AN3209 datasheet(19/42 Pages) STMICROELECTRONICS

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AN3209

Component overview

Doc ID 17419 Rev 2

19/42

2.3.2

STTS75 I2C interface

The STTS75 has a simple 2-wire I2C-compatible digital serial interface which allows to

access the data stored in the temperature register at any time.

It communicates via the serial interface with a master controller which operates at speeds

up to 400 kHz. However, for the demonstration datalogger application the master operates

at a speed of 100 kHz.

A0, A1, and A2 pins select the address and allow to connect to up to 8 devices on the same

bus without address conflict. For the demonstration application, A0, A1 and A2 are

connected to ground.

STTS75 I2C device address is 1001 0000b (0x90).

2.3.3

STTS75 I2C commands

The I2C master requests the sensor to acquire a temperature value and read the data from

the sensor register. These operations are performed by calling functions of the I2C library,

i2c_ee.c. Refer to Appendix C: STTS75 I2C commands for a detailed description of these

STTS75 functions.

Acquire temperature

To configure the temperature sensor in temperature acquisition mode, the I2C master sends

a Pointer Set Configuration Register Write frame as shown in Figure 14.

This is done by calling the I2C_SS_Config (uint16_t ConfigBytes) function.

Figure 14.

Typical Pointer Set Configuration Register Write

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