SH7205 Datasheet, PDF (1452/1904 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 26 2D Graphics Engine (2DG)
Blit (With Blending)
DMAC4
DMAC3
Input image
Number of pixels = Nb
Color value = Ca
α value = αa
SA
buffer
Input image
Number of pixels = Nb
Color value = Cb
α value = αb
DMAC2
Output image
SB
buffer
Number of pixels = Nc
Color value = Cc
α value = αc
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)
GCOLR = (The value set by user), GALFA = (The value set by user)
FBFA = (The value set by user), Resizing (Set by user)
Logical operation (Set by user)
Plane 1
Color value = Ca
α value = αa
Plane 2
Color value = Cb
α value = αb
Plane 3
Color value = Cd
α value = αd
Output image
Number of pixels = Nc
Color value = Cc
α value = αc
Image plane in the SDRAM
Executes the processing. (By setting 11 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 26.26 Example of Blit Function with Blending (1)
• Blit function with blending (2)
This section shows an example of blending graphic and character images. Set the registers as
follows:
• Set the GR_SABSET register to specify the number of pixels to be transferred to the SA/SB
buffers.
• Set the GR_DCSET register to specify the number of pixels to be transferred to the DC buffer.
• Set the BTYPE bits of the GR_BLTMODE register to 00 in order to specify blit operation for
blitter operating mode.
• To enable the blit function, set the SB_SETEN and SA_SETEN bits to 1.
In this case, if the α – value-weighted character pixels set in a rectangular area are input into the
SB buffer and graphic pixels (α value = F(H)=1) set in the same rectangular area as SB are input
into the SA buffer, the output image will be an α-blending of the graphics and characters in the
rectangular area followed by resizing. In this case, in order to place character information in the
foremost part of the image, it should be input into the SB buffer.
Rev. 1.00 Mar. 25, 2008 Page 1420 of 1868
REJ09B0372-0100