Instructions

Table Of Contents

4.3.3 Data validity

After the start condition, one data bit is transferred with each clock pulse. The transmitted

data is only valid when the SDA line data is stable (high or low) during the high period of the

clock pulse. High or low state of the data line can only change when clock pulse is in low

state.

SDA

SCL

START

Condition

STOP

Condition

Valid

data

Valid change

of data

Figure 5: Data validity, START and STOP condition

4.3.4 Byte format

Data transmission on the SDA line is always done in bytes, with each byte being 8-bits long.

Data is transferred with the most signiﬁcant bit (MSB) followed by other bits.

If the slave cannot receive or transmit another complete byte of data, it can force the master

into a wait state by holding SCL low. Data transfer continues when the slave is ready which

is indicated by releasing the SCL line.

4.3.5 Acknowledge(ACK) and No-Acknowledge(NACK)

Each byte sent on the data line must be followed by an Acknowledge bit. The receiver (mas-

ter or slave) generates an Acknowledge signal to indicate that the data byte was received

successfully and another data byte could be sent.

After one byte is transmitted, the master generates an additional Acknowledge clock pulse

to continue the data transfer. The transmitter releases the SDA line during this clock pulse

so that the receiver can pull the SDA line to low state in such a way that the SDA line

remains stable low during the entire high period of the clock pulse. This is considered as an

Acknowledge signal.

In case the receiver does not want to receive any further byte, it does not pull down the SDA

line and it remains in stable high state during the entire clock pulse. This is considered as

a No-Acknowledge signal and the master can generate either a stop condition to terminate

the data transfer or a repeated start condition to initiate a new data transfer.

Differential Pressure Sensor, Part Nr. 25131308xxx01