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MPL3115A2 warm-up drifting:

Question asked by Association ADRARE on Sep 29, 2017
Latest reply on Nov 3, 2017 by Association ADRARE

Hi all,

I'm using a MPL3115A2 in an altimeter application; during the 3 to 4 first minutes, the measured altitude decreases of about 40 to 50 ft. Then it becomes more stable. The unit is placed on a table, in a lightproof box. The only light may come from a LED on the same PCB located about 6 cm. The measurement loop is:

if (interrupt){   // interrupt from MPL3115

   read (REG_OUT);   // read result

   read(REG_CTRL1) while(OST_bit == 1);   // read register to make sure OST = 0

  write(REG_CTRL1, 0xBA);   // set OSR = 128, OST=1, mode stand-by

}

My questions are:

1/ has anyone noticed a kind of warm-up period for this device making its accuracy being poor for a while  or is this phenomena specific for mine, meaning a failure of this very device ? (I have not tested any other specimen as I have only one...)

2/ In cas this issue is known, is there any hardware or software workaround ?

3/ is my measurement procedure correct ?

Thanks a lot in advance,

Gerard

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