ADE3800SXL datasheet(88/138 Pages) STMICROELECTRONICS

88 / 138 page

ADE3800

88/138

4.15 Flicker (FLK)

The Flicker block computes a nonlinear correlation of LCD polarity inversion patterns and the LCD

output data stream and provides the correlation results as scores to the microcontroller via I2C.

The MCU polls this block regularly. In response to a high score, the MCU can adjust the polarity

signal generated in the TCON to cancel the visual flicker that arises from correlated pixel and

polarity patterns.

Figure 16 shows a block diagram of the flicker module and its connectivity with the neighboring

modules.

4.15.1 Function

A Walsh 8x8 function is used to compare the detected pattern, where each one of the 8 functions

represents a pattern. All patterns are considered to be vertically, where horizontally the pixels are

assumed to be alternating its RGB components.

Only 4 of the patterns can be measured at one time, and they are selected by means of

WF_SHIFT[2:0] by programming the number of patterns shifted i.e.

● if WF_SHIFT = 00 then the 4 results are meas0, meas1, meas2, meas3;

● if WF_SHIFT = 01 then the 4 results are meas1, meas2, meas3, meas4;

● if WF_SHIFT = 05 then the 4 results are meas5, meas6, meas7, meas0; and so on.

The score that is registered at the end of a measurement is the delta intensity between the RGB

components on pixels that are alternating horizontally and match one or more of the defined 8

patterns. Since the flickering effect occurs most of the time around the 50% of the color intensity,

two functions are used to get the delta difference between the RGB components, one is normalized

at 50%, and the other is normalized at 100%. The selection between the two can be programmed by

the FLICKER_CTRL0[5] => 0/1 (100/50%) normalization.

The horizontal setting of the RGB component of each pixel is represented by the

FLICKER_CTRL0[2:0], and for any pattern, maximum scores are calculated by having the correct

Figure 16: Block Diagram

10 bit

APC

TCON

Flicker

Detector

TFT Panel

OSD

Gamma

Output

Formatter EMI

ADE3800SXL 데이터시트(PDF) 88 Page - STMicroelectronics