AL300 datasheet(12/64 Pages) ETC

12 / 64 page

AL300

November 28, 2001

6.0 Functional Description

The AL300 provides a simple way of connecting video or graphic sources to a flat panel display such

as a LCD. A LCD panel normally supports only one fixed resolution of digital non-interlaced data

format; therefore, it can not be connected directly to a video source due to the difference in format.

Additionally, VGA or TV video usually are in analog format and can be of many different resolutions

and refresh rates. The AL300 is designed to change the various video/graphics formats into a fixed

data format to be accepted by a specific LCD panel.

The input video format can be 24-bit digital RGB or 16-bit digital YUV. Different video sources can

be connected to an AL300 via certain digitization devices. For example, analog NTSC/PAL/SECAM

can be connected to the AL300 via a digital video decoder.

Analog VGA RGB signal can be

connected to the AL300 after a high-speed three-channel analog-to-digital converter (ADC), such as

the AL875. Alternatively, digital PC graphics can also be applied to the AL300 through a Panel Link

or LVDS (low voltage differential signal) receiver.

The scan rate and resolution of the incoming video are recognized by the scan mode detection circuits.

The detected mode information stored in the AL300 registers is read through the I

2C bus by the

firmware. The firmware then will decide how to program the chip such that the input video can be

scaled up to fit into the full screen size of the display. To achieve this, the linear zoom engine needs to

be programmed to properly scale the input video to the desired output resolution.

Also, the

frequency of the display clock generated from the internal PLL needs to be programmed to the correct

level.

After the digital data is scaled, optional dithering is performed to retain color resolution for LCD

panels that support only 12-bit or 18-bit color resolutions.

The processed data is overlaid with

internal on-screen-display (OSD) for display status or control menu.

6.1 Input Data Format

The AL300 accepts three input data formats: 24-bit RGB, 16-bit CCIR601 422 and 24-bit CCIR601

444 data. The clock and sync signal pins are separate for RGB or YUV while the YUV data share the

same pins as the RGB data. The input video format is defined by the YUVIN pin. Diagram AL300-

06 Input Data Format shows how to connect the AL300 for each format.

AL300 Datasheet(PDF) 12 Page - List of Unclassifed Manufacturers