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    BME280 incorrect readings

    BME280 incorrect readings

    BenShapiro
    New Poster

    Hi,

    I have BME280 on custom board connected to CC1350 host via I2C.

    I configure BME280 to normal mode. When I read temperature right after power down I get at the first read correct values, then second read the value is about 25% higher than first read, and third read the value is about 50%-70% higher then in the first read, and I am sure the readings are incorrect.

    What could be the cause for such behaviour?

    Regards

    6 REPLIES 6

    FAE_CA1
    Community Moderator
    Community Moderator

    Hi,

    Thanks for your inquiry.

    I think you may mean you read temperature data after power on, not power down. The temperature data should be stable, not increasing 25% and 50%. Please refer to BME280 API source code at https://github.com/BoschSensortec/BME280_driver about how to initialize BME280 and how to read sensor data.

    Thanks.

    Hi,

    I am working with a driver provided in SDK by Texas Instruments, I guess this a working driver. 

    Can this beahviour happen because some HW conditions? over heating, incorrect voltage etc... 

    Or do you think this is a SW problem? 

    FAE_CA1
    Community Moderator
    Community Moderator

    Hi,

    Yes, this should be SW problem.

    If you initialize BME280 correctly with normal mode, oversampling for T, H and P sensors, then you can use the attached "sample_calculation_BME280.xlsx" to verify your SW. For example, you can manually type trimmed values from the BME280 chip that you are working with into the Excel file dig_T1 to T3, dig_P1 to P9 and dig_H1 to H6 cells. Then every time when you get the unsigned integers raw data for T, H and P sensors, you can manually type the values into the UT, UP and UH cells. The Excel file will calculate the final T in C, final H in %RH and final P in Pa. Then you can compare the results against what you get from the SDK from TI. If they match, then your SW is OK. Otherwise, there is a problem in your SW.

    Thanks.

    Minhwan
    Community Moderator
    Community Moderator

    Hello BenShapiro,

     

    At early part of data reading, if there is 40 ms delay, could you put some delay and request to read some data? 

    Thanks, 

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