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Version 3.3 – November 2024

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3.3 I2C commands

The command set of the STC31-C consists of a set of different commands:

Command

Command code (hex)

Section

Disable CRC

0x3768

3.3.1

Set measurement mode and binary gas

0x3615

3.3.2

Set relative humidity

0x3624

3.3.3

Set temperature

0x361E

3.3.4

Set pressure

0x362F

3.3.5

Measure gas concentration

0x3639

3.3.6

Forced recalibration (FRC)

0x3661

3.3.7

Automatic self-calibration (ASC)

-

3.3.8

Configure noise filter

-

3.3.9

Self-test

0x365B

3.3.10

Soft reset

-

3.3.11

Prepare and read state

0x3752, 0xE133

3.3.12

Write and apply state

0xE133, 0x3650

3.3.12

Read offset value

0x370A

3.3.13

Write offset value

0x3608

3.3.13

Enter sleep mode

0x3677

3.3.14

Exit sleep mode

-

3.3.14

Read product identifier

0x367C, 0xE102

3.3.15

3.3.1 Disable CRC

By default, the arguments written to the sensor and the data coming from the sensor are protected by CRC

(cyclic redundancy check). There may be cases where it is beneficial to disable the CRC, for example to reduce

the sensor overhead and general power consumption, or during the first stages of development.

In cases where the MCU and sensor are not close together on a PCB, and are for example connected with a

wire, it is recommended to not disable the CRC. For safety related applications it is strongly recommended not

to disable the CRC.

Command

Command code (hex)

Description

Disable CRC

0x3768

This command disables the CRC on the data for both read

and write. See section 3.2 for more details.

When the system is reset or wakes up from sleep mode, the CRC mode is reset to its default value: enabled.