SH7205 Datasheet, PDF (1453/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 26 2D Graphics Engine (2DG)
Blit (With Blending)
Number of pixels = Nb
Color value = Ca
α value = F(H)
A
SA
buffer
Number of pixels = Nb
Color value = Cb
α value = αb
SB
buffer
DMAC4
DMAC3
DMAC2
A
DC buffer
Sets the number of pixels (Nc) to be transferred to the DC buffer. (By setting the GR_DCSET register)
Sets the number of pixels (Nb) to be transferred to the SA/SB buffers. (By setting the GR_SABSET register)
Sets blitter operating mode. (By setting the BTYPE bits of the GR_BLTMODE register to 00: Blit operation)
Selects the blending coefficient value. (By setting the FBFA bits of the GR_BRDICNT register to 00: blending of 2 inputs)
Sets the global α. (By setting the GALFA bits of the GR_BRDICNT register to 1: α value = register value)
Setting for resizing (enlargement) (Set by user)
Logical operation (Set by user)
Plane 2
Plane 1
A BC
Plane 3
Color value = Cd
α value = αd
A
Number of pixels = Nc
Color value = Cc
α value = αr
Image plane in the SDRAM
Executes the processing. (By setting 1 in both the SB_SETEN
and SA_SETEN bits in the GR_BLTPLY register)
Data output to the DC buffer
2DG
The DMAC controlled by the CPU issues
the addresses of the both memories
and performs a memory-to-memory transfer.
Figure 26.27 Example of Blit Function with Blending (2)
(d) Summary of Chromakey Processing
Since the chromakey processing function is installed only on the input B path, chromakey
processing cannot be applied to the input A path. Furthermore, neither logical operations nor color
gradation processing can be executed at the same time as chromakey processing. Part of the
chromakey specification is that chromakey settings are only effective when fill operations are
running. For this reason, select fill mode by setting the BTYPE bits of the GR_BLTMODE
register to 10 if chromakey processing is to be used. Additionally, since chromakey processing
only operates with fill mode, it is not available in conjunction with the resizing function.
Examples of the effects of executing chromakey processing are as follows:
Rev. 1.00 Mar. 25, 2008 Page 1421 of 1868
REJ09B0372-0100