SAA5288 Datasheet, PDF (21/48 Pages) NXP Semiconductors – TV microcontroller with full screen On Screen Display OSD

Philips Semiconductors
TV microcontroller with full screen
On Screen Display (OSD)
Preliminary specification
SAA5288
7.5 The display
7.5.1 INTRODUCTION
The capabilities of the display are based on the
requirements of level 1 teletext, with some enhancements
for use with locally generated on screen displays.
The display consists of 25 rows each of 40 characters,
with the characters displayed being those from rows
0 to 24 of the basic page memory. If the TXT.7 STATUS
ROW TOP bit is set row 24 is displayed at the top of the
screen, followed by row 0, but normally memory rows are
displayed in numerical order.
The display memory stores 8-bit character codes which
correspond to a number of displayable characters and
control characters, which are normally displayed as
spaces. The character set of the device is described in
more detail in Section 8.
7.5.2 CHARACTER MATRIX
Each character is defined by a matrix 12 pixels wide and
10 pixels high. When displayed, each pixel is ¹â„₁₂ ms wide
and 1 TV line, in each field, high.
7.5.3 PAGE ATTRIBUTES
Columns 0 to 9 of row 25 of the memory are treated by the
display as if they contain display control information from
teletext page headers. The bits which affect the display are
shown in Table 12. Columns 0 to 4 are not used.
If C5 (newsflash) or C6 (subtitle) is set the display uses the
display mode defined in register TXT6. C7 (suppress
header) causes the header row (row 0) to be displayed as
if every character was a space. C10 (inhibit display)
displays every character on all rows as if it was a space.
C12 to C14 (language control bits) cause certain character
codes to be interpreted differently (see Section 7.5.5).
Table 12 Page attributes
COLUMN
7
5
0
6
0
7
0
8
0
9
0
PAGE ATTRIBUTE FIELD
654 3 2 1 0
0 0 0 C6 C5 0 0
0 0 0 C10 0 0 C7
0 0 0 C14 C13 C12 0
000 0 0 0 0
000 0 0 0 0
handbook, full pagewidth
1997 Jun 24
0
DISPLAY PAGE MEMORY
ROW 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25 page attributes
0
9
23
39
MGL116
Fig.4 Display page organisation.
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