CHAPTER 4 I
2
C COMMUNICATIONS
User’s Manual U18438EJ2V0UD
55
(2) Communication format
Write data to each register on the LCD controller/driver starting from the start condition, slave ID, address,
write data, then stop condition in that order.
Figure 4-9. Communication Format for Write Operation (When Writing Twice)
Access
target
<1>
ST
<2>
Slave ID
<3>
R/W
<4>
ACK
<5>
Address
<6>
ACK
LCDCTL ST 0 1 1 1 0 0
0
0
ACK A7
A6 A5 A4 A3 A2 A1 A0 ACK
LCDSEG ST 0 1 1 1 0 0
1
0
ACK A7
A6 A5 A4 A3 A2 A1 A0 ACK
<7>
Write data 1
<8>
ACK
<9>
Write data 2
<10>
ACK
<11>
SP
D7 D6 D5 D4 D3 D2 D1 D0
ACK D7 D6 D5 D4 D3 D2 D1 D0 ACK
SP
D7 D6 D5 D4 D3 D2 D1 D0
ACK D7 D6 D5 D4 D3 D2 D1 D0 ACK
SP
Note
The address is incremented by one based on the register read/write start address by continuously
performing read/write access from transmissions of the start condition to stop condition. With this function,
the address does not need to be set each time.
Cautions 1. Generate a stop condition if an access like the one shown below is made.
• An access made in a format other than specified
• An access made with a slave ID other than specified
2.
When SDA is fixed at the low level output status due to noise, input a reset signal.
Remark
ST:
Start condition
SP:
Stop condition
A7 to A0: Addresses for LCDCTL or LCDSEG
Address
Note
LCDCTL : (A7, A6, A5, A4, A3, A2, A1, A0) + 1
LCDSEG : (A7, A6, A5, A4, A3, A2, A1, A0) + 1
Address
LCDCTL : A7, A6, A5, A4, A3, A2, A1, A0
LCDSEG : A7, A6, A5, A4, A3, A2, A1, A0