26 LCD CONTROLLER (LCDC)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
26-27
When an entry data is 0x5b37 (R = 0xb, G = 0x19, B = 0x17), for example, the FPDAT signals (for TFT)
will be configured as follows:
FPDAT15 = Low (0)
FPDAT10 = Low (0)
FPDAT4 = High (1)
FPDAT14 = High (1)
FPDAT9 = High (1)
FPDAT3 = Low (0)
FPDAT13 = Low (0)
FPDAT8 = High (1)
FPDAT2 = High (1)
FPDAT12 = High (1)
FPDAT7 = Low (0)
FPDAT1 = High (1)
FPDAT11 = High (1)
FPDAT6 = Low (0)
FPDAT0 = High (1)
FPDAT5 = High (1)
FPDAT[23:16] = Low (0)
(Note) Display may be inverted depending on the LCD panel used.
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.
Setting data to LUTRAM
LUTRAM (DSTRAM) cannot be accessed from the CPU, when it is configured as the color look-up table
(DSTRAM_CFG = 1). Therefore, prepare the look-up table data in another memory (IVRAM or an external
memory) and use the LCDC reload function to set the prepared data to the LUTRAM. For more informa-
tion on the LCDC reload function, see Section 26.9.
Monochrome look-up table (MLUT)
The LCDC uses MLUT to convert VRAM data into gray scale data if the conditions shown below are all met.
• The LUT bypass function is disabled (LUTPASS/LCDC_DISPMOD register = 0).
• Monochrome mode is selected (COLOR/LCDC_DISPMOD register = 0).
• 1, 2, or 4-bpp mode is selected (BPP[2:0]/LCDC_DISPMOD register = 0x0 to 0x2).
The monochrome look-up table consists of 4 bits
×
16 entries as shown in the figure below. The software can
set a gray level out of 16 levels in each entry. The entries to be used depend on the bpp mode selected.
Brightness of the FPDAT signal
D0
D1
D2
D3
D0
D1
D2
D3
D0
D1
D2
D3
D0
D1
D2
D3
D0
D1
D2
D3
D0
D1
D2
D3
D0
D1
D2
D3
VRAM data
(selects an entry)
Monochrome look-up table
4-bit gray scale data
LSB
MSB
Entry No.
0
1
2
3
4
:
14
15
for 1-bpp
for 2-bpp
for 4-bpp
:
:
5.7.2 Monochrome Look-up Table Configuration
Figure 26.
Note: An FPDAT signal is assigned to a pixel and 4 or 8 pixel data are sent to the MSTN panel at the
same time. MSTN panels turn the pixels on and off periodically to generate gray levels. The FP-
DAT signals do not represent gray levels directly in contrast to TFT panels.
Setting data to the monochrome look-up table
Use the monochrome look-up table data registers for writing and reading 4-bit gray scale data to/from
the look-up table. The monochrome look-up table data registers are mapped to addresses 0x302090 and
0x302094.