Freescale Semiconductor MCF52277 Reference Manual page 463

In 4 bpp mode, the first 16 RAM entries are used. In 8 bpp mode, all 256 RAM entries are used. The color
RAM is not initialized at reset. Only the following settings use the mapping RAMs:
• 4 bpp gray-scale mode
• 4 bpp passive matrix color mode
• 8 bpp passive matrix color mode
• 4 bpp active matrix color mode
• 8 bpp active matrix color mode
21.3.25.1 Four Bits Per Pixel Gray-Scale Mode
In four bits per pixel gray-scale mode, a 4-bit code represents a gray-scale level. The first 16 mapping
RAM entries must be written to define the codes for all 16 combinations.
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Field
31–4 Reserved, must be cleared.
3–0 Gray palette map. Represents the gray-scale level for a given pixel code.
GPM
21.3.25.2 Four Bits Per Pixel Passive Matrix Color Mode
In four bits per pixel passive matrix color mode, a 4-bit code represents a 12-bit color. Because only four
bits are used to encode the color, a maximum of 16 colors can be selected out of a palette of 4096. The first
16 mapping RAM entries must be written to define the codes for the 16 available combinations.
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
Field
31–12 Reserved, must be cleared.
11–8 Red level (color display). Represents the red component level in the color.
R
7–4 Green level (color display). Represents the green component level in the color.
G
3–0 Blue level (color display). Represents the blue component level in the color.
B
Freescale Semiconductor
Table 21-28. Four Bits Per Pixel Gray-Scale Mode
Table 21-29. Four Bits Per Pixel Passive Matrix Color Mode
MCF52277 Reference Manual, Rev. 1
Liquid Crystal Display Controller (LCDC)
8
Description
8
R
Description
7 6 5 4 3 2 1 0
GPM
7 6 5 4 3 2 1 0
G B
21-27