26 LCD CONTROLLER (LCDC)
26-26
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
4-bpp mode (MSTN panel, LUT bypassed)
Brightness of the FPDAT signal
D0
4-bpp pixel data
D1
D2
D3
5.6.16 FPDAT Signals in LUT Bypass Mode (MSTN panel, 4-bpp mode)
Figure 26.
Look-up Tables
26.5.7
When the look-up table is enabled, a pixel data in the VRAM is used as an index to the look-up table, so that FP-
DAT signals are generated based on the color or gray level stored in the LUT entry indicated by the VRAM data,
before being output to the LCD panel.
The S1C33L26 includes two different look-up tables, LUTRAM for color mode and MLUT for monochrome
mode.
Color look-up table (LUTRAM)
The LCDC uses LUTRAM to convert VRAM data into color data if the conditions shown below are all met.
• The LUT bypass function is disabled (LUTPASS/LCDC_DISPMOD register = 0).
• Color mode is selected (COLOR/LCDC_DISPMOD register = 1).
• DSTRAM (Area 3) is configured as LUTRAM (DSTRAM_CFG/MISC_IRAM_LOC register = 1).
• 1, 2, 4, or 8-bpp mode is selected (BPP[2:0]/LCDC_DISPMOD register = 0x0 to 0x3).
Note: Ensure sufficient memory bandwidth for LCDC processing when using the color look-up table. An
external SDRAM is recommended for the VRAM.
The color look-up table consists of 16 bits
×
256 entries as shown in the figure below.
Each entry consists of 5-bit Red data (D[15:11]), 6-bit Green data (D[10:5]), and 5-bit Blue data (D[4:0]). This
allows the software to set a color out of 65,536 colors in each entry. The entries to be used depend on the bpp
mode selected.
VRAM data
(selects an entry)
Color look-up table
16-bit color data
LSB
MSB
Entry No.
0
1
2
3
4
:
14
15
16
:
154
255
:
:
:
B0
LCDC signals
TFT
CSTN
0
TFT panel
R signals
FPD
AT23
FPD
AT22
FPD
AT21
FPD
AT20
FPD
AT19
FPD
AT18
FPD
AT17
FPD
AT16
FPD
AT15
FPD
AT14
FPD
AT13
FPD
AT12
FPD
AT11
FPD
AT10
FPD
AT
9
FPD
AT
8
FPD
AT
7
FPD
AT
6
FPD
AT
5
FPD
AT
4
FPD
AT
3
FPD
AT
2
FPD
AT
1
FPD
AT
0
TFT panel
G signals
TFT panel
B signals
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
:
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
B brightness of
the FPDAT signal
G brightness of
the FPDAT signal
R brightness of
the FPDAT signal
B0
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
G3
G4
G5
R3
R4
for 1-bpp
for 2-bpp
for 4-bpp
for 8-bpp
FPDAT[7:4] (4-bit passive panel)
FPDAT[7:0] (8-bit passive panel, Format 1/2)
5.7.1 Color Look-up Table Configuration
Figure 26.