STV3550B STMicroelectronics, STV3550B Datasheet - Page 40

• Manufacturer Part Number: STV3550B
• Manufacturer: STMicroelectronics

Specifications of STV3550B

• Operating Temperature (min): 0C
• Operating Temperature (max): 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Lead Free Status / Rohs Status: Compliant

Graphics functional description
4.1.4
Caution:
40/145
Programming OSD display regions
Figure 27. Two display regions using the same display lines
The characteristics of each OSD region are contained in an OSD specification which is
stored in the 64-Mbit SDRAM. The following data is contained in the OSD specification:
●
●
●
When two regions are displayed one after the other, there must be at least one TV scan line
between them with nothing displayed. This enables the OSD to reload the 256 colors in the
CLUT.
OSD specifications are stored as linked lists, as shown in
The order that the specifications are stored in SDRAM is the order that the regions
are displayed on the screen. This self-chained mode is managed by software by
programming the address of the next OSD region to be displayed in the next OSD
specification pointer (OSDp[31:0]). The stop linked list (SLL) bit indicates the last
specification in the list.
A header which defines the boundaries of the region and contains 4 pointers that are
used to identify the SDRAM location of the current palette, the current top block, the
current bottom block, the next OSD region and other control information
A color palette which defines the colors in the SDRAM. Up to 256 colors can be used
by the bitmap. If required, one of these colors can be “transparent” allowing the
background to show through. These colors are loaded in the OSD CLUT
A bitmap composed of 2 blocks of 32-bit words
OSD Regions
A
C
B
Display lines
in both regions
Figure 28
and
Figure
STV3550
29.