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Epson Research and Development

 

Vancouver Design Center

 

 

3 Display Buffer

This section discusses how the S1D13504 stores pixels in the display buffer and where the display buffer is located.

3.1 Display Buffer Location

The S1D13504 requires either a 512K byte or a 2M byte block of memory to be decoded by the system. System logic will determine the location of this memory block; the S5U13504B00C evalu- ation board decodes the display buffer at the 12M byte location of system memory.

3.2 Display Buffer Organization

3.2.1 Memory Organization for One Bit-per-pixel (2 Colors/Gray Shades)

Eight pixels are grouped into one byte of display buffer as shown below:

Table 3-1: Pixel Storage for 1 bpp (2 Colors/Gray Shades) in One Byte of Display Buffer

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

 

 

 

 

 

 

 

 

Pixel 0

Pixel 1

Pixel 2

Pixel 3

Pixel 4

Pixel 5

Pixel 6

Pixel 7

Bit 0

Bit 0

Bit 0

Bit 0

Bit 0

Bit 0

Bit 0

Bit 0

 

 

 

 

 

 

 

 

One bit-per-pixel provides two shades of gray by indexing into positions 0 and 1 of the Green Look- Up Table (LUT) and two levels of color by indexing into positions 0 and 1 of the Red/Green/Blue LUTs.

3.2.2 Memory Organization for Two Bit-per-pixel (4 Colors/Gray Shades)

Four pixels are grouped into one byte of display buffer as shown below:

Table 3-2: Pixel Storage for 2 bpp (4 Colors/Gray Shades) in One Byte of Display Buffer

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

 

 

 

 

 

 

 

 

Pixel 0

Pixel 0

Pixel 1

Pixel 1

Pixel 2

Pixel 2

Pixel 3

Pixel 3

Bit 1

Bit 0

Bit 1

Bit 0

Bit 1

Bit 0

Bit 1

Bit 0

 

 

 

 

 

 

 

 

Two bit-per-pixel provides four shades of gray by indexing into positions 0 through 3 of the Green LUT and four levels of color by indexing into positions 0 through 3 of the Red/Green/Blue LUTs.

S1D13504

Programming Notes and Examples

X19A-G-002-07

Issue Date: 01/02/01

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Image 150
Epson S1D13504 manual Display Buffer Location, Pixel Bit