SH7205 Datasheet, PDF (1438/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 26 2D Graphics Engine (2DG)
26.4.3 Blitter Operation
(1) Pixel Format Conversion in Blitter
On the blitter, as I/O pixel formats three formats can be set: αRGB444, αRGB555, and α (4 bits).
For this reason, internally in the blitter, various operations are performed after converting a given
format into a standard format. The size of the standard format is α (4 bits) + RGB (5 bits each) for
a total of 19 bits. The formula below shows rules for the conversion of a given format to the
standard format:
• αRGB444 (AF83(H)) converted into a standard format
α: A(H) → A(H) R:F(H) → 1E(H) G:8(H) → 10(H) B:3(H) → 06(H)
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
α value
R value
G value
B value
1010111110000011
α value (4 bits)
↓ (Unchanged)
α value (4 bits)
R value (4 bits)
↓ (× 2)
R value (5 bits)
G value (4 bits)
↓ (× 2)
G value (5 bits)
B value (4 bits)
↓ (× 2)
B value (5 bits)
Bit 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
α value
R value
G value
B value
1010111101000000110
Figure 26.17 Pixel Format Conversion 1 in Blitter
Rev. 1.00 Mar. 25, 2008 Page 1406 of 1868
REJ09B0372-0100