BU9797FUV-M Datasheet, PDF (6/28 Pages) Rohm – Integrated Buffer AMP for LCD Driving

BU9797FUV-M MAX 144 segments (SEG36×COM4)
Functional descriptions
Command /Data transfer method
This device is controlled by 2wire signal (SDA, SCL).
SDA
Datasheet
SCL
START condition
STOP condition
Figure 7. 2 wire Command/Data transfer Format
It has to generate the condition such as START condition and STOP condition in 2wire serial interface transfer method.
Slave address
S 0 1 1 1 1 1 0M A C
Command
A
0
START condition
R/W Command or data judgment bit
Acknowledge
Display Data
AP
STOP condition
Figure 8. Interface protcol
Method of how to transfer command and data is shown as follows.
(1) Generate “START condition”.
(2) Issue Slave address.
(3) Transfer command and display data.
Acknowledge (ACK)
Data format is 8bits and return Acknowledge after transfer 8bits data.
When SCL 8th=‟L‟ after transfer 8bit 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 no need 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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TSZ02201-0P4P0D300430-1-2
26.Aug.2013 Rev.001