Graphic Window On Screen - Freescale Semiconductor MCF5329 Reference Manual

Liquid Crystal Display Controller (LCDC)
screen-sized window can be vertically or horizontally scrolled (panned) anywhere inside the virtual page
boundaries. The software must control the starting address in the SSA properly so that the scanning logic's
system memory pointer (SMP) stays within the VPW and VPH limits to prevent the display of strange
artifacts on the screen.
VPH is used by the programmer only for boundary checks. There is no VPH parameter internal to the
LCDC.
VPW is used in calculating the RAM starting address representing the beginning of each displayed line.
SSA sets the address of data for the first line of a frame. For each subsequent line, VPW is added to an
accumulation initialized by the SSA to yield the starting address of that line.
22.4.2

Graphic Window on Screen

Graphic window is supported in LCD color panel screens for viewfinder and graphic hardware cursor
functions. Similar to the screen, the virtual page width, graphic window start address and graphic window
width and height are software programmable. The position of the graphic window on screen is specified
by the graphic window position register.
placed on the screen.
Graphic Window Virtual Page Width
Graphic Window Image
Graphic Window Width
Graphic window
Graphic Window Start Address
The graphic window and background plane can be alpha blended. The alpha value is programmable on a
window basis, which means all the pixels in the graphic window have the same level of transparency.
There are a total of 256 levels of transparency to be configured. In addition, one of the pixel colors can be
chosen for color keying in which the selected pixel color in the graphics window is made totally
transparent. One of the applications can be a graphical hardware cursor.
The graphic window and background images must have the same bpp
setting.
22-30
Figure 22-28 shows how the graphic window is configured and
Graphic
Window
Height
Figure 22-28. Graphic Window on Screen
NOTE
MCF5329 Reference Manual, Rev 3
Background Image
Screen
Graphic Window Position
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