AN4650 datasheet(56/102 Pages) STMICROELECTRONICS

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Mode 2 - sensor hub mode

AN4650

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DocID027415 Rev 1

Mode 2 - sensor hub mode

The hardware flexibility of the LSM6DS3 allow connecting the pins with different mode

connections to external sensors to expand functionalities such as adding a sensor hub and

an auxiliary SPI.

Three different mode connections are available:



Mode 1 - Slave-only mode: I2C/SPI(3- and 4-wire) slave interface is available;



Mode 2 - Sensor Hub mode: I2C/SPI(3- and 4-wire) slave interface and I2C master

interface for the connection of external sensors are available;



Mode 3 - Auxiliary SPI mode: I2C slave interface and auxiliary SPI (3-wire) interface

for external device connection (i.e. EIS application) are available (see Chapter 7).

The pin connections and function for each mode are described in the LSM6DS3 datasheet;

Mode 2 connection mode is described in detail in the following paragraphs.

6.1

Sensor hub mode description

In sensor hub mode (Mode 2) up to 4 external sensors can be connected to the I2C master

interface of LSM6DS3 device.

External sensor data can also be stored in FIFO with a configurable decimation factor (see

Chapter 8 for details).

If both the accelerometer and the gyroscope are in Power-Down mode, the sensor hub

doesn’t work.

All external sensors have to be connected in parallel to the SDx/SCx pins of the device, as

illustrated in Figure 18 for a single external sensor. External pull-up resistors and the

external trigger signal connection are optional and depend on the configuration of the

registers.

Figure 18. External sensor connections in Mode 2

AN4650 Datasheet(PDF) 56 Page - STMicroelectronics