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Document number: BST-BME690-DS001-04

as well as in the event of applications for industrial property rights

3.5 Sensor configuration

Quick start – Forced mode

The sensor is configured by writing to a set of control registers (see Chapter 5 for a detailed list of all available registers and

their descriptions). This section illustrates, with the help of a basic step-by-step example, how to configure the sensor for

simple forced mode measurements with a single heater step. For a more detailed description of the measurement flow,

please refer to Section 3.6.

In this example, the sensor will be configured to use 2x oversampling for its temperature measurements, 16x oversampling

for the pressure signal, and 1x oversampling for humidity. Moreover, the gas sensor hot plate will be configured to be

heated for 100 ms at 300 °C before the gas measurement is performed.

First, the user must configure the oversampling settings for temperature, pressure and humidity by setting the control

registers osrs_t<2:0> and osrs_h<2:0>, respectively. Supported settings range from 16x oversampling down to 0x, which is

equivalent to skipping the corresponding sub-measurement. See Section 5.3.3 for further details.

1. Set humidity oversampling to 1x by writing 0b001 to osrs_h<2:0>

2. Set temperature oversampling to 2x by writing 0b010 to osrs_t<2:0>

3. Set pressure oversampling to 16x by writing 0b101 to osrs_p<2:0>

It is highly recommended to set first osrs_h<2:0> followed by osrs_t<2:0> and osrs_p<2:0> in one write command (see

Section 3.6).

Next, the user shall set at least one gas sensor hot plate temperature step and heating duration. Up to 10 heating duration

can be configured through the control registers gas_wait_x<7:0>, where x ranges from 0 to 9. See Section 5.3.4 for definition

of register content. The corresponding heater step are stored in the registers res_heat_x<7:0>. Section 3.6.5 explains how

to convert the target heater temperature, e.g. 300 °C, into a register code. For forced mode operation, the used heater step

is selected by setting the control register nb_conv<3:0> to the heater profile to be used, e.g. to use gas_wait_0<7:0> and

res_heat_0<7:0>, nb_conv<3:0> shall be set to 0x0. Finally, gas functionality shall be enabled by setting the run_gas_h bit

to 1.

4. Set gas_wait_0<7:0> to 0x59 to select 100 ms heat up duration

5. Set the corresponding heater step by writing the target heater resistance to res_heat_0<7:0>

6. Set nb_conv<3:0> to 0x0 to select the previously defined heater settings

7. Set run_gas_h to 1 to enable gas measurements

Now, a single forced mode measurement with the above settings can be triggered by writing 0b01 to mode<1:0>. For more

details on data readout, please see Section 5.3.1.3.

8. Set mode<1:0> to 0b01 to trigger a single measurement.

Sensor configuration flow – Forced mode

Figure 3 illustrates which control registers must be set. For details on the individual control registers, please refer to

Chapter 5. Moreover, details on the measurement flow for the individual modes can be found in Section 3.6.

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