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LPS331AP Data ready asserting sporadically

Question asked by carpenter.greggory on Feb 20, 2014
Latest reply on Feb 6, 2015 by brignoli.maurizio
Hello Folks,

Not sure where else to post this as there doesn't seem to be any subcategory for pressure sensors in the sensors category, so I'm posting it here, please forgive any offense on that count.
pressure_data_ready_issue.png
We've been working with the LPS331AP on a couple of designs and only on a recent board spin have we noticed this issue on a number of units.  The circuit we're using is identical to that detailed in the datasheet.  The device is configured in I2C communications mode, with the resolution set to 0.025 mbar, the internal averaging for both temp and pressure set to 1, continuous mode rates set for 25 Hz for both temperature and pressure, and both Interrupt pins configured as data ready interrupts.  

The problem we're having is that the data ready pulse does not fire consistently (see attached picture), so while it will operate at the correct rate periodically, it will frequently miss pulses.  Comparing a unit with identical register configurations (which works correctly) with another unit which does not shows no apparent electrical differences from a circuit standpoint nor any from a configuration register standpoint.

I'm really scratching my head as to what might be causing this and I was hoping that someone might have some idea if what could be causing the issue.  

Any ideas or relevant experiences with this part that folks could share would be much appreciated.

Thanks kindly in every case.

Regards,

Gregg     

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