26 LCD CONTROLLER (LCDC)
26-24
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
24-bpp mode (TFT panel, LUT bypassed)
B0
LCDC signals
24-bpp pixel data
TFT panel
R signals
(high bits)
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
(high bits)
TFT panel
B signals
(high bits)
TFT panel
B signals
(low bits)
TFT panel
R signals
(low bits)
TFT panel
G signals
(low bits)
B1
G0
G1
G2
R0
R1
R2
B2
B3
B4
B5
B6
B7
G3
G4
G5
G6
G7
R3
R4
R5
R6
R7
5.6.7 FPDAT Signals in LUT Bypass Mode (TFT panel, 24-bpp mode)
Figure 26.
When a pixel data is 0x123456 (R = 0x12, G = 0x34, B = 0x56), for example, the FPDAT signals will be
configured as follows:
FPDAT15 = Low (0)
FPDAT10 = Low (0)
FPDAT4 = Low (0)
FPDAT14 = Low (0)
FPDAT9 = Low (0)
FPDAT3 = High (1)
FPDAT13 = Low (0)
FPDAT8 = High (1)
FPDAT2 = Low (0)
FPDAT12 = High (1)
FPDAT7 = High (1)
FPDAT1 = High (1)
FPDAT11 = Low (0)
FPDAT6 = Low (0)
FPDAT0 = Low (0)
FPDAT23 = Low (0)
FPDAT5 = High (1)
FPDAT18 = High (1)
FPDAT22 = High (1)
FPDAT20 = Low (0)
FPDAT17 = High (1)
FPDAT21 = Low (0)
FPDAT19 = Low (0)
FPDAT16 = Low (0)
LUT bypass mode for CSTN panel
When a CSTN panel is used, LUT bypass mode is effective if the conditions shown below are all met.
• The LUT bypass function is enabled (LUTPASS/LCDC_DISPMOD register = 1).
• Color mode is selected (COLOR/LCDC_DISPMOD register = 1).
• 1, 2, 4, 8, 12, or 16-bpp mode is selected (BPP[2:0]/LCDC_DISPMOD register = 0x0 to 0x5).
In LUT bypass mode, pixel data in the VRAM specify a halftone to generate the FPDAT signals.
The following shows the relationship between pixel data and FPDAT signals in each bpp mode:
Note: CSTN panels turn the pixels on and off periodically to generate halftones. The FPDAT signals do
not represent colors directly in contrast to TFT panels.
1-bpp mode (CSTN panel, LUT bypassed)
D0
1-bpp pixel data
R brightness of the FPDAT signal
G brightness of the FPDAT signal
B brightness of the FPDAT signal
FPDAT[7:4] (4-bit passive panel)
FPDAT[7:0] (8-bit passive panel)
5.6.8 FPDAT Signals in LUT Bypass Mode (CSTN panel, 1-bpp mode)
Figure 26.
2-bpp mode (CSTN panel, LUT bypassed)
R brightness of the FPDAT signal
G brightness of the FPDAT signal
B brightness of the FPDAT signal
D0
2-bpp pixel data
D1
FPDAT[7:4] (4-bit passive panel)
FPDAT[7:0] (8-bit passive panel)
5.6.9 FPDAT Signals in LUT Bypass Mode (CSTN panel, 2-bpp mode)
Figure 26.