26 LCD CONTROLLER (LCDC)
26-20
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
24-bpp mode (16M colors for TFT)
In 24-bpp mode, each 3-byte data in the VRAM corresponds to one pixel. The bit[23:16] (8 bits), bit[15:8] (8
bits), and bit[7:0] (8 bits) in each 24-bit data represent the Red, Green, and Blue intensities, respectively, of the
pixel. This mode does not support the look-up table.
(1,0)
(2,0)
(3,0)
(4,0)
(0,0)
R7 R6 R5 R4
G3 G2 G1 G0
B7 B6 B5 B4
R3 R2 R1 R0
G7 G6 G5 G4
B3 B2 B1 B0
LCD
I/F
VRAM
Display start address
Byte address offset
24 bit / 1 pixel
LUT bypassed
FPDAT signals
Byte 2
Byte 1
Byte 0
(x, y)
MSB
LSB
+0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11 +12 +13 +14
Figure 26.5.5.13 VRAM Data Format in 24-bpp Mode
Example
VRAM start address: 0x10000000
Screen width:
320 pixels
LUT:
Bypassed
LCD characteristics: Data = 0
→
Low LCD brightness
Display image
Coordinates
(0, 0)
320 pixels
VRAM data
Address
0x1000 0000
0x1000 03c0
0x1000 0780
:
0x00 0x00 0xff 0x00 0xff 0x00 0xff 0x00 0x00 .....
0xff 0xff 0x00 0xff 0x00 0xff 0x00 0xff 0xff .....
0x00 0x00 0x00 0x80 0x80 0x80 0xff 0xff 0xff .....
: : : : : : : : :
960 bytes / line
Note) Display may be inverted depending on the LCD panel used.
5.5.14 Example of VRAM Data in 24-bpp Mode
Figure 26.
Note: When using the GE, 24-bpp mode cannot be set, as the GE does not support 24-bpp data.
LUT Bypass Mode
26.5.6
In LUT bypass mode (LUTPASS/LCDC_DISPMOD register = 1), VRAM data are converted directly into the FP-
DAT signals. This mode always displays gray scale images in 1/2/4-bpp mode or color images in 8/12/16/24-bpp
mode regardless of the COLOR/LCDC_DISPMOD register setting.
LUT bypass mode for TFT panel
When a TFT 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).
In LUT bypass mode, the FPDAT signals are generated directly from pixel data in the VRAM.
The following shows the relationship between pixel data and FPDAT signals in each bpp mode:
Note: The signal levels described in this section assume that SWINV/LCDC_DISPMOD register is set to
0. They will be inverted if SWINV is set to 1 (software inverse video enabled).