MB87P2020 Datasheet, PDF (199/356 Pages) Fujitsu Component Limited. – Colour LCD/CRT/TV Controller

Graphic Processing Unit
Table 5-1: Number of pixels per VideoRAM word according to logical color space.
Logical Color
Space Code
ppw_log
32 16 8 4 2 2 1 2 1 2 2
a. This format is only available for MB87P2020-A (Jasmine).
Table 5-2: Number of pixels per LSA word according to physical color space.
Physical Color
Space Code
ppw_phys
24 8 6 2 2 1 1
The limiting constraint (12) can now be refined to
max(T _{seg, proc}) ≤ T _{seg, out}
(18)
since every line segment has to be fully processed during a time shorter or equal to the time a segment is
output. These two periods of time are calculated as follows:
a) Time to output a line segment:
T _{seg, out}= (T _DisplayClock ⋅ SegLen ⁄ StreamFactor)
(19)
StreamFactor = (PhysSizeX ⁄ PXScanDots) ⋅ ScanFactor
= (bpsd ⁄ bpp_phys) ⋅ ScanFactor
(20)
ScanFactor =
1
 ²
for ScanMode ≠ DualScan
for ScanMode = DualScan
(21)
The values for bits per scan dot (bpsd) and bits per physical pixel (bpp_phys) are given in tables 5-3 and 5-4.
Please note that only certain combinations of bit stream formats and physical color spaces are supported (cf.
table 3-4, p. 165).
Table 5-3: Number of bits per scan dot according to bit stream format.
Bit Stream S1 S2 S4 S6 S8 S9 S12 S18 S24 AN
Format Code
bpsd
1 2 4 6 8 9 12 18 24 24
Table 5-4: Number of bits per physical pixel according to physical color space.
Physical Color
Space Code
bpp_phys
1 3 4 9 12 18 24
Bandwidth Considerations
Page 199