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HDC1008 temperature+humidity recieve problem

Krystof Vanek50
Prodigy 20 points
Other Parts Discussed in Thread: HDC1008, HDC1000

Hello,

I have some problems retrieving data from HDC1008.
I assert the measurement by writing 0x00 and waiting for DRDyN, then after repeated start addresing the device again and reading out four bytes.

The problem is the device is only giving me first byte then its outputing zeros. However, the value of first byte is correct, the temperature can be calculated from it and its refreshing without any problem.

For more detailed information about the bus, please see the attached screens from logic analyser. Betwean these two frames is about 12,5ms.


Thank you very much for your help.

  • 0
    TI__Intellectual 1960 points
    Hi Krystof
    HDC1000 wakes up with the configuration “Mode of Acquisition = Temperature only".
    Please change Mode of Acquisition in the Configuration register (0x02) to ‘1’.
    -----------------------------------------------------
    Configuration Register [12] = ‘1’
    -----------------------------------------------------It should be fix the issue.
    RegardsMassimo
  • 0 in reply to Massimo Mascotto
    Prodigy 20 points

    That seems quite confusing to me as the datasheet say on page 14 table 2 that reset value of configuration is 0x1000 which should be it.

    Nevertheless I did try to change the configuration. Well it doesnt change anything.

    I checked if the config is right by reading it and I do get the right value back..

    Do you have any other clue of what might cause the problem? Could be it soldering proces which damaged the humidity part of the sensor or maybe flux residue blocking air to completely dry sensor?

  • 0 in reply to Krystof Vanek50
    TI__Genius 9655 points

    Hi Ktrystof,

    by default the HDC1008 converts temperature and RH, so the table you mentioned is correct.

    In your case you are retrieving 4 bytes, the first 2 as you wrote are fine (temperature) and the last 2 bytes are 0.

    If you are not receiving any I2C errors it means that the last 2 byte are effectively zeros.

    It means that you have damaged the sensitive element of the HDC1008.

    In theory you could use the heater to check the functionality of the sensor. Ususually if the heater is turned on for a while the RH reading decreases, but if you are already reading 0 it doesn't help.

    Have you follews the instructions present in the DS regarding the soldering process ? Have you used no-clean flux ?

    regards,

    Domenico