27 GRAPHICS ENGINE (GE)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
27-11
Image data format
The GE module supports PackBits format compressed data (MSB first) and uncompressed data only. The
figure below shows the image data format.
1 byte
2 bytes
btType
bcWidth
2 bytes
bcHeight
1 bit
2 bits
bcTable
bcComp
5 bits
0/6/8/16 bytes
bcBitCount
CCT
n bytes
Image data
Header (6–22 bytes)
btType:
Fixed at 0x80
bcWidth:
Image width (number of pixels)
bcHeight: Image height (number of pixels)
bcTable:
CCT enable (1: Enable, 0: Disable)
bcComp:
Compression type
bcComp
Type
Other
Reserved
0b01
PackBits
0b00
Uncompressed
bcBitCount: Color depth
bcBitCount
Color depth
0b10000
16 bpp
0b01000
8 bpp
0b00100
4 bpp
0b00010
2 bpp
0b00001
1 bpp
CCT:
Color conversion table (not included when bcTable = 0)
4 bpp image data: 16-byte 4 to 8 bpp conversion data
2 bpp image data: 8-byte 2 to 8 bpp and 2 to 4 bpp conversion data
1 bpp image data: 6-byte 1 to 8 bpp, 1 to 4 bpp, and 1 to 2 bpp conversion data
CCT (0/6/8/16 bytes)
Color depth
(size)
Byte
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
4 bpp
(16 bytes)
4 to 8 bpp table
2 bpp
(8 bytes)
Image data ...
2 to 4 bpp table
2 to 8 bpp table
1 bpp
(6 bytes)
Image data ...
1 to 2 bpp
table
1 to 4 bpp
table
1 to 8 bpp
table
None
(–)
Image data ...
3.4.2 Image Data Format
Figure 27.
Note: Image data must be located in IVRAM (Area 3) or an external memory located in Areas 13 to 22.
IRAM (Area 0) cannot be used to execute command lists.
Automatic color depth (bpp mode) conversion
If the image data has a color depth (1/2/4 bpp) different from the bpp mode set in the GE module, the color
data is automatically converted according to the GE bpp mode before the image is written to the work area
(color reduction is not supported).
The GE module uses one of the two color conversion tables (CCT and CCT1) for this conversion.
CCT
Image data
CCT1
(16 + 4 + 2 bytes)
bcTable = 1
bcTable
Color depth conversion
3.4.3 Configuration of Color Conversion Tables
Figure 27.