Running the LSM6DLS (IMU) zephyr example with nrf52840 based Xiao BLE Sense

Question

Hi all,

I've been trying to get the samples/sensor/lsm6dsl example working with the nrf52840-based Xiao BLE Sense and have had no luck.

I guess that it's due to the power line for the sensor being connected to the P1.08

I dug into the xiao_ble_sense.dts and I can indeed see:

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    lsm6ds3tr-c-en {
        compatible = "regulator-fixed-sync", "regulator-fixed";
        enable-gpios = <&gpio1 8 (NRF_GPIO_DRIVE_S0H1 | GPIO_ACTIVE_HIGH)>;
        regulator-name = "LSM6DS3TR_C_EN";
        regulator-boot-on;
        startup-delay-us = <3000>;
    };
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	lsm6ds3tr-c-en {
		compatible = "regulator-fixed-sync", "regulator-fixed";
		enable-gpios = <&gpio1 8 (NRF_GPIO_DRIVE_S0H1 | GPIO_ACTIVE_HIGH)>;
		regulator-name = "LSM6DS3TR_C_EN";
		regulator-boot-on;
		startup-delay-us = <3000>;
	};

However no matter how I try and drive it from the code the sensor refuses to initialize with the console output:

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[00:00:00.794,647] <dbg> LSM6DSL: lsm6dsl_init_chip: failed to reboot device
[00:00:00.794,677] <err> LSM6DSL: Failed to initialize chip
*** Booting nRF Connect SDK d96769faceca ***
Begin init of lsm6ds3tr and regulator 
sensor: device not ready.

My code to run is based of the sample code for the sensor with the lsm6ds3tr_c_en modifications:

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/*
 * Copyright (c) 2018 STMicroelectronics
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/drivers/sensor.h>
#include <stdio.h>
#include <zephyr/sys/util.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/drivers/regulator.h>

static const struct device *lsm6ds3tr_c_en;

static inline float out_ev(struct sensor_value *val)
{
	return (val->val1 + (float)val->val2 / 1000000);
}

static int print_samples;
static int lsm6dsl_trig_cnt;

static struct sensor_value accel_x_out, accel_y_out, accel_z_out;
static struct sensor_value gyro_x_out, gyro_y_out, gyro_z_out;
#if defined(CONFIG_LSM6DSL_EXT0_LIS2MDL)
static struct sensor_value magn_x_out, magn_y_out, magn_z_out;
#endif
#if defined(CONFIG_LSM6DSL_EXT0_LPS22HB)
static struct sensor_value press_out, temp_out;
#endif

#ifdef CONFIG_LSM6DSL_TRIGGER
static void lsm6dsl_trigger_handler(const struct device *dev,
				    const struct sensor_trigger *trig)
{
	static struct sensor_value accel_x, accel_y, accel_z;
	static struct sensor_value gyro_x, gyro_y, gyro_z;
#if defined(CONFIG_LSM6DSL_EXT0_LIS2MDL)
	static struct sensor_value magn_x, magn_y, magn_z;
#endif
#if defined(CONFIG_LSM6DSL_EXT0_LPS22HB)
	static struct sensor_value press, temp;
#endif
	lsm6dsl_trig_cnt++;

	sensor_sample_fetch_chan(dev, SENSOR_CHAN_ACCEL_XYZ);
	sensor_channel_get(dev, SENSOR_CHAN_ACCEL_X, &accel_x);
	sensor_channel_get(dev, SENSOR_CHAN_ACCEL_Y, &accel_y);
	sensor_channel_get(dev, SENSOR_CHAN_ACCEL_Z, &accel_z);

	/* lsm6dsl gyro */
	sensor_sample_fetch_chan(dev, SENSOR_CHAN_GYRO_XYZ);
	sensor_channel_get(dev, SENSOR_CHAN_GYRO_X, &gyro_x);
	sensor_channel_get(dev, SENSOR_CHAN_GYRO_Y, &gyro_y);
	sensor_channel_get(dev, SENSOR_CHAN_GYRO_Z, &gyro_z);

