Instructions

4.2 SDA and SCL logic levels
The positive supply voltage to which SDA and SCL lines are pulled up (through pull-up
resistors), in turn determines the high level input for the slave devices. Input reference levels
for this sensor are set as 0.7 * VDD (for logic high) and 0.3 * VDD (for logic low). See figure 4 .
Voltage
low
high
Time
V
DD
GND
0.3 x V
DD
0.7 x V
DD
Figure 4: SDA and SCL logic levels
4.3 Communication phase
4.3.1 Idle state
During the idle state, the bus is free and both SDA and SCL lines are in logic high ’1’ state.
4.3.2 START(S) and STOP(P) condition
Data transfer on the bus starts with a START command, which is generated by the master.
A start condition is defined as a high-to-low transition on the SDA line while the SCL line is
held high. The bus is considered busy after the start condition.
Data transfer on the bus is terminated with a STOP command, which is also generated by
the master. A low-to-high transition on the SDA line, while the SCL line being high is defined
as a STOP condition. After the stop condition, the bus is considered free again and is in idle
state.
Figure 5 shows the I
2
C bus START and STOP conditions.
Master can also send a REPEATED START (SR) command instead of STOP command.
REPEATED START condition is the same as the START condition.
Differential Pressure Sensor, Part Nr. 25131308xxx01
User manual version 1.0 © August 2019
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