Toshiba 20VL44 Service Manual page 12

4. GM2221 LCD TV CONTROLLER
The gm2221 IC is a highly integrated single channel scaler that can be used for both LCD
monitors up to SXGA/UXGA resolutions and rear projection systems with DLP and HTPS
LCD engines up to 1280x720 (720P). Some of the key features include:
• Single processing channel.
• RGB and YUV signal processing with RGB to YUV and YUV to RGB color space
converters.
• Video signal processing/de-interlacing using spatial, VT (vertical-temporal) diagonal
interpolation.
• The on-chip turbo x86 micro-controller is used as the system CPU.
• The on-chip OSD controller is available for creating bitmapped OSD menus
• The keypad buttons utilize the input of the on-chip low bandwidth ADC.
• Software IR decoders is used with an external remote controller.
• One of the on-chip PWM outputs is used for controlling back-light intensity
• Integrated LVDS transmitters to LCD panels with integrated LVDS receivers.
The LCD panel resolution supported can be up to SXGA resolutions.
6. LCD PANEL INTERFACE
The L5-A board can drive panels both with LVDS and TTL interfaces. The footprints for
single LVDS and double LVDS connectors are available on the board (S503 and S502,
respectively). Either of these connectors can be used without any changes on the board.
The TTL interface is supported by a daughter board (S506 is the connector for the
daughter board). For the TTL case, connecting the daughter board to the connector will be
sufficient.
A Hirose 30-pin connector (S502) is used for double LVDS link from the board to various
LVDS panels. This connector can also be used for single LVDS, but another connector
footprint (S503) is available for single LVDS purposes. Using only S503 for single LVDS
panels decreases the cost. The LVDS traces are routed differentially from the gm2221 IC
to the connector. These are 100-Ohm differential traces.