CHAPTER 4 I
2
C COMMUNICATIONS
User’s Manual U18438EJ2V0UD
58
(2) Communication format
Read data from each register on the LCD controller/driver starting from the start condition, slave ID, address,
restart condition, slave ID, read data, then stop condition in that order.
Figure 4-12. Communication Format for Read Operation (When Reading 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>
RST
<8>
Slave ID
<9>
R/W
<10>
ACK
<11>
Read dara 1
<12>
ACK
RST 0 1 1 1 0 0 0 1
ACK D7 D6 D5 D4 D3 D2 D1 D0 ACK
RST 0 1 1 1 0 0 1 1
ACK D7 D6 D5 D4 D3 D2 D1 D0 ACK
<13>
Read data2
<14>
ACK
<15>
SP
D7 D6 D5 D4 D3 D2 D1 D0 NACK SP
D7 D6 D5 D4 D3 D2 D1 D0 NACK 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
RST:
Restart condition
SP:
Stop condition
A7 to A0: Addresses for LCDCTL or LCDSEG
Address
LCDCTL : A7, A6, A5, A4, A3, A2, A1, A0
LCDSEG : A7, A6, A5, A4, A3, A2, A1, A0
Address
Note
LCDCTL : (A7, A6, A5, A4, A3, A2, A1, A0) + 1
LCDSEG : (A7, A6, A5, A4, A3, A2, A1, A0) + 1