sed1355 ETC-unknow, sed1355 Datasheet - Page 168

• Manufacturer Part Number: sed1355
• Description: Sed1355 Embedded Ramdac Lcd/crt Controller
• Manufacturer: ETC-unknow

Page 12
3 Memory Models
3.1 Display Buffer Location
3.1.1 Memory Organization for One Bit-Per-Pixel (2 Colors/Gray Shades)
3.1.2 Memory Organization for Two Bit-Per-Pixel (4 Colors/Gray Shades)
SED1355
X23A-G-003-05
Pixel 0
Pixel 0
Bit 7
Bit 7
Bit 1
Pixel 1
Pixel 0
Bit 6
Bit 6
Bit 0
Figure 3-1: Pixel Storage for 1 Bpp (2 Colors/Gray Shades) in One Byte of Display Buffer
Figure 3-2: Pixel Storage for 2 Bpp (4 Colors/Gray Shades) in One Byte of Display Buffer
The SED1355 is capable of several color depths. The memory model for each color depth 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.
The SED1355 requires either a 512K byte or 2M byte block of memory to be decoded by the system.
System logic will determine the location of this memory block. See Section 9 of the Hardware
Functional Specification, document number X23A-A-001-xx, for details.
In this memory format each byte of display buffer contains eight adjacent pixels. Setting 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.
In this memory format each byte of display buffer contains four adjacent pixels. Setting or resetting
any pixel will require reading the entire byte, masking out the appropriate bits and, if necessary,
setting the bits to '1'.
Two bit pixels are capable of displaying four gray shade/color combinations. For monochrome
panels the four gray shades are generated by indexing into the first four elements of the green
component of the Look-Up Table. For color panels the four colors are derived by indexing into
positions 0 through 3 of the Look-Up Table.
Pixel 2
Pixel 1
Bit 5
Bit 5
Bit 1
Pixel 3
Pixel 1
Bit 4
Bit 4
Bit 0
Pixel 4
Pixel 2
Bit 3
Bit 3
Bit 1
Pixel 5
Pixel 2
Bit 2
Bit 2
Bit 0
Epson Research and Development
Programming Notes and Examples
Pixel 6
Pixel 3
Bit 1
Bit 1
Bit 1
Vancouver Design Center
Issue Date: 99/04/27
Pixel 7
Pixel 3
Bit 0
Bit 0
Bit 0