MB86290A Datasheet, PDF (49/184 Pages) Fujitsu Component Limited. – Graphics Controller Hardware Specifications

MB86290A scans the logical graphics field as if the entire field is rolled over
in both the horizontal and vertical directions. By using this function, if the
display frame crosses the border of the logical graphics field, the part outside
the border is covered with the other side of the logical graphics field, which is
assumed to be connected cyclically as shown below:
Logical Frame Origin
W
Additionally
drawn parts
L
Previous
origin
display
New display origin
Wrap Around Management of Display Frame
The relational 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 must be within the frame. To be more
specific, the parameters are subject to the following constraints:
0 ≤ DX < w î 64 × 8/bpp (bpp = 8 or 16)
0 ≤ DY < H
DX, DY, and DA must indicate the same point within the frame. In other
words, the following relationship must be established.
DA = OA + DX × bpp/8 + 64w î DY (bpp = 8 or 16)
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