LIS2DUX12TR datasheet(17/102 Pages) STMICROELECTRONICS

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4.1.1

Power-up command

The power-up command allows the LIS2DUX12 to transition from deep power-down to soft power-down. It differs

if either the I²C/I3C interface or the SPI interface is used. See Section 6 for more details on the digital

interfaces.

4.1.1.1

I²C/I3C interfaces

If the I²C or I3C interfaces are used, the following sequence should be provided to the device:

•

ST/SR+ STATIC ADDRESS+R/W (both R and W sequences are supported)

The device generates a NACK and starts power-up. The operation takes 25 ms (maximum) and once completed

LIS2DUX12 is in the SOFT_PD state. It is possible to verify the correct transition in the soft power-down state

providing again the power-up command (ST/SR+ STATIC ADDRESS+R/W) and checking the ACK generation

from the device.

To guarantee the current execution of the power-up command, the I²C/I3C master should operate at open-drain

speed using I²C fast mode plus reference timing.

In the LIS2DUX12 if the bus is at 1.2 V and the device is in deep power-down, the master should use I²C fast

mode timing instead of I²C fast mode plus to perform the power-up command. Once the device is awake, the soft

power-down rules apply in the same way as the other voltages.

If the I3C interface is used, a dynamic address should be assigned before starting device configuration. Once the

DAA procedure is performed, the dynamic address is stored inside the device and it is maintained if the device

returns to the deep power-down state. In this event, no other DAA procedures are needed and the power-up

commands can be executed directly using the dynamic address.

4.1.1.2

SPI interface

If the SPI interface is used, the LIS2DUX12 can move from deep power-down to soft power-down by writing

the bit SOFT_PD of IF_WAKE_UP (3Eh) to 1. The device starts the power-up and this operation takes 25 ms

(maximum). In order to verify that device has correctly completed the transition to soft power-down, the who_am_I

value (expected to be equal to 47h) can be checked by reading register WHO_AM_I (0Fh).

Note:

When the power-up command is performed using the SPI interface, the I²C and the I3C interfaces are

automatically disabled as soon as the device exits deep power-down condition. They are automatically re-

enabled after a deep power-off command is executed.

4.1.2

Soft power-off command

When the LIS2DUX12 is configured in one of the four operating modes, it is possible to switch to the soft

power-down condition, writing the ODR[3:0] bits in register CTRL5 (14h) to 0000.

4.1.3

Deep power-off command

When device is in soft power-down or it is configured in one of the four operating modes, it is possible to switch to

the deep power-down condition, writing the bit DEEP_PD in register SLEEP (3Dh) to 1. When a transition to deep

power-down occurs, all the registers are reset to their default value and a new power-up command and device

configuration need to be done.

LIS2DUX12

Power-up sequence

DS14071 - Rev 2

page 17/102

LIS2DUX12TR Datasheet(PDF) 17 Page - STMicroelectronics

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