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LCD CONTROLLER S3C2440A RISC MICROPROCESSOR
15-34
FRAME Buffer Start Address 3 Register
Register Address R/W Description Reset Value
LCDSADDR3 0X4D00001C R/W
STN/TFT: Virtual screen address set
0x00000000
LCDSADDR3 Bit Description Initial State
OFFSIZE [21:11] Virtual screen offset size (the number of half words).
This value defines the difference between the address of the last half
word displayed on the previous LCD line and the address of the first
half word to be displayed in the new LCD line.
00000000000
PAGEWIDTH [10:0] Virtual screen page width (the number of half words).
This value defines the width of the view port in the frame.
000000000
Note
The values of PAGEWIDTH and OFFSIZE must be changed when ENVID bit is 0.
Example 1. LCD panel = 320 x 240, 16gray, single scan
Frame start address = 0x0c500000
Offset dot number = 2048 dots ( 512 half words )
LINEVAL = 240-1 = 0xef
PAGEWIDTH = 320 x 4 / 16 = 0x50
OFFSIZE = 512 = 0x200
LCDBANK = 0x0c500000 >> 22 = 0x31
LCDBASEU = 0x100000 >> 1 = 0x80000
LCDBASEL = 0x80000 + ( 0x50 + 0x200 ) x ( 0xef + 1 ) = 0xa2b00
Example 2. LCD panel = 320 x 240, 16gray, dual scan
Frame start address = 0x0c500000
Offset dot number = 2048 dots ( 512 half words )
LINEVAL = 120-1 = 0x77
PAGEWIDTH = 320 x 4 / 16 = 0x50
OFFSIZE = 512 = 0x200
LCDBANK = 0x0c500000 >> 22 = 0x31
LCDBASEU = 0x100000 >> 1 = 0x80000
LCDBASEL = 0x80000 + ( 0x50 + 0x200 ) x ( 0x77 + 1 ) = 0x91580
Example 3. LCD panel = 320*240, color, single scan
Frame start address = 0x0c500000
Offset dot number = 1024 dots ( 512 half words )
LINEVAL = 240-1 = 0xef
PAGEWIDTH = 320 x 8 / 16 = 0xa0
OFFSIZE = 512 = 0x200
LCDBANK = 0x0c500000 >> 22 = 0x31
LCDBASEU = 0x100000 >> 1 = 0x80000
LCDBASEL = 0x80000 + ( 0xa0 + 0x200 ) x ( 0xef + 1 ) = 0xa7600