#if defined(CONFIG_LSM6DSL_EXT0_LIS2MDL)
	/* lsm6dsl external magn */
	sensor_sample_fetch_chan(dev, SENSOR_CHAN_MAGN_XYZ);
	sensor_channel_get(dev, SENSOR_CHAN_MAGN_X, &magn_x);
	sensor_channel_get(dev, SENSOR_CHAN_MAGN_Y, &magn_y);
	sensor_channel_get(dev, SENSOR_CHAN_MAGN_Z, &magn_z);
#endif

#if defined(CONFIG_LSM6DSL_EXT0_LPS22HB)
	/* lsm6dsl external press/temp */
	sensor_sample_fetch_chan(dev, SENSOR_CHAN_PRESS);
	sensor_channel_get(dev, SENSOR_CHAN_PRESS, &press);

	sensor_sample_fetch_chan(dev, SENSOR_CHAN_AMBIENT_TEMP);
	sensor_channel_get(dev, SENSOR_CHAN_AMBIENT_TEMP, &temp);
#endif

	if (print_samples) {
		print_samples = 0;

		accel_x_out = accel_x;
		accel_y_out = accel_y;
		accel_z_out = accel_z;

		gyro_x_out = gyro_x;
		gyro_y_out = gyro_y;
		gyro_z_out = gyro_z;

#if defined(CONFIG_LSM6DSL_EXT0_LIS2MDL)
		magn_x_out = magn_x;
		magn_y_out = magn_y;
		magn_z_out = magn_z;
#endif

#if defined(CONFIG_LSM6DSL_EXT0_LPS22HB)
		press_out = press;
		temp_out = temp;
#endif
	}

}
#endif

int main(void)
{
	int cnt = 0;
	char out_str[64];
	struct sensor_value odr_attr;
    const struct device *const lsm6dsl_dev = DEVICE_DT_GET_ONE(st_lsm6dsl);

	printk("Begin init of lsm6ds3tr and regulator \n");
    /* Initialize the regulator device */
	lsm6ds3tr_c_en = DEVICE_DT_GET(DT_PATH(lsm6ds3tr_c_en));
    if (!device_is_ready(lsm6ds3tr_c_en)) {
        printk("Regulator device not ready\n");
        return 0;
    }

    /* Enable the regulator */
    if (regulator_enable(lsm6ds3tr_c_en) < 0) {
        printk("Failed to enable regulator\n");
        return 0;
    }

	 k_sleep(K_MSEC(10000));

	
	if (!device_is_ready(lsm6dsl_dev)) {
		printk("sensor: device not ready.\n");
		return 0;
	}

	/* set accel/gyro sampling frequency to 104 Hz */
	odr_attr.val1 = 104;
	odr_attr.val2 = 0;

	if (sensor_attr_set(lsm6dsl_dev, SENSOR_CHAN_ACCEL_XYZ,
			    SENSOR_ATTR_SAMPLING_FREQUENCY, &odr_attr) < 0) {
		printk("Cannot set sampling frequency for accelerometer.\n");
		return 0;
	}

	if (sensor_attr_set(lsm6dsl_dev, SENSOR_CHAN_GYRO_XYZ,
			    SENSOR_ATTR_SAMPLING_FREQUENCY, &odr_attr) < 0) {
		printk("Cannot set sampling frequency for gyro.\n");
		return 0;
	}

#ifdef CONFIG_LSM6DSL_TRIGGER
	struct sensor_trigger trig;

	trig.type = SENSOR_TRIG_DATA_READY;
	trig.chan = SENSOR_CHAN_ACCEL_XYZ;

	if (sensor_trigger_set(lsm6dsl_dev, &trig, lsm6dsl_trigger_handler) != 0) {
		printk("Could not set sensor type and channel\n");
		return 0;
	}
#endif

	if (sensor_sample_fetch(lsm6dsl_dev) < 0) {
		printk("Sensor sample update error\n");
		return 0;
	}

	while (1) {
		/* Erase previous */
		printk("\0033\014");
		printf("LSM6DSL sensor samples:\n\n");

