Epson Research and Development
Page 17
Vancouver Design Center
Programming Notes and Examples
SED1352
Issue Date: 98/10/08
X16-BG-007-04
3.2.2 Look-Up Table Description
The Look-Up Table (LUT, or palette) treats the value of a pixel as an index of an array of gray shades. For example, a pixel
value of zero would point to the first LUT entry; a pixel value of 7 would point to the eighth LUT entry.
Because LUT entries represent the actual gray shades shown on the LCD panel, pixel values indirectly select which gray
shade displays.
The SED1352 supports two different data formats; 4 bits-per-pixel (16 gray shades) and 2 bits-per-pixel (4 gray shades).
In 4 bits-per-pixel mode the SED1352 provides a 16 position, 4 bit wide LUT. In 2 bits-per-pixel mode, the SED1352
provides 4 “banks” of 4 position, 4 bit wide LUTs.
The value inside each LUT entry represents the gray shade. This value ranges between 0 and 15.
The SED1352FOB Look-Up Table is linear; increasing the LUT entry number results in a lighter gray shade. For example,
a LUT entry of 0Fh into a look-up entry will always result in a bright white output. An entry of 00h into a look-up entry
will always result in a black output.
Example 3:
Initialize the Look-Up Table
The following describes how to initialize the Look-Up Table for 16 gray shades. Table 3-1 shows a LUT with gray shades
starting from black (index 0) and finishing in white (index 15, or 0Fh).
1.
Write LUT index to Look-Up Table Address Register AUX[0Eh].
2.
Write LUT entry value to Look-Up Table Data Register AUX[0Fh].
3.
Repeat steps 1 and 2 until all 16 LUT entries have been written.
Table 3-1: SED1352F0B Black-To-White Look-Up Table for 16 Gray Shades
Index
(hex)
Look-Up
Table
(hex)
Index
(hex)
Look-Up
Table
(hex)
0
0
8
8
1
1
9
9
2
2
A
A
3
3
B
B
4
4
C
C
5
5
D
D
6
6
E
E
7
7
F
F