how to add imu bsp for M5Stack CoreS3 (BSP-785)

[zhuxy12022]

I am using this board for xiaozhi and I find it can hardly add imu because lack of imu bsp, can you give me advice how to start with.

[github-actions]

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You’re right that the current ESP-IDF BSP for M5Stack CoreS3 does not expose an IMU capability: the BSP capabilities table explicitly marks IMU as unavailable (:x: :video_game: IMU). [CoreS3 BSP caps][CoreS3 BSP README]

However, the hardware definitely has an IMU (BMI270) and magnetometer (BMM150). [CoreS3 HW ref] The M5Stack docs also list their I2C addresses: BMI270 at 0x69, BMM150 at 0x10. [CoreS3 I2C addrs]

Because there is no IMU “BSP layer” yet, you have two practical options:

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1. For Arduino / M5Unified (recommended if you can)

If your XiaoZhi setup allows Arduino, you can use the M5CoreS3 Arduino library, which already wraps the IMU via M5Unified’s IMU_Class. The official example shows how to read accel/gyro/mag in just a few lines: [CoreS3 IMU Arduino]

#include <M5CoreS3.h>

void setup(void) {
    auto cfg = M5.config();
    CoreS3.begin(cfg);
}

void loop(void) {
    auto imu_update = M5.Imu.update();
    if (imu_update) {
        auto data = M5.Imu.getImuData();
        // use data.accel, data.gyro, data.mag ...
    }
    delay(100);
}

So if XiaoZhi can be built on top of Arduino/M5Unified, you “get the IMU BSP” by using this library instead of relying on the esp-bsp IMU abstraction.

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2. For ESP-IDF + esp-bsp (what you asked about)

On pure ESP-IDF with the espressif/m5stack_core_s3 BSP, there is currently:

• BSP support for display, touch, audio, camera, SD, etc.
• No sensor/IMU wrapper (no bsp_caps_imu, no sensor-hub config for CoreS3). [CoreS3 BSP caps]

So to “add IMU BSP” today you would need to:

1. Treat the IMU as a normal I2C device on the CoreS3 I2C bus and write your own driver (or integrate an existing BMI270/BMM150 driver) using the documented I2C addresses: BMI270 0x69, BMM150 0x10. [CoreS3 I2C addrs]

2. Optionally, integrate that with esp-iot-solution’s sensor hub (the generic pattern is documented, but there is no CoreS3-specific IMU config yet): [Sensor hub usage]

   bsp_sensor_config_t imu_config = {
       .type = IMU_ID,
       .mode = MODE_POLLING,
       .period = 1000
   };
   ESP_ERROR_CHECK(bsp_sensor_init(&imu_config, &imu_sensor_handle));
   iot_sensor_handler_register(imu_sensor_handle, sensor_event_handler, NULL);
   iot_sensor_start(imu_sensor_handle);

   For CoreS3, you would have to provide the actual low-level BMI270/BMM150 implementation behind this config yourself, because the BSP doesn’t ship it yet.

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What this means for you

• There is currently no ready-made IMU BSP for M5Stack CoreS3 in esp-bsp. You can’t just enable a BSP_CAPS_IMU flag.
• If you want IMU with minimal effort, use Arduino + M5CoreS3/M5Unified, which already exposes M5.Imu and works on CoreS3. [CoreS3 IMU Arduino]
• If you must stay on ESP-IDF + esp-bsp, you’ll need to:
  • Implement or port a BMI270 (+ optional BMM150) driver over I2C using the documented addresses.
  • Optionally hook it into sensor hub if you want a unified sensor API.

The current knowledge sources don’t show any official esp-bsp IMU component for CoreS3 yet, so there’s no single “add this dependency and call bsp_imu_init()” solution available.

[espzav]

Hi @zhuxy12022,
we are working on a new API for sensors in BSP, which is using Sensor HUB. We have finished ESP-BOX-3 and are planning update all boards this year.

[zhuxy12022]

Hi @zhuxy12022, we are working on a new API for sensors in BSP, which is using Sensor HUB. We have finished ESP-BOX-3 and are planning update all boards this year.

Thanks for your reply, I've done a toy demo for BMI270 on Core S3, hope you achieve better performance.