		/* lsm6dsl accel */
		sprintf(out_str, "accel x:%f ms/2 y:%f ms/2 z:%f ms/2",
							  out_ev(&accel_x_out),
							  out_ev(&accel_y_out),
							  out_ev(&accel_z_out));
		printk("%s\n", out_str);

		/* lsm6dsl gyro */
		sprintf(out_str, "gyro x:%f dps y:%f dps z:%f dps",
							   out_ev(&gyro_x_out),
							   out_ev(&gyro_y_out),
							   out_ev(&gyro_z_out));
		printk("%s\n", out_str);

#if defined(CONFIG_LSM6DSL_EXT0_LIS2MDL)
		/* lsm6dsl external magn */
		sprintf(out_str, "magn x:%f gauss y:%f gauss z:%f gauss",
							   out_ev(&magn_x_out),
							   out_ev(&magn_y_out),
							   out_ev(&magn_z_out));
		printk("%s\n", out_str);
#endif

#if defined(CONFIG_LSM6DSL_EXT0_LPS22HB)
		/* lsm6dsl external press/temp */
		sprintf(out_str, "press: %f kPa - temp: %f deg",
			out_ev(&press_out), out_ev(&temp_out));
		printk("%s\n", out_str);
#endif

		printk("loop:%d trig_cnt:%d\n\n", ++cnt, lsm6dsl_trig_cnt);

		print_samples = 1;
		k_sleep(K_MSEC(2000));
	}
}

And my prj.conf:

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CONFIG_STDOUT_CONSOLE=y
CONFIG_I2C=y
CONFIG_SPI=n
CONFIG_SENSOR=y
CONFIG_LSM6DSL_TRIGGER_GLOBAL_THREAD=y
CONFIG_CBPRINTF_FP_SUPPORT=y

CONFIG_LOG=y
CONFIG_LOG_DEFAULT_LEVEL=3
CONFIG_SENSOR_LOG_LEVEL_DBG=y

CONFIG_UART_CONSOLE=y
CONFIG_UART_INTERRUPT_DRIVEN=y
CONFIG_UART_LINE_CTRL=y

I am trying to drive this the proper way but am I missing something obvious?

Should I just ignore the config and drive P1.08 manually?

Thanks for taking a look!
I'm using nRF Connect SDK v2.6.0 (latest available at the time of posting)

Akshay Mehta · Answer

Hi mentarus , 
 It sounds like you've run into some persistent issues with the LSM6DSL sensor initialization on the nrf52840-based Xiao BLE Sense board using Zephyr. To help with this, we've developed a dedicated library that specifically addresses the power and I2C configuration challenges you're experiencing. 
 Here&rsquo;s how the library can help: 
 
 Automated Power Control : The library includes proper handling of P1.08 to ensure the sensor is powered up correctly before initialization. 
 I2C Configuration : It takes care of the correct pull-up resistor configuration to avoid common issues with back-driving and phantom power on the I2C bus. 
 Enhanced Startup Delay : We've also optimized the startup delay to ensure the sensor initializes reliably, avoiding the need for manual adjustments. 
 
