How to read magnetometer registers using the icm45686 sensor as host

[brightproject]

In this document

https://invensense.tdk.com/wp-content/uploads/2024/07/AN-000478_ICM-45605-ICM-45686-User-Guide.pdf

I found the following information:

As far as I understand the description, pass-through mode is only possible if the ICM45686 is connected via I2C.
I had trouble connecting the ICM45686 sensor to the ESP32S3.
I connected it via SPI and successfully read data from the sensor.
The code is below:

/*
 *
 * Copyright (c) [2020] by InvenSense, Inc.
 * 
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */
 
#include "ICM45686.h"

float accel_g[3];
float gyro_dps[3];

// Instantiate an ICM456XX with SPI interface and CS on pin 39
ICM456xx IMU(SPI,39);

void setup() {
  int ret;
  Serial.begin(115200);
  while(!Serial) {}

  // Initializing the ICM456XX
  ret = IMU.begin();
  if (ret != 0) {
    Serial.print("ICM456xx initialization failed: ");
    Serial.println(ret);
    while(1);
  }
  // Accel ODR = 100 Hz and Full Scale Range = 16G
  IMU.startAccel(100,16);
  // Gyro ODR = 100 Hz and Full Scale Range = 2000 dps
  IMU.startGyro(100,2000);
  // Wait IMU to start
  delay(100);
}

void loop() {

  inv_imu_sensor_data_t imu_data;

  // Read registers
  IMU.getDataFromRegisters(imu_data);

  // https://github.com/tdk-invn-oss/motion.mcu.icm45686.driver/blob/16e45db85ba817ad1ec401c602eccc09e4f4e82f/examples/basic_read_registers/basic_read_registers.c#L123

  // accel_g[0]  = (float)(d.accel_data[0] * 4 /* gee */) / 32768;
  // accel_g[1]  = (float)(d.accel_data[1] * 4 /* gee */) / 32768;
  // accel_g[2]  = (float)(d.accel_data[2] * 4 /* gee */) / 32768;
  // gyro_dps[0] = (float)(d.gyro_data[0] * 2000 /* dps */) / 32768;
  // gyro_dps[1] = (float)(d.gyro_data[1] * 2000 /* dps */) / 32768;
  // gyro_dps[2] = (float)(d.gyro_data[2] * 2000 /* dps */) / 32768;

  // Format data for Serial Plotter
  Serial.print("AccelX:");
  Serial.print(imu_data.accel_data[0]);
  Serial.print(",");
  Serial.print("AccelY:");
  Serial.print(imu_data.accel_data[1]);
  Serial.print(",");
  Serial.print("AccelZ:");
  Serial.print(imu_data.accel_data[2]);
  Serial.print(",");
  Serial.print("GyroX:");
  Serial.print(imu_data.gyro_data[0]);
  Serial.print(",");  
  Serial.print("GyroY:");
  Serial.print(imu_data.gyro_data[1]);
  Serial.print(",");
  Serial.print("GyroZ:");
  Serial.print(imu_data.gyro_data[2]);
  Serial.print(",");
  Serial.print("Temperature in degC:");
  // Serial.print(imu_data.temp_data);
  Serial.print((float)25 + ((float)imu_data.temp_data / 128));
  Serial.println("");

  // Run @ ODR 100Hz
  delay(10);
}

I had to slightly modify the class code to connect to the SPI bus using non-standard pins.

#3 (comment)

The serial port contains the following data:

AccelX:-1132,AccelY:-345,AccelZ:1681,GyroX:7,GyroY:26,GyroZ:2,Temperature:376
AccelX:-1135,AccelY:-344,AccelZ:1677,GyroX:5,GyroY:25,GyroZ:2,Temperature:344

Please tell me @tdk-invn-oss, does this library have the ability to read data from a magnetometer or other sensor connected to the I2C MAS_DA and MAS_CLK?

Similar to the ICM20948 sensor
https://github.com/therealwokewok/ICM20948/blob/master/ICM20948.c

[tdk-opensource]

Thank you for opening this issue! We will look into it shortly.

Notifying @tdk-invn-oss/motion-maintainers @tdk-invn-oss/arduino-maintainers