA935X/6x/8x. From these signals all display
timings are derived.
Display Features
Display Modes
The display section has two distinct modes with different
features available in each. The two modes are:
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 (HxV) 12x9, 12x10,
12x13, 12x16.
Italics, Underline and Overline.
Soft Colours using CLUT with 4096 colour palette.
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 re-definable 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 Caption Character set
in single device.
TDA935X/6X/8X PS/N2 series
Tentative Device Specification