raw_data

# BMI270 Six-Axis Raw Data Example

[中文说明](README_cn.md)

This example demonstrates how to connect a BMI270 (Base firmware) to a native I2C master bus via `bmi270_sensor_create_from_master_bus()`, sample six-axis accelerometer and gyroscope data, and output raw ADC counts along with converted physical units (m/s² and °/s) in CSV format.

## Hardware Connection

- Compatible with any ESP32 development board connected to a BMI270 in I2C mode.
- Ensure correct power and common ground connections, with suitable SDA/SCL pull-up resistors (400 kHz bus speed).
- SDO is tied low by default (corresponding to I2C slave address **0x68**). If SDO is driven by an MCU GPIO, configure the pin in menuconfig.

| Signal | Default GPIO (ESP32-S3) | Description |
| --- | --- | --- |
| SDA | GPIO2 | Main I2C data line |
| SCL | GPIO1 | Main I2C clock line |
| SDO | Optional (default external low) | Optional GPIO driven low by software to select 0x68 address |

## Build and Run

1. Set the target chip and build the project:
   ```sh
   idf.py set-target esp32s3
   idf.py menuconfig
   idf.py build
   ```
2. Flash and monitor:
   ```sh
   ESPBAUD=921600 idf.py -p PORT flash monitor
   ```

Under **Raw Data Example Configuration** in `menuconfig`, you can configure:
* **SDA / SCL GPIO**: Adjust according to your hardware wiring.
* **ODR (Output Data Rate)**: Supports 25 Hz, 50 Hz, 100 Hz, 200 Hz (default 100 Hz).
* **Accelerometer Range**: Supports ±2 g, ±4 g, ±8 g, ±16 g (default ±2 g).
* **Gyroscope Range**: Supports ±125, ±250, ±500, ±1000, ±2000 °/s (default ±2000 °/s).
* **Polling Interval**: Interval between reads (default 100 ms).
* **Sample Count**: Set to `0` for continuous output, or a positive integer to automatically exit and release resources after collecting the specified number of samples.

## Output Format and Conversion

The example outputs a CSV header followed by periodic sample data:

```text
timestamp_us,acc_x_raw,acc_y_raw,acc_z_raw,gyr_x_raw,gyr_y_raw,gyr_z_raw,acc_x_m_s2,acc_y_m_s2,acc_z_m_s2,gyr_x_dps,gyr_y_dps,gyr_z_dps
```

| CSV Field | Description |
| --- | --- |
| `timestamp_us` | Host microsecond timestamp when data was read |
| `acc_x_raw`, `acc_y_raw`, `acc_z_raw` | Signed 16-bit raw ADC counts for accelerometer |
| `gyr_x_raw`, `gyr_y_raw`, `gyr_z_raw` | Signed 16-bit raw ADC counts for gyroscope |
| `acc_x_m_s2`, `acc_y_m_s2`, `acc_z_m_s2` | Converted acceleration in m/s² |
| `gyr_x_dps`, `gyr_y_dps`, `gyr_z_dps` | Converted angular velocity in °/s |

### Unit Conversion Formulas

* **Acceleration (m/s²)** = `Raw Count × Accel Range (g) × 9.80665 ÷ 32768`
* **Angular Velocity (°/s)** = `Raw Count × Gyro Range (°/s) ÷ 32768`

> When stationary, the magnitude of acceleration reflects gravity (~9.8 m/s²), while gyroscope readings remain near zero. Application-level calibration and sensor fusion algorithms can be applied for higher precision.