185
CMOS VIDEO - LCD INTERFACE (VLI)
8 Levels of Gray Scale
SED1345
s DESCRIPTION
The SED1345 is a video-LCD interface (VLI) developed for a dot matrix LCD display system. It converts
separate video signals for CRT display into signals for LCD.
The SED1345 can use a conventional LCD driver to display data at eight gradation levels corresponding to
digital video signal data I, R, G and B. The on-chip color pallet for gradation display allows setting of any
gradation level for each of the 16 colors on the CRT display.
A 640
× 480 dot panel with eight gradation levels can be driven using only 256K bits of frame buffer memory.
This leads to a significant reduction in system memory cost.
With the SED1345, the user can select not only a display size but a display area to configure a display panel
of flexible size from 640
× 200 dots to 640 × 480 dots (maximum). These LCD display sizes are compatible
with various display modes such as CGA and EGA.
s FEATURES
Low-power CMOS technology
TTL-compatible signal input
LCD display size:
Horizontal: ..................................... 640 dots
Vertical: ................. 200, 350, 400, 480 lines
Supports 8 levels of gray shade
Supports single panel and dual panel
LCD driver interface:4 bits bus and 4 bits × 2 bus
Register programming by 4 bits
Maximum dot clock: ......................... 30 MHz
Supports 40KB SRAM frame buffer
Duty cycle: .............................1/200 to 1/480
Power-on clear function
Single power supply: ...................... 5V ± 5%
Package:....................... QFP5-80 pin (FOA)
s SYSTEM BLOCK DIAGRAM
SED1345
SRAM
MONO LCD
PC
HSYNC
VSYNC
DIGITAL R
DIGITAL G
DIGITAL B