ST92196A STMicroelectronics, ST92196A Datasheet - Page 145

• Manufacturer Part Number: ST92196A
• Description: 8/16-bit Mcu For Tv Applications With Up To 96k Rom, On-screen-display And 1 Or 2 Data Slicers
• Manufacturer: STMicroelectronics

OSD CONTROLLER (Cont’d)
8.5.8.5 Serial Mode
In serial mode, only 1 byte is used to describe the
character code or the attribute
– If the most significant bit (Bit 7) of this byte is 0,
– If the most significant bit (Bit 7) of this byte is 1,
A consequence of this structure is that in serial
mode, only the first 128 characters stored in the
font ROM can be accessed (the value of the 7
least significant bits of the character code = the
character number in font ROM).
The first two bytes of the row buffer describing the
row are displayed as border color. The first char-
acter to be displayed in serial mode is in fact the
3
All the attributes (background and foreground) are
displayed as space with background color.
Let’s assume that the start address of the current
row buffer is 2p (even address).
In this case the character codes and attributes are
stored in the OSDRAM at the address 2p+5+z,
where z value is 1 to RCN (RCN is the row charac-
ter count defined in
Character Code in Serial Mode
Address in Segment 22h: 2p + 5 + z. See
59.
145/268
- ON SCREEN DISPLAY CONTROLLER (OSD)
rd
the byte represents a character code.
the byte represents a serial attribute. Then the
display controller uses Bit 6 to determine wheth-
er the attribute is a foreground serial attribute (Bit
6 = 0) or a background serial attribute (Bit 6 = 1).
of the row buffer.
Section
8.5.8.2).
(Figure
59):
Figure
Bits 6:0 = CHC[6:0] Character Code in serial
mode
The CHC[6:0] value points to one of the first 128
characters stored in the font ROM.
BACKGROUND SERIAL ATTRIBUTE
Address in Segment 22h: 2p + 5 + z. See
59.
Bits 5:4 Reserved
Bits 3:0 = BP[3:0] Background Palette pointer
The BP[3:0] value points to one of the 16 prede-
fined entries of the background palette for the
background color and the translucency.
For example, BP[3:0] = 0 points to the first back-
ground palette entry, 30h & 31h if the palette swap
bit PASW of the OSDDR register is reset (see reg-
isters description for more details).
Note: the display of the background serial attribute
is affected by the use of the Italics (see the fore-
ground serial attribute) and also by the “M” bit lo-
cated in the Background Palette (see
8.5.6.4
7
7
0
1
CHC6
for further details).
1
CHC5
x
CHC4 CHC3 CHC2 CHC1 CHC0
x
BP3
BP2
BP1
Section
Figure
BP0
0
0