MB87P2020 Datasheet, PDF (44/356 Pages) Fujitsu Component Limited. – Colour LCD/CRT/TV Controller

MB87J2120, MB87P2020-A Hardware Manual
1.3 Signal synchronisation between MCU and display con-
troller
1.3.1 Write synchronization for Lavender and Jasmine
The data flow inside the ULB is divided in write- and read-direction. These data directions are completely
independent. That’s why there are two synchronisation points for ULB bus signals; one for write direction
and one for read direction.
The first synchronisation point is located inside ’Input Sync’ and is responsible for all ULB signals coming
from MCU (ULB_CSX,ULB_WRX, ULB_RDX, ULB_A, D_in). Other incoming MCU signals for
DMA are used directly inside the DMA controller which is partly clocked by ULB clock.
Note: For a correct operation of Input Synchronization ULB clock has to be equal or
slower than display controller core clock. Note that all tolerances for clocks should
be taken into consideration.
In Jasmine a configurable sample behaviour for input signals has been introduced. In order to avoid inter-
ferences from external bus different sample modes can be set. It can be chosen between four different sam-
ple modes. Each mode combines one or more out of three sample points distributed over one bus cycle.
Figure 1-2 shows these sample points. Note that the sample points are only valid for control signals
ULB_CLK
ULB_CS
ULB_WRX[n]
ULB_RDX
ULB_A _{000111000111000111000111000111000111000111000111000111000111000111000111000111000111000111}
ULB_D _{001100110011001100110011001100110011001100110011001100110011}
000111000111000111000111000111000111000111000111000111000111000111000111000111000111000111000111000111000111000111000111
00110011001100110011001100110011001100110011001100110011001100110011001100110011
Sample point:
0
1
2
Figure 1-2: Bus cycle sample points for Jasmine
(ULB_CSX,ULB_WRX, ULB_RDX); address and data bus are only sampled at point 2 (see figure 1-2).
The sampling is equal for read and write accesses.
The sample mode can be set in register IFCTRL_SMODE (see also table 2-1); table 1-2 shows all possible
settings and sample modes.
Table 1-2: Control signal sample modes for Jasmine
Mode
3 point mode [default]
2 of 3 point mode
IFCTRL_SMODE[1:0]
00
01
Comment
all three sample points have to have the
same value
two out of three sample points have to
have the same value (majority decision)
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