www.sensirion.com / D1

Version 1 – June 2025

11 / 18

3.4.7 enter_sleep_mode

The enter_sleep_mode command sets the sensor from idle to sleep mode through the I2C interface. The written

relative humidity, temperature, pressure compensation values and ASC state are retained while in sleep mode.

Command

Command

Hex Code

Argument

Consecutive Read

Execution

Time (ms)

Description

enter_sleep_

mode

0x3650

-

-

1

Sets the sensor from idle

mode into sleep mode.

3.4.8 exit_sleep_mode

The exit_sleep_mode command wakes the sensor up from sleep mode to idle mode upon receiving its

I2C address, a write data direction bit and a payload byte 0x00. Note that the payload byte is not acknowledged.

The wake up of the sensor into idle mode can be confirmed by reading out the product ID (see Section 3.4.16).

Command

Payload

Byte

Argument

Consecutive Read

Execution

Time (ms)

Description

exit_sleep_

mode

0x00

-

-

5

Wakes the sensor from sleep

into idle mode.

3.4.9 perform_conditioning

The perform_conditioning command is recommended to improve the initial CO2 sensing performance when the

sensor has not completed measurements for more than 3 hours (See Section 1.1.3).

Command

Command

Hex Code

Argument

Consecutive Read

Execution

Time (ms)

Description

perform_co

nditioning

0x29BC

-

-

22’000

Conditions the sensor with a

set operation profile.

Recommended operation sequence:

1. Power up the sensor or wake the sensor up with the exit_sleep_mode command (Section 3.4.8).

2. Send the perform_conditioning command and wait for the specified execution time.

3. Send a measurement command; e.g., the start_continuous_measurement command (Section 3.4.1) or the

measure_single_shot command (Section 3.4.6).

3.4.10 perform_soft_reset

The perform_soft_reset command triggers a soft reset of the sensor through the I2C general call reset as

implemented according to the NXP I2C-bus specification and user manual14. The perform_soft_reset command

is not acknowledged by the sensor. During the execution time, the sensor will not acknowledge its I2C address

nor accept commands. The general call I2C address is 0x00, the command is 8 bits long and all devices on the

same I2C bus designed to respond to a general call I2C reset will also complete a soft reset.

Command

Command

Hex Code

Argument

Consecutive Read

Execution

Time (ms)

Description

perform_sof

t_reset

0x06

-

-

10

Resets the sensor to the same

state as after a power cycle.

14

NXP I2C-bus specification and user manual UM10204, Rev.7, 01 November 2021