Page 16 Epson Research and Development
Vancouver Design Center
S1D13505 Programming Notes and Examples
X23A-G-003-07 Issue Date: 01/02/05
3 Memory Models
The S1D13505 is capable of several color depths. The memory model for each color d epth
is packed pixel. Packed pixel data changes with each color depth from one byte containing
eight consecutive pixels up to two bytes being required for one pixel.

3.1 Display Buffer Location

The S1D13505 supports either a 512k byte or 2M byte display buffer. The display buf fer is
memory mapped and can be accessed directly by software. The memory location allo cated
to the S1D13505 display buffer varies with each individual hardware platform, and is
determined by the OEM.
For further information on the display buffer, see the S1D13505 Hardware Functional
Specification, document number X23A-A-001-xx.

3.1.1 Memor y Organization for One Bit-Per-Pixel (2 Colors/Gray Shades)

Figure 3-1: Pixel Storage for 1 Bpp (2 Colors/Gray Shades) in One Byte of Display Buffer
In this memory format each byte of display buffer contains eight adjace nt pixels. Se tting or
resetting any pixel will require reading the entire byte, masking out the appropriate bits and ,
if necessary, setting the bits to ’1’.
One bit pixels provide two gray shade/color possibilities. For monochrome panels the two
gray shades are generated by indexing into the first two elements of the green component
of the Look-Up Table (LUT). For color panels the two colors are derived by indexing into
positions 0 and 1 of the Look-Up Table.
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
Pixel 0Pixel 1Pixel 2Pixel 3Pixel 4Pixel 5Pixel 6Pixel 7