Epson Research and Development Page 13
Vancouver Design Center
Programming Notes and Examples S1D13504
Issue Date: 01/02/01 X19A-G-002-07
3.2.3 Memory Organization for Four Bit-per-pixel (16 Colors/Gray Shades)
Two pixels are grouped into one byte of display buffer as shown below:
Four bit-per-pixel provides sixteen shad es of gray by indexing into positions 0 through F of the
Green LUT and 16 levels of color by indexing into positions 0 through F of the Red/Green/Blue
LUTs.
3.2.4 Memory Organization for Eight Bit-per-pixel (256 Colors)
One pixel is stored in one byte of display buffer as shown below:
As shown above, the 256 color pixel is divided into three parts: three bits for red, three bits for green,
and two bits for blue. The red bits represent an index into the red LUT, the green bits represent an
index into the green LUT, and the blue bits represent an index into the blue LUT. Although eight bit-
per-pixel only makes sense for a color panel, this memory model can be set on a monochrome panel,
however only eight shades of gray will be visible.
Table 3-3: Pixel Storage for 4 bpp (16 Colors/Gray Shades) in One Byte of Display Buffer
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
Pixel 0
Bit 3 Pixel 0
Bit 2 Pixel 0
Bit 1 Pixel 0
Bit 0 Pixel 1
Bit 3 Pixel 1
Bit 2 Pixel 1
Bit 1 Pixel 1
Bit 0
Table 3-4: Pixel Storage for 8 bpp (256 Colors) in One Byte of Display Buffer
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
Red Bit 2 Red Bit 1 Red Bit 0 Green Bit 2 Green Bit 1 Green Bit 0 Blue Bit 1 Blue Bit 0