LIS2DS12 datasheet(31/68 Pages) STMICROELECTRONICS

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LIS2DS12

Digital main blocks

The algorithm and its variables can be reset just by writing the STEP_CNT_ON bit to ‘0’-

logic, i.e. turning off the SD/SC routine. The RST PEDO bit in the FUNC_CK_GATE (3Dh)

value until the algorithm ends the reset procedure, which is carried out at the first execution

after the SD/SC routine has been re-enabled, before the algorithm starts.

5.5.2

Significant motion

The significant motion functionality can be used in location-based applications in order to

receive a notification indicating when the user is changing location. This function has been

implemented in hardware and works at 25 Hz, so the accelerometer ODR must be set at 25

Hz or higher values.

The significant motion interrupt signal can be driven to the interrupt pin by setting to 1 the

INT2_SIG_MOT bit of the CTRL5 (24h) register; it can also be checked by reading the

SIG_MOT_DET bit of the FUNC_CK_GATE (3Dh) register.

The significant motion function generates an interrupt when the difference between the

number of steps from its initialization is higher or equal than a threshold. The threshold

value corresponds to the number of steps to be performed by the user upon a change of

location before the significant motion interrupt is generated.

The threshold has a default value equal to 6. This threshold is configurable in the SM_THS

(34h) register in the advanced configuration registers (refer to Section 9: Advanced

configuration register mapping and Section 10: Advanced configuration registers

description). The significant motion threshold can be used if the FUNC_CFG_EN bit in

CTRL2 (21h) is set to "1".

5.5.3

Sensor hub

The embedded sensor hub allows acquiring data (up to 6 acquisition) from one external

sensor and collecting them in dedicated registers using the I2C master interface. These data

can be read by the external application processor accessing the registers through the

SPI/I2C interfaces.

The frequency of the serial clock is 40 kHz. Lines used for communication are: INT2_PAD

as auxiliary SCL bus and SDO_PAD as auxiliary SDA bus.

Sensor hub configurations can be used if the FUNC_CFG_EN bit in CTRL2 (21h) is set to

'1'.

Details of sensor hub configuration registers are available in Section 9: Advanced

configuration register mapping and Section 10: Advanced configuration registers

description.

To disable the sensor hub configurations, the FUNC_CFG_EN bit in CTRL2 (3Fh) must be

set to '0'. Refer to Section 10.8: CTRL2 (3Fh).

Once the sensor hub configuration is completed, to enable the master I2C functionality, the

MASTER_ON bit in FUNC_CTRL (3Fh) must be set to '1'.

The I2C master can read up to 6 bytes (registers SensorHub_out_1/6 from 06h to 0Bh).

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