Table 8-15: Rgb Index Selection; Look-Up Table Registers - Epson S1D13504 Technical Manual

Page 110

8.2.8 Look-Up Table Registers

Look-Up Table Address Register
REG[24h]
n/a n/a
bits 5-4
RGB Index Bits [1:0]
00
01
10
11
bits 3-0
Look-Up Table Data Register
REG[26h]
n/a n/a
bits 3-0
S1D13504
X19A-A-002-19
The S1D13504 has three internal 16 position, 4-bit wide Look-Up Tables. The 4-bit value
programmed into each table position determines the color weighting of display data; the output gray
shade is derived from the Green Look-Up Table. These tables are bypassed in 15/16-bpp mode.
These three 16 position Look-Up Tables can be arranged in many different configurations to accom-
modate all the gray shade / color display modes.
RGB Index RGB Index
Bit 1 Bit 0
RGB Index Bits [1:0]
These bits are also used to provide access to the three internal Look-Up Tables (RGB).

Table 8-15: RGB Index Selection

Look-Up Table Access
Auto-Increment R, G, B LUT
Auto-Increment Red LUT only
Auto-Increment Green LUT only
Auto-Increment Blue LUT only
A write to this register with RGB Index bits = 00 selected will position the internal pointer to the
Red LUT. Each read/write access to the LUT data will increment the counter to point to the next
LUT in order (R to G to B to R...). A read/write access to the Blue LUT will also automatically
increment the LUT address by 1. This provides an efficient method for sequential writing of RGB
data.
When the RGB Index bits = 01, 10, or 11, the internal pointer always points to the respective R, G,
or B LUT. A read/write access to the LUT data will increment the LUT address by 1.
LUT Address Bits [3:0]
These 4 bits provide a pointer into the 16 position Look-Up Table currently selected for CPU
read/write access.
The Look-Up Table configuration (e.g. 1/2/4 banks) does not affect the read/write access from the
CPU as all 16 positions can be accessed sequentially.
n/a n/a
LUT Data Bits [3:0]
These 4 bits are the gray shade/color values used for display data output. They are programmed into
the 4-bit Look-Up Table positions pointed to by LUT Address bits [3:0] and RGB Index bits [1:0]
(if in color display modes).
For example: in a 16-level gray shade display mode, a data value of 0001b (4 bits-per-pixel) will
point to Look-Up Table position one and display the 4-bit gray shade corresponding to the value
programmed into that location.
LUT Address LUT Address
Bit 3 Bit 2
R[n], G[n], B[n], R[n+1], G[n+1] . . .
LUT Data LUT Data
Bit 3 Bit 2
Epson Research and Development
Vancouver Design Center
LUT Address LUT Address
Bit 1 Bit 0
Pointer Sequence
R[n], R[n+1], R[n+2] . . .
G[n], G[n+1], G[n+2] . . .
B[n], B[n+1], B[n+2] . . .
LUT Data LUT Data
Bit 1 Bit 0
Hardware Functional Specification
Issue Date: 01/11/06
RW
RW