BSEC stop after more than one month

[hamady]

Hello,

I'm using the BME680 with a STM32WLE and everthing was working well.

https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/How-to-use-BSEC-IOT-exemple-for-the-BME6...

Between the 03/06 to 21/07 everything was ok but after the bsec IAQ values are competly wrong.

I'm wondering if that is not related to the timestamp hat can fail after reaching max value.

Thanks

[hamady]

Hello 

I think i found the issue

The issue is that after 49 days we have the rollover of HAL_GetTick();

So it restart from 0 and the BSEC algo stop working 

Here a fix 

int64_t get_timestamp_us()
{
    static uint32_t previous_tick = 0;               // La dernière valeur de tick lue
    static int64_t overflow_count = 0;               // Compte les débordements
    uint32_t tick = HAL_GetTick();

    if(tick < previous_tick) {
        overflow_count += (int64_t)0xFFFFFFFF + 1;   // Incrémente par 2^32
    }

    previous_tick = tick;
    int64_t system_current_time = 1000 * (overflow_count + tick);
    return system_current_time;
}

[Minhwan]

Hi Hamady, 

For timestamp in BSEC2, you have to use micro second unit of 64 bit timestamp.

Otherwise, you will get error like you faced. 

Thanks for letting us know.