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    BME280 output reading not changing

    BME280 output reading not changing

    itsclarelyme
    New Poster

    Hello!

    I have some BME280 sensors reading on a custom board, however, the signals have not been correct with the library driver and I am looking for technical support for it.

    I have installed the software from your github: https://github.com/BoschSensortec/BME280_driver and follow along with the instructions. I downloaded this 02/13/2020, so the library should be up-to-date.

    I am controlling the BME through SPI and Particle board (C++), I haven't changed anything in the driver file yet but here are the SPI signal readings from the SPI_READ functions declared in the main script. 

    Screen Shot 2020-02-13 at 4.15.11 PM.png

     

    Please let me know what could be the issue.

     

     

    Another questions I have is that I was wondering if you can provide the equations to convert analog signals to temperature/pressure/humidity. I cannot seem to find a clear equation in the datasheet or any sort of documentation. 

     

    Please let me know how I can resolve this. thank you!

    3 REPLIES 3

    itsclarelyme
    New Poster

    Hello!

    I looked into the signals that it is reading and noticed that the data collect burst read for register 0xF7 shows default (0x800000 0x800000 0x8000) 

    Here is a sample of the signal read/write that the driver is initiating and what the signal output is:

    Screen Shot 2020-02-13 at 5.48.15 PM.png

     

    Please let me know why the data readings are not started, the device is connected, and is responding as BME280_OK (0).

    handytech
    Community Moderator
    Community Moderator

    Could you please share a code snippet of your project (at least BME280 configuration and data read-out)? From your description alone, it seems like you may trigger only one measurement (e.g. setting the BME280 to forced mode will trigger a single measure then go back to sleep mode), then reading-out this data sample multiple times.


    @itsclarelyme wrote:

    Another questions I have is that I was wondering if you can provide the equations to convert analog signals to temperature/pressure/humidity. I cannot seem to find a clear equation in the datasheet or any sort of documentation. 


    You can find the reference implementation directly in the sensor API you linked (e.g. BME280 humidity formula in floating point).

    Antek
    Occasional Visitor

    Hi,

    I have similar problems. I  am able to read chip ID correctly, but when reading measurement registers I am keep getting 0x800..

    I am using microchip EVB, my code is based on github code.

    So my main while loop looks:

    while (1)
    {
    rslt = bme280_set_sensor_mode(BME280_FORCED_MODE, dev);
    if (rslt != BME280_OK)
    {
    // fprintf(stderr, "Failed to set sensor mode (code %+d).", rslt);
    //break;
    }

    /* Wait for the measurement to complete and print data @25Hz */
    dev->delay_us(40000, dev->intf_ptr);
    rslt = bme280_get_sensor_data(BME280_ALL, &comp_data, dev);
    if (rslt != BME280_OK)
    {
    // fprintf(stderr, "Failed to get sensor data (code %+d).", rslt);
    //break;
    }

    print_sensor_data(&comp_data);
    dev->delay_us(1000000, dev->intf_ptr);
    }

    Why are measurements still the same?

     

    BR

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