Pressure sensors

Barometric pressure transmitters for SMT

ASB series

Preliminary data

AS SEN PD

2011-05-02

Please read Cautions and warnings and

Page 7 of 16

Important notes at the end of this document

.

I²C measurement request operation (Read_MR)

The Read_MR command forces the sensor to wake up from sleep mode and to perform a complete measurement and

calculation cycle. The Read_MR command is only containing the slave address and the READ bit (HIGH state) both sent by

the master. After the sensor responds with the slave ACK, the master must create a stop condition.

S 6 5 4 3 2 1 0 R A

Device Slave Address

[0:6]

Wait for

Slave ACK

S

S

R

A

S

Start Condition

Device Slave Address (0x28h)

Read Bit (HIGH)

Acknowledge (ACK)

Stop Condition

S 6 5 4 3 2 1 0 R A

Device Slave Address

[0:6]

Wait for

Slave ACK

S

S

R

A

S

Start Condition

Device Slave Address (0x28h)

Read Bit (HIGH)

Acknowledge (ACK)

Stop Condition

I²C reduced measurement request operation (Write_MR)

The Write_MR command forces the sensor to wake up from sleep mode and to perform only a pressure measurement and

calculation cycle. (Please Note: Obsolete, maybe invalid, temperature data is used to calculate the pressure data. For using

updated temperature data, please use the I²C measurement request operation – Read_MR) The Write_MR command is

faster then the Read_MR command, but perhaps results are insufficient. The Write_MR command is only containing the

slave address and the WRITE bit (LOW state) both sent by the master. After the sensor responds with the slave ACK, the

master must create a stop condition.

S 6 5 4 3 2 1 0 W A

Device Slave Address

[0:6]

Wait for

Slave ACK

S

S

W

A

S

Start Condition

Device Slave Address (0x28h)

Write Bit (LOW)

Acknowledge (ACK)

Stop Condition

S 6 5 4 3 2 1 0 W A

Device Slave Address

[0:6]

Wait for

Slave ACK

S

S

W

A

S

Start Condition

Device Slave Address (0x28h)

Write Bit (LOW)

Acknowledge (ACK)

Stop Condition

I²C data fetch operations

For data fetch operations, the I²C master must start with the 7bit slave address (0x28h) with the 8

The sensor (I²C slave node) sends an acknowledge (ACK) indicating success. The sensor sends up to 4 data bytes

depending on the master’s NACK.

S 6 5 4 3 2 1 0 R A

S

15 14 13 12 11 10 9 8 A 7 6 5 4 3 2 1 0 A 10 9 8 7 6 5 4

A

3

Device Slave Address

[0:6]

Wait for

Slave ACK

Pressure Data

[13:8]

Master ACK

Pressure Data

[7:0]

Master ACK

Temperature Data

[10:3]

Master ACK

T. Data

[2:0]

reserved

Master NACK

S

R

A

Start Condition

Device Slave Address (0x28h)

Read Bit

Acknowledge (ACK)

No Acknowledge (NACK)

Status Bit

Pressure Data

Temperature Data

x

reserved

N

S 6 5 4 3 2 1 0 R A

S

15 14 13 12 11 10 9 8 A 7 6 5 4 3 2 1 0 A 10 9 8 7 6 5 4

A

3

Device Slave Address

[0:6]

Wait for

Slave ACK

Pressure Data

[13:8]

Master ACK

Pressure Data

[7:0]

Master ACK

Temperature Data

[10:3]

Master ACK

T. Data

[2:0]

reserved

Master NACK

S

R

A

Start Condition

Device Slave Address (0x28h)

Read Bit

Acknowledge (ACK)

No Acknowledge (NACK)

Status Bit

Pressure Data

Temperature Data

x

reserved

N