RA8806
Preliminary Version 1.0
Two Layers Character/Graphic LCD Controller
6-1-2 Command Write
According to the Table 5-1, RA8806 accept 4 cycles through MPU interface. If users want to write
command to RA8806, then a Command cycle has to execute first, and then execute a Data Write
cycle. The “Command Write” means write function data to register. After these two cycles, the Data
will write into the indicative Register. Please see the following Figure 6-5 (1).
In Table 6-1 of Section 6-1-1, each command of RA8806 is take 2 cycles, and the minimum cycle
time is 2*tc. So totally the minimum time of command write need 4*tc. See following Table 6-3.
If the secondary cycle is a “Data Read”, then user could read the register content. See the following
Figure 6-5 (2). Note the Figure 6-5 to Figure 6-7 are use the 8080 MPU interface as examples.
RS
ZCS1
ZWR
ZRD
DATA[7:0]
REG#
DATA
(1) Command Write (Write Data to Register)
RS
ZCS1
ZWR
ZRD
DATA[7:0]
REG#
DATA
(2) Read Data from Register
Figure 6-5 : Command Write and Register Read Cycle
Table 6-3 : Command Access Time Table
System Clock
4MHz
Command Access Time
1µs
6 MHz
667ns
500ns
400ns
333ns
8 MHz
10 MHz
12 MHz
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