ICM20948

TDK ICM-20648 / ICM-20948 SPI 6-axis IMU driver module for XRobot.

This module initializes the IMU over SPI, samples accelerometer / gyroscope / temperature data from the data-ready interrupt, publishes gyro and accel topics, and stores gyroscope zero-offset calibration in LibXR::Database.

The current driver covers the 6-axis IMU path only. It does not initialize or publish data from the ICM-20948 internal AK09916 magnetometer.

Required Hardware

• spi1
• IMU_CS
• IMU_INT
• ramfs
• database

The SPI, CS, and INT names are constructor arguments, so projects may use other hardware aliases if needed.

Constructor Arguments

• data_rate: default ICM20948::DataRate::DATA_RATE_1KHZ
• accl_range: default ICM20948::AcclRange::RANGE_16G
• gyro_range: default ICM20948::GyroRange::DPS_2000
• rotation: sensor-frame to application-frame quaternion
• gyro_topic_name: default "icm20948_gyro"
• accl_topic_name: default "icm20948_accl"
• task_stack_depth: default 2048
• spi_name: default "spi1"
• cs_pin_name: default "IMU_CS"
• int_pin_name: default "IMU_INT"

Published Topics

• gyro_topic_name: Eigen::Matrix<float, 3, 1>, rad/s
• accl_topic_name: Eigen::Matrix<float, 3, 1>, m/s^2

Shell Commands

The module registers bin/icm20948 in RamFS.

• bin/icm20948 or bin/icm20948 status: print chip ID, init state, and temperature
• bin/icm20948 list_offset: print current gyroscope calibration offset
• bin/icm20948 cali: collect still gyroscope data and save offset to database

XRobot Configuration Example

- id: imu
  name: ICM20948
  constructor_args:
    data_rate: ICM20948::DataRate::DATA_RATE_1KHZ
    accl_range: ICM20948::AcclRange::RANGE_16G
    gyro_range: ICM20948::GyroRange::DPS_2000
    rotation:
      w: 1.0
      x: 0.0
      y: 0.0
      z: 0.0
    gyro_topic_name: "icm20948_gyro"
    accl_topic_name: "icm20948_accl"
    task_stack_depth: 2048
    spi_name: "spi1"
    cs_pin_name: "IMU_CS"
    int_pin_name: "IMU_INT"

Validation

Validated on OpenCR / STM32F746ZG with the onboard ICM-20648-compatible IMU:

• data-ready interrupt driven sampling
• gyroscope calibration load / save through LibXR::Database
• bin/icm20948 command path through RamFS
• downstream AHRS topic consumption and VOFA+ quaternion output