we cannot use the interrupt in LPS27HHW!

[Xxia.1]

We purchased the LPS27HHW chip from your company and we are testing it. Then, we found an abnormal situation about the threshold interrupt function. When the air pressure is higher than the threshold, the interrupt can be triggered properly, but it cannot be triggered when the pressure is lower than the threshold. We set the register as below:  

Register    Data

0x12       0x03

0x0C       0x08

0x0D       0x3E 

0x0B       0x0B

What do you think could be the reason for that? And how can we make it right?

[Eleon BORLINI]

Hi @Xxia.1​ ,

please consider the application note AN5387, p.18.

It states that the threshold crossing refers to the reference pressure value that can be configured in the REF_P_L (15h) and REF_P_H (16h) registers (that in your case are left to the default 00h value, and are described in the datasheet, p. 40).

More specifically, the calculation performed by the interrupt generator is the following one:

• P_DIFF_IN = measured pressure - REF_P
• PRESS_OUT = measured pressure - REF_P

Can you try with configuring this additional registers?

-Eleon