LSM6DSO ACC and GYR setting

[JXiao.1]

Hi,

I am using LSM6DSO to measure acceleration and angular velocity. To save the power of device, I want to use accelerator in most case. Some conditions, the gyroscope will need to open.

I used the function 'lsm6dso_fifo_xl_batch_set', 'lsm6dso_fifo_gy_batch_set', 'lsm6dso_xl_data_rate_set' and 'lsm6dso_gy_data_rate_set' to control the sensor. The function is provided by lsm6dso_reg.c. It should be a official library. I used them in the following picture.

I found when I set them off simultaneously, there is no data from the sensor. But if one of them is open and another is off, two types' data can be read from sensor. It is very strange. Then I use funcition to check the parameters.

I have found the gyroscope cannot be set under 26Hz. When I set it off or 12.5Hz, it will be changed to 26 automatically. But it can be set to higher frequency.How to change the problem?

Do you have some advices?

[JXiao.1]

Does anyone meet similar condition?

[niccolò]

Hi @JXiao.1​ ,

let me try to understand your problem:

are you having trouble enabling both sensors together?

how do you read data?

it is very strange that the gyro does not go to 12.5Hz, can you check the function to set it does not return error?

Niccolò

[JXiao.1]

Hi,

This is my code for initial sensor. I want disable the gyroscope and only enable the accelerator. I use fifo to read data from sensor.

bool sensor_init(void)
{
	lsm6dso_device_id_get(&imu_dev_ctx, &whoamI);
	if(whoamI != LSM6DSO_ID)
		return false;
 
	lsm6dso_reset_set(&imu_dev_ctx, PROPERTY_ENABLE);
	do
	{
		lsm6dso_reset_get(&imu_dev_ctx, &rst);
	}while(rst);
 
	lsm6dso_i3c_disable_set(&imu_dev_ctx, LSM6DSO_I3C_DISABLE);
 
	lsm6dso_xl_full_scale_set(&imu_dev_ctx, LSM6DSO_2g);
	lsm6dso_gy_full_scale_set(&imu_dev_ctx, LSM6DSO_250dps);
	lsm6dso_block_data_update_set(&imu_dev_ctx, PROPERTY_ENABLE);
 
	lsm6dso_fifo_watermark_set(&imu_dev_ctx, PATTERN_LEN);
	lsm6dso_fifo_stop_on_wtm_set(&imu_dev_ctx, PROPERTY_ENABLE);
 
	lsm6dso_fifo_mode_set(&imu_dev_ctx, LSM6DSO_STREAM_TO_FIFO_MODE);
 
 lsm6dso_xl_power_mode_set(&imu_dev_ctx, LSM6DSO_LOW_NORMAL_POWER_MD);
 lsm6dso_gy_power_mode_set(&imu_dev_ctx, LSM6DSO_GY_NORMAL);
 
 lsm6dso_xl_data_rate_set(&imu_dev_ctx, LSM6DSO_XL_ODR_104Hz);
	lsm6dso_gy_data_rate_set(&imu_dev_ctx, LSM6DSO_GY_ODR_OFF);
 
	lsm6dso_fifo_xl_batch_set(&imu_dev_ctx, LSM6DSO_XL_BATCHED_AT_104Hz);
	lsm6dso_fifo_gy_batch_set(&imu_dev_ctx, LSM6DSO_GY_BATCHED_AT_104Hz);
}

The next is reading data from sensor. First, I use the function to get data rate. The acc data rate is same as I set which is 104Hz. But the data rate of gyroscope is 26Hz. It is not turned off. There is no error returned.

 lsm6dso_xl_data_rate_get(&imu_dev_ctx, &x);
 lsm6dso_gy_data_rate_get(&imu_dev_ctx, &y);
 LOG_INF("%d %d \n", x, y);
 lsm6dso_fifo_xl_batch_get(&imu_dev_ctx, &m);
 lsm6dso_fifo_gy_batch_get(&imu_dev_ctx, &n);
 LOG_INF("%d %d \n", m, n);
 
 u8_t tmpbuf[100] = {0};
 
 memset(data_raw_acceleration.u8bit, 0x00, 3*sizeof(int16_t));
 lsm6dso_fifo_out_raw_get(&imu_dev_ctx, data_raw_acceleration.u8bit);
 acceleration_mg[0] = lsm6dso_from_fs2_to_mg(data_raw_acceleration.i16bit[0]);
 acceleration_mg[1] = lsm6dso_from_fs2_to_mg(data_raw_acceleration.i16bit[1]);
 acceleration_mg[2] = lsm6dso_from_fs2_to_mg(data_raw_acceleration.i16bit[2]);
 
 acceleration_g[0] = acceleration_mg[0]/1000;
 acceleration_g[1] = acceleration_mg[1]/1000;
 acceleration_g[2] = acceleration_mg[2]/1000;
 
 sprintf(tmpbuf, "accx is %f, accy is %f, accz is %f", acceleration_g[0], acceleration_g[1], acceleration_g[2]);
 LOG_INF("%s", tmpbuf); 
 
 delay_ms(500);
 
 memset(data_raw_angular_rate.u8bit, 0x00, 3*sizeof(int16_t));
 lsm6dso_fifo_out_raw_get(&imu_dev_ctx, data_raw_angular_rate.u8bit);
 angular_rate_mdps[0] = lsm6dso_from_fs250_to_mdps(data_raw_angular_rate.i16bit[0]);
 angular_rate_mdps[1] = lsm6dso_from_fs250_to_mdps(data_raw_angular_rate.i16bit[1]);
 angular_rate_mdps[2] = lsm6dso_from_fs250_to_mdps(data_raw_angular_rate.i16bit[2]);
 
 angular_rate_dps[0] = angular_rate_mdps[0]/1000;
 angular_rate_dps[1] = angular_rate_mdps[1]/1000;
 angular_rate_dps[2] = angular_rate_mdps[2]/1000;
 
 sprintf(tmpbuf, "gyrx is %f, gyry is %f, gyrz is %f", angular_rate_dps[0], angular_rate_dps[1], angular_rate_dps[2]);
 LOG_INF("%s", tmpbuf); 

[niccolò]

Hi @JXiao.1​ ,

why do you use lsm6dso_fifo_gy_batch_set(&imu_dev_ctx, LSM6DSO_GY_BATCHED_AT_104Hz) if you want to turn the gyro off?

can you check what does the function do?

I fear it turns on the gyro.

Niccolò