S3C44B0X Datasheet, PDF (320/424 Pages) Samsung semiconductor – RISC MICROPROCESSOR

LCD CONTROLLER
S3C44B0X RISC MICROPROCESSOR
The LCDBASEU register value is the first address value of the frame buffer. The lowest 4 bits must be eliminated for
burst 4 word access. The LCDBASEL register value is determined by LCD size and LCDBASEU. The LCDBASEL
value is given by the following equation:
LCDBASEL = LCDBASEU + LCDBASEL offset
Example 1:
160 x 160pixel, 4-level gray, 80 frame/sec, 4-bit single scan display, system clock frequency = 66 MHz,
WLH = 1, WDLY = 1, LCD frame buffer = SDRAM, Bus width = 16bit.
System bus occupation = (LCD data transmission frequency) / (System clock frequency)
LCD data transmission frequency = (Total LCD data during 1sec) x (Transmission cycle / 1byte)
Total LCD data during 1sec = Total LCD data x frame rate
= 160 x 160pixel x (2bit / 1pixel) x 80Hz x (1byte / 8bit) = 512Kbyte
Transmission cycle per 1byte = Transmission clock per 4word / 16
Transmission clock per 4word = Trp(=2clk) + Trcd(=2clk) + C/L(=2clk) + Burst cycle(=8clk) = 14clk
System load (system bus occupation) : 448KHz / 66MHz = 0.68%
NOTE: The higher the system load is, the lower the CPU performance is.
Example 2 (Virtual screen register) :
4 -level gray, 4-bit single scan display, Vertual screen size = 1024 x 1024, LCD size = 320 x 240,
LCDBASEU = 0x64.
1 half-word = 8 pixels(4-level gray),
Virtual screen 1 line = 128 half-word = 1024 pixels,
LCD 1 line = 320 pixels = 40 half-word,
OFFSIZE = 128 - 40 = 88 = 0x58,
PAGEWIDTH = 40 = 0x28
LCDBASEL = LCDBASEU + (PAGEWIDTH + OFFSIZE) x (LINEVAL +1) = 100 + (40 +88) x 240 = 0x3C64
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