 You can integrate the library into your Zephyr project easily by following the steps in the deployment document (bundled with zip file). We've also added instructions for testing to ensure everything works smoothly. 
 Feel free to contact us on slack if you need further assistance or run into any issues while implementing it!

genmastermega · Answer

Hello All, 
 I have gotten the IMU to work. 
 There is one thing that changes form the sample code vs what the new driver needs. I think with the zephyr toolchain/version being updated the driver must have changed. 
 You can not change the sampling rate in code instead you have to use the following project config lines: 
 
 CONFIG_LSM6DSL_GYRO_ODR =1 
 CONFIG_LSM6DSL_ACCEL_ODR =1 
 
 I found that after this I just use the following functions to check if the device is working and to pull the accleration data: 
 
 ```

#include "IMU.h" 
 
 LOG_MODULE_REGISTER (imu, LOG_LEVEL_INF ); 
 
 int IMUSetup (){ 
 int err = 0 ; 
 if ( ! device_is_ready ( IMU_DEVICE )) { 
 LOG_ERR ( "IMU device is not ready" ); 
 return - 1 ; 
 } else { 
 LOG_INF ( "IMU DEVICE IS READY" ); 
 } 
 
 return 0 ; 
 }; 
 
 int readIMUData (){ 
 int err = 0 ; 
 
 static struct sensor_value accel_x , accel_y , accel_z ; 
 static struct sensor_value gyro_x , gyro_y , gyro_z ; 
 
 // Fetch accelerometer data 
 err = sensor_sample_fetch_chan ( IMU_DEVICE , SENSOR_CHAN_ACCEL_XYZ ); 
 if ( err < 0 ) { 
 LOG_ERR ( "Error fetching accelerometer data: %d " , err ); 
 return ; // Exit or handle the error appropriately 
 } 
 
 // Get accelerometer channels 
 err = sensor_channel_get ( IMU_DEVICE , SENSOR_CHAN_ACCEL_X , & accel_x ); 
 if ( err < 0 ) { 
 LOG_ERR ( "Error getting accelerometer X channel: %d " , err ); 
 } 
 
 err = sensor_channel_get ( IMU_DEVICE , SENSOR_CHAN_ACCEL_Y , & accel_y ); 
 if ( err < 0 ) { 
 LOG_ERR ( "Error getting accelerometer Y channel: %d " , err ); 
 } 
 
 err = sensor_channel_get ( IMU_DEVICE , SENSOR_CHAN_ACCEL_Z , & accel_z ); 
 if ( err < 0 ) { 
 LOG_ERR ( "Error getting accelerometer Z channel: %d " , err ); 
 } 
 
 // Fetch gyroscope data 
 err = sensor_sample_fetch_chan ( IMU_DEVICE , SENSOR_CHAN_GYRO_XYZ ); 
 if ( err < 0 ) { 
 LOG_ERR ( "Error fetching gyroscope data: %d " , err ); 
 return ; // Exit or handle the error appropriately 
 } 
 
 // Get gyroscope channels 
 err = sensor_channel_get ( IMU_DEVICE , SENSOR_CHAN_GYRO_X , & gyro_x ); 
 if ( err < 0 ) { 
 LOG_ERR ( "Error getting gyroscope X channel: %d " , err ); 
 } 
 
 err = sensor_channel_get ( IMU_DEVICE , SENSOR_CHAN_GYRO_Y , & gyro_y ); 
 if ( err < 0 ) { 
 LOG_ERR ( "Error getting gyroscope Y channel: %d " , err ); 
 } 
 
 err = sensor_channel_get ( IMU_DEVICE , SENSOR_CHAN_GYRO_Z , & gyro_z ); 
 if ( err < 0 ) { 
 LOG_ERR ( "Error getting gyroscope Z channel: %d " , err ); 
 } 
 
 // Print accelerometer data 
 LOG_INF ( "Accelerometer (m/s^2): 
	 X: %d . %06d 
	 Y: %d . %06d 
	 Z: %d . %06d " , 
 accel_x . val1 , accel_x . val2 , 
 accel_y . val1 , accel_y . val2 , 
 accel_z . val1 , accel_z . val2 ); 
 
 // Print gyroscope data 
 LOG_INF ( "Gyroscope (rad/s): 
	 X: %d . %06d 
	 Y: %d . %06d 
	 Z: %d . %06d " , 
 gyro_x . val1 , gyro_x . val2 , 
 gyro_y . val1 , gyro_y . val2 , 
 gyro_z . val1 , gyro_z . val2 ); 
 }

``` 
 
 The I used the default device tree items and have this overlay done to increase the startup delay as recommended by other posts.

``` 
 
 / { 
 lsm6ds3tr-c-en { 
 startup-delay-us = < 10000 >; 
 }; 
 }; 
 
 ``` 
 
 I am using 2.7 toolchain and the 2.7 SDK. 
 
