SAA5531 Philips Semiconductors, SAA5531 Datasheet - Page 74

• Manufacturer Part Number: SAA5531
• Description: Enhanced TV microcontrollers with On-Screen Display OSD
• Manufacturer: Philips Semiconductors

Philips Semiconductors
19.9.1
This area is covered by the screen colour. The screen
colour display area starts with a fixed offset of 8 s from
the leading edge of the horizontal sync pulse in the
horizontal direction. A vertical offset is not necessary.
Table 26 Screen colour display area
19.9.2
The text area can be defined to start with an offset in both
the horizontal and vertical direction.
Table 27 Text display area
2000 Feb 23
Horizontal
Vertical
Horizontal
Vertical
POSITION
POSITION
Enhanced TV microcontrollers with
On-Screen Display (OSD)
S
T
EXT DISPLAY AREA
CREEN COLOUR DISPLAY AREA
Start at 8 s after leading edge of
horizontal sync for 56 s.
Line 9, Field 1 (321, Field 2) to leading
edge of vertical sync (line numbering
using 625 standard).
Up to 48 full sized characters per row.
Start position setting from 8 to 64
characters from the leading edge of
horizontal sync. Fine adjustment in
quarter characters.
256 lines (nominal 41 to 297). Start
position setting from leading edge of
vertical sync, legal values are
4 to 64 lines (line numbering using
625 standard).
DESCRIPTION
525-LINE
74
The horizontal offset is set in the MMR Text Area Start.
The offset is done in full width characters using TAS<5:0>
and quarter characters using HOP<1:0> for fine setting.
The values 00H to 08H for TAS<5:0> will result in a
corrupted display.
The value 09H should also be avoided in the MMR Text
Area Start as corruption of the row 24 display can occur.
Alternative values are C8H or 49H to overcome this
problem.
The width of the text area is defined in the Text Area End
Register by setting the end character value TAE<5:0>.
This number determines where the background colour of
the Text Area will end if set to extend to the end of the row.
It will also terminate the character fetch process thus
eliminating the necessity of a row end attribute. This
entails however writing to all positions.
The vertical offset is set in the Text Position Vertical
Register. The offset value VOL<5:0> is done in number of
TV scan lines.
Note that the Text Position Vertical register should not be
set to 00H as the Display Busy interrupt is not generated
in these circumstances.
19.10 Character set
To facilitate the global nature of the device the character
set has the ability to accommodate a large number of
characters, which can be stored in different matrices.
Preliminary specification
SAA55xx