drivers/imu/bmi270: Improved and extended BMI270 drivers.

micropython/drivers/imu/bmi270/README.md

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+------------
+    License: 3-clause BSD, see https://opensource.org/licenses/BSD-3-Clause
+
+    Homepage:  https://codeberg.org/easytarget/bmi270-micropython
+    Datasheet: ./reference/bmi270-base-datasheet.pdf
+
+---------------------------
+
+# Micropython driver for the BMI270 IMU
+
+## [`bmi270.py`](bmi270.py)
+Homepage: [Here](https://codeberg.org/easytarget/bmi270-micropython)
+
+Original BMI270 driver on the micropython library had limited functionality and some issues with size and speed during init.
+
+This driver retains the original features:
+*   Setting Sensor Ranges and Output Data Rates at init
+*   Reading Accelerometer and Gyroscope reeadings
+
+Enhancements from original driver:
+*   Modifying Sensor Ranges and Output Data Rates (ODR) during use.
+*   Entering 'adavnced powersave mode' and enabling / disabling specific sensors and filter power modes.
+*   Device internal `temperature()` method has been added.
+
+Some minor code cleanup has been done; more consistent use of constants and names applied, etc.
+
+## Install
+
+Install by copying `bmi270.py` to the root (or import path) of your device in your IDE.
+*   Or install with **MIP**
+    *   `mip install https://github.com/micropython/micropython-lib/blob/master/micropython/drivers/imu/bmi270/bmi270.py`
+    *   run this on the device itself (when connected via WiFi/Network)
+*   You can also use mip via **mpremote**:
+    *   `mpremote mip install https://github.com/micropython/micropython-lib/blob/master/micropython/drivers/imu/bmi270/bmi270.py`
+    *   run this on the commandline of your host PC/system
+
+## Demos and Example
+*   [`demo_imu.py`](demo_imu.py) : demonstrates the IMU (Accelerometer and Gyroscope) detector
+    *   Press 'b' for a visual/bars mode
+
+### test.py:
+```python
+import time
+from bmi270 import BMI270
+from machine import Pin, I2C
+
+# Init in I2C mode, adjust pins as needed
+imu = BMI270(I2C(1, scl=Pin(32), sda=Pin(31))
+
+while (True):
+    print('Accelerometer: x:{:>6.3f}  y:{:>6.3f}  z:{:>6.3f}'.format(*imu.accel()))
+    print('Gyroscope:     x:{:>6.3f}  y:{:>6.3f}  z:{:>6.3f}'.format(*imu.gyro()))
+    print('Temperature: {:>4.1f}'.format(imu.temperature()))
+    print("")
+    time.sleep_ms(100)
+```
+
+## Reference
+See the [BMI270](https://www.bosch-sensortec.com/products/motion-sensors/imus/bmi270/) documentation at the Bosch site.
+
+### Datasheets:
+*   Main datasheet with base feature config: [bmi270-base-datasheet.pdf](./reference/bmi270-base-datasheet.pdf)
+    *   Detailed documentation for interrupt pin and power mode control is in this sheet
+*   Application note for FIFO mode (no features): [bmi270-fifo-appication-note.pdf](./reference/bmi270-fifo-appication-note.pdf)
+*   Application note for legacy features config [bmi270-legacy-appication-note.pdf](./reference/bmi270-legacy-appication-note.pdf)
+
+### Official reference API (C):
+https://github.com/boschsensortec/BMI270_SensorAPI
+
+# Usage:
+
+## Classes; Objects and Attributes
+
+```python
+class BMI270()
+```
+
+#### init()
+
+```python
+def __init__(i2c,
+             address = 0x68,
+             gyro_odr = 100,
+             gyro_scale = 2000,
+             accel_odr = 100,
+             accel_scale = 4,
+             force_reset = False,
+             bmm_magnet = None)
+```
+
+Initializes Device, Gyro and Accelerometer.
+*   `i2c`: `machine.I2C()` bus object
+*   `address`: I2C address, default 0x68
+*   `gyro_odr`:  Hz (0.78, 1.5, 3.1, 6.25, 12.5, 25, 50, **100**, 200, 400, 800, 1600)
+*   `gyro_scale`:  dps (125, 250, 500, 1000, **2000**)
+*   `accel_odr`: Hz (0.78, 1.5, 3.1, 6.25, 12.5, 25, 50, **100**, 200, 400, 800, 1600)
+*   `accel_scale`: g (+/-2, **+/-4**, +/-8, +/-16)
+*   `force_reset`: Forces a reset and reinitialisation of the device
+*   `bmm_magnet`:  allows passing of a magnetometer device, provided for compatibility
+
+#### sensor\_settings()
+
+```python
+def sensor_settings(gyro_odr=None,
+                    gyro_scale=None,
+                    accel_odr=None,
+                    accel_scale=None)
+```
+
+Sets or modifies sensor Output Data Rates (ODR) and Scale
+*   Values are as specified during `init()`
+*   `None` indicates the setting should be left as-is
+
+#### power()
+
+```python
+def power(powersave=None,
+          accel=None,
+          gyro=None,
+          acc_filter=None,
+          gyr_filter=None,
+          gyr_noise=None)
+```
+
+Set power modes;
+*   See `base` datasheet section 4.5 'Power Modes' (page 26)
+*   `None` indicates the setting should be left as-is
+
+Disabling the gyroscope produces greatest savings
+
+*   `powersave` = device 'advanced power save' mode, default `False`
+*   `accel` = enable/disable accellerometer, default `True`
+*   `gyro` = enable/disable gyroscope, default `True`
+*   `acc_filter` = powresave mode for accel filter, default `True`
+*   `gyr_filter` = powresave mode for gyro filter, default `True`
+*   `gyr_noise` = powersave mode for gyro noise filter, default `False`
+
+Note that gesture detection features in the extended configs do not use the gyroscope
+
+#### gyro()
+
+```python
+def gyro()
+```
+
+Returns gyroscope vector in degrees/sec.
+
+#### accel()
+
+```python
+def accel()
+```
+
+Returns acceleration vector in gravity units (9.81m/s^2).
+
+#### magnet()
+
+```python
+def magnet()
+```
+
+Compatibility method, generally unused: Returns magnetometer vector if a magnetomter has been attached and configured at init.
+
+#### temperature()
+
+```python
+def temperature()
+```
+
+Returns temperature value in degrees C. This is the chip temperature, not environmental.
+