When BSEC_OUTPUT_RAW_GAS is measured?

[matteo]

Goodmorning, 

I want to test a BME680 with the BSEC on a STM32 microcontroller system and I have two question: 

1. Where I can find information about the standard heater profile steps in continous mode used by the BSEC? 
2. I see that one of the output is BSEC_OUTPUT_RAW_GAS and i was wondering when the resistence is measured during the heater steps.

Thank you.

Best,

Matteo

[BSTRobin]

Hi matteo,

Thank for your inquiry.
If you have downloaded BSEC software package from https://www.bosch-sensortec.com/software-tools/software/bme688-software, you can find the software code read sensor data in function bsec_iot_loop() of bsec_integration.c.

[matteo]

Thank you. However i can't understand where I can find all the 10 readings of resistence (one for each heater temperature step), because as written in the datasheet only one resistance value is returned from the BSEC. These readings should be used by the library to analysed the characteristics of the gas.

Best

[BSTRobin · Accepted solution]

Hi matteo,

You can review BME68x BSEC software.
If you run IAQ mode, the software will call into BME68x force mode entry setBme68xConfigForced() to set heater configuration(read from configuration file, default temperature: 300, duration: 100 ms, run 1 step).
If you run CLASSIFICATION mode, the software will call into BME68x parallel mode entry setBme68xConfigParallel() to set heater configuration(read from configuration file, 10 step).

[matteo]

Hi,

thank you for your answer. I thought that in the IAQ mode the default 10 step temperature profile was used as well. Now it's clear why only one data is given.

Thank you.

Best