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LIS2DH12 Temperature readings

Question asked by nadargi.anil on Sep 26, 2016
Latest reply on Oct 25, 2016 by Miroslav B
Hi Team , 
We are working on LIS2DH12 chip for accelerometer and temperature readings . 

Hardware Cicuit details :
a. VDD and VDDIO : 1.8 V 

We are facing issue in the temperature readings. Please find below for the steps for reading the temperature value .

Sensor Initialization for Temperature :
a. Initialization of the temperature sensor : TEMP_CFG_REG to 11
b. CTRL_REG4 BDU bit set to 1

Reading the temperature : 
a. Reading the OUT_TEMP_L (0Ch), OUT_TEMP_H (0Dh)
b. Convert the value of OUT_TEMP_H register content ( which is in 2s complement ) to decimal .
b. Temperature Value  =  25C (Reference Temperature )  + ( Converted decimal value from above step .This value may be + or - as per value )

We are getting value as 0x09,0x08,0x0a in OUT_TEMP_H (0Dh) register content. Our ambient temperature is 22 to 23 C.

But as per calculation we are getting temperature as (25+10)=35 which is not correct . 

Please let us know what shall be valid reference temperature ( currently used as 25 ) for VDD 1.8 V . 

Datasheet says that reference temperature for VDD 2.5 V is 25 . What shall be reference temperature for VDD 1.8 V.

Thanks ,
Anil N