saa6712e NXP Semiconductors, saa6712e Datasheet - Page 51

• Manufacturer Part Number: saa6712e
• Description: Xga Rgb To Tft Graphics Engine
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Table 12 OSD window size
The whole OSD window can be zoomed in both directions
by a factor of two by setting zoom2 to logic 1. This results
in pixel doubling horizontally and vertically.
Each character can be displayed using 1 of 8 different
foreground and background colours. These sixteen
colours can be chosen from the full true colour palette with
8 bits per colour component. The definition of these
colours is in registers 144 to 191 (see OSD section of the
programming register Table 5). The first 8 colour entries
are used for foreground colours, and the second half is
used for defining the background colours. Registers
192 to 195 (see Table 5) decide the transparency and
alpha blending effects. If one of these effects is enabled for
a specific character, only the colours defined as
transparency or alpha blending colours will be used to
generate these effects.
Each character information in the OSD window memory
consists of 15 bits of information. This is given in
Tables 13 and 14.
Table 13 Character appearance definition
The character code is used to address the defined
characters inside the matrix memory.
The appearance bits decide about transparency and alpha
blending, and background and foreground colour are
indices to the colour definition registers.
1999 Aug 25
Character code
Appearance
Background colour
Foreground colour
OSD SIZE
XGA RGB to TFT graphics engine
CHARACTER INFORMATION
32
40
48
16
20
24
OSD WINDOW RESOLUTION/PIXELS
1152
768
960
24
24
384
480
576
NUMBER OF BITS
384
480
576
12
7
2
3
3
16
256
320
384
51
Table 14 Colour effects
To access a certain character position its coordinates must
be programmed into registers 196 (cursor_row) and 197
(cursor_column), see Table 5. After that, the colours and
appearance of the character must be defined in
address 198 (see Table 5). This definition is valid for all
further writes to register 199 (char_code), see Table 5.
After writing to this register the cursor position changes to
the next right position. At line end it wraps around to the
first left character in the line below. I
is not active at register 199 (see Table 5), so that
subsequent I
characters.
8.10.3
Two different font sizes are supported; 24
12
42 characters (24
128 characters (16
The definition of the characters is achieved by writing to
registers 200 and 201 (see Table 5). The first register
must be written to with the character code of the character
to be defined. Then the bytes with the pixel pattern must
be written to address 201 (see Table 5). The definition of a
character is done with 3 bytes per line at 24
(72 bytes per character), and with 3 bytes per 2 lines at
12
APPEARANCE
16 pixels. With the internal matrix memory
16 font (24 bytes per character), see Fig.16.
VALUE
0
1
2
3
OSD
2
C-bus byte write accesses will define several
CHARACTER MATRIX
OSD character colours are displayed
instead of the picture colours
OSD character colours defined as
transparency colours will be replaced
by the picture colours
OSD character colours defined as
alpha blending colours will be alpha
blended 1 : 1 with the picture colours
OSD character colours defined as
alpha blending colours will be alpha
blended 2 : 1 with the picture colours
24 pixels) can be defined, or
12 pixels).
Preliminary specification
EFFECT
2
C-bus auto-increment
SAA6712E
24 and
24 font