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    BME688/BME380 Datasheet error with Gas Measurement

    BME688/BME380 Datasheet error with Gas Measurement

    New Poster


    I've spent a few days trying to find why I can read TPH, but the ADC value for Gas was always zero.

    The datasheet shows the 'run_gas' flag in register 71h (Ctrl_gas_1), bit postion '4'. This is incorrect - it should be bit position '5'.

    Hope this saves some time for somebody!!!




    9 REPLIES 9

    I believe the correct information is that run_gas is on bits 4 AND bit 5 because the run_gas configuration can be 0x00, 0x01 and 0x02.

    Please have a look at Bosh API which has the correct information : (bme68x.c line 654)

                        if (dev->variant_id == BME68X_VARIANT_GAS_HIGH)
                            run_gas = BME68X_ENABLE_GAS_MEAS_H;   // = 0x02
                            run_gas = BME68X_ENABLE_GAS_MEAS_L;   // = 0x01

    The documentation register's table should also be corrected. 

    I kindly ask Bosch to realize how much developper's time they are currently wasting every day  and correct this mistake rapidly by posting a new datasheet version asap.


    Community Moderator
    Community Moderator

    Hi phil-by-sea, FGR,

    Sorry for the inconvience. We will check and update BME688 data sheet ASAP.

    Community Moderator
    Community Moderator

    Hi phil-by-sea,FGR,

    After check, run_gas should be position 5 in 71h(Ctrl_gas_1) register.
    run_gas is bit 4 in BME680 data sheet, run_gas is bit 5 in BME688 data sheet. To support both BME680 and BME688 in sensor API, BME68X_RUN_GAS_MSK should be 0x30, so sensor API don't need to be modified for BME68X_RUN_GAS_MSK.
    /* Mask for run gas */
    #define BME68X_RUN_GAS_MSK UINT8_C(0x30)

    We will update BME688 data sheet on official website later.


    Thanks for the answer.

    But please correct your datasheet quickly. Why waiting until "later" ?

    People like me (your customer) will waste a lot of time trying to find out the mistake in their software  based on you datasheet.

    So unless you do not care about your developper's customers please update your datasheet now.

    This mistake has been here for months why is it taking so long to updtate a table in a doc and post it on you website ? 

    Community Moderator
    Community Moderator