How do I verify if my hts221 sensor is giving the correct value and my calculations ?

[Anare.1]

 I am using the hts221 with i2c protocol for doing my calculation based on this reference:Application note for calculating relative humidity.

Observations:

1. So I tried to read the respective registers and do the calculations as per the datasheet, with assigning s16(H_OUT,H0_TOUT,H1_TOUT) and u16(H0_rH_x2,H1_rH_x2) values and I got a negative value as relative humidity along with -ve values for H_OUT and H0_TOUT(Both of them were defined as s16 type).
2. But when I switched everything to uint16, which is in contrast to the datasheet, I got a relative humidity of 36% which is ideal and real time value inside a home.

I am wondering why  this strange behavior occurs and is there something, I am doing wrong over here? 

Al l am doing is reading the respective registers and assigning the values like this(eg: here H_OUT):

uint16_t h_out_res=((uint16_t)hum_reading[1]<<8)|(uint16_t)hum_reading[0];

[Foued_KH]

Hello @Anare.1 , 

The HTS221 humidity sensor measures relative humidity and temperature and stores the values as two's complement integers (16-bit words) which can be read over the I2C.

I recommend you to refer to the : 
* Figure 3. Reference code for HTS221_Get_Humidity API

** Figure 5. Reference code for HTS221_Get_Temperature API

Foued

[niccolò]

Hi @Anare.1 ,

the answer from Foued is right, check those figure out =)

Anyway, are you sure you are applying the formula correctly?
you can also refer to the drivers to get help =)

If this answers your question, please, mark this as "best answer", by clicking on the "accept as solution" to help the other users of the community

Niccolò