
Epson Research and Development
Page 17
Vancouver Design Center
Programming Notes and Examples
S1D13706
Issue Date: 01/02/23
X31B-G-003-03
4 Look-Up Table (LUT)
This section discusses programming the S1D13706 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 S1D13706 Hardware Functional Specification, document number X31B-A-001-xx.
The S1D13706 is designed with a LUT consisting of 256 indexed red/green/blue entries.
Each LUT entry is six bits wide. The color depth (bpp) determines how many indices are
used to output the image to the display. For example, 1 bpp uses the first 2 indices, 2 bpp
uses the first 4 indices, 4 bpp uses the first 16 indices and 8 bpp uses all 256 indices. Note
that 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[10h] bit 6).
4.1 Registers
4.1.1 Look-Up Table Write Registers
These registers contain the data to be written to the blue/green/red components of the Look-
Up Table. The data is stored in these registers until a write to the LUT Write Address
Register (REG[0Bh]) moves the data to the Look-Up Table.
Note
The LUT entries are updated only when the LUT Write Address Register (REG[0Bh]) is
written to.
REG[08h] Look-Up Table Blue Write Data Register
LUT Blue
Write Data
Bit 5
LUT Blue
Write Data
Bit 4
LUT Blue
Write Data
Bit 3
LUT Blue
Write Data
Bit 2
LUT Blue
Write Data
Bit 1
LUT Blue
Write Data
Bit 0
n/a
n/a
REG[09h] Look-Up Table Green Write Data Register
LUT Green
Write Data
Bit 5
LUT Green
Write Data
Bit 4
LUT Green
Write Data
Bit 3
LUT Green
Write Data
Bit 2
LUT Green
Write Data
Bit 1
LUT Green
Write Data
Bit 0
n/a
n/a
REG[0Ah] Look-Up Table Red Write Data Register
LUT Red
Write Data
Bit 5
LUT Red
Write Data
Bit 4
LUT Red
Write Data
Bit 3
LUT Red
Write Data
Bit 2
LUT Red
Write Data
Bit 1
LUT Red
Write Data
Bit 0
n/a
n/a