Fujitsu MB86R02 Jade-D Hardware Manual page 380

MB86R02 'Jade-D' Hardware Manual V1.64
The display controller scans the logical graphics space as if the entire space is rolled over in both the
horizontal and vertical directions. Using this function, if the display frame crosses the border of the
logical graphics space, the part outside the border is covered with the other side of the logical graphics
space, which is assumed to be connected cyclically as shown below:
Logical Frame Origin
L
The expression of the X and Y coordinates in the frame and their corresponding linear addresses (in
bytes) is shown below.
×
A(x,y) = x bpp/8 + 64wy (bpp = 8 or 16)
The origin of the displayed coordinates has to be within the frame. To be more specific, the
parameters are subject to the following constraints:
0 ≤ DX < w
× ×
64 8/bpp (bpp = 8 or 16)
0 ≤ DY < H
DX, DY and DA have to indicate the same point within the frame. In short, the following relationship
must be satisfied.
×
DA = OA + DX bpp/8 + 64w
18-22
64 w
Additionally
drawn area
Wrap Around of Display Frame
×
DY (bpp = 8 or 16)
Previous display
origin
New display origin