BU97950FUV Datasheet, PDF (6/25 Pages) Rohm – Standard LCD Segment Drivers

BU97950FUV MAX 280 segments (SEG35×COM8)
●Function Description
○Command /Data transfer method
This device is controlled by 2-wire serial signal (SDA, SCL).
SDA
SCL
START condition
STOP condition
Figure 7. 2-wire Serial Command/Data Transfer Format
START and STOP conditions are required in 2-wire serial interface transfer method.
Slave address
S01111100AC
Command
A
0
START condition
Command or data judgment bit
Acknowledge
Display Data
AP
STOP condition
Figure 8. Interface Protocol
Method of transferring command and data is as follows:
1) Generate “START condition”.
2) Send Slave address.
3) Send command and display data.
4) Generate “STOP condition”.
○Acknowledge
Data format is 8-bit and an Acknowledge bit is returned after transfer of 8-bit data.
When SCL 8th=‟L‟ after transfer of 8-bit data (Slave Address, Command, Display Data), output ‟L‟ and open SDA line.
When SCL 9th=‟L‟, stop output function.
(As Output format is NMOS-Open-Drain, can‟t output „H‟ level.)
If there is no need for Acknowledge function, please input „L‟ level from SCL 8th=‟L‟ to SCL 9th=‟L‟.
SDA
SCL
1-7
8
9
S
SLAVE ADDRESS ACK
START
condition
1-7
8
9
DATA
ACK
1-7
8
9
DATA
P
ACK
STOP
condition
Figure 9. Acknowledge timing
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08.Sep.2015 Rev.004