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Liquid Crystal Display Controller (LCDC)
21.4.7
Color Generation
The value corresponding to each color pixel on the screen is represented by a 4-, 8-, 12-, 16- or 18-bit code
in the display memory.
For 4- and 8-bit modes the LCDC's color mapping RAM is used to map the data to a 12-bit and 18-bit
RGB code for passive and active matrix color displays respectively. For 4-bit and 8-bit passive matrix
color displays, the 12-bit RGB code from the mapping RAM is output to the FRC blocks that
independently process the code corresponding to the red, green, and blue components of each pixel to
generate the required shade and intensity.
For 4-bit and 8-bit active matrix display, the 18-bit output from the mapping RAM is output to the panel.
For 12-bit mode for passive matrix color display, the mapping RAM is bypassed and output directly to the
FRC block.
For 12-, 16- and 18-bit active matrix color display, pixel data is simply moved from display memory to the
LCDC output bus.
Figure 21-33
and
Figure 21-34
21-34
7 6 5 4 3 2 1 0
1 0
1 1 0 0
-
-
-
-
-
-
-
FRC
1
To Panel
Figure 21-32. Gray-Scale Pixel Generation
illustrate passive matrix and active matrix color pixel generation.
MCF52277 Reference Manual, Rev. 1
2 bpp Data
4 bpp Data
-
1
1
1 0
Freescale Semiconductor
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