Renesas SH7781 - Manual (Page 975)

19. Display Unit (DU)
Rev.1.00 Jan. 10, 2008 Page 945 of 1658
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When the PnDDF bit in PnMR is set to ARGB, and moreover the PnSPIM bit in PnMR is set to
perform blending,
α blending is performed according to the A value of the input ARGB data
format.
Transparent Colors: For each plane, transparent color processing can be performed between the
specified plane and the lower plane by setting PnSPIM bit in PnMR to 0. However, in YC format
transparent color processing cannot be performed.
When the input display data and register value match, a color is judged to be a transparent color.
• In 8 bits/pixel mode
When the PnTC bit in PnMR is 0 (initial value), transparent color processing is performed
according to the setting in the plane n transparent color 1 register (PnTC1R). When the PnTC
bit PnMR is 1, up to a maximum 16 colors can be simultaneously specified for each of color
palette 1, color palette 2, color palette 3, color palette 4 according to the settings in CP1TR to
CP4TR. Only the indexes H'00 to H'0F can be specified as transparent colors; H'10 to H'FF
cannot be specified as transparent colors.
The color palette 1 to 4 transparent color registers can be selected using the PnCPSL bits in
PnMR.
• In 16 bits/pixel mode and ARGB mode
Transparent color processing is performed according to PnTC2R, regardless of the setting of
the PnTC bit in PnMR.
In the case of ARGB, bits 14 to 0 of PnTC2R are compared, and bit 15 is ignored.
The above is summarized in table 19.12, which indicates the transparent color specification
registers which are valid when the PnTC bit in PnMR is 0 and 1.