MB87P2020 Datasheet, PDF (103/356 Pages) Fujitsu Component Limited. – Colour LCD/CRT/TV Controller

Pixel Processor
c. REQCNT is important for bandwith considerations. Large values give fast PP data throughput but increasing
risk of shortage for real-time devices GPU/VIC. If REQCNT is different from 0, data can remain in PP
FIFOs (not sufficient amount for packetized transfer). The remaining data is flushed with start of the next
command, i.e. if the drawing is finished with a NoOp command.
d. To avoid consistency problems during read-modify-write access it is recommended to set READINIT behav-
ior to ’1’. Thus read and write accesses use the same register. The copy procedure from configuration register
to the internal buffered register is controlled by the pixel processor. The internal value is fixed during running
commands.
1.3 Special Command Options
1.3.1 Bitmap Mirror
Bitmap mirror option is for enhancement of symmetric objects. Original object is drawn in any case. It is
possible in one or both X- and Y-direction. Thus only the half or the quarter of an bitmap needs to be trans-
ferred. Mirroring is usable for bitmap commands PutBM, PutCP, PutTxtBM and PutTxtCP. Mirroring axis
are defined by the end point coordinates.
XMIN XMAX
YMIN
direction
YMAX
mirror in x-direction
mirror in y-direction
Figure 1-2: Mirroring Function
mirror in x-direction
and y-direction
1.3.2 Bitmap Direction
Bitmap direction option swaps X- and Y- coordinates relative to the start point. Original bitmap is not
drawn. It could be understood as flipping the object at an axis through the start point with an angle of 45
degree. If PPCMD_DIR = 1 the new end point calculates to
Xmax’ = Xmin + Ymax - Ymin
Ymax’ = Ymin + Xmax - Xmin
Xmin
Ymin
Xmax’
Ymax
Xmax
PPCMD_DIR = 0
Ymax’
Figure 1-3: Direction Option
PPCMD_DIR = 1
Functional Description
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