An issue at generate quaternion on BMX160

[coder]

Dear moderators and engineers！

I have encountered problems when using BSXLite to generate quaternions on BMX160, as described below. Previously considering BMI160+BMM150, the problem was the same. Later, because BOSCH sales staff suggested using BMX160, the problem also exists. I think it is a simple link that has a problem. Please help me check it out:

Chip: BMX160, 

MCU: Cortex M3, 

Language: C programming, 

Compiler Environment： MDK5

System situation: BLE-Stack

1. The main functions initialization

...

2. void my_bsx_init() Functions achieve as follows：

3. Operate Algorithm library， updataing value of sensors. Program will run to this function per 30mS

My Bsx step process Functions achieve as below:

4. Get quaternion,  Program will call follows functions to take quaternion

 Finally no changes with quaternion

[coder]

Dear Marko Njirjak and Moderator

Thanks for your help!

Yes,  I have got a meaningful quaternion. Different sensor range settings may cause some errors (such as the sampling frequency you mentioned), and I am trying more.
If you have any suggestions for sensor settings, please let me know, this will be beneficial to my debugging.

Thank you very much for your help!

Andy

[mnjirjak · Accepted solution]

Dear coder,

here are the settings that I use in my project.

//Accelerometer
bmi.accel_cfg.power = BMI160_ACCEL_NORMAL_MODE;
bmi.accel_cfg.bw = BMI160_ACCEL_BW_NORMAL_AVG4;
bmi.accel_cfg.range = BMI160_ACCEL_RANGE_2G;
bmi.accel_cfg.odr = BMI160_ACCEL_ODR_100HZ;

//Gyroscope
bmi.gyro_cfg.odr = BMI160_GYRO_ODR_100HZ;
bmi.gyro_cfg.range = BMI160_GYRO_RANGE_500_DPS;
bmi.gyro_cfg.bw = BMI160_GYRO_BW_NORMAL_MODE;
bmi.gyro_cfg.power = BMI160_GYRO_NORMAL_MODE;

//Magnetometer
bmm.settings.preset_mode = BMM150_PRESETMODE_REGULAR;
APP_ERROR_CHECK(bmm150_set_presetmode(&bmm));
bmm.settings.pwr_mode = BMM150_FORCED_MODE;
APP_ERROR_CHECK(bmm150_set_op_mode(&bmm));
bmi.aux_cfg.aux_odr = 6;    // I believe this is 25Hz, but an 8 works OK too (100Hz)
bmi160_config_aux_mode(&bmi);

Kind regards,

Marko Njirjak

[coder]

Really Thanks! I am know basic applications of Quatrnion I think.