TDA935x Philips, TDA935x Datasheet - Page 45

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

Philips Semiconductors
pixel from scan line to scan line, thus achieving a checker
board display of the background colour and video.
TXT: There are two meshing attributes one that only
affects black background colours TXT4.BMESH and a
second that only affects backgrounds other than black
TXT4.CMESH. A black background is defined as CLUT
entry 8, a none black background is defined as CLUT entry
9-15.
CC: The setting of the Mesh bit in REG0:Display Control
has the effect of meshing any background colour.
C
The cursor operates by reversing the background and
foreground colours in the character position pointed to by
the active cursor position. The cursor is enabled using
TXT7.CURSOR ON. When active, the row the cursor
appears on is defined by TXT9.R<4:0> and the column is
defined by TXT10.C<5:0>. The position of the cursor can
be fixed using TXT9.CURSOR FREEZE.
CC: The valid range for row is 0 to 15. The valid range for
column is 0 to 47. The cursor remains rectangular at all
times, it’s shape is not affected by italic attribute, therefore
it is not advised to use the cursor with italic characters.
TXT: The valid range for row positioning is 0 to 24.The
valid range for column is 0 to 39.
2001 Jan 18
URSOR
Fig.16 Meshing and Meshing / Fringing (South+West)
TV signal processor-Teletext decoder with
embedded -Controller
A B
Fig.17 Cursor Display
C
D E F
45
S
CC/TXT: Several special characters are provided for
improved OSD effects. These characters provide a choice
of 4 colours within a character cell. The total number of
special graphics characters is limited to 16. They are
stored in the character codes 8Xh and 9Xh of the character
table (32 ROM characters), or in the DRCs which overlay
character codes 8Xh and 9Xh. Each special graphics
character uses two consecutive normal characters.
Fringing, underline and overline is not possible for special
graphics characters. Special graphics characters are
activated when TXT21.OSD_PLANE = 1.
The example in Fig.18 can be done with 8 special graphics
characters.
If the screen colour is transparent (implicit in mixed mode)
and inside the object the box attribute is set, then the
object is surrounded by video. If the box attribute is not set
the background colour inside the object will also be
displayed as transparent.
Table 16 Special Character Colour allocation
PECIAL
Background Colour
Background Colour
“set at” (Mode 0)
G
TDA935X/6X/8X PS/N2 series
Plane
RAPHICS
1 0
0 0
0 1
1 0
1 1
Fig.18 Special Character Example
Foreground Colour 7
VOLUME
C
HARACTERS
Colour Allocation
Background Colour
Foreground Colour
CLUT entry 6
CLUT entry 7
Serial Attribute
Foreground Colour
Normal Character
Special Character
Tentative Device Specification
Foreground Colour 6
Background Colour
“set after” (Mode 1)