 Let me know if you have more questions, I think these were the most important points to consider

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 IMU.c 
 Download 
 
 #include "IMU.h"

LOG_MODULE_REGISTER(imu, LOG_LEVEL_INF);

int IMUSetup(){
 int err = 0; 
 if (!device_is_ready(IMU_DEVICE)) {
 LOG_ERR("IMU device is not ready");
 return -1;
 } else {
 LOG_INF("IMU DEVICE IS READY");
 }

 return 0; 
};

int readIMUData(){
 int err = 0; 

 static struct sensor_value accel_x, accel_y, accel_z;
	static struct sensor_value gyro_x, gyro_y, gyro_z;


 // Fetch accelerometer data
 err = sensor_sample_fetch_chan(IMU_DEVICE, SENSOR_CHAN_ACCEL_XYZ);
 if (err < 0) {
 LOG_ERR("Error fetching accelerometer data: %d", err);
 return; // Exit or handle the error appropriately
 }

 // Get accelerometer channels
 err = sensor_channel_get(IMU_DEVICE, SENSOR_CHAN_ACCEL_X, &accel_x);
 if (err < 0) {
 LOG_ERR("Error getting accelerometer X channel: %d", err);
 }

 err = sensor_channel_get(IMU_DEVICE, SENSOR_CHAN_ACCEL_Y, &accel_y);
 if (err < 0) {
 LOG_ERR("Error getting accelerometer Y channel: %d", err);
 }

 err = sensor_channel_get(IMU_DEVICE, SENSOR_CHAN_ACCEL_Z, &accel_z);
 if (err < 0) {
 LOG_ERR("Error getting accelerometer Z channel: %d", err);
 }

 // Fetch gyroscope data
 err = sensor_sample_fetch_chan(IMU_DEVICE, SENSOR_CHAN_GYRO_XYZ);
 if (err < 0) {
 LOG_ERR("Error fetching gyroscope data: %d", err);
 return; // Exit or handle the error appropriately
 }

 // Get gyroscope channels
 err = sensor_channel_get(IMU_DEVICE, SENSOR_CHAN_GYRO_X, &gyro_x);
 if (err < 0) {
 LOG_ERR("Error getting gyroscope X channel: %d", err);
 }

 err = sensor_channel_get(IMU_DEVICE, SENSOR_CHAN_GYRO_Y, &gyro_y);
 if (err < 0) {
 LOG_ERR("Error getting gyroscope Y channel: %d", err);
 }

 err = sensor_channel_get(IMU_DEVICE, SENSOR_CHAN_GYRO_Z, &gyro_z);
 if (err < 0) {
 LOG_ERR("Error getting gyroscope Z channel: %d", err);
 }

 // Print accelerometer data
 LOG_INF("Accelerometer (m/s^2):
	X: %d.%06d
	Y: %d.%06d
	Z: %d.%06d",
 accel_x.val1, accel_x.val2, 
 accel_y.val1, accel_y.val2, 
 accel_z.val1, accel_z.val2);

 // Print gyroscope data
 LOG_INF("Gyroscope (rad/s):
	X: %d.%06d
	Y: %d.%06d
	Z: %d.%06d",
 gyro_x.val1, gyro_x.val2, 
 gyro_y.val1, gyro_y.val2, 
 gyro_z.val1, gyro_z.val2);
}

Running the LSM6DLS (IMU) zephyr example with nrf52840 based Xiao BLE Sense

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