SD1200 Datasheet, PDF (19/35 Pages) List of Unclassifed Manufacturers – Analog-Interface XGA/SXGA TFT LCD Display Controller

SmartASIC, Inc.
SD1200
PRELIMINARY DATA SHEET
3.3.3.
Dithering
The SD1200 supports 16.7 million true colors for 6-bit panel. Two dithering
algorithms are implemented and again users can chose between them through the
external micro-controller.
3.4. OSD mixer and LCD interface
At the output stage, the SD1200 performs the OSD mixer function, and then generates
24-bit RGB signal to the LCD panel with the correct timing.
3.4.1.
OSD mixer
In the OSD mixer block, the SD1200 mixes the normal output RGB signal with the
OSD signal. The OSD output data is generated based on the “R_OSD”, “G_OSD” and
“B_OSD” pins as well as the “OSD Intensity” data in EEPROM entry. When the
“EN_OSD” is active high, the OSD is active, and the SD1200 will send the OSD data
to the LCD panel. The OSD has 16 different color schemes based on the combinations
of the three OSD color pins and the “OSD Intensity” data. When R_OSD=1, and
OSD_Intensity=0, the SD1200 will output 128 to the output red channel, R_OUT.
When R_OSD=1, and OSD_Intensity=1, the SD1200 will output 255. The same
scheme is used for G_OSD to G_OUT and for B_OSD to B_OUT.
3.4.2.
LCD interface
The SD1200 support 48-bit RGB interface with XGA/SXGA LCD panels from
various panel manufacturers. The LCD panel resolution and timing information is
stored in the external EEPROM. The information in the EEPROM includes timing
related to the output back porch, synchronization pulse width and valid data window.
The timing information is used to generate the frequency divider for the output PLL,
to lock the PLL output clock with HSYNC for the LCD data clock, and to
synchronized the output VSYNC and input VSYNC.
September, 1998
SmartASIC Confidential
19