26 LCD CONTROLLER (LCDC)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
26-33
Main window
160
80
120
60
180
240
0x10000000
320
240
(unit: pixel)
600
800
Sub-window
Display area
0x101257fc (480)
0x1015fffc (768)
0x10100000
480
(768)
640 (1024)
Display area
Virtual main screen (External SDRAM)
0x1003a97c (word)
Virtual sub screen (External SDRAM)
6.5.2 Sub-Window Configuration Example
Figure 26.
1. Main window start address
LCDC_MAINADR register = 0x10000000 to 0x1003a97c (word boundary address)
This register is used to change the main window location in the virtual main screen VRAM.
If LCDC_MAINADR = 0x1003a97c, the main window on the LCD panel can display only the first 8 pix-
els. The other pixels are not displayed properly, as the virtual main screen VRAM ends at that word.
2. Main screen address offset
MW_OFS[11:0] = 800 pixels
×
4 bpp
÷
32 bits = 100 words
LCDC_MAINOFS register = 100 = 0x64
3. Sub-window start address
LCDC_SUBADR register = 0x10100000 to 0x101257fc (for 640
×
480 pixels, word boundary address)
LCDC_SUBADR register = 0x10100000 to 0x1015fffc (for 1024
×
768 pixels, word boundary address)
This register is used to change the sub-window location in the virtual sub-screen VRAM.
If LCDC_SUBADR = 0x101257fc or 0x1015fffc, the sub-window on the LCD panel can display only the
first 8 pixels. The other pixels are not displayed properly, as the virtual sub-screen VRAM ends at that
word.
4. Sub-screen address offset
SW_OFS[11:0] = 640 pixels
×
4 bpp
÷
32 bits = 80 words (for 640
×
480 pixels)
LCDC_SUBOFS register = 80 = 0x50
SW_OFS[11:0] = 1024 pixels
×
4 bpp
÷
32 bits = 128 words (for 1024
×
768 pixels)
LCDC_SUBOFS register = 128 = 0x80
5. Sub-window end position
PIP_XEND[9:0] = (80 + 160) pixels
×
4 bpp
÷
32 bits - 1 = 29 words = 0x1d
PIP_YEND[9:0] = 60 + 120 lines - 1 = 179 lines = 0xb3
LCDC_SUBEP register = 0x00b3001d