MB87P2020 Datasheet, PDF (115/356 Pages) Fujitsu Component Limited. – Colour LCD/CRT/TV Controller

AAF Antialiasing Filter
1.3.2 Supported Colour Formats
The AAF supports only pixel data manipulation for true or high colour resolutions like RGB888, RGB565
and RGB555.
Table 1-4: supported colour formats
colour Format
RGB888
Comment
true colour format (single pixel ^a)
31
23
15
red
green
blue
7
0
dummy
RGB565
high colour format (single pixel)
31
26
20
15
7
0
red green blue
dummy
RGB555
high colour format (single pixel)
31
26
2120
15
7
0
red green
blue
dummy
dummy
bpp8, bpp4, bpp2,
colour index format (single pixel)
bpp1
31
23
15
7
0
dummy
colour index byte, depend on colourcolour
resolution the left aligned bits are used
This colour formats can not be correctly manipulated by the AAF, because the
pixel data represents index information for the CLUT (Colour Lock-up Table)
and not colour information in RGB format.
If the AAF is used and one of this colour formats should be transferred to the
SDC, the AAF calculates a new colour index, which is stored in the SDC.
The visible result at the display may not be the intended one.
Note!
To avoid such problems, the programmer should disable the AAF for this col-
our format access.
a. A single pixel means one pixel in a 32bit data word at the SDC bus (SDC format in block mode; pixel data is
MSB aligned).
1.3.3 Related SDC Configuration
The information in this section is very important for the programmer, because wrong timing at the SDC can
hang up the AAF. The ‘read to write recovery time’ (tRW) in the SDC should be set to the minimum value
of 10 for Lavender or 7 for Jasmine. This timing parameter selects a delay between read and write access
to the SDRAM and thus it influences the difference between read data and write data appear on the internal
Functional Description
Page 115