BU91799KV-M Datasheet, PDF (7/29 Pages) Rohm – Low Duty LCD Segment Driver for Automotive Application

BU91799KV-M MAX 200 segments (SEG50×COM4)
Functional Descriptions
Command /Data Transfer Method
BU91799KV-M is controlled by 2-wire signal (SDA, SCL).
SDA
SCL
START condition
STOP condition
Figure 8. 2-SPI Command/Data Transfer Format
It is necessary to generate START and STOP condition when sending command or display data through this 2 wire serial
interface.
Slave address
S01111100AC
Command
A
0
START condition
Command or data judgment bit
Acknowledge
Display Data
AP
STOP condition
Figure 9. Interface Protcol
The following procedure shows how to transfer command and display data.
(1) Generate “START condition”.
(2) Issue Slave address.
(3) Transfer command and display data.
(4) Generate “STOP condition
Acknowledge
Data format is comprised of 8 bits, Acknowledge bit is returned after sending 8-bit data.
After the transfer of 8-bit data (Slave Address, Command, Display Data), release the SDA line at the falling edge of the 8th
clock. The SDA line is then pulled “Low” until the falling edge of the 9th clock SCL.
(Output cannot be pulled “High” because of open drain NMOS).
If acknowledge function is not required, keep SDA line at “Low” level from 8th falling edge to 9th falling edge of SCL.
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 10. Acknowledge Timing
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8. Feb. 2016 Rev.001