SAA5531 Philips Semiconductors, SAA5531 Datasheet - Page 68

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

Philips Semiconductors
19.6
Screen colour is displayed from 10.5 to 62.5 ms after the
active edge of the HSYNC input and on TV lines 23 to 310
inclusive, for a 625-line display, and lines 17 to 260
inclusive for a 525-line display.
CC: The screen colour is defined by the MMR Display
Control and points to a location in the CLUT table.
The screen colour covers the full video width. It is visible
when the Full Text or Mixed Screen Colour mode is set
and no foreground or background pixels are being
displayed.
TXT: The register bits TXT17.SCREEN COL<2:0> can be
used to define a colour to be displayed in place of
TV picture and the black background colour. If the bits are
all set to zero, the screen colour is defined as ‘transparent’
and TV picture and background colour are displayed as
normal. Otherwise the bits define CLUT entries 9 to 15.
19.7
19.7.1
Two types of areas are possible. The one area is static and
the other is dynamic. The dynamic area allows scrolling of
a region to take place. The areas cannot cross each other.
Only one scroll region is possible.
2000 Feb 23
Enhanced TV microcontrollers with
On-Screen Display (OSD)
Screen colour
Text display controls
T
EXT DISPLAY CONFIGURATION
(CC
MODE
)
68
19.7.2
The display map allows a flexible allocation of data in the
memory to individual rows.
Sixteen words are provided in the display memory for this
purpose. The lower 10 bits address the first word in the
memory where the row data starts. This value is an offset
in terms of 16-bit words from the start of Display memory
(8000H). The most significant bit enables the display when
not within the scroll (dynamic) area.
The display map memory is fixed at the first 16 words in
the closed caption display memory.
Table 25 Display map bit allocation
11
10
9 to 0
BIT
D
ISPLAY MAP
Text display enable, valid outside Soft Scroll
Area. 0 = disable; 1 = enable.
This bit is reserved, should be set to logic 0.
Pointer to row data.
FUNCTION
Preliminary specification
SAA55xx