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Version 1

– December 2022

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Clear Status Register

All flags (Bit 15, 11, 10, 4) in the status register can be cleared (set to zero) by sending the

command shown in Table 21

Command

Hex Code

Clear status register

0x 30 41

Table 21. Command to clear the status register (Clear blocks are controlled by the microcontroller, grey

blocks by the sensor).

4.13 Checksum Calculation

The 8-bit CRC checksum transmitted after each data word is generated by a CRC algorithm. Its

properties are displayed in Table 22. The CRC covers the contents of the two previously

transmitted data bytes. To calculate the checksum only these two previously transmitted data

bytes are used.

Property

Value

Name

CRC-8

Width

8 bit

Protected data

read and/or write data

Polynomial

0x31 (x8 + x5 + x4 + 1)

Initialization

0xFF

Reflect input

False

Reflect output

False

Final XOR

0x00

Examples

CRC (0xBEEF) = 0x92

Table 22. I2C CRC properties.

4.14 Conversion of Signal Output

Measurement data is always transferred as 16-bit values (unsigned integer). These values are

already linearized and compensated for temperature and supply voltage effects. Converting those

raw values into a physical scale can be achieved using the following formulas.

Relative humidity conversion formula (result in %RH):

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������������������

216 − 1

) %RH

( 1 )

������ = (−45 + 175 ∙

������������

216 − 1

) °C

( 2 )

������ = (−49 + 315 ∙

������������

216 − 1

) °F

( 3 )

SRH and ST denote the raw sensor output for humidity and temperature, respectively. The formulas

work only correctly when SRH and ST are used in decimal representation.