Nintendo GAME BOY Programming Manual page 148

Game Boy Programming Manual
DMG Color Palettes and SGB Color Palettes
With DMG screen data representations, colors in SGB are converted from the grayscale data
registered in the DMG color palettes, rather than being converted from the bit data for the character.
DMG palette
SGB palette
Example: When the grayscale data
shown in Table 1 are specified for the
DMG palette, the character represented
on the DMG LCD is as shown in the DMG
character image figure below and to the
right.
Accordingly, when the color data
shown in Table 2 are specified for
the SGB palette, the character
image represented on Super NES
is as shown in the SGB character
image figure below and to the right.
However, if bit 11 of the DMG palette is
set to grayscale 00, the
the DMG character image is displayed
with a 00 grayscale, and the
portion of the SGB character image is
displayed as red rather than black.
Thus, in this case, when character
data display using all of the colors on
the SGB palette is desired, a separate
grayscale palette (DMG palette) for
SGB must be provided, DMG and SGB
must be distinguished, and the
program must be made to branch
accordingly.
(See Section 4.2, Recognizing SGB.)
00 01 10 11 (m,n)
00 01 10 11
light 00> 01> 10> 11 dark
Table 1
00 01 10 11
Red Green Gray Black
Table 2
portion of
* 00-11 in the palette are
grayscale data
Bit m layer
......................................................................
DMG Character Image
10 00
00 01
00 11
SGB Character Image
Gray Red
Red Green
Red Black
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Bit n layer
00-11: grayscale data