27 GRAPHICS ENGINE (GE)
27-12
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
When the color conversion table in the header (see Figure 27.3.4.2) of the image data to be decompressed/
drawn is enabled (bcTable = 1), the CCT contents are used for color depth conversion. Although the header
in 2 bpp and 1 bpp image data includes two or more conversion data, only the data for converting into the
GE bpp mode is used.
3.4.1 CCT1 Configuration
Table 27.
Table
address
4 bpp data
(4 to 8 bpp conversion data)
2 bpp data (2 to 8
or 2 to 4 bpp conversion data)
1 bpp data (1 to 8, 1 to 4
or 1 to 2 bpp conversion data)
0x302910
8-bit color data 0
0x302911
8-bit color data 1
0x302912
8-bit color data 2
0x302913
8-bit color data 3
0x302914
8-bit color data 4
0x302915
8-bit color data 5
0x302916
8-bit color data 6
0x302917
8-bit color data 7
0x302918
8-bit color data 8
0x302919
8-bit color data 9
0x30291a
8-bit color data 10
0x30291b
8-bit color data 11
0x30291c
8-bit color data 12
0x30291d
8-bit color data 13
0x30291e
8-bit color data 14
0x30291f
8-bit color data 15
0x302920
8 or 4-bit color data 0
0x302921
8 or 4-bit color data 1
0x302922
8 or 4-bit color data 2
0x302923
8 or 4-bit color data 3
0x302924
8, 4, or 2-bit color data 0
0x302925
8, 4, or 2-bit color data 1
CCT1 is located at 22 byte from address 0x302910. This table is used for converting color depth when the
color conversion table in the header of the image data to be decompressed/drawn is disabled (bcTable = 0).
Conversion data must be written to the addresses shown above in advance.
Converting into 16 bpp colors
When the GE is set to 16 bpp mode, color depth is converted as follows:
• If the original data is made for 8 bpp mode, the GE draws the image with the source color on 16 bpp
directly.
• If the original data is made for 1/2/4 bpp mode, it is converted into 8 bpp by the color depth conver-
sion using CCT or CCT1 and then the 8 to 16 bpp conversion shown below is performed.
8 bpp data (for 1 pixel) R2 R1 R0 G2 G1 G0 B1 B0
16 bpp data (for 1 pixel)
8 bits
16 bits
R2 R1
R2 R1
R0
G2 G1
G2 G1
G0
B1 B0
G0
B1
B1
B0
3.4.4 8 to 16 bpp Conversion
Figure 27.
Note: The color depth conversion function does not support color reduction. Therefore, GE cannot
draw image data made for a higher bpp mode than that of the GE.
8 and 16 bpp image data do not support color depth conversion and are extended without
color conversion. The bcTable bit is ignored and the data header cannot contain CCT. An un-
expected drawing will result if CCT exists in 8 or 16 bpp image data .