MB87P2020 Datasheet, PDF (126/356 Pages) Fujitsu Component Limited. – Colour LCD/CRT/TV Controller

MB87J2120, MB87P2020-A Hardware Manual
much faster than VIC it can happen that one layer is displayed more than one time. On the other hand, if
VIC is much faster than GPU the display of some layers may be skipped. In any case no artefacts within
one layer are visible.
To decrease memory size needed for video input all needed layers for synchronization (two or three) may
be set to one layer number. In this case VIC and GPU uses only one layer. Of course no frame rate synchro-
nization is done and artefacts may be visible on display within video.
As an additional feature VIC supports a so called ’alpha channel’. Via a special pin (VSC_ALPHA) an ex-
ternal video scaler signals the VIC not to take the pixel color for the current coordinate but a special color
previously defined in a special register (VICALPHA). This color is written to Video memory instead of vid-
eo color.
Together with other features of display controller such as transparent color and blinking inside GPU various
effects can be achieved.
Jasmine contains a window function where a rectangular area (window) can be defined which treats as clip-
ping rectangle for video input data. Only data within this window are written to Video Memeory.
This function can be used to cut out a part of the video frame in order to save memory. It is also used to
remove blanking information in special input timing modes (see chapter 2.3 for details).
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