saa569x NXP Semiconductors, saa569x Datasheet - Page 85

• Manufacturer Part Number: saa569x
• Description: Enhanced Tv Microcontrollers With On-screen Display Osd
• Manufacturer: NXP Semiconductors

Philips Semiconductors
23.7
A number of attributes are available that affect the whole
display region of a display window, and cannot be applied
selectively to regions of the display.
23.7.1
The number of TV scan lines per field used for each
display row can be defined, the value is independent of the
character size being used. The number of lines can
be 10, 13 or 16 per display row. The number of TV scan
lines per row is defined by TXT21.DISP LINES<1:0>.
A value of nine lines per row can be achieved if the display
is forced into 525-line display mode by
TXT17.FORCE DISP<1:0>, or if the device is in 10-line
mode and the automatic detection circuit within display
finds 525-line display syncs.
The number of TV lines per row is then set for both the
display windows in double window mode.
23.7.2
There are three different character matrices available:
12
TXT21.CHAR SIZE<1:0> and is independent of the
number of display lines per row.
If the character matrix is less than the number of TV scan
lines per row, the matrix is padded with blank lines. If the
character matrix is greater than the number of TV scan
lines, the character is truncated.
The character matrix is set for all display windows.
23.7.3
CC: When the superimpose or boxing attribute
(see Table 35, Serial Mode 0/1 and bit 6) is set, the
resulting display depends on the setting of the following
screen control mode bits in the MMR Display Control
(see Table 36).
Table 36 Selection of display modes
2002 May 06
MOD1
Enhanced TV microcontrollers with
On-Screen Display (OSD)
0
0
1
1
10, 12
Screen and global controls
TV
C
D
HARACTER MATRIX
ISPLAY MODES
MOD0
SCAN LINES PER ROW
0
1
0
1
13 and 12
Video
Full Text
Mixed Screen Colour
Mixed Video
DISPLAY MODE
16. The selection is made using
(H
V)
disables all display activities, sets the RGB to true black and VDS to video
displays screen colour at all locations not covered by character foreground
or background colour; the box attribute has no effect
displays screen colour at all locations not covered by character foreground,
within boxed areas or, background colour
displays video at all locations not covered by character foreground, within
boxed areas or, background colour
85
TXT: The display mode is controlled by the bits in TXT5
and TXT6 in single window mode or for Page A in double
window mode, and by the bits in bytes TXT24 and TXT25
in Page B in double window mode. There are three control
functions: Text on, Background on and Picture on
(see Table 37). Separate sets of bits are used inside and
outside Teletext boxes so that different display modes can
be invoked. Bit (s) TXT6 and/or TXT25 are used if the
newsflash (C5) or subtitle (C6) bits in row 25 of the basic
page memory are set; otherwise, byte TXT5 and/or TXT24
is/are used. This allows the software to set up the type of
display required on newsflash and subtitle pages (e.g. text
inside boxes, TV picture outside). This will be invoked
without any further software intervention when such a
page is acquired.
When Teletext box control characters are present in the
display page memory, the appropriate Box control bit must
be set, TXT<n>.Box ON 0 (B),
TXT<n>.Box ON Row 1 to 23 (B), TXT<n>.Box ON 24 (B)
where <n> is:
This allows the display mode to be different inside the
Teletext box compared to outside. These control bits are
present to allow boxes in certain areas of the screen to be
disabled. The use of Teletext boxes for OSD messages
has been superseded in this device by the OSD box
concept. However, these bits remain to allow Teletext
boxes to be used, if required.
7 in single page mode or for Page A in double window
mode
26 for double window mode for Page B.
DESCRIPTION
SAA567x; SAA569x
Objective specification