SAA7201H Philips Semiconductors, SAA7201H Datasheet - Page 16

• Manufacturer Part Number: SAA7201H
• Description: Integrated MPEG2 AVG decoder
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Graphics unit
The SAA7201 incorporates the display support for pixel
based graphics. Possible applications are the user
interface, logos and subtitling. Graphical data should be
grouped logically in regions and will be displayed in boxes
at the screen.
The definition of each region in the decoder consists of
four parts being a region descriptor, a top-field descriptor,
a bottom-field descriptor and a table-data descriptor:
1997 Jan 29
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The region descriptor contains information relevant for
the full region like format, size, position and pointers to
the other descriptors.
Integrated MPEG2 AVG decoder
address
anchor
gfx
V-start (2)
V-size (2)
eodl
DESCRIPTOR 1
DESCRIPTOR 2
DESCRIPTOR 3
DESCRIPTOR 4
128 bit
H-start (2)
Fig.8 Graphics unit.
REGION-3 (256 ENTRY CLUT)
Fig.9 Display list.
REGION-1 (VBI-SIGNALS)
table
data
REGION-4
16
MAP
position, size, format
All descriptors should be loaded under control of the
external CPU in the external memory.
The appearance of graphical data at the display is
determined by the assembly of region descriptors in a so
called display list. An example of such a display list for the
4 regions example is shown in Fig.9.
active
video
CLUT
The top-field and bottom-field descriptor contain a pixel
based bit-map for the contents of that region for both
fields independently. The bit-maps can be stored in
either straight forward or in a compressed bit-map
format.
The table-data descriptor defines the tables to be used
for the transformation of bit-maps to display colours.
pointers to locations in SDRAM
REGION-2
H-size (2)
top-field
PIXEL
DATA
bottom-field
PIXEL
DATA
MGD328
MGD329
active
video
Objective specification
SAA7201