ADE3800XL datasheet(68/138 Pages) STMICROELECTRONICS

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4.12 sRGB (SRGB)

The sRGB block performs two primary functions:

1. Parametric gamma correction on multiple windows or full screen, used for video enhancement

in a window and digital contrast/brightness control. The window coordinates are set by TCON

registers.

2. 3D color cube warping RGB color space.

The entire backend of the ADE3800 (from Scaler output to the APC) has a 10 bit database including

the sRGB block. The sRGB controls correspond to the 8 MSBs of the data.

4.12.1 Parametric Gamma, Digital Contrast / Brightness on Multiple Windows

The function can be applied to the entire window by programming the window control to full screen.

Each color channel acts independently. Simple digital contrast and brightness can be programmed

using this hardware function. The desired window coordinates are programmed into the TCON.

Note:

If both Gamma1 and Gamma2 are enabled, Gamma1 has priority over Gamma2.

4.12.2 Color Space Warp

The 8 corners of the color cube are independently controlled in 3D space with smooth interpolation

of intermediate colors. Registers are 2’s complement color deltas.

For example:

● to make WHITE more like RED, program SRGB_WHITE_R to a small positive value.

● to turn RED into GREEN, set Gain = 2 in SRGB_CTRL0[7:6], then SRGB_RED_R = 0x80

(-128) to block the red, and SRGB_RED_G=0x30 (the higher the value (up to 0x7F) the

brighter the green).

The step value for each color delta depends on the gain setting in SRGB_CTRL0[7:6], as follows:

Figure 11: Color Space Warp

Table 26: Color Space Warp Gain Control

SRGB_CTRL0[7:6]

Gain

Step Size

Color Delta Range

0.5

[-64;+63]

[-128;+127]

[-256;+255]

Color Space Warp

OUT

ADE3800XL 데이터시트(PDF) 68 Page - STMicroelectronics