ADE3800 datasheet(57/138 Pages) STMICROELECTRONICS

57 / 138 page

57/138

ADE3800

SCLK_FREQ is greater than the max of DCLK_FREQ and (IN_HPIXEL x DCLK_FREQ) /

DEST_HPIXEL;

SCLK_FREQ < 140 MHz

SCL_LINE_START > 0; and

SCL_PIPE_RATE <= 4096

The frame synchronization between input and output can be fine tuned using the line buffer pointer

crossing feedback registers, SCL_PTR_PRE and SCL_PTR_POST. By adjusting the

SCL_TRIGGER_DLY, pointer crossing can be eliminated.

4.10.2 Context Description

The context function allows the scaler to mix the output of three filters (sharp, normal kernel and

smooth) on a per pixel basis depending on the local contrast in a 3Vx4H area. The sharpening

suppresses ringing / overshoots.

Those 3 kernels: Smooth, User (defined with H and V kernel coefficients) and Sharp run in parallel

and can be blended together to finally generate a panel pixel.

If Context is disabled, only User Kernel is used.

If Context is enabled, then the blending of the 3 kernels follows the diagram below. The horizontal

axis is the context:

● Context 0 = All neighbour pixels (3x3) have almost same RGB values (greyscale).

● Context F = All neighbour pixels (3x3) have very different RGB values (1x1 Black and White

checker pattern).

Context is used along with I2C programmable coefficients to make the kernel blending ratio, as the

drawing below shows.

Refer to the context mixing equations for more details. The vertical axis has 63 steps. (63 = 100%).

ADE3800 Datasheet(PDF) 57 Page - STMicroelectronics