Renesas SH7781 - Manual (Page 968)

19. Display Unit (DU)
Rev.1.00 Jan. 10, 2008 Page 938 of 1658
REJ09B0261-0100
• 16 bit/pixel: ARGB
The ARGB levels are represented using A:1, R:5, G:5, B:5 bits (ARGB555). In addition to the
RGB values, an alpha value is set. Blending control using the A value is valid when the
PnSPIM bit in PnMR is set to perform blending; when A = 1, blending is performed. When the
PnSPIM bit is not set to perform blending, blending is not performed even when A = 1.
D15-D0 15 14 10 9 5 4 0
A R G B
A+2 A A A+2
31 15 0 31 15 0
Address A
ARGB555 - 1 ARGB555- 0
Address A
ARGB555- 0 ARGB555- 1
Address A+4
ARGB555- 3 ARGB555- 2
Address A+4
ARGB555- 2 ARGB555- 3
Address A+8
ARGB555- 5 ARGB555- 4
Address A+8
ARGB555- 4 ARGB555- 5
Little endian Big endian
• YC
Image data has the format YC (YCbCr) = 4:2:2. A calculation circuit is used to convert each of
the 8 bits of the RGB colors of image data.
The YC data order corresponds to the UYVY format and YUYV format. The UYVY format
and YUYV format can be selected using the PnYCDF bits in PnMR.
The conversion formulae for each of the 8 bits of the RGB colors are as follows:
R = Y + 1.37
× (Cr - 128)
G = Y - 0.698
× (Cr - 128) - 0.336 x (Cb - 128)
B = Y + 1.73
× (Cb - 128)
16
≤ Y ≤ 235
16
≤ Cr ≤ 240
16
≤ Cb ≤ 240
The following coefficients are used for the above formulae.
(1) 1.37 = 1.0101111
(2) 1.73 = 1.1011110
(3) 0.698 = 0.10110010
(4) 0.336 = 0.01010110
The internal processing is performed in 16-bit units.
Calculation is performed with fixed-point arithmetic and values are rounded down.