feat(bmi270): Implement FOC and CRT calibration features for bmi270

components/bmi270/example/README.md

@@ -21,6 +21,10 @@ This example shows how to use the `espp::Bmi270` component to initialize and com
     - [Debug Tips](#debug-tips)
   - [Performance Notes](#performance-notes)
   - [Advanced Features](#advanced-features)
+    - [Data Ready Interrupt](#data-ready-interrupt)
+    - [Fast Offset Compensation (FOC)](#fast-offset-compensation-foc)
+    - [Component Re-Trim (CRT)](#component-re-trim-crt)
+    - [Built-in Features](#built-in-features)
   - [References](#references)
 
 <!-- markdown-toc end -->
@@ -32,6 +36,8 @@ This example shows how to use the `espp::Bmi270` component to initialize and com
 - **Orientation Filtering**: Both Kalman and Madgwick filter implementations
 - **Real-time Data Logging**: CSV format output suitable for plotting
 - **Interrupt Configuration**: Data ready and motion detection interrupts
+- **Fast Offset Compensation (FOC)**: Calibrate accelerometer and gyroscope offsets
+- **Component Re-Trim (CRT)**: Compensate for gyroscope sensitivity changes
 - **Advanced Configuration**: Performance modes, bandwidth settings, power management
 
 ## How to use example
@@ -187,6 +193,16 @@ The CSV output can be imported into analysis tools like:
 - Consider magnetometer integration for yaw correction
 - Check for temperature effects
 
+**Stack Overflow during Initialization**:
+- Device crashes or resets while calling `bmi270.init()`.
+- Uploading the configuration file uses a large stack buffer by default.
+- Reduce the burst write size in the configuration to limit stack usage.
+  ```cpp
+  espp::Bmi270::Config config;
+  config.burst_write_size = 128; // Use 128-byte chunks (default is 0/unlimited)
+  espp::Bmi270 imu(config);
+  ```
+
 ### Debug Tips
 
 1. **Enable verbose logging:**
@@ -218,7 +234,46 @@ The CSV output can be imported into analysis tools like:
 
 ## Advanced Features
 
-The example can be extended to demonstrate:
+### Data Ready Interrupt
+
+The BMI270 can be configured to generate an interrupt when new data is available. This is more efficient than polling the sensor.
+
+```cpp
+Imu::InterruptConfig int_config{
+    .pin = Imu::InterruptPin::INT1,
+    .output_type = Imu::InterruptOutput::PUSH_PULL,
+    .active_level = Imu::InterruptLevel::ACTIVE_HIGH,
+    .enable_data_ready = true
+};
+imu.configure_interrupts(int_config, ec);
+```
+
+### Fast Offset Compensation (FOC)
+
+FOC allows for quick calibration of the accelerometer and gyroscope offsets.
+
+```cpp
+// Accelerometer FOC (e.g., device flat on table, Z axis pointing up)
+Imu::AccelFocGValue accel_foc_target = {
+    .x = 0, .y = 0, .z = 1, .sign = 0 // 1g on Z axis
+};
+imu.perform_accel_foc(accel_foc_target, ec);
+
+// Gyroscope FOC (device must be stationary)
+imu.perform_gyro_foc(ec);
+```
+
+### Component Re-Trim (CRT)
+
+CRT is a feature to compensate for sensitivity changes in the gyroscope that may occur during assembly or over time.
+
+```cpp
+imu.perform_crt(ec);
+```
+
+### Built-in Features
+
+The BMI270 also supports several on-chip features that can be demonstrated by extending this example:
 
 - **Motion Detection**: Any motion, no motion, significant motion
 - **Step Counting**: Pedometer functionality

components/bmi270/example/main/bmi270_example.cpp

@@ -108,6 +108,45 @@ extern "C" void app_main(void) {
   // create the IMU
   Imu imu(config);
 
+  // ---------------------------------------------------------------------------
+  // [Optional] Sensor Calibration (FOC & CRT)
+  // WARNING: 
+  // 1. The device must be COMPLETELY STATIONARY on a flat surface.
+  // 2. Enable these lines only when you need calibration (e.g., once after assembly).
+  // ---------------------------------------------------------------------------
+  #if 0
+  // Perform FOC (Fast Offset Compensation)
+  // Note: This assumes the device is flat on a table (Z-axis = 1g)
+  // For a real application, you might want to trigger this based on a user action
+  // or store the offsets in NVS.
+  std::error_code ec;
+
+  logger.info("Performing Accelerometer FOC...");
+  Imu::AccelFocGValue accel_foc_target = {.x = 0, .y = 0, .z = 1, .sign = 0}; // 1g on Z axis
+  if (imu.perform_accel_foc(accel_foc_target, ec)) {
+    logger.info("Accelerometer FOC completed successfully");
+  } else {
+    logger.error("Accelerometer FOC failed: {}", ec.message());
+  }
+
+  logger.info("Performing Gyroscope FOC...");
+  // Note: Device must be stationary for Gyro FOC
+  if (imu.perform_gyro_foc(ec)) {
+    logger.info("Gyroscope FOC completed successfully");
+  } else {
+    logger.error("Gyroscope FOC failed: {}", ec.message());
+  }
+
+  // Perform CRT (Component Re-Trim)
+  // This feature compensates for sensitivity changes in the gyroscope.
+  logger.info("Performing CRT...");
+  if (imu.perform_crt(ec)) {
+    logger.info("CRT completed successfully");
+  } else {
+    logger.error("CRT failed: {}", ec.message());
+  }
+  #endif
+
   // make a task to read out the IMU data and print it to console
   auto task_fn = [&](std::mutex &m, std::condition_variable &cv) -> bool {
     // sleep first in case we don't get IMU data and need to exit early
@@ -142,24 +181,6 @@ extern "C" void app_main(void) {
         fmt::format("{:02.3f},{:02.3f},{:02.3f},", (float)accel.x, (float)accel.y, (float)accel.z);
     text += fmt::format("{:03.3f},{:03.3f},{:03.3f},", (float)gyro.x, (float)gyro.y, (float)gyro.z);
     text += fmt::format("{:02.1f},", temp);
-    // print kalman filter outputs
-    text += fmt::format("{:03.3f},{:03.3f},{:03.3f},", (float)orientation.x, (float)orientation.y,
-                        (float)orientation.z);
-    text += fmt::format("{:03.3f},{:03.3f},{:03.3f},", (float)gravity_vector.x,
-                        (float)gravity_vector.y, (float)gravity_vector.z);
-
-    auto madgwick_orientation = madgwick_filter_fn(dt, accel, gyro);
-    float roll = madgwick_orientation.roll;
-    float pitch = madgwick_orientation.pitch;
-    float yaw = madgwick_orientation.yaw;
-    float vx = sin(pitch);
-    float vy = -cos(pitch) * sin(roll);
-    float vz = -cos(pitch) * cos(roll);
-
-    // print madgwick filter outputs
-    text += fmt::format("{:03.3f},{:03.3f},{:03.3f},", roll, pitch, yaw);
-    text += fmt::format("{:03.3f},{:03.3f},{:03.3f}", vx, vy, vz);
-
     fmt::print("{}\n", text);
 
     return false;