Epson Research and Development
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Vancouver Design Center
4 Look-Up Table (LUT)
This section discusses programming the S1D13506 Look-Up Table (LUT). Included is a
summary of the LUT registers, recommendations for color/gray shade LUT values, and
additional programming considerations. For a discussion of the LUT architecture, refer to
the S1D13506 Hardware Functional Specification, document number X25B-A-001-xx.
The S1D13506 is designed with a separate LUT for both the LCD and CRT/TV. Each LUT
consists of 256 indexed red/green/blue entries. Each LUT entry is four bits wide. The color
depth determines how many indices are used to output the image to the display. 4 bpp uses
the first 16 indices, 8 bpp uses all 256 indices, and 15/16 bpp color depths bypass the LUT
entirely.
In color modes, the pixel values stored in the display buffer index directly to an RGB value
stored in the LUT. In monochrome modes, the pixel value indexes into the green
component of the LUT and the amount of green at that index controls the intensity.
Monochrome mode look-ups are done based on the Color/Mono Panel Select bit
(REG[030h] bit 2). The CRT interface receives the RGB values from the LUT even if
simultaneous display is used with a monochrome panel. Therefore, it is important to
program the R, G, and B components of the CRT LUT either with a unique set of values,
or with R, G, and B values all equivalent.
4.1 Registers
REG[1E0h] Look-Up Table Mode Register
n/a n/a n/a
LUT Mode
Bit 1
LUT Mode
Bit 0
n/a
n/a
n/a
The S1D13506 is designed with a separate LUT for both the LCD and CRT/TV. The LUT
Mode register selects which of the LUTs will be accessed by the CPU when reads/writes
are made to REG[1E2h] and REG[1E4h]. LUT mode selection allows the LUTs to be
individually written or have identical data written to both LUTs. Individual writes to these
registers are useful for Epson Independent Simultaneous Display (EISD) modes where
independent images are displayed on the LCD and the CRT/TV. For further information on
Epson Independent Simultaneous Display, see the S1D13506 Hardware Functional
Specification, document number X25B-A-001-xx.
For normal operation, this register should be set to 00h which will read the LCD LUT and
write both the LCD and CRT/TV LUTs with identical data. For selection of other LUT
modes, see REG[1E0h] in the S1D13506 Hardware Functional Specification, document
number X25B-A-001-xx.
REG[1E2h] Look-Up Table Address Register
LUT Address LUT Address LUT Address LUT Address LUT Address LUT Address LUT Address LUT Address
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Programming Notes and Examples
Issue Date: 01/02/06
S1D13506
X25B-G-003-03