All Sensors

DS-0300 Rev A

Digital Interface Data Format

For either type of digital interface, the format of data returned from the sensor is the same. The first 16 bits consist of

the 2 Status bits followed by the 14-bit the pressure value. The third byte provides the 8 most significant bits of the mea-

sured temperature; the fourth byte provides the 3 least significant bits of temperature, followed by 5 bits of undefined

filler data. With either interface, the host may terminate the transfer after receiving the first two bytes of data from the

sensor, or following the third byte (if just the most-significant 8 bits of temperature are needed). Refer to Table 2 for the

overall data format of the sensor. Table 3 shows the Status Bit definition.

Bit Definitions:

Status (S): Normal/command / busy / diagnostic

Pressure (P): Digital pressure reading

Temperature (T): Compensated temperature reading

Table 2 - Output Data Format

Table 3- Status Bit Definitions

I2C Interface

I2C Communications Overview

The I2C interface uses a set of signal sequences for communication. The following is a description of the supported

sequences and their associated pneumonic. Refer to Figure 3 for the associated usage of the following signal sequences.

Bus not Busy (I): During idle periods both data line (SDA) and clock line (SCL) remain HIGH.

START condition (ST): A HIGH to LOW transition of SDA line while the clock (SCL) is HIGH is interpreted as

START condition. START conditions are always set by the master. Each initial request for a pressure value has to

begin with a START condition.

Slave address (An): The I²C-bus requires a unique address for each device. The DLVR sensor has a preconfig-

ured slave address (0x28). After setting a START condition the master sends the address byte containing the

7 bit sensor address followed by a data direction bit (R/W). A "0" indicates a transmission from master to slave

(WRITE), a "1" indicates a datarequest (READ).

Acknowledge (A or N): Data is transferred in units of 8 bits (1 byte) at a time, MSB first. Each data-receiving

device, whether master or slave, is required to pull the data line LOW to acknowledge receipt of the data. The

Master must generate an extra clock pulse for this purpose. If the receiver does not pull the data line down, a

NACK condition exists, and the slave transmitter becomes inactive. The master determines whether to send

the last command again or to set the STOP condition, ending the transfer.

DATA valid (Dn): State of data line represents valid data when, after a START condition, data line is stable for

duration of HIGH period of clock signal. Data on line must be changed during LOW period of clock signal.

There is one clock pulse per data bit.

DATA operation: The sensor starts to send 4 data bytes containing the current pressure and temperature val-

ues. The transmission may be halted by the host after any of the bytes by responding with a NACK.

STOP condition (P): LOW to HIGH transition of the SDA line while clock (SCL) is HIGH indicates a STOP condi-

tion. STOP conditions are always generated by the master.

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