Epson S1D13705 3.2 2 Bit-Per-Pixel (4 Colors/Gray Shades), 3.3 4 Bit-Per-Pixel (16 Colors/Gray Shades)

Epson Research and Development Page 13
Vancouver Design Center
Programming Notes and Examples S1D13705
Issue Date: 02/01/22 X27A-G-002-03
3.2 2 Bit-Per-Pixel (4 Colors/Gray Shades)
2-bit pixels support four color/gray shades. In this memory format each byte of display
buffer contains four adjacent pixels. Setting or resetting any pixel requires reading the
entire byte, masking out the appropriate bits and, if necessary, setting bits to “1”.
Color panels derive their four colors by indexing into positions 0 through 3 o f the Look-Up
Table. These four LUT entries can be set to any of the 4096 possible color combinations.
Monochrome panels derive four gray shades by indexing into the first four elements of the
green component of the Look-Up Table. Any of the four LUT entries can be set to any of
the sixteen possible gray shades.
Figure 3-2: Pixel Storage for 2 Bpp (4 Colors/Gray Shades) in One Byte of Display Buffer
3.3 4 Bit-Per-Pixel (16 Colors/Gray Shades)
Four bit pixels support 16 color/gray shades. In this memory format each byte of display
buffer contains two adjacent pixels. Setting or resetting any pixel requires reading the ent ire
byte, masking out the upper or lower nibble (4 bits) and setting the appropriate bits to “1”.
Color panels can display up to sixteen colors simultaneously. These sixteen colors are
derived by indexing into the first sixteen elements of the Look-Up Table. Each of these
colors may be selected from the 4096 possible available colors.
On a monochrome panel the gray shades are generated by indexing into the first sixteen
green components of the LUT. Each of these sixteen possible gray shades can be adjusted
to any of the sixteen possible gray shades. For instance, one could program the first eight
green LUT entries to be 0 and the second green LUT entries to be FFh. This would result
in nibble values of 0 through 7 displaying as black and nibble values 8 through 0Fh
displaying as white.
Figure 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 1 Pixel 0 Bit 0 Pixel 1 Bit 1 Pixel 1 Bit 0 Pixel 2 Bit 1 Pixel 2 Bit 0 Pixel 3 Bit 1 Pixel 3 Bit 0
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 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